Radiation-resistant erbium-ytterbium-phosphorus-cerium-antimony co-doped silica fiber and preparation method and application thereof
By introducing erbium, ytterbium, phosphate, cerium, antimony co-doped silica into the fiber core and performing specific treatment, the problem of insufficient radiation resistance performance of fiber lasers in space radiation environment is solved, and the laser performance and radiation resistance performance are achieved. The preparation process is simplified.
Patent Information
- Application Number
- CN202411557916.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-04
- Publication Date
- 2024-12-27
AI Technical Summary
The existing fiber lasers lack radiation resistance in space radiation environments, especially the loss of active fibers is large, and the prior art often improves radiation resistance with a decrease in laser performance or increase in process complexity.
Erbium ytterbium phosphate cerium antimony co-doped silica as the fiber core, the valence state is regulated by introducing variable ions Ce3+/4+ and Sb3+/5+, combined with low-temperature pretreatment technology, and further through deuterium effusion, X-ray preirradiation and Vacuum treatment improves the radiation resistance of the optical fiber.
It significantly improves the radiation resistance of the optical fiber, and has little impact on the original laser performance. The preparation process is simple and fast, and can maintain good radiation resistance for a long time.
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Figure CN119200086A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of optical fiber manufacturing, and relates to a radiation-resistant erbium-ytterbium-phosphorus-cerium-antimony co-doped quartz optical fiber and a preparation method and application thereof. Background Art
[0002] Fiber lasers have the advantages of high brightness, good robustness, and a high power-to-weight ratio. They have important applications in space waste disposal, space laser communications, lidar, and remote sensing. Space is a complex environment with strong radiation, high vacuum, and large temperature differences. Studies have shown that active fiber is the most radiation-sensitive unit in the entire fiber laser. Under the same irradiation conditions, the radiation-induced loss of active fiber is three orders of magnitude higher than that of passive fiber. When a fiber laser is exposed to space ionizing radiation, the loss of the active fiber will increase dramatically and the laser output performance will be greatly degraded. However, physical shielding cannot completely block space ionizing radiation, and will increase the mass of the laser payload, making it difficult to meet the requirements of lightweight design of space payloads. Therefore, in order to improve the service life of fiber lasers in space radiation environments, active optical fibers must have radiation resistance.
[0003] In order to improve the radiation resistance of active optical fibers, the following methods are used in the prior art: (1) Reducing radiation-sensitive elements: As shown in prior art studies, the use of nanoparticle doping technology can effectively disperse Er 3+ Clusters, in ensuring Er 3+ Under the premise that the ions do not experience concentration quenching, radiation-sensitive elements such as Al and P can be doped as little as possible or even not doped, thereby improving the radiation resistance of erbium-doped optical fibers (US2010 / 0142033A1 and US2010 / 0118388A1). However, its disadvantage is that the rare earth ion doping concentration is sacrificed. In order to avoid the concentration quenching effect, this method requires that the rare earth ion doping concentration does not exceed 1000ppm.
[0004] (2) Optimizing the core material composition: In the prior art, a certain amount of Ce is introduced into Er-Yb-P co-doped quartz optical fiber. 3+ 、Ce 4+ Capturing holes and electrons generated by irradiation in optical fibers can effectively improve the radiation resistance of optical fibers (US9025925B2). However, there are certain shortcomings. On the one hand, Ce will increase the core refractive index, which is not conducive to the regulation of the core numerical aperture. On the other hand, if the co-doped Ce content is too high, the laser or gain performance of EYDF will deteriorate.
[0005] (3) Optical fiber radiation resistance reinforcement treatment: Studies in the prior art have shown that pre-loading hydrogen (H2) or pre-loading deuterium (D2) treatment can significantly improve the radiation resistance of EDF. However, its main disadvantage is that the loaded gas molecules can diffuse out of the optical fiber within a few months, resulting in a decrease in the optical fiber's radiation resistance. Although the use of airtight carbon coating or metal coating can effectively solve the gas overflow problem, it increases the complexity of the process, and the sealed coating optical fiber carrier gas requires higher temperature and pressure. High temperature carrier gas will seriously damage the mechanical properties of the outer polymer-based coating layer (IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 55, NO. 4, AUGUST 2008).
