阅读说明：本技术 一种耐辐照保偏光纤及其制备方法和应用 (Radiation-resistant polarization-maintaining optical fiber and preparation method and application thereof ) 是由 柯一礼 罗文勇 杜城 张涛 赵磊 祝威 于 2020-03-12 设计创作，主要内容包括：本申请涉及一种耐辐照保偏光纤及其制备方法,涉及光纤制备领域。该耐辐照保偏光纤包括纯石英纤芯、一对应力部以及包层,应力部由掺硼石英玻璃形成,设置于纯石英纤芯的两侧,包层包围纯石英纤芯以及应力部,包层由第一包层和第二包层组成,第二包层设置于第一包层的外周,其中,第一包层由掺氟石英玻璃形成,第二包层由纯石英玻璃形成。通过本申请制备的耐辐照保偏光纤具有优异的耐辐照性能,保偏光纤的工作波长为1310nm和1550nm双窗口,在200krad辐照总剂量下,其感生损耗在2dB/km以下。本申请的耐辐照保偏光纤能够在恶劣的辐射条件下,实现保偏光纤的低损耗信息传输,并且保持较好的全温串音。(The application relates to an irradiation-resistant polarization maintaining optical fiber and a preparation method thereof, and relates to the field of optical fiber preparation. The irradiation-resistant polarization-maintaining optical fiber comprises a pure quartz fiber core, a pair of stress parts and a cladding, wherein the stress parts are formed by boron-doped quartz glass and are arranged on two sides of the pure quartz fiber core, the cladding surrounds the pure quartz fiber core and the stress parts, the cladding is composed of a first cladding and a second cladding, the second cladding is arranged on the periphery of the first cladding, the first cladding is formed by fluorine-doped quartz glass, and the second cladding is formed by pure quartz glass. The radiation-resistant polarization maintaining optical fiber prepared by the method has excellent radiation resistance, the working wavelength of the polarization maintaining optical fiber is 1310nm and 1550nm double windows, and the induced loss of the polarization maintaining optical fiber is below 2dB/km under the total radiation dose of 200 krad. The irradiation-resistant polarization maintaining optical fiber can realize low-loss information transmission of the polarization maintaining optical fiber under severe radiation conditions, and can keep good full-temperature crosstalk.)

1. An irradiation-resistant polarization maintaining optical fiber, characterized in that: comprises that

A pure silica fiber core;

a pair of stress parts, wherein the stress parts are formed by boron-doped quartz glass, are arranged on two sides of the pure quartz fiber core and are symmetrical about the pure quartz fiber core, and the relative refractive index difference △ 1 of the stress parts is-0.60% -0.80%;

and the cladding surrounds the pure quartz fiber core and the stress part, the cladding is composed of a first cladding and a second cladding, the second cladding is arranged on the periphery of the first cladding, the first cladding is made of fluorine-doped quartz glass, the relative refractive index difference △ 2 of the first cladding is-0.30% -0.80%, and the second cladding is made of pure quartz glass.

2. The radiation-resistant polarization-maintaining optical fiber of claim 1, wherein: the relative refractive index difference of the pure quartz fiber core is-0.01%; the relative refractive index difference of the second cladding is-0.01%.

3. The radiation-resistant polarization-maintaining optical fiber of claim 1, wherein: the diameter of the pure quartz fiber core is D1 and is 4.5-9.0 mu m, the diameter of the first cladding is D2 and is 35-70 mu m, and the diameter of the second cladding is D4 and is 80-125 mu m.

4. The radiation-resistant polarization-maintaining optical fiber of claim 3, wherein: the doping component of the first cladding layer is B₂O₃The diameter D4 of the second cladding was 80 μm.

5. The radiation-resistant polarization-maintaining optical fiber of claim 1, wherein: the stress part is circular in cross section, and the diameter D3 is 22-36 mu m.

6. A method for preparing the radiation-resistant polarization maintaining optical fiber of claim 1, comprising the steps of:

(1) respectively preparing a core rod and a stress rod made of boron-doped quartz glass by adopting a PCVD (plasma chemical vapor deposition) process, wherein the core rod sequentially comprises a pure quartz fiber core, a first cladding inner layer and a pure quartz liner tube from inside to outside; polishing the core rod to remove the pure quartz liner tube;

(2) preparing a fluorine-doped pipe by adopting a PCVD (plasma chemical vapor deposition) process, wherein the fluorine-doped pipe is sequentially provided with a first cladding outer layer and a pure quartz liner pipe from inside to outside;

