US20100135629A1 - Fiber optic cables and assemblies and the performance thereof - Google Patents

Abstract

A fiber optic jumper assembly comprising at least one bend performance optical fiber comprising a core region and a cladding region surrounding the core region, the cladding region comprising an annular hole-containing region comprised of non-periodically disposed holes, a protective covering positioned over the at least one bend performance optical fiber, and at least one connector mounted upon each end of the at least one bend performance optical fiber. A preconnectorized fiber optic jumper assembly comprising a microstrucutred fiber having a delta attenuation of 0.00 dB at 5 wraps about a 6 mm diameter at a reference wavelength of 1625 nm.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a Divisional of U.S. Ser. No. 11/638,610 filed Dec. 13, 2006, the entire content of which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
• The present invention relates generally to fiber optic cables and jumper assemblies and the performance thereof. By way of example, the invention is related to assemblies such as optical fiber jumpers having at least one bend performance optical fiber, thereby enabling previously unattainable optical performance characteristics.
BACKGROUND OF THE INVENTION
• Along with the increase in the deployment of “Fiber-to-the-Premises” (FTTP) optical networks, a need has arisen for increasing the performance, manageability, handleability and flexibility of fiber optic cables, cable assemblies and network components in general. With respect to outdoor installation environments, cables, cable assemblies and other network components are being developed that are more easily interconnected and installed within their environment, such as within aerial installation environments or through small diameter conduit. With respect to indoor environments and multi-dwelling units, cables, cable assemblies, connection terminals and other network components are being developed to improve installation aesthetics and handle the interconnection of an increasing number of subscribers. Within both environments, it would be desirable to develop components that perform better, are more flexible to installation stresses and are more robust and long lasting, thus saving time and costs.
• Conventional cables, cable assemblies, fiber optic hardware and other network components typically define structure that accommodates, and is in part, limited by the physical characteristics of the optical fibers contained therein. In other words, it is oftentimes the case that the physical and performance limitations of the optical fibers partly define assembly structure and processes associated with manufacturing said assemblies. Thus, optical fibers are one limiting factor in the evolution of fiber optic networks.
• Accordingly, what is desired are fiber optic cables and jumper assemblies that include bend performance optical fiber having improved bending performance characteristics over conventional cables and assemblies. It would be desirable to provide cables and jumper assemblies capable of being significantly bent or wrapped, either stand-alone or around network structure, without suffering appreciable loss. Such cables and assemblies including bend performance fiber would be more accepting of handling without damage.
BRIEF SUMMARY OF THE INVENTION
• To achieve the foregoing and other objects, and in accordance with the purposes of the invention as embodied and broadly described herein, the present invention provides various embodiments of fiber optic cables, jumpers and other assemblies including bend performance optical fiber in at least a portion thereof. The present invention further provides bend performance optical fiber suitable for use in fiber optic cables, fiber optic hardware and other assemblies, wherein the bend performance optical fiber comprises certain physical and performance characteristics that lends itself to reduced component size, tighter bend radius tolerances without degraded performance, and relaxes fiber routing and handling requirements.
• In one embodiment, the bend performance optical fiber of the present invention is a microstructured optical fiber comprising a core region and a cladding region surrounding the core region, the cladding region comprising an annular hole-containing region comprised of non-periodically disposed holes or voids, such that the optical fiber is capable of single mode transmission at one or more wavelengths in one or more operating wavelength ranges. The non-periodically disposed holes are randomly or non-periodically distributed across a portion of the fiber. The holes may be stretched (elongated) along the length (i.e. in a direction generally parallel to the longitudinal axis) of the optical fiber, but may not extend the entire length of the entire fiber for typical lengths of transmission fiber.
• In other embodiments, the bend performance fiber of the present invention may comprise at least a portion of fiber optic cables, fiber optic cable assemblies, network connection terminals, fiber optic hardware or any other fiber optic network component including at least one optical fiber maintained therein, routed therein or routed therethrough.
• Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings.
• It is to be understood that both the foregoing general description and the following detailed description present exemplary embodiments of the invention, and 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 included to provide a further understanding of the invention, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the detailed description, serve to explain the principles and operations thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
• These and other features, aspects and advantages of the present invention are better understood when the following detailed description of the invention is read with reference to the accompanying drawings, in which:
• FIG. 1 is a schematic diagram illustrating a cross-section of a bend performance optical fiber operable in accordance with an exemplary embodiment of the present invention;