[0006] Based on the above research and combined with the application demand of space laser radar for high-brightness radiation-resistant erbium-ytterbium co-doped optical fiber in the 1.5μm band, the present invention provides a radiation-resistant erbium-ytterbium-phosphorus-cerium-antimony co-doped quartz optical fiber and a preparation method thereof. The optical fiber is innovative in both core composition and preparation process. Summary of the invention
[0007] The object of the present invention is to provide an irradiation-resistant Erbium-Ytterbium-Cerium-Antimony co-doped quartz optical fiber and its preparation method and application. The optical fiber adopts Erbium-Ytterbium-Cerium-Antimony co-doped silica as the core, and introduces a small amount of variable valence ions (Ce 3+ / 4+ and Sb 3+ / 5+ ), combined with the low-temperature pretreatment process to regulate the valence of the variable-valence ions. Not only does it not have a significant negative impact on the original laser performance and mechanical properties of the optical fiber, it can also simply and quickly improve the radiation resistance of the optical fiber.
[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:
[0009] In a first aspect, the present invention provides a radiation-resistant erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica optical fiber, the radiation-resistant erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica optical fiber comprising a coating layer, an outer cladding layer, an inner cladding layer, and a doped core, wherein the inner cladding layer is coated on the surface of the doped core, the outer cladding layer is coated on the surface of the inner cladding layer, the coating layer is coated on the surface of the outer cladding layer, and the doped core is erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica glass;
[0010] The doping ions in the Er-Yb-Ce-Sb co-doped silica glass include Er 3+ , Yb 3+ , P 5+ 、Ce 3+ / 4+ and Sb 3 + / 5+ .
[0011] The radiation-resistant erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica optical fiber of the present invention comprises a doped core, an inner cladding, an outer cladding, and a coating layer from the inside to the outside, wherein the inner cladding is made of pure silica glass, the outer cladding is made of fluorine-doped acrylate, the coating layer is made of high-modulus acrylate, and the doped core of the present invention is made of specific erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica glass.
[0012] The fiber core of the present invention is composed of Er, Yb, P, Cerium, Antimony co-doped silica glass, and the valence ions (Ce 3+ / 4+ and Sb 3+ / 5+ ) can significantly enhance the radiation resistance of optical fiber. 3+ and Sb 3+ It can effectively capture holes, thus effectively suppressing the generation of hole-type color centers in optical fibers (such as Ce 3+ +h + →Ce 4+ , Sb 3+ +2h + →Sb 5+ ); although Ce 4+ and Sb 5+ It can effectively capture electrons, thereby effectively suppressing the generation of electronic color centers in optical fibers (such as Ce 4+ +e - →Ce 3+ , Sb 5+ +2e - →Sb 3+ However, a large number of studies have shown that the electronic color center absorption is mainly in the ultraviolet and visible bands (≤500nm), for Er 3+ The working band of ions (1550nm) has little effect; while the absorption of hole-type color centers is mainly located in the visible and near-infrared bands (≥500nm), which has little effect on Er 3+ The working wavelength of the ions (1550nm) has a great influence (The Journal of Physical Chemistry B, 2018, 122(10): 2809-2820.). Therefore, it is necessary to focus on suppressing the generation of hole-type color centers during the radiation process. The present invention regulates most of the variable valence ions to a low valence state, which can effectively suppress the generation of hole-type color centers, thereby effectively improving the radiation resistance of quartz optical fiber.
