CN101305305A - Microstructured optical fiber and method of making same - Google Patents

Abstract

Microstructured optical fiber and method of making the same. Glass soot is deposited and then consolidated under conditions sufficient to cause a portion of the consolidation gases to be trapped in the glass, thereby producing an aperiodic array of holes that can be used to form void-containing regions in an optical fiber. Preferred sintering gases for creating the void include nitrogen, argon, CO₂Oxygen, chlorine, CF₄、CO、SO₂And mixtures thereof.

Description

Translated fromChinese

微结构化光纤及其制造方法Microstructured optical fiber and method of manufacturing the same

相关申请交叉引用Related Application Cross Reference

本申请根据35U.S.C.§119(e)要求2005年11月8日提交的美国临时申请系列第60/734,995号，2006年4月5日提交的临时申请系列第60/789,798号，以及2006年9月20日提交的临时申请系列第60/845,927号的优先权，这些申请的全部内容都参考结合入本文中。This application is pursuant to 35 U.S.C. § 119(e) requiring U.S. Provisional Application Serial No. 60/734,995 filed November 8, 2005, Provisional Application Serial No. 60/789,798 filed April 5, 2006, and 2006 Priority to Provisional Application Serial No. 60/845,927, filed September 20, the entire contents of which applications are hereby incorporated by reference.

发明背景Background of the invention

1.发明领域1. Field of invention

本发明一般涉及光纤，更具体来说涉及微结构化光纤和制备微结构化光纤的方法。The present invention relates generally to optical fibers, and more particularly to microstructured optical fibers and methods of making microstructured optical fibers.

2.技术背景2. Technical Background

由玻璃材料形成的光纤已经在工业应用中应用了二十多年。尽管这些光纤代表了通讯领域的一个巨大飞跃，但是人们仍在不断地对可供替代的光纤设计进行研究。一种有希望的替代光纤是微结构化的光纤，其包括沿光纤的轴纵向连续的空穴(hole)或孔穴(void)。所述空穴通常包含空气或惰性气体，但是也可包含其它材料。大多数微结构化的光纤具有位于芯周围的大量的空穴，所述空穴沿所述纤维长度方向的较长距离(例如数十米或更长)上连续分布，通常所述空穴会沿着光纤的整个长度延伸。这些包覆空穴最优选以规则的周期性的形式围绕光纤的芯排列。换而言之，如果沿光纤的长度取光纤的横截面，则可以在基本相同的周期性空穴结构中发现相同的独立的空穴。这些微结构化的纤维包括美国专利第6,243,522号中描述的那些。Optical fibers formed from glass materials have been used in industrial applications for over two decades. Although these fibers represent a quantum leap in communications, research into alternative fiber designs continues. A promising alternative optical fiber is a microstructured optical fiber that includes holes or voids that are continuous longitudinally along the axis of the fiber. The cavity typically contains air or an inert gas, but may also contain other materials. Most microstructured optical fibers have a large number of voids located around the core that are distributed continuously along the length of the fiber over a long distance (such as tens of meters or more), usually the voids will Extends along the entire length of the fiber. These cladding cavities are most preferably arranged in a regular periodic pattern around the core of the fiber. In other words, if a cross-section of the fiber is taken along its length, the same individual holes can be found in substantially the same periodic hole structure. These microstructured fibers include those described in US Patent No. 6,243,522.

微结构化的光纤可设计成具有很宽范围的性质，可用于许多种应用。例如，人们已经设计出一种微结构化的光纤，该光纤包括实心的玻璃芯，以及位于围绕所述玻璃芯的包覆区域内的大量的空穴。可以对所述空穴的位置和尺寸进行设计，得到具有从高负值到高正值范围内任意位置分散的微结构化光纤。这些光纤可用于例如色散补偿。实心芯微结构化的光纤还可设计成在很宽的波长范围内为单模形式。大多数实心芯微结构化光纤通过全内反射机理传导光；空穴的低折射率会降低该空穴所处的包覆区域的有效折射率。Microstructured optical fibers can be engineered to have a wide range of properties and can be used in many applications. For example, a microstructured optical fiber has been designed that includes a solid glass core and a large number of voids located in a cladding region surrounding the glass core. The position and size of the cavities can be engineered to obtain a microstructured optical fiber with dispersion anywhere from highly negative to highly positive. These fibers can be used, for example, for dispersion compensation. Solid core microstructured optical fibers can also be designed to be single-mode over a broad wavelength range. Most solid core microstructured optical fibers conduct light by a mechanism of total internal reflection; the low index of refraction of the void reduces the effective index of the cladding region where the void resides.

微结构化的光纤通常通过所谓的“堆叠-拉制”法制造，此方法以密堆叠方式将二氧化硅棒和/或管阵列堆叠起来，形成预成形体，然后使用常规的塔装备将其拉制成纤维。所述堆叠-拉制法存在一些缺陷。将数百根极薄的条料(cane)(通过棒或管形成)装配起来非常困难，而且还可能在堆叠和拉伸圆柱形条料的时候存在间隙空腔，这些空腔可能会引入可溶性杂质和颗粒杂质，从而显著地造成光纤的衰减，还会产生不希望有的界面，以及带来起始空穴的重新成形或变形。另外，较低的生产率和较高的成本使得这种方法并不十分适于工业生产。Microstructured optical fibers are typically fabricated by the so-called "stack-and-draw" method, in which arrays of silica rods and/or tubes are stacked in a close-packed fashion to form a preform, which is then drawn using conventional tower equipment. drawn into fibers. The stack-draw method has some drawbacks. Assembling hundreds of extremely thin canes (formed from rods or tubes) is difficult and there may be interstitial cavities when stacking and stretching cylindrical canes that may introduce soluble Impurities and particulate impurities, which contribute significantly to attenuation of the fiber, can also create undesired interfaces and cause reshaping or deformation of initiating cavities. In addition, low productivity and high cost make this method not very suitable for industrial production.

发明内容Contents of the invention

本发明的一个方面涉及一种制造光纤的方法，该方法包括通过化学气相沉积(CVD)操作形成包含烟灰的光纤预成形体。在一定的条件下，所述烟灰预成形体在围绕该预成形体的气体气氛中固结，所述固结的条件能够使得在所述固结步骤中，将一部分所述气体气氛有效地捕获在所述预成形体中，从而在所述固结的预成形体中形成非周期性分布的空穴或孔穴，各个空穴对应于至少一种捕获在所述固结的玻璃预成形体内的固结的气体的区域。然后使用所述其中包含空穴的固结的预成形体制备光纤。在固结步骤中，在所述光纤预成形体中形成的孔的至少一部分保留在拉制的光纤之内。通过将包含空穴的区域设计成对应于光纤的包覆层，使得这些所得的光纤包括芯区和包覆层区，所述芯区具有第一折射率，所述包覆层区具有低于芯的折射率的第二折射率，所述较低的折射率至少部分是由于包覆层中存在的空穴造成的。可以使用本文所述方法的替代方法或另外的方法在包覆层中提供含空穴的区域，从而改进光纤的弯曲性能。例如，通过使用本文所述的光纤设计和方法，可以制得一种光纤，该光纤在围绕10毫米的芯轴弯曲的时候，其在1550纳米的衰减增大，增大幅度小于20dB/圈，更优选小于15dB/圈，更优选小于10dB/圈。类似地，使用本文所述的光纤设计和方法，可以制得一种光纤，其在围绕直径为20毫米的芯轴弯曲的时候，在1550纳米的衰减增大，增大幅度小于3dB/圈，更优选小于1dB/圈，更优选小于0.5dB/圈，最优选小于0.25dB/圈。本文所述的方法和光纤设计可用来制造在1550纳米下为单模和多模的纤维。One aspect of the invention relates to a method of manufacturing an optical fiber comprising forming a soot-containing optical fiber preform by a chemical vapor deposition (CVD) operation. The soot preform is consolidated in the gaseous atmosphere surrounding the preform under conditions such that a portion of the gaseous atmosphere is effectively trapped during the consolidation step In the preform, thereby forming aperiodically distributed cavities or cavities in the consolidated preform, each cavity corresponding to at least one of the Regions of condensed gas. The consolidated preform containing the voids therein is then used to produce an optical fiber. During the consolidation step, at least a portion of the hole formed in the optical fiber preform remains within the drawn optical fiber. By designing the cavity-containing region to correspond to the cladding of the fiber, these resulting fibers include a core region having a first refractive index and a cladding region having a cladding region below A second index of refraction of the core, the lower index being at least in part due to the presence of voids in the cladding. Alternatives to or in addition to the methods described herein may be used to provide void-containing regions in the cladding to improve the bend properties of the fiber. For example, by using the fiber designs and methods described herein, an optical fiber can be produced that exhibits an increase in attenuation at 1550 nm of less than 20 dB/turn when bent about a 10 mm mandrel, More preferably less than 15 dB/turn, more preferably less than 10 dB/turn. Similarly, using the fiber designs and methods described herein, an optical fiber can be produced that exhibits an increase in attenuation at 1550 nm of less than 3 dB/turn when bent about a 20 mm diameter mandrel, More preferably less than 1 dB/turn, more preferably less than 0.5 dB/turn, most preferably less than 0.25 dB/turn. The methods and fiber designs described herein can be used to fabricate fibers that are single-mode and multimode at 1550 nm.

较佳的是，所述孔穴基本上位于所述光纤的包覆层内，更优选完全位于所述光纤的包覆层内，使得它们在包含孔穴的区域内包围所述芯，优选在芯区域内基本没有所述孔穴。在一些优选的实施方式中，所述孔穴位于与所述光纤的芯隔开的含孔穴区域内。例如，较薄的(例如径向宽度小于40微米，更优选小于30微米)的含孔穴区域的环可以与所述光纤的芯隔开，但是没有完全延伸到所述光纤的外周。将含孔穴的区域与芯隔开将有助于降低所述光纤在1550纳米的衰减。使用薄环将会有助于使得光纤在1550纳米处为单模。所述光纤可包含氧化锗(germania)或氟，或者也可不包含氧化锗(germania)或氟，同样用来调节光纤的芯和/或包覆层的折射率，但是这些掺杂剂也可避免使用，而单独使用孔穴来调节包覆层相对于芯的折射率，使得光被引导着沿光纤的芯传输。通过使用本文揭示的固结技术，可以形成空穴在横截面中呈非周期性分布的光纤。非周期性分布表示当观察光纤的横截面的时候，孔穴随机地或非周期性地分布在光纤的一部分上。沿光纤长度方向的不同位置所取的横截面会呈现不同的横截面空穴图案，即各横截面将具有略微不同的随机取向的空穴图案、分布和尺寸。这些空穴沿光纤的长度(即平行于纵轴)延伸(伸长)，但是并不是沿整个光纤的整个长度延伸。尽管不希望被理论所限制，但是人们认为所述空穴沿光纤长度延伸小于数米，在许多情况下延伸小于1米。Preferably, the cavities are located substantially, more preferably completely, within the cladding of the optical fiber such that they surround the core in the region containing the cavities, preferably in the region of the core There are substantially no holes in it. In some preferred embodiments, the cavity is located in a cavity-containing region spaced from the core of the optical fiber. For example, a thinner (eg radial width less than 40 microns, more preferably less than 30 microns) ring of cavity-containing regions may be spaced from the core of the fiber but not extend completely to the periphery of the fiber. Separating the cavity-containing region from the core will help reduce the attenuation of the fiber at 1550 nm. Using a thin ring will help make the fiber single mode at 1550nm. The fiber may or may not contain germania or fluorine, also used to adjust the refractive index of the fiber's core and/or cladding, but these dopants may also avoid The use of , while the holes alone are used to adjust the refractive index of the cladding relative to the core, so that light is guided along the core of the fiber. By using the consolidation techniques disclosed herein, optical fibers can be formed with a non-periodic distribution of cavities in cross-section. Aperiodic distribution means that holes are distributed randomly or aperiodically over a portion of the fiber when viewed in cross-section of the fiber. Cross-sections taken at different locations along the length of the fiber will exhibit different cross-sectional void patterns, ie each cross-section will have a slightly different randomly oriented void pattern, distribution and size. These cavities extend (elongate) along the length of the fiber (ie parallel to the longitudinal axis), but not along the entire length of the fiber. While not wishing to be bound by theory, it is believed that the cavities extend less than a few meters, in many cases less than 1 meter, along the length of the fiber.

通过使用本文所述的产生孔穴的固结技术，可以制得具有以下性质的光纤：该光纤具有包覆层区域，该包覆层区域的总光纤孔穴面积百分数(即孔穴的总横截面积除以光纤的总横截面积×100)大于0.01％，更优选大于0.025％，更优选大于0.05％，更优选约大于0.1％，更优选约大于0.5％。已经制备了光纤，其总孔穴面积百分数约大于1％，实际上更大于约5％，甚至10％。但是，人们认为根据光纤设计，当总孔穴面积百分数小于1％，甚至小于0.7％的时候，将会获得显著提高的弯曲性能。在一些优选的实施方式中，所述光纤中的总孔穴面积百分数小于20％，更优选小于10％，最优选小于5％。这些含孔穴的包覆层区域可用来降低相对于芯的折射率，从而形成引导光沿光纤的芯传输的包覆层区域。通过选择合适的烟灰固结条件(将在下文中描述)，可以完成许多种有用的光纤设计。例如，通过选择包覆层中的最大孔穴尺寸，使其小于将要传输的光的波长(例如对于一些远程通信系统是小于1550纳米)，优选小于将要沿光纤传输的光的波长的一半，可以在无需使用昂贵的掺杂剂的条件下得到低衰减的纤维。因此，对于各种应用，需要形成所述空穴，使得所述光纤中至少大于95％、优选所有的空穴都具有光纤的包覆层中的最大空穴尺寸，即小于1550纳米，更优选小于775纳米，最优选约小于390纳米。类似地，优选光纤中空穴的平均直径小于7000纳米，更优选小于2000纳米，更优选小于1550纳米，最优选小于775纳米，所有这些平均直径都可使用本文所述的方法获得。使用本文所述的方法制造的光纤可获得这些平均直径，其标准偏差在1000纳米以内，更优选在750纳米以内，最优选在500纳米以内。在一些实施方式中，本文所述的光纤在特定的光纤垂直截面内包含小于5000个空穴，在一些实施方式中包含小于1000个空穴，在一些实施方式中，总空穴数小于500。当然，最优选的光纤将表现出这些特征的组合。因此，例如，光纤的一个特别优选的实施方式将在一个光纤中具有小于200个空穴，所述空穴的最大直径小于1550纳米，平均直径小于775纳米，但是使用更大直径的和更多数量的空穴可以得到有用的耐弯曲的光纤。空穴数量、空穴的平均直径、最大直径和总孔穴面积百分数均可通过放大约800倍的扫描电子显微镜和图像分析软件(例如ImagePro，其购自美国马里兰州银春市(Silver Spring，Maryland，USA)的米迪赛博奈提科斯有限公司(Media Cybernetics，Inc.))的帮助来计算。By using the void-generating consolidation techniques described herein, an optical fiber can be produced that has a cladding region that has a percent total fiber void area (i.e., the total cross-sectional area of the void divided by The total cross-sectional area of the fiber x 100) is greater than 0.01%, more preferably greater than 0.025%, more preferably greater than 0.05%, more preferably approximately greater than 0.1%, more preferably approximately greater than 0.5%. Optical fibers have been prepared with total void area percentages greater than about 1%, in fact greater than about 5%, and even 10%. However, it is believed that, depending on the fiber design, significantly improved bend performance will be obtained when the percent total void area is less than 1%, or even less than 0.7%. In some preferred embodiments, the percent total void area in the optical fiber is less than 20%, more preferably less than 10%, most preferably less than 5%. These void-containing cladding regions can be used to lower the refractive index relative to the core, thereby forming cladding regions that guide light transmission along the core of the fiber. By selecting appropriate soot consolidation conditions (described below), many useful fiber designs can be achieved. For example, by selecting the maximum hole size in the cladding to be smaller than the wavelength of the light to be transmitted (e.g., less than 1550 nanometers for some telecommunication systems), preferably less than half the wavelength of the light to be transmitted along the optical fiber, Low attenuation fibers are obtained without the use of expensive dopants. Therefore, for various applications it is desirable to form the cavities such that at least greater than 95%, preferably all cavities in the fiber have the largest cavity size in the fiber's cladding, i.e. less than 1550 nanometers, more preferably Less than 775 nm, most preferably less than about 390 nm. Similarly, it is preferred that the average diameter of the holes in the fiber is less than 7000 nm, more preferably less than 2000 nm, more preferably less than 1550 nm, most preferably less than 775 nm, all of which average diameters can be obtained using the methods described herein. Fibers made using the methods described herein can achieve these mean diameters with a standard deviation within 1000 nanometers, more preferably within 750 nanometers, and most preferably within 500 nanometers. In some embodiments, the optical fibers described herein contain less than 5000 voids, in some embodiments less than 1000 voids, and in some embodiments less than 500 total voids in a particular vertical cross-section of the fiber. Of course, the most preferred fibers will exhibit a combination of these characteristics. Thus, for example, a particularly preferred embodiment of an optical fiber would have less than 200 cavities in one fiber with a maximum diameter of less than 1550 nanometers and an average diameter of less than 775 nanometers, although larger diameters and more A higher number of holes can result in a useful bend-resistant fiber. The number of holes, the average diameter of the holes, the maximum diameter and the total hole area percentage can be magnified by a scanning electron microscope of about 800 times and image analysis software (such as ImagePro, which is available from Silver Spring, Maryland, U.S.A. , USA) with the help of Media Cybernetics, Inc.).

本发明的另一个方面涉及可以使用上文所述的方法制备的微结构化的光纤。一种这样的微结构化的光纤包括芯区域和包覆层区域，所述芯区域具有第一折射率，所述包覆层区域具有低于所述芯区域折射率的第二折射率，这至少部分是因为其中存在非周期性分布的孔穴。因此，传输通过所述光纤的光大体上保留在所述芯内。所述孔穴的最大直径优选等于或小于1550纳米，所得的光纤在600-1550纳米的至少一种波长下(最优选波长为1550纳米)的衰减小于500dB/千米，更优选在1550纳米小于200dB/千米。在本文中，“衰减”如未具体写作“多模衰减”或“单模衰减”，则如果所述光纤在1550纳米为多模的，则表示所述光纤的多模衰减，如果所述光纤在1550纳米是单模的，则表示单模衰减。通过使用本文所述的产生孔穴的固结技术，可以制得一种光纤，该光纤具有包封区域，该包封区域的区域孔穴面积百分数大于0.5％，更优选约大于1％，更优选约大于5％，最优选约大于10％。具体来说，可以在与所述光纤的芯相距10微米的距离之内制备这种包含孔穴的包覆区域。尽管通过使用本文所述的技术可以避免使用用来调节折射率的掺杂剂，但是优选将至少一种氧化锗或氟或类似的折射率调节掺杂剂与位于所述光纤的包覆区域内的非周期性分布的孔穴结合使用。但是，是否使用氧化锗和/或氟并不是关键因素，例如，如果需要的话，所述光纤可以完全或基本不含氧化锗和氟。在本文中，“非周期性分布”表示孔穴或空穴是非周期性的，即它们没有周期性地设置在纤维结构之内。尽管本发明的方法不能使得各个独立的孔穴相对于其它的独立的孔穴周期性地设置(许多其它种类的微结构化的纤维是这样周期性设置的)，但是本文所述的方法能够在光纤径向分布的各种位置设置较大量或较小量的孔穴。例如，通过使用本文所述的方法，可以使得与光纤芯相邻的区域内孔穴的区域孔穴面积百分数高于光纤中其它区域(例如光纤芯之内或外部包覆区域)的百分数。类似地，可以沿着光纤的径向和轴向(即沿长度方向)控制所述含孔穴的区域内的平均空穴尺寸和空穴尺寸分布。因此，可以在光纤内的一个区域设置空穴的均匀非周期性阵列，沿着所述纤维的长度，将相对孔穴面积百分数和此区域内平均空穴尺寸保持恒定。尽管所述光纤不限于任意特定的直径，但是优选所述光纤的外径小于775微米，更优选小于375微米，最优选小于200微米。Another aspect of the invention relates to microstructured optical fibers that can be prepared using the methods described above. One such microstructured optical fiber includes a core region having a first index of refraction and a cladding region having a second index of refraction lower than the index of refraction of the core region, which At least in part because of the non-periodic distribution of voids. Thus, light transmitted through the fiber is substantially retained within the core. The maximum diameter of the cavity is preferably equal to or less than 1550 nanometers, and the resulting optical fiber has an attenuation of less than 500 dB/km at at least one wavelength between 600 and 1550 nanometers, most preferably at a wavelength of 1550 nanometers, more preferably less than 200 dB at 1550 nanometers /km. In this article, if "attenuation" is not specifically written as "multimode attenuation" or "single-mode attenuation", if the fiber is multimode at 1550 nm, it means the multimode attenuation of the fiber, if the fiber It is single-mode at 1550 nm, which means single-mode attenuation. By using the void-generating consolidation techniques described herein, an optical fiber can be produced having an encapsulated region with a regional void area percentage greater than 0.5%, more preferably greater than about 1%, more preferably about Greater than 5%, most preferably greater than about 10%. In particular, such a cladding region containing voids can be produced within a distance of 10 micrometers from the core of the fiber. Although the use of dopants for adjusting the refractive index can be avoided by using the techniques described herein, it is preferred to combine at least one germanium oxide or fluorine or similar index-adjusting dopant with the cladding region of the optical fiber. The non-periodic distribution of holes is used in combination. However, the use of germanium oxide and/or fluorine is not critical, for example, the optical fiber may be completely or substantially free of germanium oxide and fluorine, if desired. In this context, "non-periodic distribution" means that the cavities or cavities are non-periodic, ie they are not periodically arranged within the fibrous structure. While the method of the present invention does not allow for periodic placement of individual cavities relative to other independent cavities (as is the case with many other types of microstructured fibers), the methods described herein enable A greater or lesser number of holes is provided to various positions of the distribution. For example, by using the methods described herein, the regional void area percentage of voids in the region adjacent to the fiber core can be made higher than the percentage in other regions of the fiber (eg, within the fiber core or outside the cladding region). Similarly, the average void size and void size distribution within the void-containing region can be controlled radially and axially (ie along the length) of the fiber. Thus, a uniform non-periodic array of voids can be provided in a region within the fiber, keeping the relative void area percentage and average void size in that region constant along the length of the fiber. Although the optical fiber is not limited to any particular diameter, it is preferred that the optical fiber has an outer diameter of less than 775 microns, more preferably less than 375 microns, most preferably less than 200 microns.

这种纤维可用于远程通信网络(通常是850，1310和1550纳米窗口)，包括远程通信、地铁、存取、楼宇和数据中心，以及建筑物和移动物(小汽车、公共汽车、货车、飞机)用途的数据远程通信应用和控制区域网络(通常为600-1000纳米范围)。这种远程通信网络通常包括与光纤光学连接的发送机和接收机。因此，对于许多应用，需要形成空穴，使得光纤包覆层中的最大空穴尺寸小于1550纳米，更优选小于775纳米，最优选约小于390纳米。This fiber can be used in telecommunications networks (typically 850, 1310 and 1550 nanometer windows), including telecommunications, subways, access, buildings and data centers, as well as buildings and moving objects (cars, buses, trucks, airplanes) ) for data telecommunications applications and control area networks (typically in the 600-1000 nm range). Such telecommunication networks typically include transmitters and receivers connected optically with fiber optics. Thus, for many applications it is desirable to form the voids such that the maximum void size in the fiber cladding is less than 1550 nm, more preferably less than 775 nm, most preferably less than about 390 nm.