(3) sleeving the core rod polished in the step (1) with the fluorine-doped pipe prepared in the step (2) by an RIC process to form a fluorine-doped solid rod; the fluorine-doped solid rod comprises a pure quartz fiber core, a first cladding inner layer, a first cladding outer layer and a pure quartz liner tube from inside to outside in sequence;

(4) sleeving a pure quartz sleeve on the periphery of the fluorine-doped solid rod by an RIC process, and melting at high temperature to form an irradiation-resistant polarization-maintaining mother rod;

(5) two stress through holes matched with the stress rods are formed in the irradiation-resistant polarization-maintaining mother rod in the axial direction, are positioned on two sides of the pure quartz fiber core and are symmetrical with respect to the pure quartz fiber core; respectively embedding the two stress rods into the stress through holes to form an irradiation-resistant polarization-maintaining optical fiber preform;

(6) and (4) melting the radiation-resistant polarization maintaining optical fiber preform prepared in the step (5) at a high temperature, and drawing the preform into an optical fiber.

7. The method of claim 6, wherein the polarization maintaining optical fiber comprises: in the step (4) and the step (6), the temperature of high-temperature melting is 2000-2300 ℃.

8. The method of claim 6, wherein the polarization maintaining optical fiber comprises: in the step (6), the drawing speed is 100-400 m/min, and the drawing tension is 100-200 g.

9. The method of claim 6, wherein the polarization maintaining optical fiber comprises: the core-spun ratio of the first cladding to the pure quartz fiber core is 7.8:1, the diameter ratio of the irradiation-resistant polarization-maintaining optical fiber preform to the pure quartz fiber core is 14.9-16.7:1, and the diameter ratio of the irradiation-resistant polarization-maintaining optical fiber preform to the stress part is 25: 7-9.

10. Use of the radiation-resistant polarization maintaining optical fiber of claim 1 in an outer space environment.

Technical Field

The application relates to the technical field of optical fiber preparation, in particular to an irradiation-resistant polarization maintaining optical fiber and a preparation method and application thereof.

Background

Polarization Maintaining Fiber (Polarization Maintaining Optical Fiber) is called Polarization Maintaining Fiber (PMF) for short, because birefringence is introduced into the Fiber, linearly polarized light can keep the Polarization state thereof to be transmitted in the Fiber, and thus the Polarization Maintaining Fiber is widely applied to the Polarization related application field.

At present, the polarization maintaining fiber which is most widely applied in the polarization field is a panda type polarization maintaining fiber, and the fiber is characterized in that circular stress regions with high thermal expansion coefficients are symmetrically introduced into a cladding of the fiber to extrude cores so as to generate stress birefringence.

The conventional panda type polarization maintaining optical fiber comprises a fiber core, stress regions and a pure quartz cladding, wherein the fiber core is positioned in the center of the second cladding, and the two circular stress regions are symmetrically distributed on two sides of the fiber core. The fiber core adopts a germanium-fluorine co-doping process to generate refractive index difference so as to realize total internal reflection and ensure the normal transmission of optical signals.

In recent years, as the application field of polarization maintaining optical fibers is developed in the universe and space direction, the performance of the optical fibers is influenced by radiation in the universe environment, and therefore, the radiation resistance of the polarization maintaining optical fibers is required to be improved so that the polarization maintaining optical fibers still maintain excellent optical and polarization performance in the severe outer space environment.

The fiber core of the traditional polarization maintaining fiber is doped with germanium element, and the irradiation damage of the fiber is obviously higher than that of a pure quartz fiber due to the photosensitive characteristic of the fiber. Therefore, under the harsh space condition of the environment, the traditional polarization maintaining optical fiber cannot be used for a long time, and the performance of the polarization maintaining optical fiber is affected by irradiation to generate irreversible degradation. Considering that the polarization-maintaining photonic crystal fiber has better advantage in radiation resistance, in the related technology, the polarization-maintaining photonic crystal fiber is used for replacing the germanium-doped fiber, but the manufacturing process of the polarization-maintaining photonic crystal fiber is complex, the requirement on people is high by adopting a capillary tube stacking method, the wire drawing yield control of a porous structure is difficult, the output is limited, and the large-scale production is difficult to form in a short time.

Disclosure of Invention

The embodiment of the application provides an irradiation-resistant polarization maintaining optical fiber and a preparation method and application thereof, and aims to solve the problem that a germanium-doped optical fiber in the prior art is not irradiation-resistant.