[0013] Preferably, in the erbium, ytterbium, phosphorus, cerium and antimony co-doped silica glass, the content of Er element is 0.20-0.21wt%, for example, it can be 0.2wt%, 0.202wt%, 0.204wt%, 0.206wt%, 0.208wt% or 0.21wt%, the content of Yb element is 3.9-4.0wt%, for example, it can be 3.9wt%, 3.92wt%, 3.94wt%, 3.96wt%, 3.98wt% or 4.0wt%, the content of P element is 12-13wt%, for example, it can be 12wt%, 12.2wt%, 12.4wt%, 12.6wt%, 12.8wt% or 13wt%, and the content of Ce element is 0.1-0.2wt%. t%, for example, it can be 0.1wt%, 0.12wt%, 0.14wt%, 0.16wt%, 0.18wt% or 0.2wt%, the content of Sb element is 0.1-0.2wt%, for example, it can be 0.1wt%, 0.12wt%, 0.14wt%, 0.16wt%, 0.18wt% or 0.2wt%, the total content of Si element and O element is 82.39-83.7wt%, for example, it can be 82.39wt%, 82.6wt%, 82.8wt%, 83.0wt%, 83.2wt%, 83.4wt%, 83.6wt% or 83.7wt%, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.
[0014] The present invention reduces the influence of variable valence ions on Er by strictly controlling the doping concentration of variable valence ions. 3+ The negative impact on the ion luminescence performance will not have a significant negative impact on the original laser performance of the optical fiber.
[0015] In the erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica of the present invention, the Sb doping amount is within a specific range, which can ensure that the laser performance and radiation resistance of the optical fiber are both in the optimal state. If the Sb doping amount is too little, the laser performance of the optical fiber is high, but the radiation resistance is poor, which cannot meet the application requirements; if the Sb doping amount is too much, the radiation resistance of the optical fiber is good, but the laser efficiency is seriously reduced, which also cannot meet the application requirements.
[0016] Preferably, the radiation-resistant Er:Yb:P:C:Sb co-doped quartz optical fiber has a laser efficiency of >33%, for example, 33.1%, 33.5%, 34%, 34.5%, 35%, 35.5%, 36%, 36.5% or 37%, and a laser output power of >3.6 W, for example, 3.65 W, 3.7 W, 3.75 W, 3.8 W, 3.85 W, 3.9 W, 3.95 W or 4 W, but is not limited to the listed values, and other values within the numerical range not listed are also applicable.
[0017] In a second aspect, the present invention provides a method for preparing the radiation-resistant erbium, ytterbium, phosphorus, cerium, antimony co-doped quartz optical fiber as described in the first aspect, the preparation method comprising the following steps:
[0018] (1) preparing untreated Er / Yb / Ce / Sb co-doped silica optical fiber;
[0019] (2) The untreated erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica optical fiber of step (1) is subjected to deuterium infiltration treatment, X-ray irradiation treatment, and vacuum treatment in sequence to obtain the radiation-resistant erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica optical fiber.
[0020] The present invention can effectively control the valence state of variable valence ions by directly performing deuterium infiltration, X-ray irradiation treatment and vacuuming on the quartz optical fiber, and can control most variable valence ions to a low valence state, effectively inhibiting the generation of hole-type color centers, thereby effectively improving the radiation resistance of the quartz optical fiber. In particular, the use of X-rays for pre-irradiation treatment can effectively improve the radiation resistance of the erbium, ytterbium, phosphorus, cerium and antimony co-doped quartz optical fiber, because the pre-irradiation treatment can reduce the color center precursors and make more variable valence ions exist in a low valence state, thereby increasing the hole-type color center capture ability. Therefore, the present invention can greatly improve its radiation resistance through the coordination of the preparation process, while having little effect on its original laser performance, and can also maintain its radiation resistance for a long time.
[0021] Preferably, during the X-ray irradiation treatment in step (2), the total irradiation dose is 200-2400 Gy, for example, it can be 200 Gy, 500 Gy, 1000 Gy, 1500 Gy, 2000 Gy or 2400 Gy, but is not limited to the listed values. Other values not listed in the numerical range are also applicable, preferably 500-2400 Gy, and more preferably 1500-2400 Gy.
[0022] The present invention preferably uses a specific total irradiation dose for X-ray irradiation treatment, because X-rays can provide activation energy to promote the deuterium molecules to bind stress bonds and variable valence ions (Ce 3+ / 4+ and Sb 3+ / 5+ ) chemically react to generate Si-OD and Si-D groups, as well as more low-valent ions (such as Ce 3+ and Sb 3+ This can significantly reduce the color center precursors (stress bonds) and effectively inhibit hole-type color centers (such as Ce 3+ +h + →Ce 4+ , Sb 3+ +2h + →Sb 5+) is produced. Therefore, the radiation resistance of optical fiber can be greatly improved. However, the pre-irradiation dose needs to be optimized. If the total irradiation dose is too large, too many Si-OD and Si-D groups will be produced, resulting in increased fiber loss and decreased laser efficiency; if the total irradiation dose is too small, the radiation resistance will not be significantly improved.
