CN113551798A

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Info

Publication number: CN113551798A
Application number: CN202110029746.5A
Authority: CN
Inventors: 张慧生; 王天根; 曹江行
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2021-01-11
Filing date: 2021-01-11
Publication date: 2021-10-26

Abstract

Translated fromChinese

本发明公开一种有机硅芯层/磷酸盐微晶玻璃包层光纤及制备工艺，有机硅芯为聚二甲基硅氧烷（PDMS）；磷酸盐微晶玻璃薄为多组份包层，包层组分比例为：P₂O₅：69～71％，CaCO₃：3.8～4.1％，Li₂CO₃：3.2～3.5％，NaF：12～18％,TiO₂：6～9％，有机硅芯层/磷酸盐微晶玻璃包层杂化纤维结构中的模态干扰，可以在透射光谱中识别出共振波长。该传感器在25℃至80℃范围内的灵敏度为‑384 pm/℃，线性度为R2=0.9982，重复性好。

The invention discloses an organic silicon core layer/phosphate glass-ceramic cladding optical fiber and a preparation process. The organic silicon core is polydimethylsiloxane (PDMS); the phosphate glass-ceramic thin is a multi-component cladding layer. The composition ratio of the cladding is: P₂ O₅ : 69-71%, CaCO₃ : 3.8-4.1%, Li₂ CO₃ : 3.2-3.5%, NaF: 12-18%, TiO₂ : 6-9%, Modal interference in a silicone core/phosphate glass-ceramic clad hybrid fiber structure, resonant wavelengths can be identified in the transmission spectrum. The sensor has a sensitivity of ‑384 pm/°C in the range of 25°C to 80°C, a linearity of R2=0.9982, and good repeatability.

Description

Organic silicon core layer/phosphate microcrystalline glass cladding optical fiber and preparation process thereof

Technical Field

The invention belongs to the field of optical fiber sensing application, and particularly relates to an organic silicon core layer/phosphate microcrystalline glass cladding optical fiber applied to temperature sensing and a preparation process thereof.

Background

Temperature measurement and control play an important role in many fields, such as the biological, chemical and pharmaceutical industries. In recent years, optical fiber sensors have attracted much attention because of their advantages of electromagnetic interference resistance, high sensitivity, good stability and low cost. In certain harsh environments, fiber optic sensors are more suitable than electrical sensors. There are many novel optical fiber structures available for measuring temperature, magnetic field, pH, refractive index, displacement, etc. Incident light having a specific wavelength can be reflected by the FBG, the reflected wavelength being called bragg wavelength, which can be modified by ambient temperature. The sensing system is very flexible and distributed multi-point measurement can be achieved by cascading a series of FBGs with different bragg wavelengths.

However, the temperature sensitivity of FBGs is about 10 pm/deg.c, which is limited by the sensing principle. Fiber interferometers based on single mode-multimode-Single Mode (SMS) fiber structures have higher temperature sensitivity than FBGs. The manufacturing process of the SMS structure is also relatively simple. To increase the sensitivity of the SMS structure, the multimode fiber is etched with hydrofluoric acid. The resolution of the etched SMS sensing structure can reach 0.001 ℃. However, the etching process is difficult to control. The etching rate depends on the temperature, the properties of the fiber material and the concentration of the hydrofluoric acid solution. Moreover, the fabricated structures become fragile and difficult to use after the etching process. A variety of special optical fibers can be used in place of multimode fibers, such as hollow core fibers, coreless fibers and photonic crystal fibers, which greatly improves the flexibility, accuracy and repeatability of SMS fiber sensors. However, the thermo-optic coefficient and the thermal expansion coefficient are still the limiting factors for further improving the temperature sensing performance. To address this problem, temperature sensitive materials may be incorporated into the fiber optic sensing structure. By filling with a liquid having a large thermo-optic coefficient, an ultra-high sensitivity temperature sensor has been proposed in previous work.

The prior patent, chinese patent with the grant number CN110554455B, discloses a method for rapidly preparing a transition metal chalcogenide composite optical fiber material. The method comprises the steps of adopting molybdic acid or sodium tungstate/potassium salt solution to soak an optical fiber, and then directly depositing high-quality single-layer or few-layer transition metal chalcogenide on the inner wall of an air duct in the center of the optical fiber or on the inner walls of a cladding air hole and a fiber core air duct of the photonic crystal optical fiber under the conditions of low pressure and high temperature, wherein the optical fiber is made of quartz or quartz polymer. The characteristics of excellent optical and electrical properties of the transition metal chalcogenide and the photonic structure of the optical fiber are combined, and the multifunctional integration of the two-dimensional TMDC material and the optical fiber is realized.