• FIG. 2 is a cross-sectional image of a microstructured bend performance optical fiber illustrating an annular hole-containing region comprised of non-periodically disposed holes;
• FIG. 2ais a cross-sectional image of a fiber optic cable using the microstructured bend performance optical fiber ofFIG. 1 according to the present invention;
• FIG. 2bis a cross-sectional image of another fiber optic cable using the microstructured bend performance optical fiber ofFIG. 1 according to the present invention;
• FIG. 2cis a plan view of the fiber optic cable ofFIG. 2abeing bent in an aggressive manner to demonstrate a minimum bend radius;
• FIG. 3 illustrates one embodiment of an optical fiber jumper assembly using microstructured bend performance optical fiber ofFIG. 1 completing about one turn about a small diameter structure;
• FIG. 4 illustrates the optical fiber jumper assembly ofFIG. 3 completing multiple turns about a structure;
• FIG. 5 illustrates the optical fiber jumper assembly ofFIG. 3 shown tied in a knot;
• FIG. 6 illustrates a portion of an optical fiber jumper assembly including bend performance fiber bent about 90 degrees around generic network structure; and
• FIG. 7 illustrates a portion of an optical fiber jumper assembly including bend performance fiber bent about 180 degrees around generic network structure.
DETAILED DESCRIPTION OF THE INVENTION
• The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which exemplary embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These exemplary embodiments are provided so that this disclosure will be both thorough and complete, and will fully convey the scope of the invention and enable one of ordinary skill in the art to make, use and practice the invention. Like reference numbers refer to like elements throughout the various drawings.
• FIG. 1 depicts a representation of a bend performance optical fiber1 suitable for use in fiber optic cables, cables assemblies, fiber optic hardware and other network components of the present invention. The present invention is advantageous because it permits assemblies having aggressive bending/installation solutions while optical attenuation remains extremely low. As shown, bend performance optical fiber1 is a microstructured optical fiber having a core region and a cladding region surrounding the core region, the cladding region comprising an annular hole-containing region comprised of non-periodically disposed holes such that the optical fiber is capable of single mode transmission at one or more wavelengths in one or more operating wavelength ranges. The core region and cladding region provide improved bend resistance, and single mode operation at wavelengths preferably greater than or equal to 1500 nm, in some embodiments also greater than about 1310 nm, in other embodiments also greater than 1260 nm. The optical fibers provide a mode field at a wavelength of 1310 nm preferably greater than 8.0 microns, more preferably between about 8.0 and 10.0 microns. In preferred embodiments, optical fiber disclosed herein is thus single-mode transmission optical fiber.
• In some embodiments, the microstructured optical fibers disclosed herein comprises a core region disposed about a longitudinal centerline, and a cladding region surrounding the core region, the cladding region comprising an annular hole-containing region comprised of non-periodically disposed holes, wherein the annular hole-containing region has a maximum radial width of less than 12 microns, the annular hole-containing region has a regional void area percent of less than about 30 percent, and the non-periodically disposed holes have a mean diameter of less than 1550 nm.
• By “non-periodically disposed” or “non-periodic distribution”, we mean that when one takes a cross-section (such as a cross-section perpendicular to the longitudinal axis) of the optical fiber, the non-periodically disposed holes are randomly or non-periodically distributed across a portion of the fiber. Similar cross sections taken at different points along the length of the fiber will reveal different cross-sectional hole patterns, i.e., various cross-sections will have different hole patterns, wherein the distributions of holes and sizes of holes do not match. That is, the holes are non-periodic, i.e., they are not periodically disposed within the fiber structure. These holes are stretched (elongated) along the length (i.e. in a direction generally parallel to the longitudinal axis) of the optical fiber, but do not extend the entire length of the entire fiber for typical lengths of transmission fiber.
• For a variety of applications, it is desirable for the holes to be formed such that greater than about 95% of and preferably all of the holes exhibit a mean hole size in the cladding for the optical fiber which is less than 1550 nm, more preferably less than 775 nm, most preferably less than 390 nm. Likewise, it is preferable that the maximum diameter of the holes in the fiber be less than 7000 nm, more preferably less than 2000 nm, and even more preferably less than 1550 nm, and most preferably less than 775 nm. In some embodiments, the fibers disclosed herein have fewer than 5000 holes, in some embodiments also fewer than 1000 holes, and in other embodiments the total number of holes is fewer than 500 holes in a given optical fiber perpendicular cross-section. Of course, the most preferred fibers will exhibit combinations of these characteristics. Thus, for example, one particularly preferred embodiment of optical fiber would exhibit fewer than 200 holes in the optical fiber, the holes having a maximum diameter less than 1550 nm and a mean diameter less than 775 nm, although useful and bend resistant optical fibers can be achieved using larger and greater numbers of holes. The hole number, mean diameter, max diameter, and total void area percent of holes can all be calculated with the help of a scanning electron microscope at a magnification of about 800× and image analysis software, such as ImagePro, which is available from Media Cybernetics, Inc. of Silver Spring, Md., USA.