[0023] When the pre-irradiation dose is lower than 200 Gy, the co-doped quartz optical fiber is in an amplifier with 150 mW 1550 nm signal light and 2.9-11.5 W 940 nm reverse pump light input, and the output power attenuation is lower than 0.1 W, and the slope efficiency attenuation is lower than 0.5%. After being irradiated by X-rays with a dose rate of 60 Gy / h and a total dose of 100 Gy, the decrease in the output power is reduced by more than 15%.
[0024] When the pre-irradiation dose is lower than 2400 Gy, the co-doped quartz optical fiber is in an amplifier with 150 mW 1550 nm signal light and 2.9-11.5 W 940 nm reverse pump light input, and the output power attenuation is lower than 0.4 W, and the slope efficiency attenuation is lower than 3%. After being irradiated by X-rays with a dose rate of 60 Gy / h and a total dose of 100 Gy, the decrease in the output power is reduced by more than 45%.
[0025] Preferably, during the X-ray irradiation treatment in step (2), the irradiation dose rate is 500-1000 Gy / h, for example, it can be 500 Gy / h, 600 Gy / h, 700 Gy / h, 800 Gy / h, 900 Gy / h or 1000 Gy / h, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.
[0026] Preferably, the atmosphere of the deuterium treatment in step (2) comprises a mixed gas of nitrogen and deuterium.
[0027] Preferably, in the mixed gas of nitrogen and deuterium, the volume content of deuterium is 5-20%, for example, 5%, 10%, 15% or 20%, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.
[0028] Preferably, the pressure of the deuterium treatment in step (2) is 4.0-8.0 MPa, for example, 4.0 MPa, 5.0 MPa, 6.0 MPa, 7.0 MPa or 8.0 MPa, the temperature is 40-70°C, for example, 40°C, 50°C, 60°C or 70°C, and the time is 24-120h, for example, 24h, 50h, 70h, 90h, 110h or 120h, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.
[0029] Preferably, the vacuum treatment time in step (2) is 150-200 hours, for example, 150 hours, 160 hours, 170 hours, 180 hours, 190 hours or 200 hours, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.
[0030] The long-term vacuuming of the present invention can simulate the situation where the optical fiber is placed for a long time, and accelerate the escape of the residual deuterium gas from the pretreatment reaction inside the optical fiber out of the optical fiber; if the vacuuming treatment time is too short, the deuterium gas will still remain, resulting in increased optical fiber absorption loss and reduced laser output efficiency; if the vacuuming treatment time is too long, although it will not have a significant negative impact on the optical fiber performance, it will seriously reduce the production efficiency of the radiation-resistant optical fiber.
[0031] Preferably, the temperature of the vacuum treatment in step (2) is 50-60°C, for example, 50°C, 55°C or 60°C, and the vacuum degree is <10Pa, for example, 9Pa, 7Pa, 5Pa or 3Pa, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.
[0032] The temperature of the carrier gas and vacuum treatment of the present invention does not exceed 70°C, which is much lower than the long-term tolerance temperature (~120°C) of the optical fiber acrylate coating layer. Therefore, the present invention does not have a significant negative impact on the mechanical properties of the optical fiber.
[0033] Preferably, the method for preparing untreated Er:Yb:Ce:Sb:P co-doped silica optical fiber in step (1) comprises MCVD combined with solution doping method.