In a first aspect, an irradiation-resistant polarization-maintaining optical fiber is provided, which includes a pure silica core, a pair of stress portions, and a cladding, wherein:

the stress part is formed by boron-doped quartz glass, is arranged on two sides of the pure quartz fiber core and is symmetrical about the pure quartz fiber core, and the relative refractive index difference △ 1 of the stress part is-0.60% -0.80%;

the cladding surrounds the pure quartz fiber core and the stress part, the cladding is composed of a first cladding and a second cladding, the second cladding is arranged on the periphery of the first cladding, the first cladding is made of fluorine-doped quartz glass, the relative refractive index difference △ 2 of the first cladding is-0.30% -0.80%, and the second cladding is made of pure quartz glass.

In some embodiments, the diameter of the pure silica core D1 is 4.5-9.0 μm, the diameter of the first cladding D2 is 35-70 μm, and the diameter of the second cladding D4 is 80-125 μm. .

In some embodiments, the diameter D4 of the second cladding layer is 80 μm.

In some embodiments, the doping component of the stress portion is B₂O₃。

In some embodiments, the radiation-resistant polarization maintaining fiber has an operating wavelength of 1310nm and 1550 nm.

In some embodiments, the total irradiation dose of the radiation-resistant polarization maintaining fiber is 50-200 krad, and the dose rate is 1000 rad/h-5000 rad/h.

In a second aspect, a method for preparing a radiation-resistant polarization maintaining optical fiber is provided, which comprises the following steps:

(1) respectively preparing a core rod and a stress rod made of boron-doped quartz glass by adopting a PCVD (plasma chemical vapor deposition) process, wherein the core rod sequentially comprises a pure quartz fiber core, a first cladding inner layer and a pure quartz liner tube from inside to outside; polishing the core rod to remove the pure quartz liner tube;

(2) preparing a fluorine-doped pipe by adopting a PCVD (plasma chemical vapor deposition) process, wherein the fluorine-doped pipe is sequentially provided with a first cladding outer layer and a pure quartz liner pipe from inside to outside;

(3) sleeving the polished core Rod In the step (1) with the fluorine-doped pipe prepared In the step (2) by an RIC (Rod In Cylinder) process to form a fluorine-doped solid Rod; the fluorine-doped solid rod comprises a pure quartz fiber core, a first cladding inner layer, a first cladding outer layer and a pure quartz liner tube from inside to outside in sequence;

(4) sleeving a pure quartz sleeve on the periphery of the fluorine-doped solid rod by an RIC process, and melting at high temperature to form an irradiation-resistant polarization-maintaining mother rod;

(5) two stress through holes matched with the stress rods are formed along the axial direction of the irradiation-resistant polarization-maintaining mother rod, are positioned on two sides of the pure quartz fiber core and are symmetrical about the pure quartz fiber core; respectively embedding the two stress rods into the stress through holes to form an irradiation-resistant polarization-maintaining optical fiber preform;

(6) and (4) melting the radiation-resistant polarization maintaining optical fiber preform prepared in the step (5) at a high temperature, and drawing the preform into an optical fiber.

In some embodiments, the cross-sectional area of the pure quartz sleeve is 1600-3200mm²。

In some embodiments, the high-temperature melting temperature is 2000-2300 ℃, the drawing speed is 100-400 m/min, and the drawing tension is 100-200 g.

In some embodiments, the first clad inner layer and the first clad outer layer are co-melted at high temperature to form a first clad layer; and the pure quartz liner tube and the pure quartz sleeve are fused together at high temperature to form a second cladding.

In some embodiments, the core-clad ratio of the first clad layer to the pure silica core is 7.8:1, the ratio of the diameter of the irradiation-resistant polarization-maintaining optical fiber preform to the diameter of the pure silica core is 14.9-16.7:1, and the ratio of the diameter of the irradiation-resistant polarization-maintaining optical fiber preform to the diameter of the stress portion is 25: 7-9.

And in the third aspect, the application of the radiation-resistant polarization-maintaining optical fiber in the outer space environment is provided, the working wavelength of the radiation-resistant polarization-maintaining optical fiber is 1310nm and 1550nm double windows, and the induced loss of the working wavelength is below 2dB/km under the total radiation dose of 200krad and below and different dose rates.

The beneficial effect that technical scheme that this application provided brought includes:

(1) the irradiation-resistant polarization maintaining optical fiber adopts a total internal reflection structure combining a pure quartz fiber core and a fluorine-doped sunken cladding layer, so that coloring ions Ge are avoided⁴⁺The color center is generated under the irradiation condition, the refractive index difference required by optical fiber signal transmission is achieved, and the reliability of the optical fiber in the harsh environment of the universe is effectively improved.