• The optical fibers disclosed herein may or may not include germania or fluorine to also adjust the refractive index of the core and or cladding of the optical fiber, but these dopants can also be avoided in the intermediate annular region and instead, the holes (in combination with any gas or gases that may be disposed within the holes) can be used to adjust the manner in which light is guided down the core of the fiber. The hole-containing region may consist of undoped (pure) silica, thereby completely avoiding the use of any dopants in the hole-containing region, to achieve a decreased refractive index, or the hole-containing region may comprise doped silica, e.g. fluorine-doped silica having a plurality of holes.
• In one set of embodiments, the core region includes doped silica to provide a positive refractive index relative to pure silica, e.g. germania doped silica. The core region is preferably hole-free. As illustrated inFIG. 1, in some embodiments, thecore region170 comprises a single core segment having a positive maximum refractive index relative to pure silica Δ₁in %, and the single core segment extends from the centerline to a radius R₁. In one set of embodiments, 0.30%<Δ₁<0.40%, and 3.0 μm μm<R₁<5.0 μm. In some embodiments, the single core segment has a refractive index profile with an alpha shape, where alpha is 6 or more, and in some embodiments alpha is 8 or more. In some embodiments, the inner annular hole-free region182 extends from the core region to a radius R₂, wherein the inner annular hole-free region has a radial width W12, equal to R2−R1, and W12 is greater than 1 μM. Radius R2 is preferably greater than 5 μm, more preferably greater than 6 μm. The intermediate annular hole-containingregion184 extends radially outward from R2 to radius R3 and has a radial width W23, equal to R3−R2. The outerannular region186 extends radially outward from R3 to radius R4. Radius R4 is the outermost radius of the silica portion of the optical fiber. One or more coatings may be applied to the external surface of the silica portion of the optical fiber, starting at R4, the outermost diameter or outermost periphery of the glass part of the fiber. Thecore region170 and thecladding region180 are preferably comprised of silica. Thecore region170 is preferably silica doped with one or more dopants. Preferably, thecore region170 is hole-free. The hole-containingregion184 has an inner radius R2 which is not more than 20 μm. In some embodiments, R2 is not less than 10 μM and not greater than 20 μm. In other embodiments, R2 is not less than 10 μm and not greater than 18 μm. In other embodiments, R2 is not less than 10 μm and not greater than 14 μm. Again, while not being limited to any particular width, the hole-containingregion184 has a radial width W23 which is not less than 0.5 μm. In some embodiments, W23 is not less than 0.5 μm and not greater than 20 μm. In other embodiments, W23 is not less than 2 μm and not greater than 12 μm. In other embodiments, W23 is not less than 2 μm and not greater than 10 μm.
• Such fiber can be made to exhibit a fiber cutoff of less than 1400 nm, more preferably less than 1310 nm, a 20 mm macrobend induced loss at 1550 nm of less than 1 dB/turn, preferably less than 0.5 dB/turn, even more preferably less than 0.1 dB/turn, still more preferably less than 0.05 dB/turn, yet more preferably less than 0.03 dB/turn, and even still more preferably less than 0.02 dB/turn, a 12 mm macrobend induced loss at 1550 nm of less than 5 dB/turn, preferably less than 1 dB/turn, more preferably less than 0.5 dB/turn, even more preferably less than 0.2 dB/turn, still more preferably less than 0.01 dB/turn, still even more preferably less than 0.05 dB/turn, and a 8 mm macrobend induced loss at 1550 nm of less than 5 dB/turn, preferably less than 1 dB/turn, more preferably less than 0.5 dB/turn, and even more preferably less than 0.2 dB-turn, and still even more preferably less than 0.1 dB/turn.
• An example of a suitable fiber is illustrated inFIG. 2. The fiber inFIG. 2 comprises a core region that is surrounded by a cladding region that comprises randomly disposed voids which are contained within an annular region spaced from the core and positioned to be effective to guide light along the core region. Other optical fibers and microstructured fibers may be used in the present invention. Additional description of microstructured fibers used in the present invention are disclosed in pending U.S. patent application Ser. No. 11/583,098 filed Oct. 18, 2006; and, Provisional U.S. patent application Ser. Nos. 60/817,863 filed Jun. 30, 2006; 60/817,721 filed Jun. 30, 2006; 60/841,458 filed Aug. 31, 2006; and 60/841,490 filed Aug. 31, 2006; all of which are assigned to Corning Incorporated; and incorporated herein by reference.
• Optical fiber cables of the present invention allow aggressive bending such as for installation, slack storage, and the like while inhibiting a bend radii that allows damage and/or breaks the optical fiber.FIG. 2ashows a cross-sectional view of explanatoryfiber optic cable100 having optical fiber1 within aprotective covering8. Generally speaking, optical fiber1 is maintained within at least one protective covering such as a buffer layer and/or a jacket and is referred to herein as a “fiber optic cable”. As shown,protective covering8 includes abuffer layer8adisposed about optical fiber1 and ajacket8b. Additionally,fiber optic cable100 also includes a plurality ofoptional strength members14 disposed betweenbuffer layer8aandjacket8b.Strength members14 can also include a water-swellable component for blocking the migration of water along the fiber optic cable.FIG. 2bdepicts an alternatefiber optic cable100′ that is similar tofiber optic cable100, but it does not include strength members and consequently has a smaller outer diameter such as about 4 millimeters if the jacket wall thickness remains the same. Additionally, since the strength members are omitted it is possible to remove the buffer layer and jacket from the fiber optic cable in a single step. Other fiber optic cables and/or other assembly designs are also possible according to the concepts of the invention. By way of example, variations offiber optic cables100 and100′ can be preconnectorized with a connector for plug and play connectivity. For instance, fiber optic cables can include a hardened plug and connector such as an Opti-Tap or Opti-Tip available from Corning Cable Systems of Hickory, N.C.