[0034] Preferably, the MCVD combined with solution doping method comprises:
[0035] (i) chemically polishing the inner wall of the liner, and then depositing 3 to 7 layers of phosphosilicate loose bodies by MCVD, for example, 3 layers, 4 layers, 5 layers, 6 layers or 7 layers;
[0036] (ii) soaking the phosphosilicate loose body in Er 3+ , Yb 3+ 、Ce 3+ , Sb 5+ After the immersion is completed, the mixture is dried to obtain a doped loose body;
[0037] (iii) dehydroxylating the doped loose body obtained in step (ii), and then heat treating the body to prepare a solid rod;
[0038] (iv) The solid rod obtained in step (iii) is subjected to rod sleeve and octagon optical processing, and then drawn into an optical fiber to obtain the untreated Erbium Ytterbium Phosphorus Ce Antimony co-doped silica optical fiber.
[0039] Preferably, sulfur hexafluoride is used to chemically polish the inner wall of the liner in step (i).
[0040] Preferably, during the MCVD deposition in step (i), phosphorus oxychloride and silicon tetrachloride are introduced.
[0041] Preferably, the soaking time in step (ii) is 1-2 hours, for example, 1 hour, 1.5 hours or 2 hours, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.
[0042] Preferably, the drying method in step (ii) comprises nitrogen purging.
[0043] Preferably, chlorine gas is introduced during the dehydroxylation treatment in step (iii), and the heating temperature of the liner is 1000-1050°C, for example, it can be 1050°C, 1025°C or 1050°C, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.
[0044] Preferably, the heat treatment in step (iii) includes first depositing at above 1600°C, for example, 1600°C, 1700°C or 1800°C, and then depositing at above 2200°C, for example, 2200°C, 2300°C, 2400°C or 2500°C, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.
[0045] In a third aspect, the present invention provides an application of the radiation-resistant Er:Yb:Ce:Sb co-doped quartz optical fiber as described in the first aspect, wherein the application is mainly used in a 1.5 μm band spatial optical fiber laser.
[0046] Compared with the prior art, the present invention has the following beneficial effects:
[0047] (1) The present invention uses co-doping with variable valence ions (Ce 3+ / 4+ and Sb 3+ / 5+ ), using erbium, ytterbium, phosphorus, cerium and antimony co-doped silica as the fiber core can improve the radiation resistance of the optical fiber, and sequentially performing deuterium doping, pre-irradiation and vacuum treatment on the optical fiber can greatly improve its radiation resistance while having little effect on its original laser performance.
[0048] (2) The present invention directly processes the optical fiber itself, which takes a short time and has a quick effect, thus facilitating the rapid preparation of radiation-resistant optical fiber.
[0049] (3) The erbium, ytterbium, phosphorus, cerium and antimony co-doped quartz optical fiber provided by the present invention has been confirmed by vacuum experiments to maintain its radiation resistance for a long time.
[0050] (4) During the preparation of the Er-Yb-Ce-Sb co-doped quartz optical fiber provided by the present invention, the ambient temperature during the deuterium infiltration process is strictly controlled, which can reduce the impact on the optical fiber coating layer and ensure the mechanical properties and structural strength of the optical fiber. BRIEF DESCRIPTION OF THE DRAWINGS
[0051] Figure 1 This is a flow chart of the preparation of the co-doped silica optical fiber described in Example 3 of the present invention;
[0052] Figure 2 This is a slope efficiency diagram of the co-doped quartz fiber laser described in Examples 1-3 and Comparative Examples 1-2 of the present invention;
[0053] Figure 3 This is a diagram showing the radiation-induced gain change of the co-doped quartz optical fiber described in Examples 1-3 of the present invention and Comparative Examples 1-2 after X-ray irradiation at a dose rate of 60 Gy / h and a total dose of 100 Gy. DETAILED DESCRIPTION
[0054] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.