However, thermal degradation of PDMS during the soldering process, temperature sensitivity of the optical fiber material, and the preparation method still need to be further improved.

Disclosure of Invention

Aiming at the problems, the invention adopts the following technical scheme:

an organic silicon core layer/phosphate microcrystalline glass cladding optical fiber, wherein the organic silicon core is Polydimethylsiloxane (PDMS); the phosphate microcrystalline glass film is a multi-component coating, and the coating comprises the following components in percentage by weight: p₂O₅:69～71%，CaCO₃:3.8～4.1%，Li₂CO₃:3.2～3.5%，NaF:12～18%, TiO₂6-9%, and the resonance wavelength can be identified in the transmission spectrum due to the mode interference in the organic silicon core layer/phosphate microcrystalline glass cladding hybrid fiber structure. The sensor has sensitivity of-384 pm/DEG C in the range of 25-80 ℃, linearity of R2 = 0.9982, and good repeatability.

Preferably, the entire cross-section of the clad layer corresponding to the plurality of holes of the core layer is polygonal, and the number of holes is 4 to 6.

Preferably, the diameter of the organosilicon core layer/phosphate microcrystalline glass cladding optical fiber is 325-380 μm.

The invention also comprises a preparation process of the organic silicon core layer/phosphate microcrystalline glass cladding optical fiber, which comprises the following steps:

1) preparation of preforms, CaCO₃，P₂O₅，Li₂CO₃NaF and TiO₂Mixing the raw materials, and preparing a phosphate glass-ceramic preform by using a melting cold extraction method;

2) preparing a porous preform, namely placing the phosphate glass-ceramic preform prepared in the step 1 in a soft glass infrared drawing tower, obtaining a phosphate glass-ceramic prefabricated small rod with the diameter of 325 mu m by a hot drawing method, and punching the phosphate glass-ceramic preform with the aperture size of 20-30 mu m;

3) filling PDMS, namely fully stirring the mixture of PDMS and a curing agent in a ratio of 10:1, filling the PDMS into the hollow fiber by adopting a pressure difference method, wherein the occupied length of the filled PDMS in the hollow fiber is 20mm, taking the PDMS out of the fiber end after the filling process is finished, and keeping the pressure difference of 10s so as to facilitate the manufacture of an air gap, wherein the reserved length of the air gap is 1 mm;

4) and (3) curing, namely standing the product prepared in the step (3) for one hour, curing at the temperature of 80 ℃, and precisely controlling the cutting position to ensure that the hollow fiber with the length of 1mm can be remained in the organic silicon core layer/phosphate glass ceramic cladding so as to avoid thermal degradation of PDMS in the welding process.

Preferably, the melting temperature of the step 1 is 720-820 ℃, and cold extraction is carried out by adopting an ice bath.

Preferably, the hot drawing temperature in the step 2 is 410-420 ℃, and Ar gas is adopted as the protective gas for protection in the step 2 and the step 4.

The invention has the beneficial effects that:

1) according to the organic silicon core layer/phosphate microcrystalline glass cladding optical fiber prepared by the method, air gap structures are manufactured on two sides of the mixed fiber structure, so that thermal degradation of PDMS in the optical fiber fusion welding process is effectively avoided;

2) the temperature sensitivity of the prepared organic silicon core layer/phosphate microcrystalline glass cladding optical fiber can reach-384 pm/DEG C, and the stability is excellent;

3) the organic silicon core layer/phosphate microcrystalline glass cladding optical fiber has the advantages of simple structure, low cost and easy manufacture.

Drawings

FIG. 1 is a graph of the transmission spectrum of example 1.

FIG. 2 is a graph showing the relationship between the shift of the resonance wavelength and the temperature in example 2.

Fig. 3 is a graph of the characteristic wavelength shift versus temperature for comparative example 3.

Detailed Description

The technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In the present invention, the raw materials are all commercially available products.