• Protective covering8 uses a bend radius control mechanism for protecting the optical fiber by inhibiting damage and/or breaking of the optical fiber as the fiber optic cable is bent into small bend radii while still providing a highly flexible fiber optic cable design. In other words, the bend radius control mechanism maintains a minimum bend radii for the optical fiber so damage and/or breaking is avoided. By way of example,fiber optic cable100 can be tied in a knot, bent about small structures, and the like while having extremely low optical attenuation; however, the fiber optic cable still should prevent damage and/or breaking of the optical fiber during these installations. Previously, conventional fiber optic cables would have high optical attenuation or go dark before breaking the optical fiber was a concern, thus the craft avoided using small bend radii for preserving optical performance. One benefit of the present invention is that the fiber optic cable designs are suitable for rugged installations both by the craft and untrained individuals.
• Robustness of the fiber optic cable design is accomplished by suitable coupling with the protective covering for inhibiting buckling of the optical fiber within the same. Additionally, maintaining coupling betweenjacket8bandstrength members14 inhibits the transfer of tensile forces to optical fiber1. Coupling is accomplished using a pressure extrusion process and can allow aggressive bending of the fiber optic cable while maintaining a suitable coupling level. Consequently, the coupling results in very little to no construction stretch for the strength members. As used herein, construction stretch means that all of the cable components are not simultaneously stretched when applying a tensile force to the fiber optic cable. Illustratively, a fiber optic cable exhibiting construction stretch typically has the jacket and optical fiber supporting the initially applied tensile force, but the strength members do not. Thus, as the jacket and optical fiber are stretched to a point where the slack in the strength members is removed and the strength members also begin to support the load. This construction stretch is problematic since it initially allows the optical fiber to strain, which limits the ultimate tensile strength of the fiber optic cable. Additionally, after the tensile force is removed from the fiber optic cable the jacket stretched before the optical fiber, thereby allowing buckling and/or compression of the optical fiber within the fiber optic cable that can cause optical losses. Any suitable type of material may be used forprotective covering8 such as polyurethanes (PU), polyvinylchloride (PVC), polyethylenes (PE), polyproplyenes (PP), UV curable materials, etc. depending on the desired construction and characteristics. Additionally,protective coverings8 can use flame-retardant materials such as a flame-retardant PVC or the like as known in the art. Desirably, fiber optic cables of the invention uses highly-flexible and robust designs that allow aggressive bending of the cable while maintaining a minimum bend radii.
• More specifically,fiber optic cable100 is designed so that it is highly flexible, maintains a minimum bend radius to inhibit breaking of the optical fiber when aggressively bent, and have enough coupling betweenprotective covering8 and optical fiber1 to inhibit buckling of the optical fiber withinprotective covering8. By way of example,fiber optic cable100 includes optical fiber1 having a plenum-grade buffer layer8awith an outer diameter of about 900 microns. Other types of materials, sizes, shapes, etc are also possible for the buffer layer. Thereafter, fourstrength members14 were run in a parallel configuration (i.e., no stranding) about the buffered optical fiber beforejacket8bwas applied. Eliminating stranding ofstrength members14 is also advantageous since it allows for increased line speeds.Jacket8bwas pressure extruded using a PU material available from Huntsman available under the tradename Irogran A78 P 4766. The jacket material used had a relatively high ultimate elongation (i.e., elongation before breaking) measured according to DIN 53504 (a German measurement standard), thereby providing a highly flexible fiber optic cable design. Jackets for fiber optic cables of the invention have an ultimate elongation that is about 500% or greater such as about 600% or greater, and even about 700% or greater. The PU jacket material used had an ultimate elongation of about 800% along with a 300% tensile modulus of about 8.0 MPa. Additionally,jacket8bhad an outer diameter of about 5 millimeters with an inner diameter of about 1.7 millimeters. Consequently,fiber optic cable100 had an excellent flexibility while still inhibiting breaking of the optical fiber when aggressively bent for instance when fiber optic cable is bent like a hairpin as shown inFIG. 2cthe bend radius control mechanism is provided byjacket8balong with its coupling characteristics. In other words, the bend radius control mechanism ofjacket8bprovides a minimum bend diameter of about 5 millimeters (e.g., about two times the radius of the fiber optic cable) for inhibiting breaking of the optical fiber when bent as shown inFIG. 2c. Using the bend radius control mechanism also improves crush performance of the fiber optic cable since the jacket is relatively thick and highly flexible. Furthermore, the optical performance offiber optic cable100 during aggressive bendng is impressive compared with conventional fiber optic cables.
• To test the optical performance offiber optic cable100, a corner bend test was conducted as described below. The corner bend test routed a portion offiber optic cable100 over a 90 degree edge (i.e., nearly a zero bend radius) and weights were hung from the fiber optic cable to apply a constant force at the bend while measuring a delta attenuation (e.g., change in attenuation) at a reference wavelength of 1625 nanometers due to the applied force. The corner bend test usedfiber optic cable100 and a similar fiber optic cable design using a SMF28-e optical fiber available from Corning, Inc. The results for the corner bend test are summarized in Table 1 below.