[0055] Example 1
[0056] This embodiment provides a radiation-resistant Erbium, Yb, P, Cerium, Antimony co-doped silica optical fiber. The radiation-resistant Erbium, Yb, P, Cerium, Antimony co-doped silica optical fiber includes a core. The core is Erbium, Yb, P, Cerium, Antimony co-doped silica. The doping ions in the Erbium, Yb, P, Cerium, Antimony co-doped silica include Er. 3+ , Yb 3+ , P 5+ 、Ce 3+ / 4+ and Sb 3+ / 5+ ;
[0057] Electron probe microanalysis test shows that the actual composition of the core of the optical fiber is as follows: the content of Er element is 0.2wt%, the content of Yb element is 3.9wt%, the content of P element is 12wt%, the content of Ce element is 0.1wt%, the content of Sb element is 0.1wt%, and the total content of Si element and O element is 83.7wt%;
[0058] The flow chart of the method for preparing the radiation-resistant Er / Yb / P / Ce / Sb co-doped silica optical fiber is as follows: Figure 1 As shown, the preparation method comprises the following steps:
[0059] (1) Preparation of optical fiber materials: Er-Yb-P-Ce-Sb co-doped double-clad optical fiber was prepared by MCVD combined with solution doping method, in which the core material was Er-Yb-P-Ce-Sb co-doped SiO2 glass;
[0060] S1.1: Chemical polishing of the inner wall of the liner with sulfur hexafluoride; preparation of Er according to the theoretical core composition 3+ , Yb 3+ 、Ce 3+ , Sb 5+ Co-doped alcohol solution;
[0061] S1.2: Using MCVD to pass phosphorus oxychloride and silicon tetrachloride, first deposit 5 layers of phosphosilicate loose body;
[0062] S1.3: Place the loose body of step S1.2 in a 3+ , Yb 3+ 、Ce 3+ , Sb 5+ Immerse in an alcohol solution for 1.5 hours and dry with nitrogen purge;
[0063] S1.4: Chlorine gas is introduced into the doped loose body in step S1.3 for dehydroxylation treatment, and the liner heating temperature is 1050°C;
[0064] S1.5: heating the deposited tube in step S1.4 to 1800°C to achieve vitrification, and then rapidly heating to 2300°C to collapse the deposited tube into a solid rod;
[0065] S1.6: After the solid rod in step S1.5 is processed by rod sleeve and octagonal optical processing, it is drawn into an optical fiber using an optical fiber drawing tower;
[0066] (2) Optical fiber carrier gas treatment: The optical fiber preform is subjected to high temperature and high pressure carrier gas treatment in a high temperature and high pressure reactor. The gas is a mixture of 10% deuterium gas and 90% nitrogen gas by volume. The reactor is heated to 55°C at a certain heating rate. At this time, the gas pressure is 6.0 MPa. The temperature is kept at 55°C for 72 hours and then cooled with the furnace.
[0067] (3) Fiber pre-irradiation treatment: X-rays are used to pre-irradiate the optical fiber after carrier gas, with an irradiation dose rate of 500 Gy / h and a total dose of 200 Gy;
[0068] (4) Fiber vacuum treatment: The pre-irradiated optical fiber is subjected to constant temperature vacuum treatment. The vacuum environment temperature is kept constant at 55°C and the vacuum degree of the vacuum environment is maintained within 10Pa for 150 hours.
[0069] Example 2
[0070] This embodiment provides a radiation-resistant Er / Yb / Ce / Anti co-doped silica optical fiber. The Er / Yb / Ce / Anti co-doped silica optical fiber is the same as that of Embodiment 1 except that the content of Ce element is 0.2wt% and the total content of Si element and O element is adaptively changed.
[0071] The preparation method of the Er-Yb-Ce-Sb co-doped silica optical fiber is the same as that of Example 1 except that the formula amounts are changed.