这种光纤还可用作医学、照明、光刻和工业应用的紫外至红外光导管。一种优选的光纤的包覆层包括位于包覆层之内、优选与芯径向相距10微米以内的大量非周期性分布的孔穴区域，沿光纤的径向(垂直于光纤纵轴的横截方向)测得所述孔穴的最大直径等于或小于1550纳米，更优选等于或小于775纳米。另一种优选的光纤的包覆层，在包覆层中包含大量非周期性分布的孔穴区域，它们与芯间隔开，与芯径向距离相距在20微米以内，所述孔穴沿光纤径向测量的最大直径等于或小于1550纳米，更优选等于或小于775纳米，最优选约小于390纳米。另一种优选的光纤的包覆层，在包覆层中包含大量非周期性分布的孔穴区域，它们与芯的外边缘的径向距离在40微米以内，沿所述光纤的径向距离测得，所述孔穴的最大直径等于或小于1550纳米，更优选等于或小于775纳米，最优选约小于390纳米。与现有技术已知的各种光纤相比，本文所揭示的光纤表现出大量优点。例如，与现有技术的光纤相比，本文所揭示的光纤能够具有优良的抗弯曲性能，同时表现出极佳的模场直径。说它优良，是指通过使用本文所揭示的方法，可以制造一种光纤，该光纤在1550纳米为单模，在进行直径20纳米的弯曲的时候，能够表现出每圈小于0.5dB的衰减增加，同时在1550纳米表现出大于10微米、更优选大于11微米的模场直径。这种极佳的弯曲性能使得这些光纤成为以下应用的吸引人的候选材料：光纤到户、接入光纤(access fiber)、户内光纤应用以及光纤跨接线(这些通常是短的光纤段(1-20米)，在各端具有连接器以与光学系统或器件相连)。例如，本文所揭示的光纤可用于包括发送器、接收器、与所述发送器和接收器光学连接的光纤在内的光纤远程通信系统。较佳的是，在这些应用中(即当所述光纤在远程通信系统中作为传导光纤的时候)，所述光纤不含铒之类的任意活性元素。This fiber can also be used as a UV to IR light guide for medical, lighting, photolithography and industrial applications. A preferred optical fiber cladding comprises a large number of non-periodically distributed hole regions within the cladding, preferably within 10 microns of the radial direction of the core, along the radial direction of the optical fiber (the cross section perpendicular to the longitudinal axis of the optical fiber The maximum diameter of the pores measured in the direction) is equal to or less than 1550 nanometers, more preferably equal to or less than 775 nanometers. Another preferred optical fiber cladding, comprising a large number of non-periodically distributed hole regions in the cladding, they are spaced apart from the core, within 20 micrometers of the radial distance from the core, and the holes are along the radial direction of the fiber The largest measured diameter is equal to or less than 1550 nanometers, more preferably equal to or less than 775 nanometers, most preferably less than about 390 nanometers. Another preferred optical fiber cladding comprises a large number of non-periodically distributed cavity regions in the cladding, and their radial distance from the outer edge of the core is within 40 micrometers, measured along the radial distance of the optical fiber Thus, the maximum diameter of the pores is equal to or less than 1550 nanometers, more preferably equal to or less than 775 nanometers, most preferably less than about 390 nanometers. The optical fibers disclosed herein exhibit a number of advantages over various optical fibers known in the prior art. For example, the optical fibers disclosed herein can have superior bending resistance while exhibiting excellent mode field diameters compared to prior art optical fibers. It is excellent in the sense that by using the methods disclosed herein it is possible to fabricate an optical fiber which is single-mode at 1550 nm and which exhibits an attenuation increase of less than 0.5 dB per turn when bent with a diameter of 20 nm , while exhibiting a mode field diameter at 1550 nm of greater than 10 microns, more preferably greater than 11 microns. This excellent bendability makes these fibers attractive candidates for fiber-to-the-home, access fiber, indoor fiber applications, and fiber jumpers (these are typically short lengths of fiber (1 -20 meters), with connectors at each end to connect to optical systems or devices). For example, the optical fibers disclosed herein can be used in a fiber optic telecommunications system that includes a transmitter, a receiver, and an optical fiber optically coupled to the transmitter and receiver. Preferably, in these applications (ie when the fiber is used as a conducting fiber in a telecommunication system), the fiber does not contain any active elements such as erbium.

另外，本文所述的光纤可支承具有高数值孔径(例如在1550纳米大于0.2，更优选大于0.4，最优选大于0.6)，这促进了它们与其它光学激光源相连的能力和提高光纤连接器的耐受性。这种光纤还是用于车辆用途的极佳候选材料。在这样的应用中，最优选光纤的最大孔穴尺寸约小于1550纳米，更优选小于775纳米，最优选约小于390纳米。Additionally, the optical fibers described herein can be supported with a high numerical aperture (e.g., greater than 0.2, more preferably greater than 0.4, and most preferably greater than 0.6 at 1550 nanometers), which facilitates their ability to connect to other optical laser sources and increases the reliability of fiber optic connectors. tolerance. This fiber is also an excellent candidate for vehicular applications. In such applications, it is most preferred that the fiber have a maximum cavity size of less than about 1550 nanometers, more preferably less than 775 nanometers, and most preferably less than about 390 nanometers.

本文揭示的光纤可通过较低成本的制造工艺来制造，因为如果需要的话，可以避免使用氟和/或氧化锗之类的昂贵的掺杂剂，类似地，可以避免堆叠-拉制制造法。本发明还可进行灵活的色散控制(正的，平的或负的)，例如，对于信号处理完成大的正色散(在1550纳米＞30ps/nm/Km)，或者可以用于色散补偿的负色散光纤(例如在1550纳米＜-200ps/nm/Km)。或者本文所述的方法可简单地为光纤的包覆层添加孔穴以提高其抗弯曲性，所述包覆层中掺杂了一种或多种以下材料：氧化锗、磷、铝、镱、铒、氟或其它常规光纤掺杂剂材料。在另一个实施方式中，本文所述的方法可用来制备二氧化硅芯的光纤(即芯内不含锗掺杂剂的光纤)，其截止波长低于800纳米，在1550纳米下，其数值孔径约大于0.08，更优选约大于0.10。The optical fibers disclosed herein can be fabricated by a lower cost fabrication process since the use of expensive dopants such as fluorine and/or germanium oxide can be avoided if desired, and similarly stack-draw fabrication can be avoided. The present invention also allows for flexible dispersion control (positive, flat or negative), for example, for signal processing to achieve large positive dispersion (>30 ps/nm/Km at 1550 nanometers), or negative for dispersion compensation. Dispersion fiber (eg <-200 ps/nm/Km at 1550 nm). Alternatively, the methods described herein can simply add holes to the optical fiber's cladding layer doped with one or more of the following materials: germanium oxide, phosphorous, aluminum, ytterbium, Erbium, fluorine, or other conventional fiber optic dopant materials. In another embodiment, the methods described herein can be used to prepare silica-core optical fibers (i.e., optical fibers without germanium dopants in the core) with cutoff wavelengths below 800 nanometers, and at 1550 nanometers, the values The pore size is greater than about 0.08, more preferably greater than about 0.10.

在下文的详述中将更具体地描述本发明的其它特征和优点，本领域普通技术人员通过本文的描述或者通过实施本发明，可以很容易认识到这些特征和优点，本文的内容包括以下的详述、权利要求书以及附图。In the following detailed description, other features and advantages of the present invention will be described in more detail. Those of ordinary skill in the art can easily recognize these features and advantages through the description herein or by implementing the present invention. The content of this article includes the following Detailed Description, Claims and Drawings.

应当理解，以上概述和以下本发明实施方式的详述是用来提供概况或框架，以便理解所要求的本发明的性质和特征。用附图来进一步理解本发明，附图结合在说明书中，构成说明书的一部分。附图显示了本发明的各个实施方式，与说明书一起用来解释本发明的原理和操作。It is to be understood that both the foregoing general description and the following detailed description of the embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are used to further understand the present invention, and the accompanying drawings are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operations of the invention.

附图简述Brief description of the drawings

图1显示了用来形成烟灰预成形体的OVD法。Figure 1 shows the OVD process used to form a soot preform.

图2显示了根据本发明的固结法的侧视截面图。Figure 2 shows a side cross-sectional view of the consolidation method according to the invention.

图3显示了用来形成芯条料的再拉制法。Figure 3 shows the redrawing process used to form the core strip.

图4显示了已经沉积在芯条料上的烟灰的固结。Figure 4 shows the consolidation of soot that has been deposited on the core strip.

图5显示了通过图4所示固结步骤得到的完全固结的预成形体。FIG. 5 shows the fully consolidated preform obtained through the consolidation step shown in FIG. 4 .

图6显示了根据本发明的一个实施方式制造的光纤的显微照片。Figure 6 shows a photomicrograph of an optical fiber fabricated in accordance with one embodiment of the present invention.

图7和图8一起显示了可用于本发明的各种方法的管材制造法中的棒。Figures 7 and 8 together show rods in the tubing manufacturing process that can be used in various methods of the present invention.

图9显示了可用于本发明的方法的拉制法和设备。Figure 9 shows a drawing process and equipment that can be used in the method of the present invention.

图10显示了根据本发明的一个实施方式制造的光纤的SEM显微照片。Figure 10 shows a SEM micrograph of an optical fiber fabricated according to one embodiment of the present invention.

优选实施方式的详述DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

本发明的方法采用预成形体固结条件，该条件足以使得显著量的气体被俘获在固结的玻璃坯件中，从而在所述固结的玻璃光纤预成形体中形成孔穴。我们没有通过一些步骤除去这些孔穴，而是使用所得的预成形体形成其中具有孔穴的光纤。The method of the present invention employs preform consolidation conditions sufficient such that a significant amount of gas is trapped in the consolidated glass blank, thereby forming voids in the consolidated glass optical fiber preform. Instead of going through steps to remove these cavities, we used the resulting preform to form optical fibers with cavities in them.

在通过常规的烟灰沉积法(例如外部气相沉积(OVD)法或气相轴向沉积(VAD)法)中，二氧化硅和掺杂的二氧化硅颗粒在火焰中通过火烧形成，以烟灰的形式沉积。对于OVD，通过使带有烟灰的火焰横过圆柱形靶棒的轴，逐层地将颗粒沉积在所述圆柱形靶棒的外面。然后，这种多孔的烟灰预成形体用干燥剂(例如氯)处理，以除去水和金属杂质，然后在固结炉内，在1100-1500℃的温度下进行固结或煅烧，形成不含孔穴的玻璃坯件。表面能驱动粘性流烧结是烧结的主要机理，造成密实化和烟灰孔的封闭，从而形成密实化的玻璃预成形体。在烧结的最后阶段，随着开放孔封闭，用于固结的气体会被捕获。如果玻璃内被捕获的气体在煅烧温度下的溶解性和渗透性很高，则所述气体将能够在固结过程中迁移，穿过玻璃并到达玻璃以外。或者，在光纤制造过程的固结阶段之后仍然被捕获的气体可通过以下方式排出：保持所述光纤预成形体一段时间，直至气体迁移通过所述玻璃预成形体而排出，从而在所述预成形体内留下一个或多个中为真空的孔穴。在由所述预成形体拉制光纤的拉制操作过程中，这些孔穴会闭合，留下无孔穴或基本无孔穴的光纤。在用来制造常规传输光纤的固结过程中，目标是使制得的光纤的芯区域和包覆层区域中都完全不含孔穴。氦气是一种在对常规光纤预成形体进行固结的过程中常用来形成气氛的气体。因为氦气在玻璃中具有极高的可渗透性，其很容易在固结过程中从烟灰预成形体和玻璃中排出，使得在氦气中固结之后，所述玻璃基本不含空穴或孔穴。In conventional soot deposition methods such as external vapor deposition (OVD) or vapor axial deposition (VAD), silica and doped silica particles are formed by firing in a flame, in the form of soot deposition. For OVD, particles are deposited layer by layer on the outside of a cylindrical target by passing a soot-laden flame across its axis. This porous soot preform is then treated with a desiccant such as chlorine to remove water and metal impurities, and then consolidated or calcined at a temperature of 1100-1500°C in a consolidation furnace to form a Cavity glass blank. Surface energy driven viscous flow sintering is the primary mechanism of sintering, resulting in densification and closure of the soot pores to form a densified glass preform. During the final stages of sintering, the gases used for consolidation are trapped as the open pores close. If the solubility and permeability of the gas trapped within the glass is high at the firing temperature, the gas will be able to migrate during the consolidation process, through the glass and out of the glass. Alternatively, gases that are still trapped after the consolidation stage of the optical fiber manufacturing process can be vented by holding the fiber preform for a period of time until the gas migrates through the glass One or more voids are left in the form within the vacuum. During the drawing operation in which the optical fiber is drawn from the preform, these voids close, leaving a void-free or substantially void-free fiber. In the consolidation process used to make conventional delivery fibers, the goal is to have a fiber that is completely free of voids in both the core region and the cladding region. Helium is a gas commonly used to form the atmosphere during the consolidation of conventional optical fiber preforms. Because helium is extremely permeable in glass, it is easily expelled from the soot preform and glass during consolidation so that after consolidation in helium, the glass is substantially free of voids or hole.

本发明使用一种预成形体固结条件，该条件能够导致显著量的气体被捕获在固结的玻璃坯件中，从而在固结的玻璃光纤预成形体中形成非周期性分散的孔穴。人们不是采取一些步骤来除去这些孔穴，而是故意地使用制得的预成形体形成其中具有孔穴的光纤。具体来说，通过使用可渗透性较低的气体和/或较高的烧结速率，可以在固结过程中将孔穴捕获在固结的玻璃内。在本文中，术语烧结玻璃或固结玻璃表示在化学气相沉积烟灰沉积法(例如OVD或VAD沉积工艺)之后，经历过烟灰固结步骤的玻璃。在所述烟灰固结步骤中，所述烟灰通过受到高热而经历致密化过程，从而除去开放的空隙(即没有被致密化的玻璃包围烟灰之间的孔穴或孔)，留下完全致密化的玻璃(尽管在本发明中仍然明显剩余一些封闭的孔(即被完全致密化的玻璃包围的孔穴或孔))。这种烟灰固结步骤优选在烟灰固结炉内进行。所述烧结速率可通过提高烧结温度和/或提高烟灰预成形体通过固结炉的烧结区的向下进料速率而提高。在某些烧结条件下，可以制得一种玻璃，其中捕获的气体所占的面积分数占预成形体总面积或体积的显著一部分。The present invention utilizes preform consolidation conditions that can result in a significant amount of gas being trapped within the consolidated glass blank, thereby forming non-periodically dispersed voids in the consolidated glass optical fiber preform. Rather than taking steps to remove these voids, the resulting preform is deliberately used to form an optical fiber having the voids therein. Specifically, by using less permeable gases and/or higher sintering rates, voids can be trapped within the consolidated glass during the consolidation process. In this context, the term sintered glass or consolidated glass means glass that has undergone a soot consolidation step after a chemical vapor deposition soot deposition process such as an OVD or VAD deposition process. During the soot consolidation step, the soot undergoes a densification process by subjecting it to high heat, thereby removing open voids (i.e., voids or pores between the soot not surrounded by densified glass), leaving a fully densified Glass (although some closed pores (ie cavities or pores surrounded by fully densified glass) still apparently remain in the present invention). This soot consolidation step is preferably carried out in a soot consolidation furnace. The sintering rate can be increased by increasing the sintering temperature and/or increasing the downfeed rate of the soot preform through the sintering zone of the consolidation furnace. Under certain sintering conditions, a glass can be produced in which the area fraction of trapped gas is a significant fraction of the total area or volume of the preform.

在本发明的一个优选的实施方式中，通过使用本文所述的方法形成的光纤中的非周期性分布的空穴或孔穴位于光纤的包覆层中。这种孔穴用来降低折射率。通过设计固结参数，使空穴或孔穴的最大直径小于将要沿所述光纤长度传输的光的波长(即对于用于远程通信应用的光纤，为小于1550纳米)，该光纤可有效地用来传输特定波长的信息。In a preferred embodiment of the present invention, the aperiodically distributed cavities or cavities in the optical fiber formed by using the methods described herein are located in the cladding of the optical fiber. Such holes serve to lower the refractive index. By designing the consolidation parameters such that the maximum diameter of the cavities or cavities is smaller than the wavelength of light to be transmitted along the length of the fiber (i.e., less than 1550 nanometers for fibers used in telecommunication applications), the fiber can be effectively used to Transmits information at a specific wavelength.

图1显示了可根据本发明使用的烟灰光纤预成形体20的制造方法。在图1所示的实施方式中，通过将含二氧化硅的烟灰22沉积在旋转并平移的芯轴或饵棒(bait rod)24上，形成了烟灰预成形体2。该工艺被称为OVD或外部气相沉积法。芯轴24优选是锥形的。所述烟灰22通过以下方式形成：将气态形式的玻璃前体28送入燃烧器26的火焰30使其氧化。向燃烧器26提供甲烷(CH₄)之类的燃料32以及氧气之类的燃烧支持气体34，并引燃以形成火焰30。质量流量控制器标为V，向燃烧器26计量提供合适量的合适掺杂剂化合物36二氧化硅玻璃前体28、燃料32和燃烧支持气体34，所有这些组分都优选是气态形式的。玻璃形成体化合物28、36在火焰30中氧化，形成大体呈圆柱形的烟灰区23。具体来说，如果需要，可包含掺杂剂化合物36。例如，可以包含锗化合物作为提高折射率的掺杂剂(例如提高光纤芯内的折射率)，或者可以包含含氟的化合物以降低折射率(例如光纤的包覆层和/或含孔穴的区域的折射率)。Figure 1 shows a method of making a sootoptical fiber preform 20 that may be used in accordance with the present invention. In the embodiment shown in FIG. 1 , soot preform 2 is formed by depositing silica-containingsoot 22 onto a rotating and translating mandrel orbait rod 24 . The process is known as OVD or outside vapor deposition. Themandrel 24 is preferably tapered. Thesoot 22 is formed by feeding aglass precursor 28 in gaseous form into aflame 30 of aburner 26 to oxidize it. Afuel 32 such as methane (CH₄ ) and acombustion support gas 34 such as oxygen are supplied to theburner 26 and ignited to form aflame 30 . A mass flow controller, designated V, meters suitable amounts ofsuitable dopant compound 36,silica glass precursor 28,fuel 32, andcombustion support gas 34, all of which components are preferably in gaseous form, toburner 26. The glassformer compounds 28, 36 are oxidized in theflame 30 to form a generally cylindrical soot zone 23. In particular,dopant compound 36 may be included if desired. For example, germanium compounds may be included as index-increasing dopants (e.g., to increase the index of refraction within the core of the fiber), or fluorine-containing compounds may be included to lower the index (e.g., in the cladding and/or cavity-containing regions of the fiber). the refractive index).

如图2所示，包含所述圆柱形烟灰区域23的烟灰预成形体20可以在固结炉29内固结，以形成固结的坯件31(下面的图3中所示)。在固结之前，除去图1所示的芯轴24以形成空心的圆柱形烟灰坯件预成形体。在固结过程中，烟灰预成形体20例如通过固定机械结构21悬置在固结炉29的纯石英马弗管27中。较佳的是，在固结步骤之前，所述预成形体20暴露于干燥气氛。例如，合适的干燥气氛可包含约95-99％的氦气以及1-5％的氯气，干燥温度约为950-1250℃，合适的干燥时间约为0.5-4.0小时。如果需要的话，可以使用例如包含氟或其它光纤掺杂剂的掺杂剂气体对所述烟灰预成形体进行掺杂。例如，为了用氟掺杂，可以使用SiF₄和/或CF₄气体。这种掺杂剂气体可使用常规的掺杂温度，例如在约950-1250℃下掺杂0.25-4小时。As shown in Figure 2, thesoot preform 20 comprising the cylindrical soot region 23 may be consolidated in a consolidation furnace 29 to form a consolidated blank 31 (shown in Figure 3 below). Prior to consolidation, themandrel 24 shown in Figure 1 is removed to form a hollow cylindrical soot blank pre-form. During the consolidation process, thesoot preform 20 is suspended in a pure quartz muffle 27 of a consolidation furnace 29 , for example by means of a fixed mechanical structure 21 . Preferably, thepreform 20 is exposed to a dry atmosphere prior to the consolidation step. For example, a suitable drying atmosphere may contain about 95-99% helium and 1-5% chlorine, the drying temperature is about 950-1250° C., and the suitable drying time is about 0.5-4.0 hours. The soot preform can be doped, if desired, with a dopant gas, for example comprising fluorine or other fiber dopants. For example, for doping with fluorine, SiF₄ and/or CF₄ gases can be used. Such dopant gases may be doped using conventional doping temperatures, eg, at about 950-1250° C. for 0.25-4 hours.

在固结步骤(优选在烟灰干燥步骤之后进行)中，升高固结炉的温度，预成形体20在合适的温度下固结，例如在大约1390-1535℃下固结，以形成固结的预成形体。或者可以采用梯度烧结，使烟灰预成形体20被向下驱动通过固结炉29中温度保持在大约1225-1550℃、更优选约1390-1535℃的热区。例如，所述预成形体可保持在等温区(在该区域内保持所需的干燥温度(950-1250℃))，然后以一定的速率驱动所述烟灰预成形体通过保持在所需固结温度(例如1225-1550℃，更优选1390-1535℃)的区域，所述速率足以使预成形体20的温度以大于1℃/分钟的速率升高。所述固结炉的上部区域可保持在较低的温度，这有助于干燥和杂质去除步骤。下部区域可保持在固结所需的较高温度。在一个优选的实施方式中，所述包含烟灰的预成形体以第一向下进料速率向下进料通过固结热区，然后该预成形体以第二向下进料速率向下进料通过第二热区，所述第二向下进料速率小于第一向下进料速率。这种固结技术导致烟灰预成形体的外部比该预成形体其余部分更早地烧结，从而有助于捕获气体，这又有助于在所得的固结的玻璃中形成孔穴和保留这些孔穴。例如，所述预成形体可以以第一速度接触这些合适的固结温度(例如约高于1390℃)，所述第一速度足以使得预成形体的温度以大于15℃/分钟、更优选大于17℃/分钟的速率升高，然后采用至少第二向下进料速率/固结温度的组合，该组合足以使得所述预成形体以至少约12℃/分钟、更优选大于14℃/分钟的速率加热。较佳的是，所述第一固结速率造成所述预成形体外部的升温速率比所述第二固结速率的升温速率高2℃/分钟以上，更优选高10℃/分钟以上，更优选约高20℃/分钟以上，最优选高50℃/分钟以上。如果需要的话，可以采用第三固结步骤甚至五个或更多个另外的固结步骤，这些步骤以更慢的速率(例如小于10℃/分钟)进行加热。或者，所述烟灰预成形体可以通过以下方式以更快的速率烧结，以产生更多的孔穴：驱动烟灰预成形体通过温度高于1550℃、更优选高于1700℃、更优选高于1900℃的烧结炉热区。或者，可以使用与烟灰接触的明火或者等离子炬在固结炉以外，以更快的速率使所述烟灰预成形体烧结。In the consolidation step (preferably carried out after the soot drying step), the temperature of the consolidation furnace is increased, and thepreform 20 is consolidated at a suitable temperature, for example at about 1390-1535°C, to form a consolidated preforms. Alternatively, gradient sintering may be employed whereby thesoot preform 20 is driven downward through a hot zone in the consolidation furnace 29 maintained at a temperature of about 1225-1550°C, more preferably about 1390-1535°C. For example, the preform may be maintained in an isothermal zone (in which the desired drying temperature (950-1250°C) is maintained) and the soot preform driven at a rate through the A region of temperature (eg, 1225-1550°C, more preferably 1390-1535°C) at a rate sufficient to increase the temperature ofpreform 20 at a rate greater than 1°C/minute. The upper zone of the consolidation furnace can be kept at a lower temperature, which facilitates the drying and impurity removal steps. The lower zone can be maintained at the higher temperature required for consolidation. In a preferred embodiment, the soot-containing preform is fed down through the consolidation hot zone at a first down feed rate, and then the preform is fed down at a second down feed rate The feed passes through a second hot zone, the second down feed rate being less than the first down feed rate. This consolidation technique results in the exterior of the soot preform being sintered earlier than the rest of the preform, thereby aiding in gas capture, which in turn aids in the formation and retention of voids in the resulting consolidated glass . For example, the preform may be exposed to these suitable consolidation temperatures (eg, above about 1390° C.) at a first rate sufficient to cause the temperature of the preform to increase at a rate of greater than 15° C./minute, more preferably greater than A rate increase of 17°C/minute followed by at least a second downfeed rate/consolidation temperature combination sufficient to cause the preform to flow at least about 12°C/minute, more preferably greater than 14°C/minute rate of heating. Preferably, the first consolidation rate causes the temperature rise rate of the exterior of the preform to be higher than that of the second consolidation rate by at least 2°C/min, more preferably at least 10°C/min, even more Preferably above about 20[deg.]C/minute, most preferably above 50[deg.]C/minute. If desired, a third consolidation step or even five or more additional consolidation steps can be employed, heating at a slower rate (eg, less than 10° C./minute). Alternatively, the soot preform may be sintered at a faster rate to create more voids by driving the soot preform through a temperature above 1550°C, more preferably above 1700°C, more preferably above 1900°C ℃ hot zone of the sintering furnace. Alternatively, the soot preform may be sintered at a faster rate outside of the consolidation furnace using an open flame or plasma torch in contact with the soot.

