Preparation method of deuterium-doped and carrier gas synergistic anti-radiation optical fiber, optical fiber and application

Abstract

The invention provides a preparation method of a deuterium-doped and carrier gas synergistic anti-radiation optical fiber, the optical fiber and application, and belongs to the technical field of anti-radiation optical fibers, the preparation method comprises the following steps: firstly, preparing an optical fiber preform with a fiber core doped with rare earth ions and OD groups by adopting an improved chemical vapor deposition and solution doping combined technology; drawing the optical fiber preform to prepare a double-cladding rare earth ion doped optical fiber; and finally carrying out carrier gas treatment on the double-clad rare earth ion doped optical fiber, the carrier gas being at least one of deuterium gas, hydrogen gas or oxygen gas, and obtaining the anti-radiation optical fiber. Through the synergistic effect of introduced OD groups and loaded gas molecules, the anti-radiation stability of the prepared anti-radiation optical fiber is jointly enhanced, after the finally prepared anti-radiation optical fiber is irradiated by gamma rays with the total dose of 200Gy (Si), the laser slope efficiency change at the 1080nm wave band is less than 5%, the radiation darkening effect is thoroughly inhibited, and the anti-radiation stability of the prepared anti-radiation optical fiber is improved. The problem that in the prior art, the anti-radiation performance is insufficient or cannot be maintained for a long time is solved.

Description

Technical Field

[0001] This invention relates to the field of optical fiber manufacturing technology, specifically a method for preparing radiation-resistant optical fibers using a combination of deuterium doping and carrier gas, the optical fiber itself, and its applications. Background Technology

[0002] Fiber lasers, due to their high efficiency, excellent heat dissipation, and compact structure, have been widely used in industrial processing, medical, and communication fields. In recent years, with the rapid development of cutting-edge fields such as aerospace, nuclear energy development, and radiation medicine, the demand for fiber lasers in high-radiation environments such as satellite laser communication, space lidar, and nuclear facility monitoring has become increasingly urgent. However, high-energy radiation particles (such as gamma rays and protons) in space and nuclear environments interact with fiber materials, inducing radio-induced darkening, resulting in a large number of color center defects in the fiber. This leads to a surge in transmission loss, a decrease in output power, and beam mode degradation, severely limiting the long-term reliability and service life of fiber devices in radiation environments.

[0003] To improve the radiation resistance of optical fibers, various technical approaches have been proposed. Among them, deuterium (D2) loading, through the diffusion of gas molecules into the fiber interior, can effectively passivate radiation-induced color centers and is currently recognized as one of the more effective methods. However, this technology has a fundamental drawback: the loaded D2 molecules gradually escape from the fiber under environmental conditions, causing its radiation resistance to deteriorate significantly over time, failing to meet the stringent requirements of long lifespan and high stability in aerospace, nuclear industry, and other fields. To overcome the problem of easy gas leakage, researchers have tried combining gas loading with pre-irradiation of the fiber preform or preparing barrier coatings on the fiber surface. These methods are either complex and costly, or still cannot completely suppress performance degradation during long-term service, failing to fundamentally solve the dual problems of gas escape and incomplete suppression of radiation-induced darkening.

[0004] Therefore, how to achieve long-term stable consolidation of deuterium in optical fibers and further enhance its radiation resistance has become a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a method for preparing radiation-resistant optical fibers using a synergistic combination of deuterium doping and carrier gas, along with the optical fiber itself and its applications. This method employs a two-step synergistic process of solution doping with OD groups on a preform and gas loading into the optical fiber. This combines the structural stability of the OD groups with the dynamic defect passivation capability of the carrier gas treatment, achieving complete suppression of radiation-induced darkening effects and long-term performance stability.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: A method for fabricating radiation-resistant optical fibers with synergistic effects of deuterium doping and carrier gas includes the following steps: Step 1: Using an improved chemical vapor deposition combined with solution doping technology, optical fiber preforms with rare earth ions and OD groups in the fiber core are prepared. Step 2: After inserting the optical fiber preform into the quartz glass sleeve, the fiber is drawn to obtain a double-clad rare earth ion-doped optical fiber. Step 3: The double-clad rare-earth ion-doped optical fiber is subjected to carrier gas treatment to obtain radiation-resistant optical fiber, wherein the carrier gas is at least one of deuterium, hydrogen or oxygen. In this process, the OD group introduced in step one works synergistically with the gas molecules loaded in step three to enhance the radiation resistance of the prepared radiation-resistant optical fiber. The final radiation-resistant optical fiber, after being irradiated with a total dose of 200 Gy (Si) of γ-rays, exhibits a laser slope efficiency change of less than 5% in the 1080 nm band.