[0072] Example 3
[0073] This embodiment provides a radiation-resistant Erbium, Yb, P, Cerium, Antimony co-doped silica optical fiber. The radiation-resistant Erbium, Yb, P, Cerium, Antimony co-doped silica optical fiber includes a core. The core is Erbium, Yb, P, Cerium, Antimony co-doped silica. The doping ions in the Erbium, Yb, P, Cerium, Antimony co-doped silica include Er. 3+ , Yb 3+ , P 5+ 、Ce 3+ / 4+ and Sb 3+ / 5+ ;
[0074] Electron probe microanalysis test shows that the actual composition of the core of the optical fiber is as follows: the content of Er element is 0.21wt%, the content of Yb element is 4.0wt%, the content of P element is 13wt%, the content of Ce element is 0.2wt%, the content of Sb element is 0.2wt%, and the total content of Si element and O element is 82.39wt%;
[0075] The method for preparing the radiation-resistant Er / Yb / P / Ce / Sb co-doped quartz optical fiber comprises the following steps:
[0076] (1) Preparation of optical fiber materials: Er-Yb-P-Ce-Sb co-doped double-clad optical fiber was prepared by MCVD combined with solution doping method, in which the core material was Er-Yb-P-Ce-Sb co-doped SiO2 glass;
[0077] S1.1: Chemical polishing of the inner wall of the liner with sulfur hexafluoride; preparation of Er according to the theoretical core composition 3+ , Yb 3+ 、Ce 3+ , Sb 5+ Co-doped alcohol solution;
[0078] S1.2: Use MCVD to pass phosphorus oxychloride and silicon tetrachloride to first deposit three layers of phosphosilicate loose bodies;
[0079] S1.3: Place the loose body of step S1.2 in a 3+ , Yb 3+ 、Ce 3+ , Sb 5+ Immerse in an alcohol solution for 1 hour and dry with nitrogen purge;
[0080] S1.4: Chlorine gas is introduced into the doped loose body in step S1.3 for dehydroxylation treatment, and the liner heating temperature is 1050°C;
[0081] S1.5: heating the deposited tube in step S1.4 to 1600°C to achieve vitrification, and then rapidly heating to 2200°C to collapse the deposited tube into a solid rod;
[0082] S1.6: After the solid rod in step S1.5 is processed by rod sleeve and octagonal optical processing, it is drawn into an optical fiber using an optical fiber drawing tower;
[0083] (2) Optical fiber carrier gas treatment: The optical fiber preform is subjected to high temperature and high pressure carrier gas treatment in a high temperature and high pressure reactor. The gas is a mixture of 5% deuterium gas and 95% nitrogen gas by volume. The reactor is heated to 60°C at a certain heating rate. At this time, the gas pressure is 5.0 MPa. The temperature is kept at 60°C for 72 hours and then cooled with the furnace.
[0084] (3) Fiber pre-irradiation treatment: X-rays are used to pre-irradiate the optical fiber after carrier gas, with an irradiation dose rate of 1000 Gy / h and a total dose of 2400 Gy;
[0085] (4) Fiber vacuum treatment: The pre-irradiated optical fiber is subjected to constant temperature vacuum treatment. The vacuum environment temperature is kept constant at 60°C and the vacuum degree of the vacuum environment is maintained within 1 Pa for 200 hours.
[0086] Example 4
[0087] This embodiment provides a radiation-resistant Er / Yb / Ce / Sb co-doped silica optical fiber. The Er / Yb / Ce / Sb co-doped silica optical fiber is the same as that of Embodiment 3 except that the content of Sb is 0.05wt% and the total content of Si and O is adaptively changed.
[0088] The preparation method of the Er-Yb-Ce-Sb co-doped silica optical fiber is the same as that of Example 3 except for the change in the formula amount.
[0089] Example 5
[0090] This embodiment provides a radiation-resistant Er / Yb / Ce / Sb co-doped silica optical fiber. The Er / Yb / Ce / Sb co-doped silica optical fiber is the same as that of Embodiment 3 except that the content of Sb is 3wt% and the total content of Si and O is adaptively changed.
[0091] The preparation method of the Er-Yb-Ce-Sb co-doped silica optical fiber is the same as that of Example 3 except for the change in the formula amount.
[0092] Example 6
[0093] The present embodiment provides an erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber that is resistant to radiation. The erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber is the same as that of Embodiment 3 except that in the preparation method thereof, the total irradiation dose in step (3) is 3000 Gy so that the adaptability of the obtained erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber changes.
[0094] Example 7
[0095] The present embodiment provides an erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber that is resistant to radiation. The erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber is the same as that of Embodiment 3 except that in the preparation method thereof, the total irradiation dose in step (3) is 1500 Gy so that the adaptability of the obtained erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber changes.
[0096] Example 8
[0097] The present embodiment provides an erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber that is resistant to radiation. The erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber is the same as that of Embodiment 3 except that in the preparation method thereof, the total irradiation dose in step (3) is 500 Gy so that the adaptability of the obtained erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber is changed.