可用于所述固结步骤的优选的烧结气体(即在烧结步骤中围绕所述预成形体的气体)包含选自以下的至少一种气体：氮气、氩气、CO₂、氧气、氯气、CF₄、CO、SO₂、氪以及它们的混合物。这各种气体在等于或低于所述根据本发明的方法适于形成孔穴的固结温度的条件下在二氧化硅玻璃中具有较低的可渗透性。优选这些产生孔穴的气体单独或结合使用，其用量为5-100体积％，更优选约为20-100体积％，最优选约为40-100体积％。剩余的烧结气体气氛由合适的稀释剂或载气组成，例如氦气、氢气、氘或其混合物。在本文所述的一些实施方式中，例如当计划在所述产生孔穴的固结过程之后，要通过OVD法在所得的玻璃预成形体或条料上沉积另外的烟灰的时候，优选使用包含小于10％的氧气、更优选包含小于5％的氧气、最优选基本不含氧气的烧结气体，否则便会由于与OVD过程中形成的氢气接触，造成一些种子(seed)的损失。一般来说，在烧结气体中使用的产生孔穴的气体(氮气，Ar，CO₂，O₂，Cl₂，CF₄，CO，SO₂，氪，或其混合物)的体积百分数越大，则所得的固结玻璃中会产生更大和更多的孔穴。更佳的是，用来在固结步骤过程中形成孔穴的烧结气体包含选自以下的至少一种气体：氮气、氩气、CO₂、氧气和氪，以及它们的混合物。这些气体可以完全单独使用，或者以这些气体与氦气之类的载气的混合物的形式使用。一种特别优选的产生孔穴的气体是氮气。申请人已经发现，当氮气和/或氩气一起使用或独立使用，作为产生孔穴的气体的时候，优选所述氮气和/或氩气在所述烧结气氛中的用量大于10体积％，更优选大于30体积％，更优选约大于50体积％，最优选约大于65体积％，剩余的烧结气氛为氦气之类的载气。这些气体已经以大于85体积％的浓度成功地使用。实际上，最高100％的氮气、最高100％的氩气，以及最高100％的氧气已经被成功地使用。人们还通过在部分真空(，例如其中将预成形体置于压力约40-750托的烧结气氛中)，在低可渗透性气体(例如氮气，氩气，CO₂，氧气，氯气，CF₄，CO，SO₂)中烧结烟灰来产生孔穴。通过使用本文所述的产生孔穴的固结技术，可以制得一种光纤，该光纤具有包覆层，所述包覆层包括具有孔穴的区域，该区域的孔穴区域孔穴面积％大于0.5％，更优选约大于1％，更优选约大于5％，最优选约大于10％。在本文中，区域孔穴面积％表示含孔穴的区域内孔穴的总面积除以所述含孔穴区域的总面积(沿垂直于所述光纤轴的横截面观察所述光纤)×100，所述含孔穴的区域由所述含孔穴区域的内边界和外边界限定。例如，如果光纤中最靠内的孔穴的最内边缘的径向位置与光纤轴中线相距4微米，而所述光纤中最靠外的孔穴的外部边界的径向位置与中线相距60微米，则所述包含孔穴的区域的面积约为11309-50＝11259平方微米。如果所述含孔穴的区域内所含的孔穴的总横截面积为1100平方微米，则所述含孔穴的区域的孔穴面积％约为9.8％。Preferred sintering gases that can be used in the consolidation step (i.e. the gas that surrounds the preform during the sintering step) comprise at least one gas selected from the group consisting of nitrogen, argon,_CO2 , oxygen, chlorine, CF_4. CO, SO₂ , krypton and their mixtures. These gases are less permeable in silica glass at or below said consolidation temperature suitable for the formation of cavities by the method according to the invention. Preferably, these cavitation-generating gases are used alone or in combination in an amount of 5-100 vol%, more preferably about 20-100 vol%, most preferably about 40-100 vol%. The remaining sintering gas atmosphere consists of a suitable diluent or carrier gas, such as helium, hydrogen, deuterium or mixtures thereof. In some of the embodiments described herein, for example when it is planned to deposit additional soot on the resulting glass preform or strand by OVD after the void-generating consolidation process, it is preferred to use a method comprising less than 10% oxygen, more preferably a sintering gas containing less than 5% oxygen, most preferably substantially free of oxygen, otherwise some seed will be lost due to contact with the hydrogen formed during the OVD process. In general, the greater the volume percentage of the void-generating gas (nitrogen, Ar, CO₂ , O₂ , Cl₂ , CF₄ , CO, SO₂ , krypton, or mixtures thereof) used in the sintering gas, the greater the resulting Larger and more voids are produced in the consolidated glass. More preferably, the sintering gas used to form the voids during the consolidation step comprises at least one gas selected from the group consisting of nitrogen, argon,_CO2 , oxygen and krypton, and mixtures thereof. These gases may be used entirely alone or in the form of a mixture of these gases with a carrier gas such as helium. A particularly preferred cavitation-generating gas is nitrogen. Applicants have found that when nitrogen and/or argon are used together or independently as a gas for creating voids, it is preferred that said nitrogen and/or argon be used in an amount greater than 10% by volume in said sintering atmosphere, more preferably Greater than 30% by volume, more preferably greater than about 50% by volume, most preferably greater than about 65% by volume, the remainder of the sintering atmosphere is a carrier gas such as helium. These gases have been used successfully in concentrations greater than 85% by volume. In fact, up to 100% nitrogen, up to 100% argon, and up to 100% oxygen have been used successfully. One has also obtained a low permeability gas (such as nitrogen, argon, CO₂ , oxygen, chlorine, CF₄ , CO, SO₂ ) to generate pores by sintering soot. By using the void-generating consolidation techniques described herein, an optical fiber can be produced having a cladding comprising a region having voids having a void area % void area greater than 0.5%, More preferably greater than about 1%, more preferably greater than about 5%, most preferably greater than about 10%. As used herein, the area % of voids in a region means the total area of voids in the void-containing region divided by the total area of the void-containing region (viewing the fiber in a cross-section perpendicular to the axis of the fiber) x 100, the A region of voids is defined by inner and outer boundaries of said void-containing region. For example, if the radial position of the innermost edge of the innermost cavity in an optical fiber is 4 microns from the centerline of the fiber axis, and the radial position of the outer boundary of the outermost cavity in said fiber is 60 microns from the centerline, then The area containing the pores is approximately 11309-50 = 11259 square microns. If the total cross-sectional area of the voids contained within the void-containing region is 1100 square microns, the void area % of the void-containing region is about 9.8%.

使用上述优选的烧结气体时，需要使用一种固结方法，该方法包括以一定的速率和温度条件，将所述预成形体向下进料，所述速率和温度条件足以使得至少一部分所述固结气体被故意捕获。这可通过以下方式进行，例如：以至少约10℃/分钟，更优选大于约12℃/分钟，更优选大于约14℃/分钟的方式对烟灰预成形体的至少一部分进行加热。用于本发明的烧结温度优选高于1100℃，更优选高于1300℃，更优选高于1400℃，最优选高于1450℃。一种特别优选的烧结温度约为1490℃。When using the preferred sintering gases described above, it is necessary to use a consolidation method that includes feeding the preform downward at a rate and temperature sufficient to allow at least a portion of the Consolidation gases are intentionally trapped. This can be done, for example, by heating at least a portion of the soot preform at least about 10°C/minute, more preferably greater than about 12°C/minute, more preferably greater than about 14°C/minute. The sintering temperature used in the present invention is preferably higher than 1100°C, more preferably higher than 1300°C, more preferably higher than 1400°C, most preferably higher than 1450°C. A particularly preferred sintering temperature is about 1490°C.

图3显示了用来拉制用于本发明的芯条料的方法。例如在一个这样的实施方式中，如上文结合图1所述形成了烟灰预成形体，然后使用常规的固结技术(例如使用高于1300℃的固结温度，使用100％的氦气气氛)使得所述烟灰预成形体固结，形成不含孔穴的预成形体。例如，在使用光纤预成形体制备纯二氧化硅芯光纤的时候，所述芯预成形体由较纯的二氧化硅组成，其中不含显著量的折射率调节掺杂剂。或者，在使用光纤预成形体制造纯氧化锗掺杂的芯光纤的时候，所述芯预成形体可由氧化锗掺杂的芯区域以及任选的一部分包覆层(例如未掺杂的二氧化硅包覆层)组成。所得的固结的芯坯件31置于芯条料拉制炉37中，由其拉制至少一类具有减小的外直径的棒形芯条料段33。将所述预成形体坯件31加热至例如约1700-2000℃的温度。控制器38通过给张力机械装置40(此处显示为两个驱动轮)提供合适的控制信号，以便以合适的速度下拉所述条料33，从而控制对所述条料施加的张力。通过这种方式，可以得到外径为例如约1-16毫米的一定长度的芯条料33。然后将所述芯条料用作靶或芯轴24进行另外的烟灰沉积，或者在管内棒(rodin tube)过程中用作棒，这将在下文中进一步进行描述。Figure 3 shows the method used to draw the core strands used in the present invention. For example, in one such embodiment, a soot preform is formed as described above in connection with FIG. 1 and then consolidated using conventional consolidation techniques (e.g., using a consolidation temperature above 1300° C., using a 100% helium atmosphere) The soot preform is allowed to consolidate to form a preform free of voids. For example, when optical fiber preforms are used to make pure silica core optical fibers, the core preform consists of relatively pure silica that does not contain significant amounts of index modifying dopants. Alternatively, when an optical fiber preform is used to make a pure germania-doped core fiber, the core preform may consist of a germania-doped core region and optionally a portion of the cladding (e.g., undoped silicon coating) composition. The resulting consolidated core blank 31 is placed in a corerod drawing furnace 37 from which at least one type of rod-shapedcore rod segment 33 having a reduced outer diameter is drawn. The preform blank 31 is heated, for example, to a temperature of about 1700-2000°C. Controller 38 controls the tension applied to the strip by providing appropriate control signals to tension mechanism 40 (shown here as two drive wheels) to pull down thestrip 33 at the appropriate speed. In this way, a length ofcore strip 33 with an outer diameter of, for example, about 1-16 mm can be obtained. The core strip is then used as a target ormandrel 24 for additional soot deposition, or as a rod in a rodin tube process, as will be described further below.

在一个优选的实施方式中，使用上文结合图3所述的方法形成芯条料试件，其可作为另外的烟灰沉积的靶或者芯轴，然后其可使用本文所述的孔穴形成技术进行固结，从而最终成为光纤的包覆层。在一个这样的实施方式中，例如，可使用完全固结的、无孔穴的玻璃芯条料作为图1所示烟灰沉积步骤中的饵棒24。所述玻璃芯条料可以是未掺杂的二氧化硅，因而所得的光纤将是芯基本为纯二氧化硅的二氧化硅芯光纤。或者，所述芯条料可以由一个或两个掺杂的区域组成，这些掺杂的区域一起形成光纤的光传输芯区域。在将烟灰沉积在玻璃芯条料上之后，所述外部烟灰区域120可以如图4所示在固结炉129内完全固结。较佳的是，在此固结步骤中，如图5所示，如上所述进行形成孔穴的固结过程，以形成包含孔穴的固结的光纤预成形体150。In a preferred embodiment, the method described above in connection with FIG. 3 is used to form a core strip sample that can serve as a target or mandrel for additional soot deposition, which can then be performed using the hole formation techniques described herein. Consolidation, which eventually becomes the cladding layer of the optical fiber. In one such embodiment, for example, a fully consolidated, void-free glass core rod may be used as thebait rod 24 in the soot deposition step shown in FIG. 1 . The glass core rod can be undoped silica, so the resulting fiber will be a silica core fiber with a core of substantially pure silica. Alternatively, the core rod may consist of one or two doped regions which together form the optically transmissive core region of the fiber. After depositing the soot on the glass core strand, theouter soot region 120 may be fully consolidated in aconsolidation furnace 129 as shown in FIG. 4 . Preferably, in this consolidation step, as shown in FIG. 5 , the consolidation process for forming the cavity is performed as described above to form a consolidated optical fiber preform 150 including the cavity.

如上所述，用于形成孔穴的固结步骤的优选的气体包括选自以下的至少一种气体：氮气、氩气、CO₂、氧气、氯气、CF₄、CO、SO₂、氪以及它们的混合物。优选这些产生孔穴的气体单独或组合使用，其用量为5-100体积％，更优选约为20-100体积％，最优选约为40-100体积％。剩余的烧结气氛由合适的稀释剂或载气组成，例如氦气、氢气、氘或其混合物。一般来说，用于烧结气体中的产生孔穴的气体(氮气，Ar，CO₂，Kr，O₂，Cl₂，CF₄，CO，SO₂)的百分数越大，则所得的固结的玻璃中的孔穴将会越大和越多。一种特别优选的产生孔穴的气体是氮气，其用量优选大于10体积％，更优选大于30体积％，更优选约大于50体积％，最优选约大于65体积％，剩余的烧结气氛为载气，例如氦气。人们还通过在部分真空(例如其中将预成形体置于压力约40-750托的烧结气氛中)，在低可渗透性气体(例如氮气，氩气，CO₂，氧气，氯气，CF₄，CO，SO₂)中烧结烟灰来产生孔穴，在此情况下不需要使用可渗透性较高的稀释气体，例如氦气。通过使用本文所述的产生孔穴的固结技术，可以制得一种光纤，该光纤的包覆层包括含有孔穴的区域，该区域的区域孔穴面积百分数大于0.5％，更优选约大于1％。甚至还可能使用这些技术获得约大于5％、甚至约大于10％的区域孔穴面积％。所述区域孔穴面积％优选小于50％，更优选小于20％。最优选的是，所述具有空穴的区域不会延伸到包覆层外部边缘，以使得光纤外部之上具有开放的孔穴或空穴。As mentioned above, preferred gases for the consolidation step of forming the pores include at least one gas selected from the group consisting of nitrogen, argon, CO₂ , oxygen, chlorine, CF₄ , CO, SO₂ , krypton, and their mixture. Preferably, these cavitation-generating gases are used alone or in combination in an amount of 5-100 volume percent, more preferably about 20-100 volume percent, most preferably about 40-100 volume percent. The remaining sintering atmosphere consists of a suitable diluent or carrier gas, such as helium, hydrogen, deuterium or mixtures thereof. In general, the greater the percentage of void-forming gases (nitrogen, Ar, CO₂ , Kr, O₂ , Cl₂ , CF₄ , CO, SO₂ ) used in the sintering gas, the greater the resulting consolidated glass The holes in will be larger and more numerous. A particularly preferred cavitating gas is nitrogen, preferably in an amount greater than 10% by volume, more preferably greater than 30% by volume, more preferably greater than about 50% by volume, and most preferably greater than about 65% by volume, with the remainder of the sintering atmosphere being the carrier gas , such as helium. It has also been achieved by low permeability gases (such as nitrogen, argon, CO₂ , oxygen, chlorine, CF₄ , CO, SO₂ ) to create pores by sintering the soot, in which case it is not necessary to use a more permeable diluent gas such as helium. By using the void-generating consolidation techniques described herein, an optical fiber can be produced having a cladding comprising a void-containing region with a regional void area percentage greater than 0.5%, more preferably greater than about 1%. It is even possible to obtain a regional void area % of about greater than 5%, or even about greater than 10%, using these techniques. The porosity area % of said region is preferably less than 50%, more preferably less than 20%. Most preferably, the region with voids does not extend to the outer edge of the cladding such that there is an open void or cavity above the exterior of the fiber.

本发明所用的烧结温度优选为1100-1550℃，更优选为1300-1500℃，最优选为1350-1500℃。一种优选的烧结温度约为1490℃。对固结过程中使用的气氛、在固结炉内的温度以及预成形体固结速率进行选择，使得在烟灰固结过程中，气体被故意地捕获在预成形体中，在固结的玻璃中形成空穴。这些包含气体的孔穴优选在光纤拉制过程之前和/或过程中不会完全脱气，使得在拉制成光纤之后，所述孔穴残留在所述光纤中。可以对许多种工艺参数进行控制，以改变和控制孔穴的尺寸。例如，通过延长固结试件或升高固结温度可以增大孔穴的尺寸，这是因为升高的温度会造成捕获在孔穴内的气体膨胀。类似地，所述孔穴的尺寸和面积会受拉制条件的影响。例如，拉制炉内较长的加热区和/或较快的拉制速度会增大所述孔的尺寸以及孔的面积百分数。通过选择在固结温度下在玻璃内渗透性更高的气体，将会得到较小的孔穴。烧结速率还会对空穴尺寸和空穴数量造成显著的影响。较快的烧结速率将会导致形成更多和更大的孔穴。但是采用过慢的烧结速率会导致不形成孔穴，这是因为气体将会有时间通过玻璃而排出。因此，预成形体的向下进料速率和/或所用的固结温度优选足够高，以便对所述预成形体的至少一部分以约高于10℃/分钟、更优选约高于12℃/分钟、更优选约高于14℃/分钟的速率进行加热。一般来说，具有较低烟灰密度的光纤预成形体将会导致形成更多的孔穴。但是，在需要的时候，特殊光纤预成形体中沉积的烟灰的密度可以改变，以产生更多的空穴(更高的区域孔穴面积百分数)。例如，可以将高密度烟灰区域直接设置在固结的玻璃(例如纯二氧化硅)芯条料上，然后在其上沉积密度低于第一烟灰区域的第二烟灰区域。我们发现这会使得芯附近(即在高密度烟灰区域)具有更高的孔穴面积百分数。所述含二氧化硅的烟灰的堆积密度优选约为0.10-1.7g/cc，更优选约为0.30-1.0g/cc。这种效果还可用来形成固结的包含孔穴的预成形体，其在包含低孔穴或不含孔穴的区域与含较高孔穴的区域之间交替；在至少100微米的距离内初始烟灰密度径向变化大于3％。这种预成形体可用来例如制造具有包覆层区域的光纤，所述包覆层区域在无孔穴的玻璃和含孔穴的玻璃区域之间交替变化。具有这种交替的含孔穴区域和不含孔穴区域的纤维将表现出用作布拉格栅(Bragg grating)的性质。The sintering temperature used in the present invention is preferably 1100-1550°C, more preferably 1300-1500°C, most preferably 1350-1500°C. A preferred sintering temperature is about 1490°C. The atmosphere used in the consolidation process, the temperature in the consolidation furnace, and the rate of preform consolidation are selected such that during soot consolidation, gases are intentionally trapped in the preform and the consolidated glass Holes are formed in the . These gas-containing cavities are preferably not completely degassed prior to and/or during the fiber drawing process such that the cavities remain in the fiber after it has been drawn. A variety of process parameters can be controlled to vary and control the size of the pores. For example, the size of the cavities can be increased by lengthening the consolidation test piece or increasing the consolidation temperature, since the increased temperature causes the gas trapped in the cavities to expand. Similarly, the size and area of the voids can be affected by the drawing conditions. For example, longer heating zones and/or faster draw speeds within a draw furnace increase the size of the pores and the percent area of the pores. By selecting a gas that is more permeable within the glass at the consolidation temperature, smaller voids will be obtained. The sintering rate also has a significant effect on the size and number of voids. Faster sintering rates will result in more and larger voids. But using a sintering rate that is too slow will result in no voids being formed because the gas will have time to escape through the glass. Accordingly, the feed-down rate of the preform and/or the consolidation temperature used are preferably high enough to heat at least a portion of the preform at about greater than 10°C/min, more preferably about greater than 12°C/min. minutes, more preferably at a rate of about greater than 14° C./minute. In general, an optical fiber preform with a lower soot density will result in more voids being formed. However, the density of deposited soot in a particular fiber preform can be varied to produce more voids (higher percent areal void area) if desired. For example, a high density soot region may be placed directly on a consolidated glass (eg, pure silica) core rod, upon which a second soot region having a lower density than the first soot region is deposited. We have found that this results in a higher percentage of void area near the core (ie in the high density soot region). The silica-containing soot preferably has a bulk density of about 0.10-1.7 g/cc, more preferably about 0.30-1.0 g/cc. This effect can also be used to form a consolidated void-containing preform that alternates between regions containing low or no voids and regions of higher voids; initial soot density diameter at a distance of at least 100 microns to a change greater than 3%. Such preforms can be used, for example, to produce optical fibers having cladding regions that alternate between void-free glass regions and void-containing glass regions. Fibers with such alternating void-containing and non-void-free regions will exhibit properties useful as Bragg gratings.

参见图5，使用上述技术，可以形成光纤预成形体150，其包括无孔穴的芯区域151，该芯区域151被包含大量孔穴的包覆层152包围。通过在包覆层152中形成包含足量的具有合适尺寸孔穴的含孔穴区域，包覆层152将作为光学包覆层，在所述光纤预成形体被拉制成光纤之后，用来导引光通过芯区域151。或者所述含孔穴的区域可用来提高光纤的弯曲性能。如果需要的话，在将预成形体150拉制成光纤之前，可以将另外的烟灰沉积在包覆层区域152上并进行固结。所述另外的沉积的包覆材料可根据需要固结成包括孔穴，也可固结成不包括孔穴。Referring to FIG. 5, using the techniques described above, an optical fiber preform 150 can be formed that includes a void-free core region 151 surrounded by a cladding layer 152 that contains a large number of voids. By forming a void-containing region in cladding 152 containing a sufficient number of voids of appropriate size, cladding 152 will serve as an optical cladding for guiding the optical fiber preform after it has been drawn into an optical fiber. Light passes through the core region 151 . Alternatively, the cavity-containing region can be used to improve the bending properties of the fiber. If desired, additional soot may be deposited on the cladding region 152 and consolidated prior to drawing the preform 150 into an optical fiber. The additional deposited cladding material may be consolidated to include voids, or may be consolidated to exclude voids, as desired.