(2) The high-temperature fusion of the first cladding inner layer and the first cladding outer layer is realized by adopting the RIC process twice, so that the first cladding of the optical fiber and the pure silicon core layer have enough core-spun ratio to realize the total internal reflection of optical signals, the second cladding of the optical fiber and the pure quartz fiber core have enough core-spun ratio to realize the accurate control of the geometric dimension of the optical fiber, the batch consistency is ensured, and the yield is high.

The embodiment of the application provides an irradiation-resistant polarization-maintaining optical fiber and a preparation method and application thereof, on one hand, photosensitive effect caused by introduction of germanium element is avoided through a pure quartz fiber core, on the other hand, stress double refraction is formed on two sides of the fiber core due to the fact that the thermal expansion coefficient of stress part boron-doped glass is 1 order of magnitude larger than that of the pure quartz glass, and in addition, signal light transmission is achieved through the proper size proportion and fluorine-doped depth of a fluorine-doped cladding layer and the pure quartz fiber core, therefore, the prepared irradiation-resistant polarization-maintaining optical fiber can achieve low-loss information transmission of the polarization-maintaining optical fiber, and good full-temperature characteristics are kept.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a cross-sectional view of a radiation-resistant polarization maintaining optical fiber provided in an embodiment of the present application;

fig. 2 is a structural diagram of a core rod in a method for manufacturing a radiation-resistant polarization maintaining optical fiber according to an embodiment of the present application;

fig. 3 is a structural diagram of a fluorine-doped tube in a method for manufacturing a radiation-resistant polarization maintaining optical fiber according to an embodiment of the present disclosure;

fig. 4 is a structural diagram of a fluorine-doped solid rod formed after a core rod is inserted into a fluorine-doped tube after polishing an irradiation-resistant polarization maintaining optical fiber provided in an embodiment of the present application;

fig. 5 is a structural diagram of an irradiation-resistant polarization-maintaining mother rod provided in an embodiment of the present application;

FIG. 6 is a schematic structural diagram of a radiation-resistant polarization-maintaining optical fiber preform provided in an embodiment of the present application;

FIG. 7 is a cross-sectional view of refractive index of a radiation-resistant polarization maintaining fiber provided in an embodiment of the present application;

FIG. 8 is a graph showing the relationship between radiation-induced loss of a radiation-resistant polarization maintaining fiber and the irradiation dose of gamma rays at different dose rates according to an embodiment of the present application;

the quartz tube comprises a 1-pure quartz fiber core, a 2-first cladding inner layer, a 3-pure quartz liner tube, a 4-first cladding, a 5-stress part, a 6-second cladding, a 7-pure quartz liner tube and a 8-first cladding outer layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. 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 application.

The embodiment of the application provides an irradiation-resistant polarization maintaining optical fiber, which can solve the problem that the polarization maintaining optical fiber cannot be used for a long time in a severe space radiation environment in the prior art.

As shown in FIG. 1, the radiation-resistant polarization-maintaining optical fiber provided by the application is composed of a pure quartz core, a first cladding, a stress part and a second cladding.

As shown in fig. 2, the core rod is composed of a pure silica core, a first clad inner layer, and a pure silica liner tube.

As shown in fig. 3, the fluorine doped tube consists of a first clad outer layer and a pure quartz liner tube.

As shown in fig. 4, the first cladding of the fluorine-doped solid rod is formed by high-temperature melting of the first cladding inner layer and the first cladding outer layer.

As shown in fig. 5, the second cladding layer of the irradiation-resistant polarization-maintaining mother rod is formed by melting a pure quartz liner tube of a fluorine-doped solid rod and a pure quartz sleeve at a high temperature.

As shown in fig. 6, a pair of symmetrical round holes is longitudinally processed along both sides of the central line of the anti-radiation polarization-maintaining mother rod, and a stress rod is plugged into the round holes to form a stress part, and finally, the stress part is combined and drawn to form the anti-radiation polarization-maintaining optical fiber.

It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. The term "relative refractive index" refers to the refractive index of a material relative to pure quartz glass.

The present application will be specifically described below by way of examples. In the following examples, pure quartz glass with a purity of 99.9999% was used for both the pure quartz sleeve and the pure quartz liner, the refractive index was 1.457, the outer diameter of the pure quartz liner was 30mm, the inner diameter was 26mm, and the cross-sectional area of the pure quartz sleeve was 1600-²。