Example 1

The preparation process of the organosilicone core layer/phosphate microcrystalline glass clad optical fiber provided by the embodiment comprises the following steps of:

1) preparation of preform, 69% P₂O₅，3.8%CaCO₃，3.2%Li₂CO₃，12%NaF，9%TiO₂Mixing the raw materials, placing the mixture in a crucible, heating the crucible containing the mixture to 720 ℃ through an electric furnace to be in a molten state, keeping for 30min, taking out the crucible, placing the crucible in a vessel containing ice blocks, and performing cold extraction to obtain a phosphate glass-ceramic preform;

2) preparing a porous prefabricated rod, namely placing the phosphate glass-ceramic prefabricated rod prepared in the step 1 in a soft glass infrared drawing tower, obtaining a phosphate glass-ceramic prefabricated small rod with the diameter of 325 mu m by a hot drawing method, and punching the phosphate glass-ceramic prefabricated rod with the aperture size of 20 mu m;

The transmission spectrum test is carried out on the organic silicon core layer/phosphate microcrystalline glass optical fiber, when the temperature is changed from 25 ℃ to 80 ℃, the recording of the transmission spectrum is shown in figure 1, according to the experimental result, the resonance wavelength generates blue shift in the measuring range, and the experimental sensitivity is-384 pm/DEG C. It can be found that the sensitivity of the sensor obtained in the experiment is close to the sensitivity of the sensor obtained by simulation.

Example 2

1. preparation of preform, 71% P₂O₅，4.1%CaCO₃，3.5%Li₂CO₃，18%NaF，9%TiO₂Mixing the raw materials, placing the raw materials in a crucible, heating the crucible containing the mixed raw materials to 720 ℃ through an electric furnace to be in a molten state, keeping for 30min, taking out the crucible, placing the crucible in a vessel containing ice blocks, and performing cold extraction to obtain a phosphate glass-ceramic preform;

2. preparing a porous prefabricated rod, namely placing the phosphate glass-ceramic prefabricated rod prepared in the step 1 in a soft glass infrared wire drawing tower to be heated to 420 ℃, obtaining a phosphate glass-ceramic prefabricated rod with the diameter of 325 mu m by a hot drawing method, and punching the phosphate glass-ceramic prefabricated rod with the aperture size of 30 mu m;

filling PDMS, namely fully stirring the mixture of PDMS and a curing agent in a ratio of 10:1, filling the PDMS into the hollow fiber by adopting a pressure difference method, wherein the filled PDMS occupies 20mm of length in the hollow fiber, taking the PDMS out of the fiber end after the filling process is finished, and keeping the pressure difference of 10s so as to facilitate the manufacture of an air gap, wherein the length of the air gap is kept to be 1mm;

4. And (3) curing, namely standing the product prepared in the step (3) for one hour, curing at the temperature of 80 ℃, and precisely controlling the cutting position to ensure that the hollow fiber with the length of 1mm can be remained in the organic silicon core layer/phosphate glass ceramic cladding so as to avoid thermal degradation of PDMS in the welding process.

The relationship between the resonance wavelength shift and the temperature of the prepared organic silicon core layer/phosphate microcrystalline glass optical fiber is tested, and an experimental system consists of a spectrometer (Yokogawa, AQ 6370D) with a wavelength resolution of 0.02nm and a light source with a wavelength range of 1520nm to 1570nm and the manufactured sensing structure. And the fiber optic sensor was calibrated using a standard thermometer (Pt 100) with an accuracy of 0.01 deg.c. To test the stability of the proposed sensor, three measurements of temperature were made over three days, with an interval of 24 hours between each two tests, each experiment measuring the temperature drop from 80 ℃ to 25 ℃. The measurement results are shown in fig. 2. It can be seen that the measurements of the sensor obtained by three repeated experiments are relatively close, which can prove that the proposed sensor has good stability.

Comparative example 1 this comparative example adjusted the hollow core fiber lengths of example 1 to 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, and the other steps were completely identical to example 1.

When the inner diameters of the hollow fibers are 60 μm, 50 μm, 40 μm, 30 μm and 20 μm respectively, the relationship between the temperature and the resonance wavelength deviation is shown in fig. 3, and it can be seen that the sensitivity of the sensor is remarkably increased along with the increase of the diameter of the hollow fiber core.

Claims

Translated fromChinese

1.一种有机硅芯层/磷酸盐微晶玻璃包层光纤及制备工艺，其特征在于，所述有机硅芯层/磷酸盐微晶玻璃包层光纤中有机硅芯为聚二甲基硅氧烷（PDMS）；磷酸盐微晶玻璃薄为多组份包层，包层组分比例为：P₂O₅:69～71%，CaCO₃:3.8～4.1%，Li₂CO₃:3.2～3.5%，NaF:12～18% ，TiO₂:6～9%。1. a kind of organosilicon core layer/phosphate glass-ceramic cladding optical fiber and preparation technology, it is characterized in that, in described organosilicon core layer/phosphate glass-ceramic cladding optical fiber, the organosilicon core is polydimethylsilicon Oxane (PDMS); Phosphate glass-ceramic thin is a multi-component cladding, and the cladding component ratios are: P₂ O₅ : 69～71%, CaCO₃ : 3.8～4.1%, Li₂ CO₃ : 3.2 ～3.5%, NaF: 12～18%, TiO₂ : 6～9%.