• TABLE 1
  Corner Bend Test

  		FiberOptic
  	Conventional	Cable
  100
  	Cable Delta	Delta
  	Attenuation (dB)	Attenuation (dB)

  	1310	1550	1625	1310	1550	1625
  Load (kg)	nm	nm	nm	nm	nm	nm

  0	0.00	0.00	0.00	0.00	0.01	0.02
  0.6	1.16	3.16	5.21	0.01	0.02	0.04
  1	2.51	8.14	11.06	0.01	0.06	0.09
  5	—	—	—	0.03	0.18	0.22
  10	—	—	—	0.03	0.15	0.22

• As depicted in Table 1, the conventional cable had elevated levels of delta attenuation at all wavelengths with a load of 0.6 kilograms. Moreover, the delta attenuation was so high above a load of 1 kilogram that measurements were not taken. On the other hand,fiber optic cable100 had low delta attenuation values with loads up to 10 kilograms. By way of example,fiber optic cable100 had a delta attenuation of about 0.1 dB or less for the corner bend test with a load of 1 kilogram at a reference wavelength of 1625 nanometers. Other testing was also performed such as bendingfiber optic cable100 about a mandrel with a given diameter along with a conventional fiber optic cable for comparison purposes. More specifically, a delta attenuation (dB) for the loss was measured after wrapping a predetermined number of turns (i.e., each turn is about 360 degrees) of fiber optic cable around a mandrel with a given diameter.