[0007] Accordingly, the present invention also provides a radiation-resistant optical fiber prepared by the above method. The core of this radiation-resistant optical fiber contains OD groups and has undergone the aforementioned carrier gas treatment, wherein the carrier gas is at least one of deuterium, hydrogen, or oxygen. The radiation-resistant optical fiber exhibits a laser slope efficiency change of less than 5% in the 1080 nm band before and after being irradiated with a total dose of 200 Gy (Si) of gamma rays.

[0008] Accordingly, the present invention also provides the application of the above-mentioned radiation-resistant optical fiber in space laser communication systems, satellite lidar systems, nuclear facility environmental monitoring systems, or high-energy physics experimental devices.

[0009] This invention proposes a novel technical approach: First, by directly introducing chemically bonded OD groups into the optical fiber preform through solution doping, the structural stability of the glass network is enhanced from the material's origin, providing a durable and stable foundation for the fiber's radiation resistance. Building upon this, gas loading treatment is combined with the dynamic passivation effect of gas molecules on newly formed defects during radiation, achieving synergistic suppression of radiation-induced darkening effects and comprehensive performance enhancement. This synergistic strategy aims to simultaneously address the dual challenges of long-term deuterium retention and dynamic defect suppression under radiation, providing a new technical approach for the development of next-generation high-reliability radiation-resistant optical fibers.

[0010] Compared with the prior art, the beneficial effects of the present invention are: On the one hand, an improved chemical vapor deposition (MCVD) combined with solution doping technology is used to prepare optical fiber preforms with rare earth ions and OD groups in the fiber core. That is, in the preform preparation stage, OD groups are directly bonded into the quartz glass network through solution doping, which enhances the structural stability of the glass network from the material source and provides a durable and stable foundation for the radiation resistance performance of optical fibers. Specifically, it includes: (1.1) depositing a SiO2 barrier layer in a quartz deposition tube; (1.2) depositing a porous layer on the SiO2 barrier layer; (1.3) immersing the quartz deposition tube with the SiO2 barrier layer and the porous layer in an Al-containing solution. 3+ In a mixed solution of rare earth ions and OD groups, the OD groups are adsorbed onto a porous layer; (1.4) The quartz deposition tube that has completed step (1.3) is dried, sintered, and collapsed to produce an optical fiber preform doped with OD groups. In this way, the OD groups are adsorbed onto the porous layer, and the OD groups are pre-filled into the porous layer. The OD groups that are chemically bonded to the glass network enhance the structural stability from the source. The stable OD bonds can effectively reduce or even avoid the generation of radiation-induced color centers, thereby greatly improving the intrinsic radiation resistance of the optical fiber and providing long-term radiation resistance performance.

[0011] On the other hand, in the carrier gas treatment stage after fiber drawing, high-pressure gas molecules can penetrate into the microstructure of the optical fiber glass. The carrier gas is not limited to deuterium, but can also be hydrogen or oxygen. This invention does not rely on loading deuterium (D2) into the optical fiber through gas molecule diffusion during the carrier gas treatment stage. The carrier gas of this invention can also be hydrogen or oxygen, because in the previous preform preparation stage, OD groups are directly bonded into the quartz glass network through solution doping, and the OD groups are already chemically bonded to the glass network. During the carrier gas stage, under irradiation conditions, gas molecules can react with residual defects or newly formed color center defects generated by irradiation, passivating them and forming stable chemical bonds.