图6显示了由这种预成形体拉制成的光纤的一个例子。所述图6的光纤包括纯二氧化硅芯区域，该芯区域被包覆层区域包围，所述包覆层区域包含孔穴，这些孔穴的位置能够有效地引导光通过所述二氧化硅芯。图6的光纤的基谐模式在1550纳米下的衰减为0.28dB/km，即使该光纤是由较为粗糙的试验制造设备制成的。但是，通过使用更为合适的设备，肯定可以达到在1550纳米下小于0.2dB/km的衰减。Figure 6 shows an example of an optical fiber drawn from such a preform. The optical fiber of FIG. 6 includes a pure silica core region surrounded by a cladding region containing cavities positioned to efficiently guide light through the silica core. The attenuation of the fundamental mode in the fiber of Figure 6 is 0.28 dB/km at 1550 nm, even though the fiber was made with relatively crude experimental fabrication equipment. However, an attenuation of less than 0.2dB/km at 1550nm can certainly be achieved by using more suitable equipment.

或者，可以不将烟灰沉积在已经形成的芯条料上，而采用上述的成形方法形成上文结合图2所述的其中具有含孔穴的区域的固结玻璃管材，该管材可作为芯条料的套管。例如，上述方法可用来在可移除的芯轴24上形成烟灰预成形体，然后移除所述芯轴，如上所述使所述烟灰预成形体固结，形成固结的包含孔穴的玻璃管。所得的其中包含孔穴的管材65可作为芯条料35的套管。这种套管可通过例如管材制造技术中的常规的棒完成，如图7和图8所示。在图7中，将纯(即基本不含增大折射率的掺杂剂，例如锗)二氧化硅芯条料35插入包含孔穴的包覆套管部分65中，但是所述芯区域或包覆层也可用常规的折射率调节剂(例如锗或氟)进行掺杂。在图8中，将芯条料35和包覆套管部分65加热至合适的温度(例如约高于1300℃至1500℃)，然后使用管材制造工艺步骤中公知的棒再拉制至较小直径，从而形成光纤预成形体，该预成形体可以拉制成光纤，该光纤具有根据本发明被包含孔穴的包覆层区域包围的纯的二氧化硅芯区域。Alternatively, instead of depositing soot on an already formed core strand, the forming method described above can be used to form the consolidated glass tube described above in connection with FIG. casing. For example, the method described above may be used to form a soot preform on aremovable mandrel 24, then remove the mandrel and consolidate the soot preform as described above to form a consolidated void-containing glass Tube. The resultingtubing 65 containing the cavities therein may serve as a sleeve for thecore strip 35 . Such casings can be accomplished, for example, by rods conventional in pipe manufacturing technology, as shown in FIGS. 7 and 8 . In FIG. 7, a pure (i.e., substantially free of index-increasing dopants, such as germanium)silica core strip 35 is inserted into acladding sleeve portion 65 containing voids, but the core region or cladding The cladding layer can also be doped with conventional index modifiers such as germanium or fluorine. In FIG. 8, thecore strip 35 andcladding sleeve portion 65 are heated to a suitable temperature (eg, approximately above 1300° C. to 1500° C.) and then redrawn to a smaller size using rods known in the tubing manufacturing process steps. diameter, thereby forming an optical fiber preform that can be drawn into an optical fiber having a pure silica core region surrounded by a cladding region containing voids in accordance with the present invention.

在本文所述的任意实施方式中，所得的最终固结的光纤预成形体50可通过以下方式拉制成光纤：将所述预成形体置于图9所示的拉制炉52内，然后用常规的方法和设备加热和拉制光纤54。然后将光纤54在冷却室55内冷却，并用无接触传感器56测量最终直径。可以使用涂敷设备58(也是常规设备)施涂一层或多层涂层并固化。在拉制过程中，所述光纤54通过张力组件60，从而施加张力，由所述预成形体50拉制光纤54。通过控制设备61控制所述张力，以将光纤的直径保持在预定的设定点。最后，用进料头62将涂敷后的光纤54缠绕在光纤储存线轴64上。In any of the embodiments described herein, the resulting final consolidated optical fiber preform 50 can be drawn into an optical fiber by placing the preform in a drawing furnace 52 as shown in FIG. 9 , and then Fiber 54 is heated and drawn using conventional methods and equipment. The fiber 54 is then cooled in a cooling chamber 55 and the final diameter is measured with a contactless sensor 56 . One or more coatings may be applied and cured using coating equipment 58 (also conventional equipment). During the drawing process, the optical fiber 54 passes through the tensioning assembly 60 , thereby applying tension, and the optical fiber 54 is drawn from the preform 50 . The tension is controlled by the control device 61 to maintain the diameter of the fiber at a predetermined set point. Finally, the coated optical fiber 54 is wound onto a fiber storage spool 64 using a feed head 62 .

上面结合图3所述用来形成芯条料的相同方法还可用来对包含孔穴的固结的管材进行再拉制。这种再拉制法可用来改变所述管材中包含的孔穴的尺寸。例如，在对包含孔穴的预成形体进行再拉制的时候，直径减小得越厉害，则该预成形体中的孔穴尺寸将越小。The same method described above in connection with FIG. 3 for forming the core strip can also be used to redraw consolidated tubing containing voids. This redrawing method can be used to change the size of the cavities contained in the tubing. For example, the more the diameter is reduced when redrawing a preform containing a cavity, the smaller the size of the cavity in the preform will be.

通过使用本文所述的产生孔穴的固结技术，我们制得了光纤，该光纤由具有第一折射率的芯区域和具有第二折射率的包覆层区域组成，所述第二折射率低于芯区域的第一折射率，使得传输通过所述光纤的光基本保持在芯内，使得所述孔穴位于其中，形成所述光纤的包覆层，所述孔穴的孔穴面积百分数基本不为零。By using the cavitation-generating consolidation technique described herein, we fabricated optical fibers consisting of a core region with a first refractive index and a cladding region with a second refractive index lower than A first index of refraction in the core region such that light transmitted through the optical fiber remains substantially within the core such that the voids are located therein forming a cladding of the optical fiber, the voids having a void area percentage that is substantially non-zero.

通过使用本文所述的技术，可以制得一种光纤，其中在光的功率分数大于80％的区域之内的任意孔穴的最大尺寸小于将要用于远程通信自动化应用的传输的光的波长。所谓最大尺寸表示在沿着光纤轴向观察的垂直横截面中，任意特定孔穴的最大直径。例如，人们已经制得这样的光纤，其中在光的功率分数大于80％(更优选大于90％)的区域内，所有所述孔穴的最大尺寸小于5微米，更优选小于2微米，更优选小于1微米，最优选小于0.5微米。By using the techniques described herein, an optical fiber can be produced in which the largest dimension of any void within the region where the power fraction of light is greater than 80% is smaller than the wavelength of light to be transmitted for telecommunication automation applications. The so-called maximum dimension means the maximum diameter of any particular cavity in a vertical cross-section viewed along the fiber axis. For example, people have made such optical fibers, wherein in the region where the power fraction of light is greater than 80%, more preferably greater than 90%, the largest dimension of all the holes is less than 5 microns, more preferably less than 2 microns, more preferably less than 1 micron, most preferably less than 0.5 micron.

通过使用本文所述的技术，可以制得具有含孔穴区域的光纤，其中区域孔穴面积百分数大于1％，更优选大于10％，最优选大于30％。By using the techniques described herein, optical fibers can be produced having void-containing regions wherein the region has a void area percentage greater than 1%, more preferably greater than 10%, and most preferably greater than 30%.

上述方法主要局限于制造二氧化硅芯光纤，即具有被含孔穴的包覆区包围的较纯的二氧化硅芯区的光纤。或者，如果需要，可以使用调节折射率的掺杂剂(单独使用或共同使用)，以进一步相对于包覆层的折射率调节芯的折射率。例如，在一个这样的优选实施方式中，将锗芯条料用作起始棒，优选使用上述OVD沉积技术在其上沉积另外的烟灰包覆材料。然后如上所述使所述烟灰包覆区域固结，在掺杂氧化锗的二氧化硅芯区域周围形成包含孔穴的包覆区域。在包括折射率调节掺杂剂的另一个实施方式中，使用二氧化硅芯条料作为烟灰包覆区的起始棒。但是，在产生孔穴的固结步骤中，除了产生孔穴的掺杂剂气体以外，还提供了氟掺杂剂源(例如SiF₄气体)以同时用氟掺杂所述含孔隙的区域。通过这种方式，可以在二氧化硅芯区域周围形成氟掺杂的含孔穴的区域。The methods described above are primarily limited to the manufacture of silica core optical fibers, ie optical fibers having a relatively pure silica core region surrounded by a cladding region containing voids. Alternatively, index adjusting dopants may be used (either alone or in combination) to further adjust the refractive index of the core relative to that of the cladding, if desired. For example, in one such preferred embodiment, a strip of germanium core is used as the starting rod upon which additional soot coating material is deposited, preferably using the OVD deposition technique described above. The soot clad region is then consolidated as described above, forming a clad region containing voids around the germania doped silica core region. In another embodiment that includes a refractive index modifying dopant, a silica core rod is used as the starting rod for the soot clad region. However, in the void-generating consolidation step, in addition to the void-creating dopant gas, a fluorine dopant source (eg SiF₄ gas) is provided to simultaneously dope the void-containing region with fluorine. In this way, a fluorine-doped cavity-containing region can be formed around the silica core region.

实施例Example

下面将通过以下实施例更进一步描述本发明。The present invention will be further described by the following examples.

步骤1-芯条料制备：通过标准OVD工艺制备了直径为8毫米和15毫米的纯二氧化硅芯条料。首先将SiO₂烟灰(密度为0.5g/cc)沉积在可移除的饵棒上，然后移除所述饵棒，所得的烟灰使用标准固结法(在氦气+3％的氯气中，在1000℃下干燥2小时)固结，然后在仅含He的气氛中，以6毫米/分钟的向下进料速率使其向下驱动通过热区(相当于3℃/分钟的加热速率)，以将烟灰烧结成透明的无孔穴的固结玻璃试件。该试件在500托的压力(部分真空)下，在1900℃下沿中线再拉制，使得中线的空穴闭合，得到直径为8毫米或15毫米的无空穴固结二氧化硅芯条料。除非另外说明，在下面的各个实施例中，当拉制光纤的时候，使用常规涂料(即常规的丙烯酸制剂一次涂料和二次涂料)对所述光纤进行涂敷。Step 1 - Core Strip Preparation: Pure silica core strips with diameters of 8 mm and 15 mm were prepared by standard OVD process._SiO2 soot (density 0.5 g/cc) was first deposited on a removable bait rod which was then removed and the resulting soot was consolidated using standard methods (in helium + 3% chlorine, Dry at 1000 °C for 2 h) to consolidate and then drive it down through the hot zone at a down feed rate of 6 mm/min (equivalent to a heating rate of 3 °C/min) in an atmosphere containing only He , to sinter the soot into transparent, void-free consolidated glass specimens. The test piece was redrawn along the centerline at 1900°C under a pressure of 500 Torr (partial vacuum), so that the cavity in the centerline was closed to obtain a hole-free consolidated silica core rod with a diameter of 8 mm or 15 mm material. Unless otherwise stated, in the following examples, the optical fibers were coated with conventional coatings (ie, conventional acrylic primary and secondary coatings) when the optical fibers were drawn.

实施例1：Example 1:

使用外部气相沉积法(即通过沉积在1米长×10毫米直径的可移除氧化铝饵棒上)沉积3000克SiO₂(密度为0.48g/cc)烟灰，形成SiO₂烟灰试件。然后移除所述氧化铝饵棒，将由纯(未掺杂)的固结的二氧化硅形成的直径为8毫米的芯条料插入所述SiO₂烟灰试件。然后如下对所述烟灰内的棒组件进行烧结。该组件首先在97％氦气和3％氯气的气氛中，在1000℃下干燥，然后以32毫米/分钟的速度驱动该组件在100％的氮气烧结气氛中，通过(使预成形体的升温约为16℃/分钟)设定在1500℃的热区。然后所述预成形体组件再次向下驱动(即第二次)，以25毫米/分钟的速率(预成形体加热速率约为12.5℃/分钟)通过热区，最后以6毫米/分钟的速率(约3℃/分钟的加热速率)进行最后烧结，以将所述烟灰烧结成接种氮气(nitrogen-seeded)的外部包覆试件。使用所述第一个较高的向下进料速率以使得光纤预成形体的外部变光滑，这有助于将气体捕获在所述预成形体之内。然后将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时。Si02 soot coupons were formed by depositing 3000 grams of_Si02 (density 0.48 g/cc) soot using external vapor deposition (ie by deposition on a 1 meter long_x 10 mm diameter removable alumina bait rod). The alumina bait rod was then removed and an 8 mm diameter core rod formed of pure (undoped) consolidated silica was inserted into the_SiO2 soot coupon. The rod assembly within the soot was then sintered as follows. The assembly is first dried at 1000°C in an atmosphere of 97% helium and 3% chlorine, and then the assembly is driven at a speed of 32 mm/min in a sintering atmosphere of 100% nitrogen through (heating of the preform approx. 16°C/min) in the hot zone set at 1500°C. The preform assembly was then driven down again (i.e. a second time) through the hot zone at a rate of 25 mm/min (preform heating rate of approximately 12.5°C/min) and finally at a rate of 6 mm/min A final sintering was performed (heating rate of about 3°C/min) to sinter the soot into nitrogen-seeded outer cladding coupons. Using the first higher downfeed rate to smooth the exterior of the fiber preform helps trap gas within the preform. The coupons were then placed in an argon purged holding furnace set at 1000°C for 24 hours.

使用热区长度约2.54厘、设定在2100℃的拉制炉，以1米/秒的速度将所得的光纤预成形体拉制成直径为125微米的光纤。对所得光纤的横截面端面的SEM分析(图6)显示了大约22微米直径的实心二氧化硅芯和包覆层，所述包覆层的区域空穴面积％(空穴面积除以含空穴的区域的面积×100)为3.5，平均直径为0.3微米(300纳米)，最大空穴直径为0.50微米(500纳米)，标准偏差为0.08微米，包括约3400个空穴，在整个光纤横截面上得到共约7900个空穴。光纤的总空穴面积％(空穴的面积除以光纤横截面总面积×100)约为3.4％。该光纤的光学性质为：在1550纳米下的多模衰减为2.2dB/Km，在1550纳米下的基谐模式的衰减为0.28dB/km。The resulting optical fiber preform was drawn into an optical fiber having a diameter of 125 microns at a rate of 1 m/s using a drawing furnace with a hot zone length of approximately 2.54 cm and set at 2100°C. SEM analysis of a cross-sectional end face of the resulting fiber (FIG. 6) revealed a solid silica core of approximately 22 microns in diameter and a cladding with a areal void area % (hole area divided by void-containing The area of the hole area × 100) is 3.5, the average diameter is 0.3 microns (300 nanometers), the largest hole diameter is 0.50 microns (500 nanometers), and the standard deviation is 0.08 microns, including about 3400 holes, across the entire fiber A total of about 7900 holes were obtained on the cross section. The total void area % of the fiber (the area of the void divided by the total cross-sectional area of the fiber x 100) is about 3.4%. The optical properties of the optical fiber are: the multimode attenuation at 1550 nm is 2.2 dB/Km, and the attenuation of the fundamental harmonic mode at 1550 nm is 0.28 dB/km.

实施例2：Example 2:

将3000克SiO₂(密度为0.47g/cc)烟灰以火焰沉积方式沉积在1米长×8毫米直径的纯二氧化硅芯条料上。然后该组件如下所述进行烧结。该组件首先在由氦气和3％的氯气组成的气氛中在1000℃下干燥2小时，然后在70体积％氮气和30体积％氦气的气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区，然后以25毫米/分钟的速率再向下驱动通过所述热区，最后以6毫米/分钟的速率烧结，以烧结所述烟灰，形成氮气/氦气接种的外覆试件。然后所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时，以从试件中排出氦气。3000 grams_{of SiO2} (density 0.47 g/cc) soot was deposited by flame deposition on a 1 m long x 8 mm diameter pure silica core strip. The assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 hours in an atmosphere consisting of helium and 3% chlorine, and then driven downward at a rate of 32 mm/min in an atmosphere of 70 vol% nitrogen and 30 vol% helium The nitrogen/helium inoculum was formed by sintering the soot through a hot zone set at 1500°C, then driven down through the hot zone at a rate of 25 mm/min, and finally sintered at a rate of 6 mm/min. outer covering test piece. The coupons were then placed in an argon purged holding furnace set at 1000°C for 24 hours to vent helium from the coupons.

依照与实施例1所述类似的方式将所述试件拉制成直径为125微米的光纤。对所得光纤的端面的SEM分析显示了大约22微米直径的实心二氧化硅芯和包覆层，所述包覆层的区域空穴面积氮气填充孔穴％为4.5，平均直径为0.45微米，最小直径的空穴为0.03微米，最大直径为1.17微米，标准偏差为0.19微米，包括约2300个空穴，在整个光纤横截面上总共得到约8400个空穴。总光纤空穴面积％(空穴面积除以光纤总横截面积×100)约为4.4％。按照多模衰减测量的时候，该光纤在1550纳米下的光学性质为9.8dB/Km。The sample was drawn into an optical fiber with a diameter of 125 microns in a similar manner to that described in Example 1. SEM analysis of the end face of the resulting fiber showed a solid silica core of approximately 22 microns in diameter and a cladding with a regional void area of 4.5% nitrogen filled voids, an average diameter of 0.45 microns, and a minimum diameter of The voids are 0.03 microns, the maximum diameter is 1.17 microns, and the standard deviation is 0.19 microns, including about 2300 holes, and a total of about 8400 holes are obtained in the entire fiber cross-section. The total fiber void area % (void area divided by total fiber cross-sectional area x 100) is about 4.4%. The optical properties of this fiber were 9.8 dB/Km at 1550 nm when measured as multimode attenuation.

实施例3：Example 3:

将3000克SiO₂(密度为0.46g/cc)烟灰以火焰沉积方式沉积在来自步骤1的1米长×8毫米直径的纯二氧化硅芯条料上。然后该组件如下所述进行烧结。该组件首先在由3％的氯气和余量的氦气组成的气氛中在1000℃下干燥2小时，然后在50体积％氮气和50体积％氦气的气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区，然后以6毫米/分钟的速率再次通过相同的热区以进行最后烧结，以烧结所述烟灰，形成氮气/氦气接种的外覆试件。然后将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时，以从预成形试件中排出氦气。3000 grams_{of Si02} (density 0.46 g/cc) soot were deposited by flame deposition on the 1 meter long x 8 mm diameter pure silica core strip from step 1 . The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere consisting of 3% chlorine and the balance helium, and then dried at a rate of 32 mm/min in an atmosphere of 50 vol% nitrogen and 50 vol% helium. Drive down through a thermal zone set at 1500 °C. The assembly is then driven down again through the same hot zone at 25 mm/min and then again at 6 mm/min for final sintering to sinter the soot to form nitrogen/helium Inoculated overcoated test piece. The coupons were then placed in an argon purged holding furnace set at 1000°C for 24 hours to vent the helium from the preformed coupons.

依照与实施例1所述类似的方式将所述试件拉制成直径为125微米的光纤。对所得光纤的端面的SEM分析显示了22微米直径的实心二氧化硅芯和包覆层，所述包覆层的区域空穴面积(氮气)％为2.6，平均直径为0.42微米，最小直径的空穴为0.03微米，最大直径为0.80微米，标准偏差为0.14微米，包括约2300个空穴，在整个光纤横截面上总共得到约5700个空穴。总光纤空穴面积％(空穴面积除以光纤总横截面积×100)约为2.5％。按照多模衰减测量的时候，该光纤在1550纳米下的光学性质为11.9dB/Km。The sample was drawn into an optical fiber with a diameter of 125 microns in a similar manner to that described in Example 1. SEM analysis of the end face of the resulting fiber showed a 22 micron diameter solid silica core and a cladding with a % Domain Void Area (Nitrogen) of 2.6, an average diameter of 0.42 microns, and a minimum diameter of The voids were 0.03 microns, with a maximum diameter of 0.80 microns and a standard deviation of 0.14 microns, including approximately 2300 voids, resulting in a total of approximately 5700 voids across the entire fiber cross-section. The total fiber void area % (void area divided by total fiber cross-sectional area x 100) is about 2.5%. The fiber had an optical property of 11.9 dB/Km at 1550 nm when measured as multimode attenuation.

实施例4：Example 4:

将3000克SiO₂(密度为0.40g/cc)烟灰以火焰沉积方式沉积在来自步骤1的1米长×8毫米直径的纯二氧化硅芯条料上。然后该组件如下所述进行烧结。该组件首先在由氦气和3％的氯气组成的气氛中在1000℃下干燥2小时，然后在30体积％氮气和70体积％氦气的气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区，然后以6毫米/分钟的速率再次通过相同的热区以进行最后烧结，以烧结所述烟灰，形成氮气/氦气接种的外覆试件。然后所述将试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时，以从试件中排出氦气。3000 grams of_SiO2 (density 0.40 g/cc) soot were deposited by flame deposition on the 1 meter long x 8 mm diameter pure silica core strip from step 1 . The assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 h in an atmosphere consisting of helium and 3% chlorine, and then driven downward at a rate of 32 mm/min in an atmosphere of 30 vol% nitrogen and 70 vol% helium By setting the heat zone at 1500°C. The assembly is then driven down again through the same hot zone at 25 mm/min and then again at 6 mm/min for final sintering to sinter the soot to form nitrogen/helium Inoculated overcoated test piece. The test piece was then placed in an argon purged holding furnace set at 1000° C. for 24 hours to vent helium from the test piece.

依照与实施例1所述类似的方式将所述试件拉制成直径为125微米的光纤。对所得光纤的端面的SEM分析显示了22微米直径的实心二氧化硅芯和包覆层，所述包覆层的区域空穴面积(氮气)％为2.0，平均直径为0.37微米，最小直径的空穴为0.03微米，最大直径为0.89微米，标准偏差为0.13微米，包括约2100个空穴，在整个光纤横截面上总共得到约8100个空穴。总光纤空穴面积％(空穴面积除以光纤总横截面积×100)约为2.6％。按照多模衰减测量的时候，该光纤在1550纳米下的光学性质为4.4dB/Km。The sample was drawn into an optical fiber with a diameter of 125 microns in a similar manner to that described in Example 1. SEM analysis of the end face of the resulting fiber showed a 22 micron diameter solid silica core and cladding with a % Domain Void Area (Nitrogen) of 2.0, an average diameter of 0.37 microns, and a minimum diameter of The voids were 0.03 microns, with a maximum diameter of 0.89 microns and a standard deviation of 0.13 microns, including approximately 2100 voids, resulting in a total of approximately 8100 voids across the entire fiber cross-section. The total fiber void area % (hole area divided by total fiber cross-sectional area x 100) is about 2.6%. The fiber has an optical property of 4.4 dB/Km at 1550 nm when measured as multimode attenuation.