• TABLE 2
  Mandrel Wrap Test at a Reference Wavelength of 1625 nanometers

  	Conventional Cable	Fiber Optic Cable 100
  	Delta Attenuation (dB)	Delta Attenuation (dB)

  Number of	4.6 mm	7.5mm	15 mm	4.6 mm	7.5mm	15 mm
  Turns	mandrel	mandrel	mandrel	mandrel	mandrel	mandrel

  0	—	—	0.00	0.00	0.00	0.00
  1	—	—	3.10	0.39	0.10	0.07
  2	—	—	7.96	0.56	0.18	0.11
  3	—	—	11.58	0.83	0.33	0.17
  4	—	—	16.03	1.18	0.53	0.23
  5	—	—	20.19	1.43	0.68	0.23

• As depicted in Table 2, the conventional cable had elevated levels of delta attenuation when it was wrapped about a 15 millimeter mandrel. Moreover, the delta attenuation was so large with mandrels smaller than 15 millimeters that the measurements were not taken. On the other hand,fiber optic cable100 had delta attenuation values that were more than an order of magnitude lower using a 15 millimeter mandrel. By way of example,fiber optic cable100 had a delta attenuation of about 0.33 dB or less when wrapped 3 turns about a 7.5 millimeter mandrel at a reference wavelength of 1625 nanometers.
• Another example of assemblies useful with the concepts of the present invention are optical fiber jumper assemblies that are, generally speaking, used within structures for interconnection purposes.FIGS. 3-5 depict an explanatory optical fiber jumper assembly15 (hereinafter “jumper assembly”) using optical fiber1 and is shown in various configurations to illustrate physical and performance capabilities of assemblies according to the concepts of the invention. Moreover, jumper assemblies represented byjumper assembly15 were tested for optical performance and compared with conventional jumper assemblies as presented below. Jumper assemblies of the invention preserve optical attenuation during, for example, macrobending down to levels not previously attainable with previous constructions.
• As shown,jumper assembly15 is connectorized at each end usingSC connectors12, such as those available from Coining Cable Systems of Hickory, N.C., using techniques known in the art. Of course, jumper assemblies may include any length of fiber optic cable, type of connector and/or number of optical fibers capable of performing interconnections within an optical network. It is envisioned that a jumper assembly may be connectorized at each end using similar or dissimilar connector types such as LC, FC, MT, MTP, among others. Thejumper assembly15 may be aggressively bent, either stand-alone or about network structure, such as for installation, slack storage and routing without suffering appreciable attenuation and without damage and/or breaks to the optical fiber. The at least one optical fiber1 is within aprotective covering10 such as, but not limited to, a coating, a buffer, or a jacket. In one example, the fiber1 may be upjacketed to about 500 um or about 900 um. The jumper assembly may further include strength members, such as aramid strength members, as is commonly known in the art. Other fiber optic jumper assemblies are also possible according to the concepts of the invention.
• Theprotective covering10 may be made from material including bend radius control properties for protecting the at least one optical fiber within by inhibiting damage and/or breaking of the optical fiber as the jumper assembly is bent into small bend radii while still providing a highly flexible juniper design. By way of example, thejumper assembly15 can be tied in a knot, bent about small structures, and the like while having extremely low optical attenuation.
• Referring specifically toFIG. 3,jumper assembly15 is shown completing one turn or wrap about amandrel14.Mandrel14 is shown to provide a guide for bendingjumper assembly15 about a structure, and genericallymandrel14 represents a portion of network structure about which the jumper assembly is installed (e.g., a network interface device (NID), a cabinet, routing guide, connector housing, connector port or the like).Mandrel14 defines a diameter, for example, the diameter is about 10 millimeters or about 6 millimeters, but other sizes are possible. Referring specifically toFIG. 4,jumper assembly15 is shown wrapped about themandrel14 and completing about five turns. Referring specifically toFIG. 5,jumper assembly15 is shown tied in a knot.
• Table 3 details optical performance data for different fiber optic cable designs at a reference wavelength of 1625 nanometers. More specifically, a delta attenuation (dB) for the loss was measured after wrapping a predetermined number of turns (i.e., each turn is about 360 degrees) of fiber optic cable around a mandrel with a given diameter. Table 3 depicts the results for two different single fiber cable (SFC) designs (i.e., a 2.0 millimeter SFC and a 2.9 millimeter SFC) that were used as a portion of the tested jumper assemblies. Each of the SFC designs used a conventional optical fiber and a microstructured bend performance optical fiber, thereby resulting in four jumper assemblies for testing. Additionally, two different microstructured bend performance optical fibers were used in the jumper assemblies of the present invention to compare performance, listed in the table below as Type I and Type II bend performance fibers. The conventional optical fiber used in the conventional jumper assemblies was a SMF-28e optical fiber available from Corning Incorporated of Corning, N.Y. Both the 2.0 millimeter and the 2.9 SFC designs included an optical fiber having a 900 micron buffer layer thereon that was surrounded by a plurality of aramid strength members and a jacket. The differences between the 2.0 millimeter and 2.9 millimeter SFC include the jacket wall thickness (e.g., respectively about 0.33 millimeters and about 0.45 millimeters) and the quantity of aramid used.