[0012] This invention achieves a fundamental breakthrough in the radiation resistance of optical fibers through a synergistic strategy of solution doping with OD groups and carrier gas treatment. OD groups, pre-bonded chemically to the glass network during the preform preparation stage, alter the local chemical environment of the glass network. Meanwhile, carrier gas treatment compensates for potential concentration deficiencies associated with simple doping. The synergistic effect of both ensures the optical fiber network remains highly stable both before and after irradiation. Specifically, this invention elevates the radiation resistance of optical fibers to a new level through the synergistic strategy of solution doping with OD groups and carrier gas treatment, resulting in a laser slope efficiency attenuation of less than 5% after 200 Gy(Si) irradiation, and preferably, complete suppression of radiation-induced darkening effects.

[0013] The OD groups in this invention exist stably in the fiber core in the form of chemical bonds, eliminating gas leakage and ensuring long-term stability of radiation resistance. Even if the effect of subsequent carrier gas treatment slowly decreases due to trace diffusion, the fiber can still maintain excellent radiation resistance thanks to the solidified OD groups. Furthermore, the process is compatible with standard MCVD combined with solution doping, and the carrier gas treatment is a room-temperature, high-pressure process with simple equipment and easy implementation. This method is widely applicable to various rare-earth-doped fibers such as ytterbium-doped, erbium-doped, and thulium-doped fibers, providing a key technical guarantee for the long-term reliable operation of fiber lasers in extreme radiation environments. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0015] Figure 1 This is a process flow diagram of the synergistic enhancement method of the present invention; Figure 2 This is a schematic diagram of the oscillator used in an experimental example and a comparative example for testing the slope efficiency of a fiber optic laser. Figure 3 This is a comparison chart showing the effects of an example and a comparative example in an experiment; Figure 2 Explanation of the designation numbers: 1. Pump source; 2. Pump combiner; 3. High reflectivity fiber Bragg grating; 4. Double-clad ytterbium-doped fiber; 5. Low reflectivity fiber Bragg grating; 6. Cladding power stripper; 7. Quartz output cap. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] In one embodiment, a method for fabricating radiation-resistant optical fiber with synergistic deuterium doping and carrier gas is provided, comprising the following steps: Step 1: Using an improved chemical vapor deposition combined with solution doping technology, optical fiber preforms with rare earth ions and OD groups in the fiber core are prepared. Step 2: After inserting the optical fiber preform into the quartz glass sleeve, the fiber is drawn to obtain a double-clad rare earth ion-doped optical fiber. Step 3: The double-clad rare-earth ion-doped optical fiber is subjected to carrier gas treatment to obtain radiation-resistant optical fiber, wherein the carrier gas is at least one of deuterium, hydrogen or oxygen. In this process, the OD group introduced in step one works synergistically with the gas molecules loaded in step three to enhance the radiation resistance of the prepared radiation-resistant optical fiber. The final radiation-resistant optical fiber, after being irradiated with a total dose of 200 Gy (Si) of γ-rays, exhibits a laser slope efficiency change of less than 5% in the 1080 nm band.

[0018] In the above embodiments, an improved chemical vapor deposition combined with solution doping technology is used in step one to prepare an optical fiber preform with rare earth ions and OD groups in the fiber core. The OD groups introduced into the fiber core are more chemically stable and less prone to precipitation during long-term use. Therefore, the radiation-resistant optical fiber obtained is not temporary in its radiation resistance performance, but rather long-term, reliable, and stable, solving the problem of performance degradation over time in optical fibers obtained solely through carrier gas treatment. During the optical fiber preform preparation process, the OD groups exist stably in the fiber core in the form of chemical bonds. During the fiber formation stage, a highly efficient and synergistic defect suppression system is constructed through the carrier gas treatment, where the pressure, time, and gas are flexibly selectable and controllable. This ultimately achieves near-complete immunity to radiation-induced darkening effects, ensuring that the optical fiber network remains highly stable before and after irradiation.