实施例5：Example 5:

将3000克SiO₂(密度为0.38g/cc)烟灰以火焰沉积方式沉积在来自步骤1的1米长×8毫米直径的纯二氧化硅芯条料上。然后该组件如下所述进行烧结。该组件首先在由3％的氯气和余量的氦气组成的气氛中在1000℃下干燥2小时，然后在15体积％氮气和85体积％氦气的气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区，然后以6毫米/分钟的速率再次通过相同的热区以进行最后烧结，以烧结所述烟灰，形成氮气/氦气接种的外覆试件。然后将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时，以从试件中排出氦气。3000 grams of_SiO2 (density 0.38 g/cc) soot was deposited by flame deposition on the 1 meter long x 8 mm diameter pure silica core strip from step 1 . The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere consisting of 3% chlorine and the balance helium, and then dried at a rate of 32 mm/min in an atmosphere of 15 vol% nitrogen and 85 vol% helium. Drive down through a thermal zone set at 1500 °C. The assembly is then driven down again through the same hot zone at 25 mm/min and then again at 6 mm/min for final sintering to sinter the soot to form nitrogen/helium Inoculated overcoated test piece. The coupons were then placed in an argon purged holding furnace set at 1000°C for 24 hours to vent helium from the coupons.

依照与实施例1所述类似的方式将所述试件拉制成直径为125微米的光纤。对所得光纤的端面的SEM分析显示了22微米直径的实心二氧化硅芯和包覆层，所述包覆层的区域空穴面积(氮气)％为2.0，平均直径为0.37微米，最小直径的空穴为0.03微米。按照多模衰减测量的时候，该光纤在1550纳米下的光学性质为9.1dB/Km。The sample was drawn into an optical fiber with a diameter of 125 microns in a similar manner to that described in Example 1. SEM analysis of the end face of the resulting fiber showed a 22 micron diameter solid silica core and cladding with a % Domain Void Area (Nitrogen) of 2.0, an average diameter of 0.37 microns, and a minimum diameter of The voids are 0.03 microns. The fiber has an optical property of 9.1 dB/Km at 1550 nm when measured in terms of multimode attenuation.

实施例6：Embodiment 6:

将3000克SiO₂(密度为0.5g/cc)沉积在1米长×10毫米直径的可移除氧化铝饵棒上；沉积烟灰之后，移除氧化铝饵棒。然后该组件如下所述进行烧结。该组件首先在由3％的氯气和余量的氦气组成的气氛中在1000℃下干燥2小时，然后在100％氮气气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区，然后以6毫米/分钟的速率再次通过相同的热区以进行最后烧结，以烧结所述烟灰，形成氮气/氦气接种的外覆试件。然后将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时，以排出氦气。将来自步骤1的3毫米的纯二氧化硅芯条料插入氮气接种的SiO₂玻璃试件的中线。3000 grams_{of SiO2} (density 0.5 g/cc) was deposited on a 1 meter long x 10 mm diameter removable alumina bait rod; after deposition of soot, the alumina bait rod was removed. The assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 hours in an atmosphere consisting of 3% chlorine and the balance helium, and then driven downward at a rate of 32 mm/min at a rate of 1500 °C in a 100% nitrogen atmosphere. ℃ hot zone. The assembly is then driven down again through the same hot zone at 25 mm/min and then again at 6 mm/min for final sintering to sinter the soot to form nitrogen/helium Inoculated overcoated test piece. The coupons were then placed in an argon-purged holding furnace set at 1000°C for 24 hours to vent the helium. Insert a 3 mm strip of pure silica core from step 1 into the midline of the nitrogen-seeded_SiO2 glass coupon.

然后依照与实施例1相类似的方式将所得的光纤预成形体拉制成直径为125微米的光纤，在中线上从试件顶部以＜250托(真空)的压力牵拉，以确保在拉制过程中，包覆层与芯条料相匹配。对光纤端面的SEM分析显示出8微米直径的实心二氧化硅芯和包覆层，所述包覆层的区域空穴面积百分数(氮气)为4.0％，平均直径为0.33微米，最小直径的空穴为0.03微米，最大直径为0.82微米，标准偏差为0.14微米，包含约4100个空穴。该光纤的光学性质显示其在大于大约800纳米的波长下的单模形式，在850纳米和1550纳米下的衰减分别为4.8和4.5dB/Km，在1550纳米下的模场直径约为11微米。该光纤表现出高的抗弯曲性；其具有极低的衰减增大，在围绕直径10毫米的芯轴绕曲的时候，在1550纳米下的衰减增大仅为每周2-8dB(相比之下，标准的市售SiO₂-GeO₂ 0.35Δ阶跃折射率的常规单模光纤，对于相同的径向弯曲，在1550纳米下每周约为25dB的Δ衰减)。这说明本发明的含孔穴的包覆光纤在1550纳米(即在直线长度上测得的衰减减去在绕芯轴绕转(绕直径为10毫米的芯轴卷绕)的相同长度的光纤上测得的衰减)可以具有小于40，更优选小于30，更优选小于20，最优选小于10dB/周的弯曲产生的Δ衰减(即衰减增大)。Then draw the resulting optical fiber preform into an optical fiber with a diameter of 125 microns in a manner similar to Example 1, and pull it from the top of the test piece on the center line with a pressure of <250 torr (vacuum) to ensure that During the manufacturing process, the cladding layer matches the core strip material. SEM analysis of the fiber endface showed an 8 micron diameter solid silica core and cladding with a regional void area percentage (nitrogen) of 4.0% and an average diameter of 0.33 microns with the smallest diameter void The cavities were 0.03 microns, with a maximum diameter of 0.82 microns and a standard deviation of 0.14 microns, containing about 4100 cavities. The optical properties of the fiber show that it is single-mode at wavelengths greater than about 800 nm, with attenuations of 4.8 and 4.5 dB/Km at 850 nm and 1550 nm, respectively, and a mode field diameter of about 11 microns at 1550 nm . The fiber exhibits high bending resistance; it has an extremely low attenuation increase of only 2-8 dB per week at 1550 nm when bent around a 10 mm diameter mandrel (compared to Below, a standard commercially available_SiO2 -_GeO2 0.35Δ step-index conventional single-mode fiber has a Δ attenuation of about 25 dB per week at 1550 nm for the same radial bend). This illustrates the attenuation measured at 1550 nm (i.e., measured over a straight-line length) of the hole-containing clad fiber of the present invention minus the same length of fiber orbiting a mandrel (wound around a mandrel with a diameter of 10 mm). The measured attenuation) may have a bending-induced delta attenuation (ie attenuation increase) of less than 40, more preferably less than 30, more preferably less than 20, most preferably less than 10 dB/cycle.

实施例7：Embodiment 7:

将3000克SiO₂(0.5g/cc密度)以火焰沉积方式沉积在1米长×8毫米直径的条料上，其具有小基座(pedestal)，且具有阶跃折射率(与条料中心相距0-1.3毫米半径为0.39％Δ阶跃(step)，与条料中心相距1.3-2.3毫米半径为0.06％Δ基座，与条料中心相距2.3-4毫米半径为纯二氧化硅)，即GeO₂-SiO₂芯-基座，SiO₂包覆条料依照与制备步骤1的条料类似的方法制造。然后该组件如下所述进行烧结。该组件首先在100％的空气气氛(～78体积％N₂+～21体积％O₂+～1体积％Ar+～0.03体积％CO₂)中，在1000℃下保持2小时，然后在100％的空气气氛(～78体积％N₂+～21体积％O₂+～1体积％Ar+～0.03体积％CO₂)中，该组件以6毫米/分钟的速度向下驱动通过设定在1500℃的热区，以烧结所述烟灰，形成空气接种的(～78体积％N₂+～21体积％O₂+～1体积％Ar+～0.03体积％CO₂)外包覆试件。该试件置于用氩气吹扫的设定在1000℃的保持加热炉内24小时。3000 grams of_SiO2 (0.5 g/cc density) were flame deposited on a 1 m long x 8 mm diameter strip with a small pedestal and a step index (with the center of the strip 0-1.3mm radius 0.39% Δstep, 1.3-2.3mm radius 0.06% Δbase from strip center, 2.3-4mm radius pure silica), That is, the GeO₂ -SiO₂ core-substrate, SiO₂ coated strips were fabricated in a similar manner to the strips prepared in Step 1. The assembly was then sintered as described below. The assembly was first maintained at 1000°C for 2 hours in a 100% air atmosphere (~78 vol% N₂ +~21 vol% O₂ +~1 vol% Ar+~0.03 vol% CO₂ ), then at 100% In an air atmosphere (~78 vol% N₂ +~21 vol% O₂ +~1 vol% Ar+~0.03 vol% CO₂ ), the assembly was driven downward at a speed of 6 mm/min through a setting at 1500°C A hot zone to sinter the soot to form an air-seeded (~78 vol%_N2 + ~21 vol%_O2 + ~1 vol% Ar + ~0.03 vol%_CO2 ) overclad specimen. The test piece was placed in a holding furnace set at 1000°C purged with argon for 24 hours.

依照与实施例1类似的方式将所得的光纤预成形体拉制成直径为125微米的光纤。对光纤端面的SEM分析显示，其具有半径约为22微米的无孔穴实心芯条料(包含上面条料中所述的GeO₂-SiO₂芯)，其被外径约为39微米的含孔穴的包覆区以及空穴包覆环包围，空穴的区域孔穴面积百分数(～78体积％N₂+～21体积％O₂+～1体积％Ar+～0.03体积％CO₂)为2.9％，平均直径为0.29微米，最小直径的空穴为0.03微米，最大直径为1.4微米，其又被外径为125微米的不含孔穴的纯二氧化硅外包覆层包围(所有的径向尺寸是从所述光纤的中心测量的)，光纤横截面中总共具有约350个空穴。因为较慢的向下驱动和烧结速率，所述空穴位于某一区域附近，该区域对应于GeO₂-SiO₂芯-SiO₂包覆层芯条料在固结时的位置，从与光纤中线径向距离22微米的位置延伸到光纤横截面上径向距离约为39微米处。总孔穴面积％(空穴的面积除以光纤总横截面积×100)约为0.12％。该光纤的光学性质为：当作为多模衰减测量的时候，在850纳米、1310纳米和1550纳米下分别为2.94，1.58和1.9dB/Km，当叠接成单模光纤的时候，对于基谐模式，在1310纳米和1550纳米下分别为0.42和0.29dB/Km。The obtained optical fiber preform was drawn into an optical fiber with a diameter of 125 micrometers in a similar manner to that of Example 1. SEM analysis of the fiber endface showed a solid core strip (containing the_GeO2 -_SiO2 core described in the strip above) with a radius of approximately 22 microns surrounded by a void-containing strip with an outer diameter of approximately 39 microns. Surrounded by the coating area and the hole coating ring, the hole area percentage of the hole (~78vol%_N2 +~21vol%_O2 +~1vol%Ar+~0.03vol%_CO2 ) is 2.9%, The average diameter is 0.29 microns, the smallest diameter of the cavity is 0.03 microns, and the largest diameter is 1.4 microns, which is surrounded by a pure silica outer coating with an outer diameter of 125 microns (all radial dimensions are Measured from the center of the fiber, there were a total of about 350 voids in the fiber cross-section. Because of the slower down-drive and sintering rates, the voids are localized near a region corresponding to the position of the_GeO2 -_SiO2 core-_SiO2 clad core strip during consolidation, from the A radial distance of 22 microns from the centerline extends to a radial distance of approximately 39 microns in the cross-section of the fiber. The total void area % (the area of the void divided by the total cross-sectional area of the fiber x 100) is about 0.12%. The optical properties of the fiber are: when measured as a multimode attenuation, they are 2.94, 1.58 and 1.9dB/Km at 850 nm, 1310 nm and 1550 nm, respectively. When spliced into a single-mode fiber, the fundamental harmonic mode, 0.42 and 0.29 dB/Km at 1310 nm and 1550 nm, respectively.

实施例8：Embodiment 8:

在1900℃下，在再拉制炉内，将实施例2制得的固结的试件再拉制成8毫米的条料。将750克SiO₂(密度为0.54g/cc)烟灰的外包覆层以火焰沉积方式沉积在1米长×8毫米直径的包覆的芯条料上(即纯二氧化硅芯，通过在实施例2中用70％氮气+30％氦气制成的空气衬里(airline)包覆层)。然后该组件如下所述进行烧结。该组件首先在由氦气和3％的氯气组成的气氛中在1000℃下干燥2小时，然后在100％氦气的气氛中，以6毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时，以将氦气从试件中排出。位于包含空穴的包覆层区域外部的外包覆部分是不含空穴的无孔穴固结玻璃。The consolidated test pieces from Example 2 were redrawn into 8 mm strips at 1900°C in a redraw furnace. An outer coating of 750 grams of_SiO2 (density 0.54 g/cc) soot was flame deposited on a 1 m long x 8 mm diameter coated core strip (i.e. a pure silica core, passed through the Airline cladding made with 70% nitrogen + 30% helium in Example 2). The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere consisting of helium and 3% chlorine, and then driven downward at a rate of 6 mm/min through a set at 1500°C in an atmosphere of 100% helium. hot zone. The coupons were then placed in an argon purged holding furnace set at 1000°C for 24 hours to vent the helium from the coupons. The portion of the overcladding outside the void-containing cladding region is void-free consolidated glass.

依照与实施例1所述类似的方式将所述试件拉制成直径为125微米的光纤。对所得光纤的端面的SEM分析显示了大约4微米半径的实心二氧化硅芯，其被半径约为18微米的含空气衬里的近包覆层区域包围，区域孔穴面积％(氮气)为2.9％，平均直径0.45微米，最小直径空穴为0.03微米，最大直径为1.26微米，标准偏差为0.19微米，包含约300个空穴。所述含空气衬里的包覆区域外面的外包覆部分是不含空穴的无孔穴固结玻璃(所有的径向尺寸从中心测量)。总光纤孔穴面积％(空穴面积除以光纤总横截面积×100)约为3.4％。该光纤在1550纳米的多模衰减为10.5dB/Km。The sample was drawn into an optical fiber with a diameter of 125 microns in a similar manner to that described in Example 1. SEM analysis of the end-face of the resulting fiber showed a solid silica core of approximately 4 microns radius surrounded by an air-lined near-cladding region of approximately 18 microns radius with a region void area % (nitrogen) of 2.9% , with an average diameter of 0.45 microns, a minimum diameter of 0.03 microns, a maximum diameter of 1.26 microns, and a standard deviation of 0.19 microns, containing approximately 300 voids. The portion of the overcladding outside the air-lined cladding region is a void-free, void-free consolidated glass (all radial dimensions measured from the center). The % total fiber hole area (hole area divided by total fiber cross-sectional area x 100) is about 3.4%. The fiber has a multimode attenuation of 10.5dB/Km at 1550nm.

实施例9：Embodiment 9:

将7000克SiO₂(密度为0.5g/cc)以火焰沉积方式沉积在1米长×22毫米直径的、具有阶跃折射率的(0.35％Δ，0.33芯/包覆层直径比)GeO₂-SiO₂芯-SiO₂包覆层条料上(类似于用来制备步骤1的条料的方法)。然后该组件如下所述进行烧结。该组件首先在由氦气和3％的氯气组成的气氛中在1000℃下干燥2小时，然后在2体积％CO+98体积％氦气的气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率，再次向下驱动通过相同的热区和烧结气氛，然后所述组件以6毫米/分钟的速率再次向下驱动通过相同的热区和烧结气氛，以烧结所述烟灰，形成CO/氦气接种的外包覆试件。将该试件置于用氩气吹扫的设定在1000℃的保持加热炉内24小时。7000 grams of SiO₂ (density 0.5 g/cc) were deposited by flame deposition on 1 m long x 22 mm diameter step-index (0.35% Δ, 0.33 core/cladding diameter ratio) GeO₂ -SiO₂ core -SiO₂ cladding on the strip (similar to the method used to prepare the strip from step 1). The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere consisting of helium and 3% chlorine, and then driven downward at a rate of 32 mm/min in an atmosphere of 2 vol% CO + 98 vol% helium By setting the heat zone at 1500°C. The assembly was then driven down again through the same hot zone and sintering atmosphere at a rate of 25 mm/min, and then the assembly was driven down again through the same hot zone and sintering atmosphere at a rate of 6 mm/min to sinter The soot, forms a CO/helium inoculated outer cladding test piece. The coupon was placed in a holding furnace set at 1000°C purged with argon for 24 hours.

所得的光纤预成形体依照与实施例1类似的方式拉制成直径为125微米的光纤。对光纤末端的SEM分析显示，其具有直径24微米的实心芯和内包覆层(8微米直径的GeO₂-SiO₂芯，24微米直径的SiO₂内包覆层)，以及外包覆层，所述外包覆层的区域孔穴面积％(CO)为1.8％，平均直径为0.41微米，最小直径空穴为0.03微米，最大直径为0.84微米，标准偏差为0.21微米，包括约1100个空穴。该光纤的光学性质为，当作为多孔衰减测量的时候，在850、1310和1550纳米分别为1.95，1.44和0.72dB/Km，当叠接成单模光纤，测量该光纤的基谐模式的时候，在1310纳米和1550纳米分别为0.30和0.43dB/Km。The obtained optical fiber preform was drawn into an optical fiber with a diameter of 125 microns in a manner similar to that of Example 1. SEM analysis of the end of the fiber showed a 24 micron diameter solid core and inner cladding (8 micron diameter_GeO2 -_SiO2 core, 24 micron diameter_SiO2 inner cladding), and an outer cladding , the outer cladding has a regional void area % (CO) of 1.8%, an average diameter of 0.41 microns, a minimum diameter of 0.03 microns, a maximum diameter of 0.84 microns, and a standard deviation of 0.21 microns, including about 1100 voids hole. The optical properties of the fiber are, when measured as porous attenuation, 1.95, 1.44 and 0.72dB/Km at 850, 1310 and 1550 nanometers, respectively. When spliced into a single-mode fiber, the fundamental harmonic mode of the fiber is measured , are 0.30 and 0.43dB/Km at 1310 nm and 1550 nm, respectively.

实施例10：Example 10:

将3000克SiO₂(密度为0.4g/cc)沉积在1米长×10毫米直径的可移除氧化铝饵棒上；沉积烟灰之后，移除所述氧化铝饵棒。然后该组件如下所述进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在100％CF₄的气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区和气氛，然后该组件以6毫米/分钟的速率再次向下驱动通过相同的热区和气氛以进行最后的烧结，将所述烟灰烧结成CF₄(以及/或者CF₄-气体与二氧化硅的反应产物，包括CO和CO₂)-接种的外包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时。3000 grams of_Si02 (density 0.4 g/cc) were deposited on a 1 meter long x 10 mm diameter removable alumina bait rod; after deposition of soot, the alumina bait rod was removed. The assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 hours in an atmosphere of helium + 3% chlorine, and then driven downward at a rate of 32 mm/min through a heat sink set at 1500 °C in an atmosphere of 100%_CF4 . district. The assembly was then driven down again through the same hot zone and atmosphere at a rate of 25 mm/min, and then the assembly was driven down again through the same hot zone and atmosphere at a rate of 6 mm/min for final sintering, the The soot was sintered to CF₄ (and/or the reaction products of CF₄ -gas and silica, including CO and CO₂ )-seeded overclad specimens. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours.

然后依照与实施例1类似的方式将所得的光纤预成形体拉制成直径为125微米的光纤，不同之处在于，在中线上保持约850托氮气正压力的背压，以保持中间的孔开放。对光纤端面的SEM分析显示125微米的光纤，其具有直径28微米的空穴作为芯，还具有包覆层，所述包覆层的区域孔穴面积％(CF₄/CO/CO₂)为2.8％，平均直径为0.67微米，最小直径的空穴为0.17微米，最大直径为1.4微米，标准偏差为0.26微米，包括约700个空穴。The resulting optical fiber preform was then drawn into an optical fiber having a diameter of 125 microns in a manner similar to that of Example 1, except that a positive nitrogen backpressure of about 850 Torr was maintained on the centerline to maintain the center hole open. SEM analysis of the fiber end face showed a 125 micron fiber with a 28 micron diameter cavity as the core and a cladding with a %areal void area (CF₄ /CO/CO₂ ) of 2.8 %, the average diameter is 0.67 μm, the smallest diameter of the cavity is 0.17 μm, the largest diameter is 1.4 μm, and the standard deviation is 0.26 μm, including about 700 cavities.

实施例11：Example 11:

在再拉制炉中，在1900℃下，将实施例2中制得的固结的试件再拉制成8毫米的条料。将750克SiO₂(密度为0.56g/cc)烟灰的外包覆层以火焰沉积方式沉积在1米长×8毫米直径的纯二氧化硅芯、空气衬里包覆层(在实施例17中，通过100％的氮气制成)条料上。然后该组件如下所述进行烧结。该组件首先在氦气+3％氯气的气氛中、在1000℃下干燥2小时，然后在100体积％氮气气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区，然后以25毫米/分钟的速率再次向下驱动通过所述热区，然后以6毫米/分钟的速率进行最后的烧结，以烧结所述烟灰，形成氮气/氦气接种的外包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时。The consolidated test pieces prepared in Example 2 were redrawn into 8 mm strips in a redraw furnace at 1900°C. An outer cladding of 750 grams of_SiO2 (density 0.56 g/cc) soot was flame deposited onto a 1 meter long x 8 mm diameter pure silica core, air lined cladding (in Example 17 , made by 100% nitrogen) on strips. The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of helium + 3% chlorine and then driven down at a rate of 32 mm/min through a hot zone set at 1500°C in a 100 vol% nitrogen atmosphere , then driven down again through the hot zone at 25 mm/min, followed by a final sintering at 6 mm/min to sinter the soot to form nitrogen/helium seeded overclad specimens . The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours.

依照与实施例1类似的方式将所述试件拉制成直径为125微米的光纤。对光纤端面的扫描电子显微图像分析显示半径约4微米的实心二氧化硅芯区域被外径约16微米的含孔穴邻近包覆层区域包围，其包含约11.6体积％的空穴(氮气)，平均空穴直径为0.70微米，其被外径为125微米的含孔穴二氧化硅外包覆层包围(所有的径向尺寸都是从光纤中心测量)，其包含4.7体积％的空穴(氮气)，平均空穴直径为0.54微米，最小直径空穴为0.03微米，最大直径为0.87微米，标准偏差为0.23微米。这就证明，相对于光纤半径可以形成不同的孔穴含量，因此可以得到不同孔穴百分数的不同水平的折射率曲线。作为多模衰减测得，该光纤的光学性质为在1550纳米为17.4dB/Km。The sample was drawn into an optical fiber with a diameter of 125 micrometers in a manner similar to that of Example 1. Scanning electron microscopic image analysis of the fiber endface reveals a solid silica core region of approximately 4 microns in radius surrounded by a void-containing region adjacent to the cladding of approximately 16 microns in outer diameter containing approximately 11.6 vol% voids (nitrogen) , with an average hole diameter of 0.70 microns, surrounded by a hole-containing silica outer cladding layer with an outer diameter of 125 microns (all radial dimensions are measured from the center of the fiber), which contains 4.7% by volume of holes ( Nitrogen), the average hole diameter is 0.54 microns, the smallest diameter hole is 0.03 microns, the largest diameter is 0.87 microns, and the standard deviation is 0.23 microns. This demonstrates that different void contents can be formed with respect to fiber radius, and thus different levels of refractive index profiles with different void percentages can be obtained. The optical properties of the fiber, measured as multimode attenuation, were 17.4 dB/Km at 1550 nm.