• TABLE 3
  Delta Attenuation (dB) at 1625 nanometers after
  Wrapping Around a Mandrel

  				Delta
  				At-
  	Delta	Delta	Delta	tenuation
  Mandrel	Attenuation	Attenuation	Attenuation	2.9 mm
  Diameter - #	Conventional	Conventional	2.0 mm SFC	SFC
  of Turns	2.0 mm SFC	2.9 mm SFC	Type I	Type II
  10 mm - 1 Turns	25.42 dB	27.20 dB	0.11 dB	0.00dB
  10 mm - 2 Turns	41.30 dB	42.30 dB	0.27 dB	0.00dB
  10 mm - 3 Turns	45.00 dB	45.00 dB	0.42 dB	0.00dB
  10 mm - 4 Turns	45.89 dB	45.80 dB	0.70 dB	0.00dB
  10 mm - 5 Turns	46.20 dB	46.20 dB	0.93 dB	0.00 dB
  6 mm - 1 Turns	46.20 dB	46.00 dB	0.46 dB	0.00 dB
  6 mm - 2 Turns	46.20 dB	46.00 dB	0.98 dB	0.00 dB
  6 mm - 3 Turns	46.20 dB	46.00 dB	1.70 dB	0.00 dB
  6 mm - 4 Turns	46.20 dB	46.00 dB	2.72 dB	0.00 dB
  6 mm - 5 Turns	46.20 dB	46.00 dB	3.12 dB	0.00 dB
  90 degree bend	0.86 dB	0.53 dB	0.03 dB	0.00 dB

• As depicted in Table 3, the conventional SFC jumpers had elevated levels of delta attenuation at all turns about both mandrel diameters. In comparison, the jumper assemblies including both Type I and II fiber had delta attenuation orders of magnitude lower, and with respect to the jumper assembly including Type II bend performance fiber, there was no delta attenuation at all turns about each mandrel diameter. Further, both the conventional and Type I and II jumper assemblies were bent about a 90 degree bend, such as a corner bend test, and the jumper assemblies including bend performance fiber outperformed the conventional jumpers. By way of example, thejumper assembly15 including bend performance fiber had a delta attenuation of about 0.03 dB or less for the 90 degree bend test at a reference wavelength of 1625 nanometers.
• Bend performance fibers of the present invention may be included within various cable types and cable assemblies to achieve highly flexible cables to facilitate installation and require less skill in handling. The cables and cable assemblies described herein may be installed within fiber optic hardware such as local convergence points for multi-dwelling units, cross-connect frames and modules, and surface, pad and pole mounted local convergence points showing smaller size and higher density. Referring toFIGS. 6-7, a portion of the jumper assembly with theprotective covering10 is shown wrapped aroundgeneric network structure20. Anangle theta22 corresponds to a portion of a turn about thegeneric structure20.Generic structure20 may include, but is not limited to, structure of fiber optic cable assemblies, hardware, spools, thru holes, connector ports, routing guides, cabinets or any other structure within the network.
• The foregoing is a description of various embodiments of the invention that are given here by way of example only. Although fiber optic cables and jumper assemblies including bend performance fiber in at least a portion thereof have been described with reference to preferred embodiments and examples thereof, other embodiments and examples may perform similar functions and/or achieve similar results. All such equivalent embodiments and examples are within the spirit and scope of the present invention and are intended to be covered by the appended claims.