[0019] In one embodiment, step one involves using an improved chemical vapor deposition combined with solution doping technology to prepare an optical fiber preform with rare earth ions and OD groups in the fiber core. Specific steps include: (1.1) A SiO2 barrier layer was deposited in a quartz deposition tube using an improved chemical vapor deposition (MCVD) method; (1.2) Further, a porous layer is deposited on the SiO2 barrier layer using an improved chemical vapor deposition (MCVD) method; (1.3) Immerse the quartz deposition tube with the SiO2 barrier layer and porous loose layer in an Al-containing solution. 3+ In a mixed solution of rare earth ions and OD groups, the OD groups are adsorbed onto the porous and loose layer. (1.4) The quartz deposition tube obtained in step (1.3) is dried, sintered, and collapsed to produce an optical fiber preform doped with OD groups. The content of OD groups in the optical fiber preform doped with OD groups is 20ppm to 200ppm.

[0020] In the above embodiment, a high-purity, dense SiO2 barrier layer is first deposited on the inner wall of the quartz deposition tube. Commercial quartz tubes (such as Heraeus F-300) themselves contain trace amounts of metallic impurities (such as Fe, Cu, etc.). The SiO2 barrier layer effectively prevents these impurities from diffusing into the core region during subsequent high-temperature processes, ensuring the extremely high purity of the core glass matrix, which is a prerequisite for obtaining low intrinsic loss and excellent radiation resistance. The porous layer is a porous, loose layer with a high specific surface area, composed of nano-sized SiO2 particles. This porous structure allows it to efficiently and fully adsorb the subsequent mixed solution through capillary action, like a sponge, removing Al contained in the mixed solution. 3+ Rare earth ions and OD groups are introduced into the glass network structure. The mixed solution can penetrate into every pore of the porous layer, realizing Al 3+ The highly uniform distribution of rare earth ions and OD groups avoids the concentration gradient and agglomeration problems that may occur in traditional gas-phase doping. The porous, loosely layered quartz deposition tube is immersed in an Al-containing solution. 3+ In a mixed solution of rare earth ions and OD groups (from D2O or other deuterated compounds), the OD groups directly enter the surface and interior of the porous layer, pre- and uniformly distributing the OD groups within the porous layer. During subsequent drying, sintering, and collapse processes, these OD groups directly and firmly bond into the final SiO2 glass network at high temperatures, forming a stable Si-OD structure. This ensures that the OD groups do not exist in a physically adsorbed form, but rather exist stably as part of the glass network structure, thus enabling them to play a durable and reliable role in subsequent carrier gas treatment and long-term irradiation.

[0021] In one embodiment, in step (1.3), the mixed solution contains Al. 3+ A mixed solution of rare earth ions and OD groups, wherein the OD groups are derived from D2O or other deuterated compounds. In step (1.3) above, the rare earth ions can be Yb³. + Er³ + Tm³ + Ho³ + 、Nd³ + At least one of them. As in one embodiment, Al³ in the mixed solution. + Concentrations ranging from 0.5 mol / L to 4 mol / L, Yb³ + The concentration is 0.1 mol / L to 2 mol / L, and the solvent is 50% heavy water and 50% anhydrous ethanol.

[0022] In another embodiment, in step (1.3), the rare earth ions in the mixed solution may also include Yb³. + Er³ + Tm³+ Ho³ + 、Nd³ + The mixed solution may also include at least one of the following: Al³⁺ + P 5+ At least one of them.

[0023] In one embodiment, the mixed solution contains Al 3+ Yb 3+ and OD groups, of which Al 3+ Concentrations range from 0.5 mol / L to 4 mol / L, Yb 3+ The concentration ranges from 0.1 mol / L to 2 mol / L, and the solvent for the mixed solution is 50% heavy water and 50% anhydrous ethanol. In practical applications, the content of OD groups in the mixed solution can be changed by altering the proportion of heavy water in the solvent. Furthermore, the heavy water can be replaced with other deuterated compounds.