实施例12：Example 12:

将500克SiO₂(密度为0.46g/cc)烟灰以火焰沉积方式沉积在1米长×15毫米直径的纯二氧化硅芯条料上。然后该组件如下所述进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在70体积％氮气+30体积％CF₄的气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区和气氛，然后该组件以6毫米/分钟的速率再次向下驱动通过相同的热区和气氛以进行最后的烧结，将所述烟灰烧结成F掺杂+氮气接种的外包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时。500 grams_{of SiO2} (density 0.46 g/cc) soot were deposited by flame deposition on a 1 m long x 15 mm diameter pure silica core strip. The assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 h in an atmosphere of helium + 3% chlorine, and then driven down through the device at a rate of 32 mm/min in an atmosphere of 70 vol% nitrogen + 30 vol%_CF4 . Set in the hot zone at 1500°C. The assembly was then driven down again through the same hot zone and atmosphere at a rate of 25 mm/min, and then the assembly was driven down again through the same hot zone and atmosphere at a rate of 6 mm/min for final sintering, the The soot was sintered into an F-doped + nitrogen seeded outer clad specimen. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours.

依照与实施例1类似的方式将所述试件拉制成直径为125微米的光纤。对光纤端面进行的放大200倍和500倍的光学图像分析显示直径约82微米的实心二氧化硅芯和包覆层，所述包覆层包含约9.0体积％的空穴(氮气)，平均空穴直径为0.73微米，最小直径的空穴为0.03微米，最大直径为2.0微米，标准偏差为0.40微米，包括约1200个空穴。当作为多模衰减测量的时候，该光纤的光学性质为在850纳米、1310纳米和1550纳米分别为16.1、14.5和13.2dB/Km。当所述光纤围绕半径为5毫米的芯轴卷绕一圈的情况下，光学弯曲性能数据显示在850和1550纳米的衰减增加分别为1.85和0.67dB。制造了没有孔穴的参比光纤，在包覆的时候使用SiF₄+He烧结气氛，得到没有孔穴的光纤。该参比光纤的光学弯曲性质为：当所述光纤围绕半径为5毫米的芯轴卷绕一圈的情况下，光学弯曲性能数据显示在850和1550纳米的衰减增加分别为8.06和9.33dB。这些结果说明，包覆层中包含孔穴的光纤具有优良的弯曲性能。The sample was drawn into an optical fiber with a diameter of 125 micrometers in a manner similar to that of Example 1. Analysis of optical images at 200X and 500X magnification of the fiber endface revealed a solid silica core of approximately 82 microns in diameter and a cladding layer containing approximately 9.0 volume percent voids (nitrogen), with an average void The diameter of the holes was 0.73 microns, the smallest diameter of the holes was 0.03 microns, the largest diameter was 2.0 microns, the standard deviation was 0.40 microns, and about 1200 holes were included. The optical properties of the fiber, when measured as multimode attenuation, were 16.1, 14.5, and 13.2 dB/Km at 850 nm, 1310 nm, and 1550 nm, respectively. When the fiber is wound once around a mandrel with a radius of 5 mm, the optical bend performance data shows an increase in attenuation of 1.85 and 0.67 dB at 850 and 1550 nm, respectively. A reference optical fiber without holes was manufactured, and a SiF₄ +He sintering atmosphere was used during cladding to obtain an optical fiber without holes. The optical bending properties of the reference fiber are as follows: when the fiber is wound around a mandrel with a radius of 5 mm, the optical bending performance data shows an increase in attenuation of 8.06 and 9.33 dB at 850 and 1550 nm, respectively. These results indicate that optical fibers containing voids in the cladding have excellent bending properties.

实施例13：Example 13:

将500克SiO₂(密度为0.53g/cc)烟灰以火焰沉积方式沉积在1米长×15毫米直径的GeO₂-SiO₂渐变折射率实心玻璃条料上(具有抛物线形折射率分布，峰上Δ折射率为2％(相对于二氧化硅))。然后该组件如下所述进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在100％氮气气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区和气氛，然后该组件以6毫米/分钟的速率在100％的氮气中进行最后的烧结，以烧结所述烟灰，形成氮气接种的外包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时。500 g of SiO₂ (density 0.53 g/cc) soot was deposited by flame deposition on a 1 m long x 15 mm diameter GeO₂ -SiO₂ graded index solid glass strip (with parabolic refractive index profile, peak The upper delta refractive index is 2% (relative to silica)). The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of helium + 3% chlorine, and then driven down through a hot zone set at 1500°C at a rate of 32 mm/min in a 100% nitrogen atmosphere. The assembly is then driven down again through the same hot zone and atmosphere at 25 mm/min, and the assembly is then subjected to a final sintering at 6 mm/min in 100% nitrogen to sinter the soot to form Overcoated specimens inoculated with nitrogen. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours.

然后依照与实施例1类似的方式将所述试件拉制成直径为125微米的试件。对光纤端面进行的放大200倍和500倍的光学图像分析显示，具有直径约为81微米的实心氧化锗掺杂的二氧化硅芯和包覆层，所述包覆层包含约3.5体积％的空穴(氮气)，平均空穴直径为0.46微米，最小直径的空穴为0.04微米，最大直径为0.97微米，标准偏差为0.16微米，包括约1500个空穴。当作为多模衰减测量的时候，所述光纤的光学性质为，在850纳米、1310纳米和1550纳米下分别为3.36、1.09和0.84dB/Km。当所述光纤围绕半径为5毫米的芯轴卷绕一圈的情况下，光学弯曲性能数据显示在850和1550纳米的衰减增加分别小于0.70dB和0.55dB。测量了市售的62.5微米芯(GeO₂-SiO₂渐变折射率(具有抛物线形折射率分布，峰上Δ折射率为2％(相对于二氧化硅)))、直径为125微米的无孔穴参比光纤的抗弯曲性能。当所述光纤围绕半径为5毫米的芯轴卷绕一圈的情况下，光学弯曲性能数据显示在850和1550纳米的衰减增加分别为1.13和1.20dB。这些结果说明包覆层中包含孔穴的光纤具有优良的弯曲性能。The test piece was then drawn into a test piece having a diameter of 125 micrometers in a similar manner to Example 1. Optical image analysis at 200X and 500X magnification of the fiber endface revealed a solid germania-doped silica core approximately 81 microns in diameter and a cladding comprising approximately 3.5% by volume of Cavitation (nitrogen gas), the average hole diameter is 0.46 microns, the smallest diameter hole is 0.04 microns, the largest diameter is 0.97 microns, the standard deviation is 0.16 microns, including about 1500 holes. The optical properties of the fiber, when measured as multimode attenuation, were 3.36, 1.09, and 0.84 dB/Km at 850 nm, 1310 nm, and 1550 nm, respectively. When the fiber is wound once around a mandrel with a radius of 5 mm, the optical bend performance data shows an increase in attenuation of less than 0.70 dB and 0.55 dB at 850 and 1550 nm, respectively. Measurements were made on a commercially available 62.5 micron core (_GeO2 -_SiO2 graded index (with a parabolic refractive index profile with a delta index of 2% at the peak (relative to silica))), 125 micron diameter void-free The bending resistance of the reference fiber. When the fiber is wound once around a mandrel with a radius of 5 mm, the optical bend performance data shows an increase in attenuation of 1.13 and 1.20 dB at 850 and 1550 nm, respectively. These results indicate that the optical fibers containing holes in the cladding have excellent bending properties.

实施例14：Example 14:

将1200克SiO₂(密度为0.47g/cc)烟灰以火焰沉积方式沉积在1米长×15毫米直径的GeO₂-SiO₂渐变折射率实心玻璃条料上(具有抛物线形折射率分布，峰上Δ折射率为2％(相对于二氧化硅))。然后该组件如下所述进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在100％氧气气氛中，以32毫米/分钟的速率向下驱动通过设定在1500℃的热区。然后该组件以25毫米/分钟的速率再次向下驱动通过相同的热区和气氛，然后该组件再以6毫米/分钟的速率在100％的氧气中进行最后的烧结，以烧结所述烟灰，形成氧气接种的外包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时。1200 g of SiO₂ (density 0.47 g/cc) soot was deposited by flame deposition on a 1 m long x 15 mm diameter GeO₂ -SiO₂ graded index solid glass strip (with a parabolic refractive index profile, peak The upper delta refractive index is 2% (relative to silica)). The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of helium + 3% chlorine, and then driven down through a hot zone set at 1500°C at a rate of 32 mm/min in a 100% oxygen atmosphere. The assembly is then driven down again through the same hot zone and atmosphere at 25 mm/min, and the assembly is then subjected to a final sintering at 6 mm/min in 100% oxygen to sinter the soot, Oxygen-inoculated overcoated test pieces are formed. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours.

然后依照与实施例1类似的方式将所述试件拉制成直径为125微米的试件。对光纤端面进行的放大200倍和500倍的光学图像分析显示，具有直径约62.5微米的实心二氧化硅-氧化锗芯和包覆层，所述包覆层包含约9.0体积％的空穴(氧气)，平均空穴直径为0.45微米，最小直径的空穴为0.03微米，最大直径为1.2微米，标准偏差为0.21微米，包括约400个空穴。当作为多模衰减测量的时候，所述光纤的光学性质为，在850纳米、1310纳米和1550纳米下分别为3.00、0.74和0.45dB/Km。当所述光纤围绕半径为5毫米的芯轴卷绕一圈的情况下，光学弯曲性能数据显示在850和1550纳米的衰减增加分别小于0.03dB和0.01dB。测量了市售的62.5微米芯(GeO₂-SiO₂渐变折射率(具有抛物线形折射率分布，峰上Δ折射率为2％(相对于二氧化硅)))、直径125微米的无孔穴参比光纤的抗弯曲性能。当所述光纤围绕半径为5毫米的芯轴卷绕一圈的情况下，光学弯曲性能数据显示在850和1550纳米的衰减增加分别为1.13和1.20dB。这些结果说明包覆层中包含孔穴的光纤具有优良的弯曲性能。带宽测量(过满激励(overfill launch))结果为，在850nm＝200MHz*km，在1300nm＝500MHz*km。该实施例说明了在1550纳米为多模的微结构化的光纤。该光纤包括具有第一折射率的芯区域和具有第二折射率的包覆层区域，所述第二折射率低于芯区域的第一折射率，使得将要传输通过所述光纤的光基本保持在芯内，所述包覆层中包括至少一个包括大量非周期性设置的孔穴的区域。该光纤优选在1550纳米下是多模的，当围绕半径为5毫米的芯轴卷绕一周的时候，在1550纳米下的衰减增加小于1dB/km，更优选小于0.75，最优选小于0.5db/km。The test piece was then drawn into a test piece having a diameter of 125 micrometers in a similar manner to Example 1. Optical image analysis at 200X and 500X magnification of the fiber endface revealed a solid silica-germania core with a diameter of approximately 62.5 microns and a cladding containing approximately 9.0% by volume of voids ( Oxygen), the average hole diameter is 0.45 microns, the smallest diameter hole is 0.03 microns, the largest diameter is 1.2 microns, the standard deviation is 0.21 microns, including about 400 holes. The optical properties of the fiber, when measured as multimode attenuation, were 3.00, 0.74, and 0.45 dB/Km at 850 nm, 1310 nm, and 1550 nm, respectively. When the fiber is wound once around a mandrel with a radius of 5 mm, the optical bend performance data show an increase in attenuation of less than 0.03 dB and 0.01 dB at 850 and 1550 nm, respectively. A commercially available 62.5 micron core (_GeO2 -_SiO2 graded index (with a parabolic refractive index profile with a delta index of 2% at the peak (relative to silica))), 125 micron in diameter, without holes, was measured. Than the bending resistance of optical fiber. When the fiber is wound once around a mandrel with a radius of 5 mm, the optical bend performance data shows an increase in attenuation of 1.13 and 1.20 dB at 850 and 1550 nm, respectively. These results indicate that the optical fibers containing holes in the cladding have excellent bending properties. The bandwidth measurement (overfill launch) results in = 200MHz*km at 850nm and = 500MHz*km at 1300nm. This example illustrates a microstructured optical fiber that is multimode at 1550 nm. The optical fiber includes a core region having a first refractive index and a cladding region having a second refractive index lower than the first refractive index of the core region such that light to be transmitted through the optical fiber remains substantially Within the core, said cladding includes at least one region comprising a plurality of non-periodically arranged cavities. The optical fiber is preferably multimode at 1550 nm and exhibits an attenuation increase of less than 1 dB/km at 1550 nm, more preferably less than 0.75, most preferably less than 0.5 db/km when wound around a mandrel with a radius of 5 mm. km.

实施例15：Example 15:

在具有长8英寸的设定在2000℃的热区的炉内，以3米/秒的速率将实施例8所述的光纤预成形体拉制成直径为125微米的光纤。对光纤端面的SEM分析显示半径约为4微米的实心二氧化硅芯被半径约18微米的含空气衬里的邻近包覆层区域包围，其区域孔穴面积％(氮气填充的)为8.5％，平均空穴直径为0.63微米，最小空穴直径为0.03微米，最大直径为1.9微米，标准偏差为0.32微米，其又被外径为125微米的不含孔穴的纯二氧化硅外部包覆层包围(所有的径向尺寸都是从光纤的中心测量的)。实施例8中拉制的光纤的区域孔穴面积百分数(氮气)仅为2.9％，平均直径为0.45微米；因此证明拉制条件(此时为较长的热区和更快的拉制速度)可用来控制空穴空气填充比例和空穴直径。位于含空气衬里的包覆层区域外面的外包覆部分是不含空穴的无孔穴固结玻璃。The optical fiber preform described in Example 8 was drawn into a fiber having a diameter of 125 microns at a rate of 3 m/s in a furnace having an 8 inch long hot zone set at 2000°C. SEM analysis of the fiber endface showed a solid silica core of approximately 4 microns in radius surrounded by an air-lined adjacent cladding region of approximately 18 microns in radius with a regional void area % (nitrogen filled) of 8.5%, averaging The cavity diameter is 0.63 microns, the minimum cavity diameter is 0.03 microns, the maximum diameter is 1.9 microns, and the standard deviation is 0.32 microns, which in turn is surrounded by an outer coating of pure silica without voids with an outer diameter of 125 microns ( All radial dimensions are measured from the center of the fiber). The fiber drawn in Example 8 had a zone void area percentage (nitrogen) of only 2.9% and an average diameter of 0.45 microns; thus demonstrating that the drawing conditions (in this case longer hot zone and faster draw speed) were usable To control the cavity air filling ratio and cavity diameter. The portion of the outer cladding outside the air-lined cladding region is void-free, void-free consolidated glass.

实施例16：Example 16:

将3000克SiO₂(密度为0.53g/cc)烟灰以火焰沉积方式沉积在1米长×8毫米直径的纯二氧化硅芯条料上。然后该组件如下所述进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在100体积％氩气气氛中，以32毫米/分钟的速度通过设定为1500℃的热区，然后以25毫米/分钟的速度再次向下驱动通过所述热区，然后以6毫米/分钟的速度在氩气中进行最后烧结，以烧结所述烟灰，形成氩气接种的外包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时。该试件以与实施例1类似的方式拉制成直径为125微米的光纤。SEM对光纤端面的分析显示了直径约22微米的实心二氧化硅芯和包覆层，所述包覆层的区域孔穴面积％(氩气)约为8.0％，平均空穴直径为0.35微米，最小直径空穴为0.03微米，最大直径为0.85微米，标准偏差为0.15微米。当作为多模衰减测量的时候，该光纤的光学性质为：在1310纳米和1550纳米下分别为1.65和1.20dB/Km。3000 grams_{of SiO2} (density 0.53 g/cc) soot was deposited by flame deposition on a 1 meter long x 8 mm diameter pure silica core strip. The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of helium + 3% chlorine, then passed through a hot zone set at 1500°C at a speed of 32 mm/min in an atmosphere of 100 vol% argon, and then The soot was driven down again at 25 mm/min through the hot zone, followed by a final sintering at 6 mm/min in argon to sinter the soot to form an argon seeded overclad coupon. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours. This test piece was drawn into an optical fiber having a diameter of 125 µm in a similar manner to Example 1. SEM analysis of the fiber endface revealed a solid silica core of approximately 22 microns in diameter and a cladding with a regional void area % (argon) of approximately 8.0% and an average void diameter of 0.35 microns, The smallest diameter cavities are 0.03 microns, the largest diameter is 0.85 microns, and the standard deviation is 0.15 microns. The optical properties of the fiber, when measured as multimode attenuation, were 1.65 and 1.20 dB/Km at 1310 nm and 1550 nm, respectively.

实施例17：Example 17:

将3000克SiO₂(密度为0.55g/cc)烟灰以火焰沉积方式沉积在1米长×8毫米直径的纯二氧化硅芯条料上。然后该组件如下所述进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在100体积％氮气气氛中，以32毫米/分钟的速度通过设定为1500℃的热区，然后以25毫米/分钟的速度再次向下驱动通过所述热区，然后以6毫米/分钟的速度进行最后烧结，以烧结所述烟灰，形成氮气接种的外包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时。该试件以与实施例1类似的方式拉制成直径为125微米的光纤。SEM对光纤端面的分析显示了直径约为22微米的实心二氧化硅芯和包覆层，所述包覆层的区域孔穴面积％(氮气)为2.0％，平均直径为0.22微米，最小直径空穴为0.03微米，最大直径为0.50微米，标准偏差为0.08微米。当作为多模衰减测量的时候，该光纤的光学性质为：在1310纳米和1550纳米下分别为1.28和0.87dB/Km，当该光纤叠接成单模光纤的时候，测量该光纤的基谐模式，在1550纳米下为0.28dB/Km。3000 grams_{of SiO2} (density 0.55 g/cc) soot were deposited by flame deposition on a 1 meter long x 8 mm diameter pure silica core strip. The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of helium + 3% chlorine, then passed through a hot zone set at 1500°C at a speed of 32 mm/min in a 100 vol% nitrogen atmosphere, and then The speed of 25 mm/min was driven down again through the hot zone, followed by final sintering at 6 mm/min to sinter the soot to form nitrogen seeded overclad coupons. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours. This test piece was drawn into an optical fiber having a diameter of 125 µm in a similar manner to Example 1. SEM analysis of the fiber endface revealed a solid silica core approximately 22 microns in diameter and a cladding with a regional void area % (nitrogen) of 2.0%, an average diameter of 0.22 microns, and a minimum diameter void The holes were 0.03 microns, with a maximum diameter of 0.50 microns and a standard deviation of 0.08 microns. When measured as multimode attenuation, the optical properties of the fiber are: 1.28 and 0.87dB/Km at 1310 nm and 1550 nm, respectively. When the fiber is spliced into a single-mode fiber, the fundamental harmonic of the fiber is measured mode, 0.28dB/Km at 1550nm.

实施例18：Example 18:

将4600克SiO₂(密度为0.42g/cc)烟灰以火焰沉积方式沉积在1米长×10毫米直径的、具有阶跃折射率的(0.35％Δ，0.33芯/包覆层直径比)GeO₂-SiO₂芯-SiO₂包覆层条料上(类似于用来制备步骤1的条料的方法)。然后该组件如下所述进行烧结。该组件首先在由氦气和3％的氯气组成的气氛中在1000℃下干燥2小时，然后在100体积％氧气的气氛中，以6毫米/分钟的速率向下驱动通过设定在1500℃的热区，以烧结所述烟灰，形成氧气接种的外包覆试件。将该试件置于用氩气吹扫的设定在1000℃的保持加热炉内24小时，以将氦气从所述试件中排出。4600 g of SiO₂ (density 0.42 g/cc) soot was flame deposited on 1 m long x 10 mm diameter, step-index (0.35% Δ, 0.33 core/cladding diameter ratio) GeO₂ -SiO₂ core-SiO₂ cladding on strips (similar to the method used to prepare the strips from step 1). The assembly was then sintered as described below. The assembly was first dried at 1000°C for 2 h in an atmosphere consisting of helium and 3% chlorine, and then driven downward at a rate of 6 mm/min through a set at 1500°C in an atmosphere of 100 vol% oxygen. The hot zone to sinter the soot to form an oxygen inoculated outer cladding test piece. The test piece was placed in a holding furnace set at 1000° C. purged with argon for 24 hours to vent the helium from the test piece.

所得的光纤预成形体以18米/秒的速度，在具有设定在2000℃的8英寸长的热区的炉内拉制成直径为125微米的光纤。该试件以与实施例15类似的方式拉制成直径为125微米的光纤。对光纤端面的SEM分析显示，其具有半径约为4微米的GeO₂-SiO₂中心芯区域，其被外半径约12微米的无孔穴邻近包覆层区域包围，后者又被外半径约为18微米的含孔穴的包覆层区域包围，而所述半径约为18微米的含孔穴的包覆层区域又被外直径为125微米的无孔穴的纯二氧化硅包覆层包围(所有的径向尺寸都是从光纤中心测量的)。所述含孔穴的环区域在该区域内的区域空穴面积％为4.2％(100体积％的O₂)，平均直径为0.53微米，最小直径的空穴为0.18微米，最大直径为1.4微米，光纤横截面中空穴总数约为85。由于较慢的向下驱动和烧结速率，孔的位置与某一区域相邻，所述区域对应于GeO₂-SiO₂芯-SiO₂包覆层芯条料在固结过程的位置，在光纤横截面上从与光纤中线径向相距12微米的位置延伸到约18微米的径向距离。总光纤孔穴面积％(空穴面积除以光纤总横截面积×100)约为0.21％。该光纤的光学性质为：在1310和1550纳米下分别为0.34和0.21dB/Km，光纤截止(fiber cutoff)显示该光纤在高于1230纳米时为单模形式，使得光纤在高于1230纳米的波长下为单模形式。测量该光纤的一部分围绕直径为10毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.7dB/圈，从而证明使用本发明揭示的方法，围绕直径为10毫米的芯轴甚至可以达到小于5dB/圈的衰减增大。测量了光纤的相同部分围绕直径为20毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.08dB/圈，因此证明使用本发明的方法，在围绕直径为20毫米的芯轴的时候，衰减增大可以小于1dB/圈，更优选小于0.5dB/圈。The resulting fiber preform was drawn at a speed of 18 m/sec into a 125 micron diameter fiber in a furnace with an 8 inch long hot zone set at 2000°C. This test piece was drawn into an optical fiber having a diameter of 125 micrometers in a similar manner to Example 15. SEM analysis of the fiber endface revealed a_GeO2 -_SiO2 central core region with a radius of approximately 4 microns surrounded by a void-free adjacent cladding region with an outer radius of approximately 12 microns, which in turn was surrounded by an outer radius of approximately A void-containing cladding region of 18 microns is surrounded by a void-containing cladding region of about 18 microns in radius, which is in turn surrounded by a void-free pure silica cladding with an outer diameter of 125 microns (all Radial dimensions are all measured from the center of the fiber). The void-containing annulus region has a region void area % of 4.2% (100% by volume of_O2 ) within the region, an average diameter of 0.53 microns, a minimum diameter of 0.18 microns, and a maximum diameter of 1.4 microns, The total number of holes in the fiber cross-section is about 85. Due to the slower down-drive and sintering rates, the location of the hole is adjacent to a region corresponding to the position of the_GeO2 -_SiO2 core-_SiO2 cladding core strip during the consolidation process, in the fiber The cross-section extends from a position radially spaced 12 microns from the centerline of the fiber to a radial distance of about 18 microns. The % total fiber hole area (hole area divided by total fiber cross-sectional area x 100) is about 0.21%. The optical properties of the fiber are: 0.34 and 0.21dB/Km at 1310 and 1550 nanometers, respectively. It is single-mode at the wavelength. A portion of the optical fiber is measured around a diameter of 10 mm core shaft bending properties, the attenuation of the optical fiber at 1550 nanometers increases by about 0.7dB/circle, thereby demonstrating that using the method disclosed by the present invention, around a diameter of 10 mm core shaft even Attenuation increases of less than 5dB/turn can be achieved. Measured the bending performance of the same part of the optical fiber around a core with a diameter of 20 millimeters, the attenuation of the optical fiber at 1550 nanometers increases by about 0.08 dB/circle, so it is proved that using the method of the present invention, the bending performance around a core with a diameter of 20 millimeters When, the attenuation increase can be less than 1dB/turn, more preferably less than 0.5dB/turn.