Claims (15)

1. A fiber optic jumper assembly, comprising:

at least one bend performance optical fiber comprising a core region, a hole-free inner annular cladding region surrounding the core region, an annular hole-containing cladding region surrounding the inner annular cladding region and comprised of non-periodically disposed holes, and an outer hole-free cladding region surrounding the annular hole-containing cladding region;

a protective covering positioned over the at least one bend performance optical fiber; and

at least one connector mounted upon at least one end of the at least one bend performance optical fiber.

2. The jumper assembly ofclaim 1, wherein the jumper assembly has a delta attenuation of 0.11 dB or less at one turn about a 10 mm diameter structure at a reference wavelength of 1625 nanometers.

3. The jumper assembly ofclaim 1, wherein the jumper assembly has a delta attenuation of 0.93 dB or less at five turns about a 10 mm diameter structure at a reference wavelength of 1625 nanometers.

4. The jumper assembly ofclaim 1, wherein the jumper assembly has a delta attenuation of 0.46 dB or less at one turn about a 6 mm diameter structure at a reference wavelength of 1625 nanometers.

5. The jumper assembly ofclaim 1, wherein the jumper assembly has a delta attenuation of 3.12 dB or less at five turns about a 6 mm diameter at a reference wavelength of 1625 nanometers.

6. The jumper assembly ofclaim 1, wherein the at least one bend performance optical fiber has a 12 mm macrobend induced loss at 1550 nm of less than 0.1 dB/turn.

7. The jumper assembly ofclaim 1, wherein the at least one bend performance optical fiber has a 12 mm macrobend induced loss at 1550 nm of less than 0.05 dB/turn.

8. The jumper assembly ofclaim 1, wherein the at least one bend performance optical fiber has an 8 mm macrobend induced loss at 1550 nm of less than 0.2 dB/turn.

9. The jumper assembly ofclaim 1, wherein the at least one bend performance optical fiber has an 8 mm macrobend induced loss at 1550 nm of less than 0.1 dB/turn.

10. A fiber optic assembly for performing interconnections within a fiber optic network, the assembly comprising:

at least one microstructured optical fiber having an outer surface and comprising a core region that is surrounded by a cladding region that comprises randomly disposed cladding material voids that are contained within an annular region spaced from the core and outer surface respectively by a hole-free inner and outer cladding regions, the void-containing annular region having a radial width W23 in the range from 0.5 um to 20 μm;

a protective covering surrounding at least a portion of the at least one microstructured optical fiber; and

at least one connector mounted upon at least one end of the at least one microstructured optical fiber.

11. The fiber optic assembly ofclaim 10, wherein the assembly has a delta attenuation of 0.11 dB or less when wrapped one turn about a 10 mm diameter structure at a reference wavelength of 1625 nm.

12. The fiber optic assembly ofclaim 10, wherein the assembly has a delta attenuation of 0.46 or less when wrapped one turn about a 6 mm diameter structure at a reference wavelength of 1625 nm.

13. The fiber optic assembly ofclaim 10, wherein the assembly has a delta attenuation of 0.00 when wrapped 5 turns about a 6 mm diameter structure at a reference wavelength of 1625 nm.

14. The fiber optic jumper assembly ofclaim 1, wherein the core region has a radius R1 in the range from 1 μm to 5 μm, the inner annular cladding region has an inner radius R2 in the range from 10 μm to 20 μm, and the annular hole-containing cladding region has an annular width W23 in the range from 0.5 μm to 20 μm.

15. The fiber optic assembly ofclaim 10, wherein the core region has a radius R1 in the range from 1 μm to 5 μm, the inner annular cladding region has an inner radius R2 in the range from 10 μm to 20 μm.

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