[0024] In one embodiment, in step three, the carrier gas treatment is carried out in a closed environment, where deuterium gas is loaded at a pressure of 5 MPa to 13 MPa and a temperature of 10°C to 40°C, for a treatment time of 5 to 30 days. Preferably, in step three, the carrier gas treatment is carried out in a closed environment, where deuterium gas is loaded at a pressure of 7 MPa to 10 MPa and a temperature of 20°C to 35°C, for a loading time of 7 to 20 days.

[0025] This invention provides a method for synergistically enhancing the radiation resistance of optical fibers through doping with OD groups and carrier gas. The core of this method lies in the synergy of two key steps: firstly, OD groups are introduced through solution doping during the preform preparation stage, and secondly, carrier gas treatment is performed after fiber formation.

[0026] The technical solution of this application will be described below with reference to specific comparative experiments, so as to demonstrate the effectiveness and superiority of the present invention.

[0027] Example 1: Reference Figure 1 A method for fabricating radiation-resistant optical fibers with synergistic effects of deuterium doping and carrier gas includes the following steps: Step 1: Using chemical vapor deposition combined with solution doping technology, optical fiber preforms with rare earth ions and OD groups in the fiber core are prepared. (1.1) Using the MCVD process, SiCl4 and O2 are introduced into a Heraeus F-300 quartz deposition tube at 1900℃ to deposit and sinter to form a SiO2 barrier layer.

[0028] (1.2) At 1500°C, SiCl4, POCl3 and O2 are introduced to deposit a porous layer on the SiO2 barrier layer.

[0029] (1.3) After the quartz deposition tube has cooled, it is vertically immersed in an Al-containing solution. 3+ Yb 3+ Immerse in a mixed solution of Al³ and OD groups for 30 to 120 minutes, where Al³ + Concentration approximately 2 mol / L, Yb³ + The concentration is approximately 0.4 mol / L, and the solvent for the mixed solution is 50% heavy water and 50% anhydrous ethanol.

[0030] (1.4) After removing the quartz deposition tube, the quartz deposition tube was installed on an MCVD lathe and dried at 800°C in an atmosphere of Cl2, He and O2. Subsequently, it was sintered at 2000°C in an atmosphere of O2 and He, and collapsed into a solid optical fiber preform at 2150°C. The concentration of OD groups in the optical fiber preform was measured to be approximately 50 ppm.

[0031] Step 2: According to the size requirements, the solid optical fiber preform is inserted into the quartz glass sleeve and drawn at 2000℃ in the drawing tower to form a double-clad ytterbium-doped optical fiber with a core / cladding diameter of 20 / 400μm. Step 3: Place the double-clad rare-earth ion-doped optical fiber in a sealed pipeline for carrier gas treatment, fill it with deuterium gas to a pressure of 7MPa~10MPa, and keep it at a constant temperature of 25℃ for 15 days to obtain radiation-resistant optical fiber.

[0032] Comparative Example 1: The method for preparing radiation-resistant optical fiber in Comparative Example 1 includes: Step 1: Prepare optical fiber preforms; (1.1) Using the MCVD process, SiCl4 and O2 are introduced into a Heraeus F-300 quartz deposition tube at 1900℃ to deposit and sinter to form a SiO2 barrier layer.

[0033] (1.2) At 1500°C, SiCl4, POCl3 and O2 are introduced to deposit a porous layer on the SiO2 barrier layer.

[0034] (1.3) After the quartz deposition tube has cooled, it is vertically immersed in an Al-containing solution. 3+ Yb 3+ Soak in a mixed solution for 30 to 120 minutes, in which Al³ + Concentration approximately 2 mol / L, Yb³ + The concentration is approximately 0.4 mol / L, and the solvent for the mixed solution is anhydrous ethanol.

[0035] (1.4) After removing the quartz deposition tube, the quartz deposition tube is dried at 800°C in an atmosphere of Cl2, He and O2, and then sintered at 2000°C in an atmosphere of O2 and He, and collapsed into a solid optical fiber preform at 2150°C.