2.根据权利要求1所述一种有机硅芯层/磷酸盐微晶玻璃包层光纤及制备工艺，其特征在于，所述磷酸盐微晶玻璃包层截面上对应于芯层的多个孔整体为多边形，孔数在4~6孔。2 . The organosilicon core layer/phosphate glass-ceramic cladding optical fiber and its preparation process according to claim 1 , wherein the cross-section of the phosphate glass-ceramic cladding corresponds to a plurality of holes in the core layer. 3 . The whole is polygonal, and the number of holes is 4~6 holes.

3.根据权利要求1所述一种有机硅芯层/磷酸盐微晶玻璃包层光纤及制备工艺，其特征在于，所述有机硅芯层/磷酸盐微晶玻璃包层光纤丝径为325~380μm。3. a kind of organosilicon core layer/phosphate glass-ceramic cladding optical fiber and preparation process according to claim 1, is characterized in that, described organosilicon core layer/phosphate glass-ceramic cladding optical fiber filament diameter is 325 mm ~380μm.

4.本发明还包括一种有机硅芯层/磷酸盐微晶玻璃包层光纤的制备工艺，该工艺包括以下步骤：4. The present invention also includes a preparation process of an organic silicon core layer/phosphate glass-ceramic cladding optical fiber, the process comprising the following steps:

预制棒的制备，CaCO₃，P₂O₅, Li₂CO₃，NaF和TiO₂原料混合，利用熔融冷萃法制备得到磷酸盐微晶玻璃预制棒；Preparation of preform, CaCO₃ , P₂ O₅ , Li₂ CO₃ , NaF and TiO₂ raw materials are mixed, and phosphate glass-ceramic preform is prepared by melting cold extraction method;

多孔预制棒的制备，将步骤1制备得到的磷酸盐微晶玻璃预制棒置于软玻璃红外拉丝塔中，通过热拉制法得到磷酸盐微晶玻璃预制小棒直径为325μm，对磷酸盐微晶玻璃预制棒进行打孔处理，孔径大小为20~30μm；For the preparation of porous preform, place the phosphate glass-ceramic preform prepared in step 1 in a soft glass infrared drawing tower, and obtain a small phosphate glass-ceramic preform with a diameter of 325 μm by thermal drawing method. The crystal glass preform is punched, and the aperture size is 20~30μm;

PDMS填充，将PDMS和固化剂以比例为10:1的混合物充分搅拌，采用压差法将PDMS填充到空心纤维中，填充的PDMS在空心纤维中占用长度为20mm，填充过程结束后，将PDMS从纤维端取出，并保持10s的压差，以方便气隙制造，气隙保留的长度为1mm；PDMS filling, fully stirring PDMS and curing agent in a ratio of 10:1, using differential pressure method to fill PDMS into hollow fibers, the filled PDMS occupies a length of 20mm in hollow fibers, after the filling process, the PDMS Take it out from the fiber end and maintain a pressure difference of 10s to facilitate the manufacture of the air gap, and the length of the air gap reserved is 1mm;

固化，将步骤3制备得到的产物静置一小时后在80℃的温度下固化，通过精确控制切割位置，长度为1mm的中空纤维会保留在有机硅芯层/磷酸盐微晶玻璃包层，以避免PDMS在熔接过程中发生热降解。For curing, the product prepared in step 3 is left standing for one hour and then cured at a temperature of 80 ° C. By precisely controlling the cutting position, the hollow fiber with a length of 1 mm will remain in the silicone core layer/phosphate glass-ceramic cladding, To avoid thermal degradation of PDMS during the welding process.

5.根据权利要求4所述一种有机硅芯层/磷酸盐微晶玻璃包层光纤的制备工艺，其特征在于，所述步骤1熔融温度为720~820℃，采用冰浴进行冷萃。5 . The preparation process of an organic silicon core layer/phosphate glass-ceramic clad optical fiber according to claim 4 , wherein the melting temperature in step 1 is 720-820° C., and an ice bath is used for cold extraction. 6 .

6.根据权利要求4所述一种有机硅芯层/磷酸盐微晶玻璃包层光纤的制备工艺，其特征在于，所述步骤2热拉制温度为410-420℃，步骤2和步骤4均采用Ar气作为保护气进行保护。6 . The preparation process of an organic silicon core layer/phosphate glass-ceramic clad optical fiber according to claim 4 , wherein the thermal drawing temperature in the step 2 is 410-420° C., and the step 2 and the step 4 Ar gas was used as protective gas for protection.