实施例19Example 19

通过OVD将290克SiO₂(密度为0.47g/cc)烟灰沉积在完全固结的1米长×10.4毫米直径的、具有阶跃折射率的(0.35％Δ，0.33芯/包覆层直径比)GeO₂-SiO₂芯-SiO₂包覆层芯条料上，从而制得一种预成形体，该预成形体包括固结的芯区域，该芯区域被固结的二氧化硅包覆区域包围，后者又被烟灰二氧化硅区域包围。然后如下所述对该组件的烟灰包覆层进行烧结。该组件首先在氦气和3％氯气的气氛中，在1000℃下干燥2小时，然后以200毫米/分钟的速度向下驱动该组件在100％的氧气烧结气氛中，通过设定在1490℃的热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为100℃/分钟)。然后所述预成形体组件再次向下驱动(即第二次)，以100毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为50℃/分钟)。然后，所述预成形体组件再次向下驱动(即第三次)，以50毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为25℃/分钟)。然后，所述预成形体组件再次向下驱动(即第四次)，以25毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为12.5℃/分钟)。然后，在6毫米/分钟的速度下(约3℃/分钟的加热速率)进行最后的烧结，以将所述烟灰烧结成接种氧气的外部包覆试件。利用所述第一系列较高的向下进料速率使光纤预成形体的外部变光滑，这有助于将气体捕获在所述预成形体之内。然后，将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时。然后将所述预成形体放回车床内，在其中通过OVD再沉积3600克另外的SiO₂(密度为0.42g/cc)烟灰。然后，用于该组件中该包覆层(可称为外部包覆层)的烟灰如下所述进行烧结。该组件首先在97％氦气和3％氯气的气氛中，在1000℃下干燥2小时，然后在100体积％氦气的气氛中，以6毫米/分钟的速度向下驱动其通过设定在1500℃的热区，以烧结所述烟灰，形成含氧化锗的无孔穴芯、二氧化硅无孔穴内部包覆层、二氧化硅氧气接种环(即具有含氧气的空穴的二氧化硅)，以及不含孔穴的外部包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时，以使氩气从试件中排出。然后在具有8英寸长的设置在2000℃的热区的炉内，在20米/秒的速度下将所述光纤预成形件拉制成直径约为125微米的光纤。对光纤端面的SEM分析显示，其具有半径约为4微米的GeO₂-SiO₂芯，该芯被外部半径为12微米的无孔穴邻近包覆层区域包围，后者又被外部半径为18微米的含孔穴的包覆层区域(环厚度约6微米)包围，所述外部半径为18微米的含孔穴的包覆层区域又被外部直径约为125微米的无孔穴纯二氧化硅外部包覆层包围(所有的径向尺寸都是从光纤的中心测量)。所述含孔穴的环区域中区域空穴面积百分数为2.7％(100体积％的氧气)，平均直径为0.36微米，最小直径空穴为0.05微米，最大直径为0.8微米，在光纤横截面中总共有大约105个空穴。光纤总空穴面积百分数(空穴面积除以光纤总横截面积×100)约为0.1％。该光纤的光学性质为：在1310和1550纳米分别为0.33和0.19dB/Km，光纤截止波长约为1250纳米，使得该光纤在高于1250纳米的波长下为单模形式。测量该光纤的一部分围绕直径为10毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.2dB/圈，从而证明围绕直径为10毫米的芯轴甚至可以达到小于1dB/圈、优选小于0.5dB/圈的衰减增大。测量了光纤的相同部分围绕直径为20毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.02dB/圈，因此证明在围绕直径为20毫米的芯轴的时候，衰减增大可以小于1dB/圈，更优选小于0.1dB/圈，更优选小于0.05dB/圈。测量了光纤的相同部分围绕直径为6毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为2dB/圈，因此证明在围绕直径为6毫米的芯轴的时候，衰减增大可以小于10dB/圈，更优选小于5dB/圈，更优选小于3dB/圈。290 grams of_SiO2 (density 0.47 g/cc) soot was deposited by OVD on a fully consolidated 1 m long x 10.4 mm diameter, step-index (0.35% Δ, 0.33 core/cladding diameter ratio ) GeO₂ -SiO₂ core-SiO₂ cladding core strips to produce a preform comprising a consolidated core region clad with consolidated silica region, which in turn is surrounded by a soot silica region. The soot coating of the assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 h in an atmosphere of helium and 3% chlorine, and then the assembly was driven down at a speed of 200 mm/min in a sintering atmosphere of 100% oxygen by setting at 1490 °C The hot zone (so that during the downward drive, the temperature rise rate outside the soot preform is about 100°C/min). The preform assembly is then driven down again (i.e. a second time) through the hot zone at a rate of 100 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 50°C /minute). Then, the preform assembly is driven down again (i.e. the third time) through the hot zone at a rate of 50 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 25 °C/min). The preform assembly is then driven down again (i.e. the fourth time) through the hot zone at a rate of 25 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 12.5 °C/min). A final sintering was then carried out at a speed of 6 mm/min (heating rate of about 3°C/min) to sinter the soot into an oxygen-seeded outer cladding test piece. Smoothing the exterior of the fiber preform with the first series of higher downfeed rates helps trap gas within the preform. The test piece was then placed in an argon purged holding furnace set at 1000°C for 24 hours. The preform was then placed back into the lathe where an additional 3600 grams of_Si02 (density 0.42 g/cc) soot was deposited by OVD. The soot used for the cladding (which may be referred to as the outer cladding) in the assembly is then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of 97% helium and 3% chlorine, and then driven downward at a speed of 6 mm/min in an atmosphere of 100 vol% helium through a set at A hot zone at 1500°C to sinter the soot to form a non-porous core containing germanium oxide, a non-porous inner cladding of silica, an oxygen seeding ring of silica (i.e. silica with voids containing oxygen) , and externally clad specimens without cavities. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours to allow the argon to vent from the coupon. The optical fiber preform was then drawn into an optical fiber having a diameter of approximately 125 microns at a speed of 20 m/s in a furnace having an 8 inch long hot zone set at 2000°C. SEM analysis of the fiber endface revealed a_GeO2 -_SiO2 core with a radius of approximately 4 microns surrounded by a void-free adjacent cladding region with an outer radius of 12 microns, which in turn was surrounded by an outer radius of 18 microns Surrounded by a void-containing cladding region (annular thickness approximately 6 microns) of 18 microns outer radius, which is in turn externally clad with non-voided pure silica having an external diameter of approximately 125 microns Layer surround (all radial dimensions are measured from the center of the fiber). The hole area percentage in the hole-containing ring region is 2.7% (100 volume percent oxygen), the average diameter is 0.36 microns, the smallest diameter holes are 0.05 microns, and the largest diameters are 0.8 microns, totaling in the fiber cross-section There are approximately 105 cavities. The percentage of the fiber's total cavity area (hole area divided by the total cross-sectional area of the fiber x 100) is about 0.1%. The optical properties of the optical fiber are: 0.33 and 0.19 dB/Km at 1310 and 1550 nanometers, respectively, and the cut-off wavelength of the fiber is about 1250 nanometers, so that the optical fiber is single-mode at wavelengths higher than 1250 nanometers. The bending performance of a part of the fiber around a core with a diameter of 10 mm was measured, and the attenuation of the fiber at 1550 nm increased by about 0.2 dB/turn, thus proving that even less than 1 dB/turn can be achieved around a core with a diameter of 10 mm. An attenuation increase of less than 0.5 dB/turn is preferred. The bending performance of the same portion of the fiber was measured around a 20 mm diameter mandrel, and the attenuation increase of the fiber at 1550 nm was about 0.02dB/turn, thus demonstrating the increase in attenuation around a 20 mm diameter mandrel It may be less than 1 dB/turn, more preferably less than 0.1 dB/turn, more preferably less than 0.05 dB/turn. The bending performance of the same part of the fiber around a core with a diameter of 6 mm was measured, and the attenuation increase of the fiber at 1550 nm was about 2dB/turn, thus proving that the increase in attenuation around a core with a diameter of 6 mm can be Less than 10 dB/turn, more preferably less than 5 dB/turn, more preferably less than 3 dB/turn.

实施例20Example 20

通过OVD将450克SiO₂(密度为0.37g/cc)烟灰沉积在完全固结的1米长×22毫米直径的、具有阶跃折射率的(0.35％Δ，0.33芯/包覆层直径比)GeO₂-SiO₂芯-SiO₂包覆层芯条料上，从而制得一种预成形体，该预成形体包括固结的芯区域，该芯区域被固结的二氧化硅包覆区域包围，后者又被烟灰二氧化硅区域包围。然后如下所述对该组件的烟灰包覆层进行烧结。该组件首先在氦气和3％氯气的气氛中，在1000℃下干燥2小时，然后以200毫米/分钟的速度向下驱动该组件在100％的氮气烧结气氛中，通过设定在1490℃的热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为100℃/分钟)。然后，所述预成形体组件再次向下驱动(即第二次)，以100毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为50℃/分钟)。然后，所述预成形体组件再次向下驱动(即第三次)，以50毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为25℃/分钟)。然后，所述预成形体组件体再次向下驱动(即第四次)，以25毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为12.5℃/分钟)，然后在6毫米/分钟的速度下(约3℃/分钟的加热速率)进行最后的烧结，以将所述烟灰烧结成接种氮气的外部包覆试件。利用所述第一系列较高的向下进料速率使光纤预成形体的外部变光滑，这有助于将气体捕获在所述预成形体之内。然后将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时。然后在再拉制炉内，在1900℃的温度下将该试件再拉制成直径为13毫米的条料。将之前步骤制得的1米长×13毫米直径的条料放回车床内，在其中通过OVD再沉积4700克另外的SiO₂(密度为0.37g/cc)烟灰。然后，用于该组件中该包覆层(可称为外部包覆层)的烟灰如下所述进行烧结。该组件首先在97％氦气和3％氯气的气氛中，在1000℃下干燥2小时，然后在100体积％氦气的气氛中，以6毫米/分钟的速度向下驱动其通过设定在1500℃的热区，以烧结所述烟灰，形成含氧化锗的无孔穴芯、二氧化硅无孔穴内部包覆层、二氧化硅氮气接种环(即具有含氮气的空穴的二氧化硅)，以及不含孔穴的外部包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时，以使得氩气从试件中排出。然后在具有8英寸长的设置在2000℃的热区的炉内，在10米/秒的速度下将所述光纤预成形件拉制成直径约为125微米的光纤。对光纤端面的光学纤维图像分析显示，其具有半径约为4微米的GeO₂-SiO₂芯，该芯被外部半径为12微米的无孔穴邻近包覆层区域包围，后者又被外部半径为15微米的含孔穴的包覆层区域(环厚度约为3微米)包围，所述外部半径为15微米的含孔穴的包覆层区域又被外部直径约为125微米的无孔穴纯二氧化硅外部包覆层包围(所有的径向尺寸都是从光纤的中心测量)。所述含孔穴的环区域中，区域空穴面积百分数约为3％(100体积％的氮气)，平均直径为0.2微米。光纤总空穴面积百分数(空穴面积除以光纤总横截面积×100)约为0.1％。该光纤的光学性质为：在1310和1550纳米分别为0.34和0.196dB/Km，光纤截止波长约为1290纳米，使得该光纤在高于1290纳米的波长下为单模形式。测量该光纤的一部分围绕直径为10毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.11dB/圈，从而证明围绕直径为10毫米的芯轴甚至可以达到小于1dB/圈、优选小于0.5dB/圈的衰减增大。测量了光纤的相同部分围绕直径为20毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.016dB/圈，因此证明在围绕直径为20毫米的芯轴的时候，衰减增大可以小于1dB/圈，更优选小于0.1dB/圈，更优选小于0.05dB/圈。450 grams of_SiO2 (density 0.37 g/cc) soot was deposited by OVD on a fully consolidated 1 m long x 22 mm diameter, step-index (0.35% Δ, 0.33 core/cladding diameter ratio ) GeO₂ -SiO₂ core-SiO₂ cladding core strips to produce a preform comprising a consolidated core region clad with consolidated silica region, which in turn is surrounded by a soot silica region. The soot coating of the assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 h in an atmosphere of helium and 3% chlorine, and then the assembly was driven down at a speed of 200 mm/min in a sintering atmosphere of 100% nitrogen by setting at 1490 °C The hot zone (so that during the downward drive, the temperature rise rate outside the soot preform is about 100°C/min). Then, the preform assembly is driven downward again (i.e. a second time) through the hot zone at a rate of 100 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 50 °C/min). Then, the preform assembly is driven down again (i.e. the third time) through the hot zone at a rate of 50 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 25 °C/min). Then, the preform assembly is driven downward again (i.e. the fourth time), passing through the hot zone at a rate of 25 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 12.5°C/min), followed by a final sintering at a speed of 6 mm/min (heating rate of about 3°C/min) to sinter the soot into an externally clad specimen inoculated with nitrogen. Smoothing the exterior of the fiber preform with the first series of higher downfeed rates helps trap gas within the preform. The coupons were then placed in an argon purged holding furnace set at 1000°C for 24 hours. The test pieces were then redrawn in a redrawing furnace at a temperature of 1900° C. into rods with a diameter of 13 mm. The 1 meter long x 13 mm diameter strip from the previous step was returned to the lathe where an additional 4700 grams of_SiO2 (density 0.37 g/cc) soot was deposited by OVD. The soot used for the cladding (which may be referred to as the outer cladding) in the assembly is then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of 97% helium and 3% chlorine, and then driven downward at a speed of 6 mm/min in an atmosphere of 100 vol% helium through a set at 1500°C hot zone to sinter the soot to form a non-porous core containing germanium oxide, a non-porous inner cladding layer of silica, a nitrogen seeded ring of silica (i.e. silica with voids containing nitrogen) , and the outer cladding test piece without holes. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours to allow the argon to escape from the coupon. The optical fiber preform was then drawn into an optical fiber having a diameter of approximately 125 microns at a speed of 10 m/s in a furnace having an 8 inch long hot zone set at 2000°C. Analysis of the fiber optic image of the fiber endface revealed a_GeO2 -_SiO2 core with a radius of approximately 4 microns surrounded by a void-free adjacent cladding region with an outer radius of 12 microns, which in turn was surrounded by an outer radius of 12 microns. A 15 micron void-containing cladding region (ring thickness approximately 3 microns) surrounded by a void-free cladding region of approximately 125 micron external diameter Surrounded by an outer cladding (all radial dimensions are measured from the center of the fiber). In the void-containing ring region, the area percentage of voids in the region is about 3% (100% nitrogen by volume), and the average diameter is 0.2 microns. The percentage of the fiber's total cavity area (hole area divided by the total cross-sectional area of the fiber x 100) is about 0.1%. The optical properties of the optical fiber are: 0.34 and 0.196 dB/Km at 1310 and 1550 nanometers respectively, and the cut-off wavelength of the fiber is about 1290 nanometers, so that the optical fiber is single-mode at wavelengths higher than 1290 nanometers. By measuring the bending performance of a part of the fiber around a core with a diameter of 10 mm, the attenuation of the fiber at 1550 nm increases by about 0.11 dB/turn, thus proving that even less than 1 dB/turn can be achieved around a core with a diameter of 10 mm. An attenuation increase of less than 0.5 dB/turn is preferred. The bending performance of the same portion of the fiber was measured around a 20mm diameter mandrel, and the attenuation increase of the fiber at 1550nm was about 0.016dB/turn, thus demonstrating the increase in attenuation around a 20mm diameter mandrel It may be less than 1 dB/turn, more preferably less than 0.1 dB/turn, more preferably less than 0.05 dB/turn.

实施例21Example 21

通过OVD将130克SiO₂(密度为0.37g/cc)烟灰沉积在完全固结的1米长×10.5毫米直径的、具有阶跃折射率的(0.35％Δ，0.33芯/包覆层直径比)GeO₂-SiO₂芯-SiO₂包覆层芯条料上，从而制得一种预成形体，该预成形体包括固结的芯区域，该芯区域被固结的二氧化硅包覆区域包围，后者又被烟灰二氧化硅区域包围。然后如下所述对该组件的烟灰包覆层进行烧结。该组件首先在氦气和3％氯气的气氛中，在1000℃下干燥2小时，然后以200毫米/分钟的速度向下驱动该组件在100％的氩气烧结气氛中，通过设定在1490℃的热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为100℃/分钟)。然后，所述预成形体组件再次向下驱动(即第二次)，以100毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为50℃/分钟)。然后，所述预成形体组件再次向下驱动(即第三次)，以50毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为25℃/分钟)。然后，所述预成形体组件再次向下驱动(即第四次)，以25毫米/分钟的速率通过热区(使得在向下驱动的过程中，烟灰预成形体外部的升温速率约为12.5℃/分钟)，然后在6毫米/分钟的速度下(约3℃/分钟的加热速率)进行最后的烧结，以将所述烟灰烧结成接种氩气的外部包覆试件。利用所述第一系列较高的向下进料速率使光纤预成形体的外部变光滑，这有助于将气体捕获在所述预成形体之内。然后将所述试件置于设定在1000℃的氩气吹扫的保持加热炉内24小时。然后将所述预成形体放回车床内，在其中通过OVD再沉积5000克另外的SiO₂(密度为0.44g/cc)烟灰。然后，用于该组件中该包覆层(可称为外部包覆层)的烟灰如下所述进行烧结。该组件首先在97％氦气和3％氯气的气氛中，在1000℃下干燥2小时，然后在100体积％氦气的气氛中，以6毫米/分钟的速度向下驱动其通过设定在1500℃的热区，以烧结所述烟灰，形成含氧化锗的无孔穴芯、二氧化硅无孔穴内部包覆层、二氧化硅氩气接种环(即具有含氩气的空穴的二氧化硅)，以及不含孔穴的外部包覆试件。然后将该试件置于设定在1000℃的氩气吹扫的保持加热炉中24小时，以使得氩气从试件中排出。然后在具有8英寸长的设置在2000℃的热区的炉内，在20米/秒的速度下将所述光纤预成形件拉制成直径约为125微米的光纤。对光纤端面的光学纤维图像分析显示，其具有半径约4微米的GeO2-SiO2芯，该芯被外部半径为12微米的无孔穴邻近包覆层区域包围，后者又被外部半径为16微米的含孔穴的包覆层区域(环厚度约为4微米)包围，所述外部半径为16微米的含孔穴的包覆层区域又被外部直径约为125微米的无孔穴纯二氧化硅外部包覆层包围(所有的径向尺寸都是从光纤的中心测量)。所述含孔穴的环区域中包含氩气，孔穴的平均直径约0.3微米。该光纤的光学性质为：在1310和1550纳米分别为0.37和0.226dB/Km，光纤截止波长约为1270纳米，使得该光纤在高于1270纳米的波长下为单模形式。测量该光纤的一部分围绕直径为10毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.27dB/圈，从而证明围绕直径为10毫米的芯轴甚至可以达到小于1dB/圈、优选小于0.5dB/圈的衰减增大。测量了光纤的相同部分围绕直径为20毫米的芯轴的弯曲性能，光纤在1550纳米下的衰减增加约为0.026dB/圈，因此证明在围绕直径为20毫米的芯轴的时候，衰减增大可以小于1dB/圈，更优选小于0.1dB/圈，更优选小于0.05dB/圈。130 g of_SiO2 (density 0.37 g/cc) soot was deposited by OVD on a fully consolidated 1 m long x 10.5 mm diameter, step-index (0.35% Δ, 0.33 core/cladding diameter ratio ) GeO₂ -SiO₂ core-SiO₂ cladding core strips to produce a preform comprising a consolidated core region clad with consolidated silica region, which in turn is surrounded by a soot silica region. The soot coating of the assembly was then sintered as described below. The assembly was first dried at 1000 °C for 2 hours in an atmosphere of helium and 3% chlorine, and then the assembly was driven down at a speed of 200 mm/min in a sintering atmosphere of 100% argon by setting at 1490 °C hot zone (such that the rate of temperature rise outside the soot preform during the drive down is about 100 °C/min). Then, the preform assembly is driven downward again (i.e. a second time) through the hot zone at a rate of 100 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 50 °C/min). Then, the preform assembly is driven down again (i.e. the third time) through the hot zone at a rate of 50 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 25 °C/min). The preform assembly is then driven down again (i.e. the fourth time) through the hot zone at a rate of 25 mm/min (so that during the downward drive, the temperature rise rate outside the soot preform is about 12.5 °C/min), followed by a final sintering at a speed of 6 mm/min (about 3 °C/min heating rate) to sinter the soot into an argon-seeded outer cladding test piece. Smoothing the exterior of the fiber preform with the first series of higher downfeed rates helps trap gas within the preform. The coupons were then placed in an argon purged holding furnace set at 1000°C for 24 hours. The preform was then placed back into the lathe where an additional 5000 grams of_Si02 (density 0.44 g/cc) soot was deposited by OVD. The soot used for the cladding (which may be referred to as the outer cladding) in the assembly is then sintered as described below. The assembly was first dried at 1000°C for 2 hours in an atmosphere of 97% helium and 3% chlorine, and then driven downward at a speed of 6 mm/min in an atmosphere of 100 vol% helium through a set at A hot zone of 1500°C to sinter the soot to form a non-porous core containing germanium oxide, a non-porous inner cladding of silica, an argon seeding ring of silica (i.e. silicon), and externally coated specimens without voids. The coupon was then placed in an argon purged holding furnace set at 1000°C for 24 hours to allow the argon to escape from the coupon. The optical fiber preform was then drawn into an optical fiber having a diameter of approximately 125 microns at a speed of 20 m/s in a furnace having an 8 inch long hot zone set at 2000°C. Fiber optic image analysis of the fiber endface revealed a GeO2-SiO2 core of approximately 4 microns radius surrounded by a void-free adjacent cladding region with an outer radius of 12 microns, which in turn was surrounded by a 16 microns outer radius Surrounded by a void-containing cladding region (annular thickness approximately 4 microns) which is externally clad with a void-free pure silica having an external radius of approximately 16 microns Layer surround (all radial dimensions are measured from the center of the fiber). The annulus region containing voids contained argon gas, and the average diameter of the voids was about 0.3 microns. The optical properties of the optical fiber are: 0.37 and 0.226 dB/Km at 1310 and 1550 nanometers respectively, and the cut-off wavelength of the fiber is about 1270 nanometers, so that the optical fiber is single-mode at wavelengths higher than 1270 nanometers. By measuring the bending properties of a part of the fiber around a core with a diameter of 10 mm, the attenuation of the fiber at 1550 nm increases by about 0.27 dB/turn, thus proving that even less than 1 dB/turn can be achieved around a core with a diameter of 10 mm. An attenuation increase of less than 0.5 dB/turn is preferred. The bending performance of the same portion of the fiber was measured around a 20 mm diameter mandrel, and the attenuation increase of the fiber at 1550 nm was about 0.026dB/turn, thus demonstrating the increase in attenuation around a 20 mm diameter mandrel It may be less than 1 dB/turn, more preferably less than 0.1 dB/turn, more preferably less than 0.05 dB/turn.