[0036] Step 2: According to the size requirements, the solid optical fiber preform is inserted into the quartz glass sleeve and drawn in the drawing tower at 2000℃ to form a double-clad ytterbium-doped optical fiber with a core / cladding diameter of 20 / 400μm.

[0037] The difference between Comparative Example 2 and Example 1 is that the mixed solution used for soaking in step one does not contain OD groups, and ordinary double-clad ytterbium-doped optical fibers without OD groups are prepared, and the carrier gas treatment in step three is not performed.

[0038] Comparative Example 2: The method for preparing radiation-resistant optical fiber in Comparative Example 2 includes: Step 1: Using an improved chemical vapor deposition combined with solution doping technology, optical fiber preforms with rare earth ions and OD groups in the fiber core are prepared. (1.1) Using the MCVD process, SiCl4 and O2 are introduced into a Heraeus F-300 quartz deposition tube at 1900℃ to deposit and sinter to form a SiO2 barrier layer.

[0039] (1.2) At 1500°C, SiCl4, POCl3 and O2 are introduced to deposit a porous layer on the SiO2 barrier layer.

[0040] (1.3) After the quartz deposition tube has cooled, it is vertically immersed in an Al-containing solution. 3+ Yb 3+ Immerse in a mixed solution containing Al³⁺ and OD groups for 30 to 120 minutes, wherein the mixed solution contains Al³⁺. + Concentration approximately 2 mol / L, Yb³ + The concentration is approximately 0.4 mol / L, and the solvent for the mixed solution is 50% heavy water and 50% anhydrous ethanol.

[0041] (1.4) After removing the quartz deposition tube, the quartz deposition tube was installed on an MCVD lathe and dried at 800°C in an atmosphere of Cl2, He, and O2. Subsequently, it was sintered at 2000°C in an atmosphere of O2 and He, and collapsed into a solid optical fiber preform at 2150°C. The concentration of OD groups in the solid optical fiber preform was measured to be approximately 50 ppm.

[0042] Step 2: According to the size requirements, the optical fiber preform is inserted into the quartz glass sleeve and drawn at 2000℃ in the drawing tower to form a double-clad ytterbium-doped optical fiber with a core / cladding diameter of 20 / 400μm.

[0043] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 does not perform the carrier gas treatment in step three.

[0044] Comparative Example 3: The method for preparing radiation-resistant optical fiber in Comparative Example 3 includes: Step 1: Prepare optical fiber preforms; (1.1) Using the MCVD process, SiCl4 and O2 are introduced into a Heraeus F-300 quartz deposition tube at 1900℃ to deposit and sinter to form a SiO2 barrier layer.

[0045] (1.2) At 1500°C, SiCl4, POCl3 and O2 are introduced to deposit a porous layer on the SiO2 barrier layer.

[0046] (1.3) After the quartz deposition tube has cooled, it is vertically immersed in an Al-containing solution. 3+ Yb 3+ Soak in a mixed solution for 30 to 120 minutes, wherein the mixed solution contains Al³ + Concentration approximately 2 mol / L, Yb³ + The concentration is approximately 0.4 mol / L, and the solvent for the mixed solution is anhydrous ethanol.

[0047] (1.4) After removing the quartz deposition tube, the quartz deposition tube is dried at 800°C in an atmosphere of Cl2, He and O2, and then sintered at 2000°C in an atmosphere of O2 and He, and collapsed into a solid optical fiber preform at 2150°C.

[0048] Step 2: According to the size requirements, the solid optical fiber preform is inserted into the quartz glass sleeve and drawn in the drawing tower at 2000℃ to form a double-clad ytterbium-doped optical fiber with a core / cladding diameter of 20 / 400μm.

[0049] Step 3: Place the double-clad rare-earth ion-doped optical fiber in a sealed pipeline for carrier gas treatment, fill it with deuterium gas to a pressure of 7MPa~10MPa, and keep it at a constant temperature of 25℃ for 15 days to obtain radiation-resistant optical fiber.