比较例：Comparative example:

依照与实施例1类似的方式制备了试件，不同之处在于在仅含氦气的气氛中进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在100％氦气气氛中，以32毫米/分钟的速度向下驱动所述组件通过设定在1500℃的热区。然后该组件以25毫米/分钟的速度通过相同的热区和气氛，然后该组件以6毫米/分钟的速度再次通过相同的热区和气氛以进行最后的烧结。如我们所预期，发现所述包覆玻璃不含种子。该试件在设定在1000℃的氩气吹扫的保持加热炉内放置24小时以排出氦气。然后依照与实施例1类似的方式将所述试件拉制成125微米的光纤，发现其不含空穴(如预期)。通过回切法(cutback method)测得2.4Km长的光纤无法传输光(说明衰减大于100dB/Km)；这是预料之中的，因为在芯和包覆层之间没有折射率差异。A test piece was prepared in a similar manner to Example 1 except that sintering was performed in an atmosphere containing only helium. The assembly was first dried at 1000 °C for 2 hours in an atmosphere of helium + 3% chlorine, and then the assembly was driven down at a speed of 32 mm/min in a 100% helium atmosphere through a setting at 1500 °C hot zone. The assembly was then passed through the same hot zone and atmosphere at a speed of 25 mm/min, and then the assembly was passed through the same hot zone and atmosphere again at a speed of 6 mm/min for final sintering. As expected, the coated glass was found to be free of seeds. The test piece was placed in an argon-purged holding furnace set at 1000°C for 24 hours to vent helium. The sample was then drawn into a 125 micron fiber in a similar manner to Example 1, which was found to contain no voids (as expected). The 2.4Km long fiber was unable to transmit light as measured by the cutback method (indicating an attenuation greater than 100dB/Km); this is expected since there is no refractive index difference between the core and cladding.

比较例：Comparative example:

依照与实施例1类似的方式制备了试件，不同之处在于在仅含氦气的气氛中进行烧结。该组件首先在氦气+3％氯气的气氛中，在1000℃下干燥2小时，然后在100％氦气气氛中，以32毫米/分钟的速度向下驱动所述组件通过设定在1500℃的热区。然后该组件以25毫米/分钟的速度通过相同的热区和气氛，然后该组件以6毫米/分钟的速度再次通过相同的热区和气氛以进行最后的烧结。如我们所预期，发现所述包覆玻璃不含种子。该试件在设定在1000℃的氩气吹扫的保持加热炉内放置24小时以排出氦气。然后依照与实施例1类似的方式将所述试件拉制成125微米的光纤，发现其不含空穴(如预期)。通过回切法测得2.4Km长的光纤无法传输光(说明衰减大于100dB/Km)；这是预料之中的，因为在芯和包覆层之间没有折射率差异。A test piece was prepared in a similar manner to Example 1 except that sintering was performed in an atmosphere containing only helium. The assembly was first dried at 1000 °C for 2 hours in an atmosphere of helium + 3% chlorine, and then the assembly was driven down at a speed of 32 mm/min in a 100% helium atmosphere through a setting at 1500 °C hot zone. The assembly was then passed through the same hot zone and atmosphere at a speed of 25 mm/min, and then the assembly was passed through the same hot zone and atmosphere again at a speed of 6 mm/min for final sintering. As expected, the coated glass was found to be free of seeds. The test piece was placed in an argon-purged holding furnace set at 1000°C for 24 hours to vent helium. The sample was then drawn into a 125 micron fiber in a similar manner to Example 1, which was found to contain no voids (as expected). The 2.4Km long fiber was unable to transmit light (indicating an attenuation greater than 100dB/Km) as measured by the cutback method; this is expected since there is no refractive index difference between the core and cladding.

本领域技术人员可以很明显地看出，可以在不背离本发明精神和范围的前提下进行各种改良和改变。因此本发明包括所有的这些改良和改变，只要其包括在所附权利要求书及其等价内容的范围内。It will be apparent to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the invention. Accordingly, the present invention includes all such modifications and changes provided they come within the scope of the appended claims and their equivalents.

Claims (41)

Translated fromChinese

1.一种微结构化的光纤，其包括：1. A microstructured optical fiber comprising:具有第一折射率的芯区域和具有第二折射率的包覆层区域，所述第二折射率小于芯区域的第一折射率，使得通过所述光纤传输的光基本被保持在所述芯内，所述包覆层中包括至少一个由大量非周期性定位的孔穴组成的区域，大于95％的所述孔穴的最大直径等于或小于1550纳米，所述光纤在600-1550纳米之间的至少一种波长下的衰减小于500dB/km。a core region having a first index of refraction and a cladding region having a second index of refraction that is less than the first index of refraction of the core region such that light transmitted through the optical fiber is substantially retained within the core In the cladding layer, there is at least one region consisting of a large number of non-periodically positioned holes, more than 95% of the holes have a maximum diameter equal to or smaller than 1550 nanometers, and the optical fiber is between 600-1550 nanometers The attenuation at at least one wavelength is less than 500dB/km.2.如权利要求1所述的微结构化的光纤，其特征在于，所述光纤中大于95％的所述孔穴的最大直径等于或小于775纳米。2. The microstructured optical fiber of claim 1, wherein greater than 95% of said cavities in said optical fiber have a maximum diameter equal to or less than 775 nanometers.3.如权利要求1所述的微结构化的光纤，其特征在于，所述光纤在1550纳米的衰减小于200dB/km。3. The microstructured optical fiber of claim 1, wherein said optical fiber has an attenuation of less than 200 dB/km at 1550 nm.4.如权利要求3所述的微结构化的光纤，其特征在于，所述光纤的包覆层中整个含孔穴的区域的区域孔穴面积百分数约大于0.5％且约小于20％。4. The microstructured optical fiber of claim 3, wherein the optical fiber cladding has a regional void area percentage of the entire void-containing region greater than about 0.5% and less than about 20%.5.如权利要求1所述的微结构化的光纤，其特征在于，所述包含非周期性分布的空穴的区域不是与芯直接相邻的。5. The microstructured optical fiber of claim 1, wherein the region containing the non-periodically distributed voids is not directly adjacent to the core.6.如权利要求3所述的微结构化的光纤，其特征在于，与所述芯相距在10微米以内的所述光纤包覆层的至少一部分的区域孔穴面积百分数约大于1.0％。6. The microstructured optical fiber of claim 3, wherein at least a portion of the fiber cladding within 10 microns of the core has a region void area percentage greater than about 1.0%.7.如权利要求1所述的微结构化的光纤，其特征在于，所述芯包含锗。7. The microstructured optical fiber of claim 1, wherein the core comprises germanium.8.如权利要求3所述的微结构化的光纤，其特征在于，所述芯包含锗。8. The microstructured optical fiber of claim 3, wherein the core comprises germanium.9.如权利要求7所述的微结构化的光纤，其特征在于，所述光纤在围绕直径为10毫米的芯轴弯曲的时候，在1550纳米下的衰减增大小于20dB/圈。9. The microstructured optical fiber of claim 7, wherein the attenuation increase at 1550 nm is less than 20 dB/turn when the optical fiber is bent about a mandrel having a diameter of 10 mm.10.如权利要求1所述的微结构化的光纤，其特征在于，所述各个孔穴的最大直径小于375纳米。10. The microstructured optical fiber of claim 1, wherein said individual cavities have a maximum diameter of less than 375 nanometers.11.一种微结构化的光纤，其包括：11. A microstructured optical fiber comprising:具有第一折射率的芯区域和具有第二折射率的包覆层区域，所述第二折射率低于芯区域的第一折射率，使得在所述光纤中传输的光基本保持在芯区域内，所述包覆层中包括含有孔穴的区域，所述含有孔穴的区域由大量非周期性定位的孔穴组成，所述含孔穴的区域中至少95％的孔穴的最大直径等于或小于1550纳米，所述光纤的总光纤孔穴面积百分数大于0.01％。a core region having a first index of refraction and a cladding region having a second index of refraction lower than the first index of refraction of the core region such that light transmitted in the optical fiber remains substantially within the core region In the cladding layer, a void-containing region is comprised of a plurality of non-periodically positioned voids, and at least 95% of the voids in the void-containing region have a maximum diameter equal to or less than 1550 nanometers , the optical fiber has a percentage of total fiber hole area greater than 0.01%.12.如权利要求11所述的微结构化的光纤，其特征在于，所述光纤的总光纤孔穴面积百分数小于10％。12. The microstructured optical fiber of claim 11, wherein the optical fiber has a percent total fiber hole area of less than 10%.13.如权利要求11所述的微结构化的光纤，其特征在于，所述光纤的平均光纤直径小于1550纳米，所述空穴的标准偏差小于1微米。13. The microstructured optical fiber of claim 11, wherein said optical fiber has an average fiber diameter of less than 1550 nanometers and said voids have a standard deviation of less than 1 micron.14.如权利要求11所述的微结构化的光纤，其特征在于，所述光纤在围绕直径为10毫米的芯轴弯曲的时候，其在1550纳米下的衰减增大小于20dB/圈。14. The microstructured optical fiber of claim 11, wherein the optical fiber exhibits an attenuation increase of less than 20 dB/turn at 1550 nm when the optical fiber is bent about a mandrel having a diameter of 10 mm.15.如权利要求12所述的微结构化的光纤，其特征在于，所述含孔穴的区域与所述芯隔开。15. The microstructured optical fiber of claim 12, wherein the cavity-containing region is spaced apart from the core.16.如权利要求11所述的微结构化的光纤，其特征在于，所述含孔穴的区域包含至少25个空穴，所述含孔穴的区域中空穴的平均直径小于2000纳米。16. The microstructured optical fiber of claim 11, wherein the void-containing region comprises at least 25 voids, and the average diameter of the voids in the void-containing region is less than 2000 nanometers.17.如权利要求11所述的微结构化的光纤，其特征在于，所述含孔穴的区域包含至少25个空穴，所述含孔穴的区域内空穴的平均直径小于775纳米。17. The microstructured optical fiber of claim 11, wherein the void-containing region contains at least 25 voids, and the average diameter of the voids in the void-containing region is less than 775 nanometers.18.一种微结构化的光纤，其包括：18. A microstructured optical fiber comprising:具有第一折射率的芯区域和具有第二折射率的包覆层区域，所述第二折射率低于芯区域的第一折射率，使得在所述光纤中传输的光基本保持在芯区域内，所述包覆层中包括一个区域，所述区域包围所述芯区域，由平均直径约小于2000纳米、标准偏差约小于750纳米的孔穴组成，所述包含孔穴的区域与所述光纤的芯区域隔开。a core region having a first index of refraction and a cladding region having a second index of refraction lower than the first index of refraction of the core region such that light transmitted in the optical fiber remains substantially within the core region Within, the cladding layer includes a region surrounding the core region consisting of cavities with an average diameter of less than about 2000 nanometers and a standard deviation of less than about 750 nanometers, the region containing the cavities being aligned with the optical fiber The core area is separated.19.如权利要求18所述的微结构化的光纤，其特征在于，所述包含空穴的区域包含约25-200个空穴。19. The microstructured optical fiber of claim 18, wherein the void-containing region contains about 25-200 voids.20.如权利要求18所述的微结构化的光纤，其特征在于，所述包含空穴的区域内空穴的平均直径小于775纳米。20. The microstructured optical fiber of claim 18, wherein the average diameter of the voids in the void-containing region is less than 775 nanometers.21.如权利要求18所述的微结构化的光纤，其特征在于，所述光纤在围绕直径为10毫米的芯轴弯曲的时候，其在1550纳米下的衰减增大小于20dB/圈。21. The microstructured optical fiber of claim 18, wherein the attenuation at 1550 nm increases by less than 20 dB/turn when said optical fiber is bent about a 10 mm diameter mandrel.22.如权利要求18所述的微结构化的光纤，其特征在于，所述光纤在围绕直径为10毫米的芯轴弯曲的时候，其在1550纳米下的衰减增大小于15dB/圈。22. The microstructured optical fiber of claim 18, wherein the attenuation at 1550 nm increases by less than 15 dB/turn when said optical fiber is bent about a 10 mm diameter mandrel.23.一种制造光纤的方法，该方法包括：23. A method of manufacturing an optical fiber, the method comprising:通过CVD操作形成包含烟灰的光纤预成形体；forming a soot-containing optical fiber preform by a CVD operation;在一定的气体气氛和条件下使得所述含烟灰的预成形体中的烟灰固结，所述条件足以在所述固结步骤中将所述气体气氛的一部分捕获在所述预成形体中，从而形成在所述预成形体中具有孔穴的固结的预成形体，consolidating the soot in said soot-containing preform under a gas atmosphere and conditions sufficient to trap a portion of said gas atmosphere within said preform during said consolidating step, thereby forming a consolidated preform having cavities in said preform,在制造过程中使用所述预成形体制造光纤，所述光纤包括具有第一折射率的芯区域和具有第二折射率的包覆层区域，所述第二折射率小于芯区域的第一折射率，所述包覆层中包括一个区域，该区域中包含围绕所述芯的非周期性定位的孔穴，在从横截面观察所述光纤的时候，总光纤孔穴面积百分数大于0.05％。The preform is used in a manufacturing process to make an optical fiber comprising a core region having a first index of refraction and a cladding region having a second index of refraction, the second index of refraction being less than the first index of refraction of the core region The cladding includes a region comprising non-periodically positioned voids around the core, the total fiber void area percentage being greater than 0.05% when the fiber is viewed in cross-section.24.如权利要求23所述的方法，其特征在于，所述固结步骤包括：在炉内，在高于1500℃的温度下使得所述包含烟灰的预成形件固结，以大于10℃的至少一个第一温度变化速率加热所述预成形件，所述气体气氛包括选自以下的至少一种气体：氮气、氩气、CO₂、氧气、氯气、CF₄、CO、SO₂和它们的混合物，在制造过程中使用所述预成形体的步骤包括用所述预成形体拉制光纤，使得在固结步骤中形成的所述孔穴保留在所述光纤中。24. The method of claim 23, wherein the step of consolidating comprises consolidating the soot-containing preform in a furnace at a temperature greater than 1500° C. to greater than 10° C. The preform is heated by at least one first rate of temperature change, the gas atmosphere includes at least one gas selected from the group consisting of nitrogen, argon, CO₂ , oxygen, chlorine, CF₄ , CO, SO₂ and the like The step of using the preform in the manufacturing process includes drawing an optical fiber with the preform such that the cavity formed during the consolidation step remains in the optical fiber.25.如权利要求23所述的方法，其特征在于，在所述固结步骤中，所述包含烟灰的预成形体包括至少一个无孔穴的芯区域，在其上已经通过所述CVD操作沉积了另外的烟灰，所述固结步骤得到在所述固结的预成形体的所述包覆层区域中具有孔穴的所述预成形体。25. The method of claim 23, wherein, in the step of consolidating, the soot-containing preform comprises at least one void-free core region on which has been deposited by the CVD operation Without additional soot, the consolidation step results in the preform having voids in the cladding region of the consolidated preform.26.如权利要求23所述的方法，其特征在于，各个所述孔穴的最大横截面直径小于1550纳米。26. The method of claim 23, wherein each of said cavities has a maximum cross-sectional diameter of less than 1550 nanometers.27.如权利要求24所述的方法，其特征在于，所述烟灰预成形体包括管形预成形体，所述固结的预成形体包括管形预成形体。27. The method of claim 24, wherein the soot preform comprises a tubular preform and the consolidated preform comprises a tubular preform.28.如权利要求23所述的方法，其特征在于，所述形成包含烟灰的光纤预成形体的步骤包括：通过CVD将烟灰沉积在玻璃芯棒的外面，所述固结步骤在所述形成包含烟灰的光纤预成形体的步骤之后进行。28. The method of claim 23, wherein said step of forming an optical fiber preform comprising soot comprises depositing soot on the outside of a glass core rod by CVD, said step of consolidating said forming The step of optical fiber preform containing soot follows.29.如权利要求23所述的方法，其特征在于，所述将所述预成形体用于制造过程的步骤还包括：将所述固结的预成形体拉制成光纤，在所述固结步骤中形成的所述孔穴在所述拉制步骤中保留下来并变形，在所述拉制步骤之后，所述孔穴保留在所述光纤中。29. The method of claim 23, wherein said step of using said preform in a manufacturing process further comprises: drawing said consolidated preform into an optical fiber, said The cavities formed in the junction step are retained and deformed in the drawing step, and the cavities remain in the optical fiber after the drawing step.30.如权利要求23所述的方法，其特征在于，所述气体气氛包括选自以下的至少一种气体：氩气、氮气、一氧化碳、二氧化碳、氧气、CF₄、C₂F₆、Kr以及它们的混合物。30. The method of claim 23, wherein the_gas atmosphere comprises at least one gas selected from the group consisting of argon, nitrogen, carbon monoxide, carbon dioxide, oxygen,_CF4 ,_C2F6 , Kr and their mixture.31.一种制造光纤的方法，该方法包括：31. A method of manufacturing an optical fiber, the method comprising:通过CVD操作形成包含烟灰的光纤预成形体；forming a soot-containing optical fiber preform by a CVD operation;在一种气体气氛中、在一定的条件下固结所述烟灰预成形体，所述气体包含选自以下的至少一种气体：氮气、氩气、CO₂、氧气、氯气、CF₄、CO、SO₂和它们的混合物，所述条件能够在所述固结步骤中有效地将所述气体气氛的一部分捕获在所述预成形体中，从而在所述固结的预成形体中形成孔穴，Consolidating the soot preform under certain conditions in an atmosphere of a gas comprising at least one gas selected from the group consisting of nitrogen, argon, CO₂ , oxygen, chlorine, CF₄ , CO , SO₂ , and mixtures thereof, said conditions being effective to trap a portion of said gaseous atmosphere within said preform during said consolidation step, thereby forming voids in said consolidated preform ,在制造过程中使用所述固结的预成形体形成光纤，所述光纤包括具有第一折射率的芯区域和具有第二折射率的包覆层区域，所述第二折射率低于所述芯的第一折射率，使得通过所述光纤传输的光基本上都保持在芯之内，所述孔穴至少基本上位于所述光纤的包覆层中。The consolidated preform is used in a manufacturing process to form an optical fiber comprising a core region having a first refractive index and a cladding region having a second refractive index lower than the The core has a first index of refraction such that substantially all light transmitted through the fiber remains within the core and the cavity is located at least substantially in the cladding of the fiber.32.如权利要求31所述的方法，其特征在于，所述固结步骤包括：首先对所述预成形体施加约高于1500℃的温度，并以一定的进料速率向固结炉内进料，所述温度和进料速率足以使得所述预成形体的至少一部分以约大于12℃/分钟的速率升温。32. The method according to claim 31, wherein the step of consolidating comprises: first applying a temperature higher than about 1500° C. to the preform, and feeding the preform into the consolidating furnace at a certain feed rate. feeding, the temperature and the feeding rate are sufficient to cause at least a portion of the preform to heat at a rate of greater than about 12°C/minute.33.如权利要求31所述的方法，其特征在于，所述固结步骤包括：首先对所述预成形体施加一定的温度，并以一定的进料速率向固结炉进料，所述温度和进料速率足以使得所述预成形体以约大于14℃/分钟的速率升温。33. The method according to claim 31, wherein the step of consolidating comprises: firstly applying a certain temperature to the preform, and feeding material to a consolidation furnace at a certain feed rate, the The temperature and feed rate are sufficient to heat the preform at a rate of greater than about 14°C/minute.34.如权利要求33所述的方法，其特征在于，所述固结步骤包括将所述预成形件置于保持在等于或高于1390℃的温度的炉内。34. The method of claim 33, wherein the step of consolidating includes placing the preform in a furnace maintained at a temperature equal to or greater than 1390°C.35.如权利要求32所述的方法，其特征在于，所述固结步骤还包括：在所述第一次经受处理的步骤之后，对所述预成形体施加一定温度并以一定进料速度向固结炉内进料，所述温度和进料速度足以使得所述预成形体的升温速率至少比第一次经受处理步骤中的升温速率低2℃/分钟。35. The method of claim 32, wherein said step of consolidating further comprises: after said first subjecting step, applying a temperature to said preform at a feed rate Feed into the consolidation furnace at a temperature and at a rate sufficient to cause the preform to heat up at a rate at least 2° C./minute lower than the rate of temperature ramp during the first exposure to the treatment step.36.如权利要求32所述的方法，其特征在于，所述固结步骤还包括在所述第一次经受处理步骤之后，对所述预成形体施加一定温度并以一定进料速度向固结炉内进料，所述温度和进料速度足以使得所述预成形体的升温速率至少比第一次经受处理步骤中的升温速率低2℃/分钟。36. The method of claim 32, wherein said consolidating step further comprises applying a temperature and a feed rate to said preform after said first subjecting to said treating step. With the feed into the furnace, the temperature and feed rate are sufficient such that the temperature ramp rate of the preform is at least 2° C./minute lower than that of the first time it was subjected to the treatment step.37.如权利要求35所述的方法，其特征在于，所述气氛包括85体积％以上选自以下的至少一种气体：氮气、氩气以及它们的组合，所述气氛中剩余的气体至少基本由氦气组成。37. The method of claim 35, wherein the atmosphere comprises more than 85% by volume of at least one gas selected from the group consisting of nitrogen, argon, and combinations thereof, and the remaining gas in the atmosphere is at least substantially Composed of helium gas.38.如权利要求31所述的方法，其特征在于，所述气氛包含大于65体积％的氮气和/或氩气。38. The method of claim 31, wherein the atmosphere comprises greater than 65% by volume nitrogen and/or argon.39.如权利要求31所述的方法，其特征在于，所述方法还包括以下(1)或(2)：(1)通过将所述烟灰沉积在用锗掺杂的芯条料上，形成所述包含烟灰的预成形体，或者(2)将锗掺杂的芯条料插入通过所述固结步骤形成的包含孔穴的包覆层区域。39. The method of claim 31, further comprising the following (1) or (2): (1) forming The soot-containing preform, or (2) germanium-doped core strip is inserted into the void-containing cladding region formed by the consolidation step.40.如权利要求31所述的方法，其特征在于，所述包含非周期性分布的空穴的区域不与所述芯直接相邻。40. The method of claim 31, wherein the region containing a non-periodic distribution of voids is not directly adjacent to the core.41.一种在1550纳米下为多模形式的微结构化的光纤，所述光纤包括：41. A microstructured optical fiber that is multimode at 1550 nanometers, said optical fiber comprising:具有第一折射率的芯区域和具有第二折射率的包覆层区域，所述第二折射率小于芯区域的第一折射率，使得通过所述光纤传输的光基本被保持在所述芯内，所述包覆层中包括至少一个由大量非周期性定位的孔穴组成的区域，所述光纤在1550纳米下是多模的，当所述光纤围绕半径为5毫米的芯轴卷绕一圈的时候，所述光纤在1550纳米下的衰减增大小于1dB/圈。a core region having a first index of refraction and a cladding region having a second index of refraction that is less than the first index of refraction of the core region such that light transmitted through the optical fiber is substantially retained within the core Inside, the cladding includes at least one region consisting of a large number of non-periodically positioned cavities, and the fiber is multimode at 1550 nm when the fiber is wound around a core with a radius of 5 mm for a The attenuation of the optical fiber at 1550 nanometers increases less than 1dB/turn.

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