[0050] The difference between Comparative Example 3 and Example 1 is that the mixed solution used for soaking in step one does not contain OD groups, thus preparing a conventional double-clad ytterbium-doped optical fiber without OD groups. Unlike Comparative Example 1, Comparative Example 3 underwent the same deuterium loading treatment as Example 1.

[0051] The performance of the optical fiber samples prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 was tested and the results were analyzed. The optical fiber samples obtained in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were subjected to the following tests: (1) Gamma-ray irradiation: All optical fiber samples were subjected to gamma-ray irradiation treatment with a total dose of 200 Gy (Si) and a dose rate of 1.5 Gy / min (Si).

[0052] (2) Laser performance testing: Refer to Figure 2An all-fiber oscillator was constructed, comprising a pump source 1, a pump combiner 2, a high-reflectivity fiber Bragg grating 3, a double-clad ytterbium-doped fiber 4, a low-reflectivity fiber Bragg grating 5, a cladding power stripper 6, and a quartz output cap 7. The laser output characteristics of the fiber before and after irradiation were tested using this all-fiber oscillator. Pump source 1 consists of two laser diodes operating at 976 nm. The pump light is coupled into the high-reflectivity fiber Bragg grating 3, the double-clad ytterbium-doped fiber 4, and the low-reflectivity fiber Bragg grating 5 through a pump combiner 2 (in this scheme, a (2+1)×1 pump combiner). The signal output fiber of pump combiner 2 is 20 / 250 µm long. All ytterbium-doped fibers are 20 cm long to ensure sufficient pump absorption. The high-reflectivity fiber Bragg grating 3 and the corresponding low-reflectivity fiber Bragg grating 5 have reflectivities of approximately 99.9% and 9.3% at a center wavelength of 1080 nm, respectively, and 3dB bandwidths of approximately 3.8 nm and 1.9 nm, respectively. To eliminate unabsorbed pump light, a cladding power stripper 6 is placed at the output end of the laser, and the output laser is output through a quartz output cap 7. Double-clad ytterbium-doped fiber 4 was prepared using the methods described in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 to compare the radiation resistance of double-clad ytterbium-doped fiber 4 prepared by different methods.

[0053] The results are as follows Figure 3 As shown, in Comparative Example 1, the laser slope efficiency decreased from 58% before irradiation to 9%, reflecting the severe suppression effect of radiation-induced loss on the output power of the fiber laser. In Comparative Example 2, the laser slope efficiency decreased from 58% before irradiation to 15%, with a lower performance degradation than in Comparative Example 1, indicating that doping with a small amount of OD groups improved the radiation resistance of the fiber to some extent. In Comparative Example 3, the laser slope efficiency was 51% after irradiation, recovering to 88% of the pre-irradiation level. This result shows that D2 loading effectively passivated the irradiation-induced color centers and significantly suppressed the increase in irradiation loss. In Example 1, the laser slope efficiency was 58% after irradiation, completely consistent with the pre-irradiation level, indicating that the synergistic effect of OD group doping combined with D2 loading can completely suppress the radiation-induced darkening effect.

[0054] The above results demonstrate that the present invention can significantly improve the radiation resistance of optical fibers through the synergistic effect of liquid-phase doping OD groups and carrier gas treatment. Preferably, it can completely suppress the radiation-induced darkening effect. If hydrogen or oxygen is used as the loading gas, the synergistic effect with the OD groups can also reduce the laser slope efficiency attenuation to less than 5%, meeting the radiation resistance requirements. This is mainly because the OD groups pre-stabilize the fiber core structure, and the subsequently loaded gas molecules can further passivate the color center defects generated during radiation, thereby achieving zero attenuation of fiber laser performance under harsh radiation environments.

[0055] The method described in this invention is not only applicable to ytterbium-doped optical fibers, but also, by replacing rare earth ions, to other rare earth-doped optical fibers such as erbium-doped, thulium-doped, and erbium-ytterbium co-doped fibers, as well as pure quartz power transmission fibers that require improved radiation resistance.

[0056] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0057] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for preparing a deuterium-doped and carrier-gas-assisted radiation-resistant optical fiber, characterized in that, The method comprises the following steps: Step one, using improved chemical vapor deposition combined with solution doping technology, a fiber preform rod doped with rare earth ions and OD groups in the core is prepared; Step two, the fiber preform rod is sleeved into a quartz glass sleeve and then drawn to obtain a double-clad rare earth ion doped optical fiber; Step three, the double-clad rare earth ion doped optical fiber is treated with a carrier gas to obtain an anti-radiation optical fiber, wherein the carrier gas is at least one of deuterium, hydrogen or oxygen; In step one, the OD groups introduced and the gas molecules loaded in step three synergistically enhance the anti-radiation stability of the prepared anti-radiation optical fiber, and the final anti-radiation optical fiber has a laser slope efficiency change of less than 5% at a wavelength of 1080 nm after being subjected to a total dose of 200 Gy (Si) of gamma ray irradiation.

2. The method of claim 1, wherein the deuterium-doped anti-radiation optical fiber is prepared in cooperation with a carrier gas. Step one comprises: (1.1) depositing a SiO2 barrier layer in a quartz deposition tube; (1.2) depositing a porous loose layer on the SiO2 barrier layer; (1.3) soaking the quartz deposition tube, on which the porous loose layer and the SiO2 barrier layer are deposited, in a mixed solution containing Al 3+ , rare earth ions and OD groups, so as to adsorb the OD groups on the porous loose layer; (1.4) drying, sintering and collapsing the quartz deposition tube after step (1.3) to obtain a solid optical fiber preform rod doped with OD groups.

3. The method of claim 2, wherein the deuterium-doped anti-radiation optical fiber is prepared by the steps of: In the step (1.3), the rare earth ions in the mixed solution are at least one of Yb3 + , Er3 + , Tm3 + , Ho3 + , and Nd3 + . ​ 4. The method of claim 2, wherein the deuterium-doped anti-radiation optical fiber is prepared in cooperation with a carrier gas. The rare earth ions in the mixed solution in the step (1.3) include at least one of Yb3 + , Er3 + , Tm3 + , Ho3 + , and Nd3 + , and the mixed solution further includes at least one of Al3 + , P 5+ .

5. The method of claim 2, wherein the deuterated anti-radiation optical fiber is prepared by the steps of: In the step (1.3), the mixed solution is a mixed solution containing Al 3+ , Yb³ + and OD groups, wherein the OD groups are derived from a deuterated compound, which includes D2O. ​ 6. The method of claim 5, wherein the deuterated anti-radiation optical fiber is prepared by the steps of: Al3+ in the mixed solution + Yb3+ concentration is 0.5mol / L~4mol / L + Yb3+ concentration is 0.1mol / L~2mol / L, the solvent is a mixture of heavy water and anhydrous ethanol, and the content of OD group in the mixed solution is changed by changing the proportion of heavy water in the solvent. ​ 7. The method of claim 1 to 6, wherein the method is characterized by, In step (1.4), the content of OD groups in the optical fiber preform rod doped with OD groups is 20 ppm to 200 ppm.

8. The method of claim 7, wherein the deuterated anti-radiation optical fiber is prepared by the steps of: providing a deuterated anti-radiation optical fiber; and providing a carrier gas; and combining the deuterated anti-radiation optical fiber and the carrier gas. In step three, the carrier gas treatment is carried out in a closed environment, the closed environment is loaded with deuterium, the pressure is 5 MPa to 13 MPa, the temperature is 10°C to 40°C, and the treatment time is 5 days to 30 days.

9. Radiation resistant optical fiber, characterized in that, Prepared by the method of claim 1 or 2 or 3 or 4 or 5 or 6 or 8.

10. The anti-radiation optical fiber of claim 9 is applied in a space laser communication system, a satellite laser radar system, a nuclear facility environmental monitoring system or a high-energy physics experiment device.

Images