[0098] Example 9
[0099] The present embodiment provides a radiation-resistant erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber. The erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber is the same as that of Embodiment 3 except that in the preparation method thereof, the vacuum environment in step (4) is maintained for 100 hours to allow the obtained erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber to adapt to changes.
[0100] Example 10
[0101] The present embodiment provides a radiation-resistant erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber. The erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber is the same as that of Embodiment 3 except that in the preparation method thereof, the vacuum environment in step (4) is maintained for 250 hours to allow the obtained erbium, ytterbium, phosphide, cerium, and antimony co-doped silica optical fiber to adapt to changes.
[0102] Comparative Example 1
[0103] This comparative example provides a co-doped silica optical fiber, which is the same as Example 1 except that in its preparation method, step (2), step (3) and step (4) are not performed to make the obtained co-doped silica optical fiber adaptable.
[0104] Comparative Example 2
[0105] This comparative example provides an Erbium-Ytterbium-Cerium-Antimony co-doped silica optical fiber. The radiation-resistant Erbium-Ytterbium-Cerium-Antimony co-doped silica optical fiber comprises a core, wherein the core is Erbium-Ytterbium-Cerium-Antimony co-doped silica, and the doping ions in the Erbium-Ytterbium-Cerium-Antimony co-doped silica include Er 3+ , Yb 3+ , P 5+ 、Ce 3+ / 4+ and Sb 3+ / 5+ ;
[0106] Electron probe microanalysis test shows that the actual composition of the core of the optical fiber is as follows: the content of Er element is 0.2wt%, the content of Yb element is 3.9wt%, the content of P element is 12wt%, the content of Ce element is 0.1wt%, the content of Sb element is 0.2wt%, and the total content of Si element and O element is 83.6wt%;
[0107] The method for preparing the radiation-resistant Er / Yb / P / Ce / Sb co-doped quartz optical fiber comprises the following steps:
[0108] (1) Preparation of optical fiber materials: Er-Yb-P-Ce-Sb co-doped double-clad optical fiber was prepared by MCVD combined with solution doping method, in which the core material was Er-Yb-P-Ce-Sb co-doped SiO2 glass;
[0109] S1.1: Chemical polishing of the inner wall of the liner with sulfur hexafluoride; preparation of Er according to the theoretical core composition 3+ , Yb 3+ 、Ce 3+ , Sb 5+ Co-doped alcohol solution;
[0110] S1.2: Using MCVD to pass phosphorus oxychloride and silicon tetrachloride, first deposit 7 layers of phosphosilicate loose body;
[0111] S1.3: Place the loose body of step S1.2 in a 3+ , Yb 3+ 、Ce 3+ , Sb 5+ Immerse in an alcohol solution for 2 hours and dry with nitrogen purge;
[0112] S1.4: introducing chlorine gas into the doped loose body in step S1.3 for dehydroxylation treatment, and the liner heating temperature is 1000°C;
[0113] S1.5: heating the deposited tube in step S1.4 to 1600°C to achieve vitrification, and then rapidly heating to 2200°C to collapse the deposited tube into a solid rod;
[0114] S1.6: After the solid rod in step S1.5 is processed by rod sleeve and octagonal optical processing, it is drawn into an optical fiber using an optical fiber drawing tower;
[0115] (2) Optical fiber carrier gas treatment: The optical fiber preform is subjected to high temperature and high pressure carrier gas treatment in a high temperature and high pressure reactor. The gas is a mixture of 10% deuterium gas and 90% nitrogen gas by volume. The reactor is heated to 60°C at a certain heating rate. At this time, the gas pressure is 5 MPa. The temperature is kept at 60°C for 72 hours and then cooled with the furnace.
[0116] (3) Fiber pre-irradiation treatment: None, this comparative example does not perform X-ray pre-irradiation treatment;
[0117] (4) Fiber vacuum treatment: The pre-irradiated optical fiber is subjected to constant temperature vacuum treatment. The vacuum environment temperature is kept constant at 60°C and the vacuum degree of the vacuum environment is maintained within 1 Pa for 150 hours.
[0118] The erbium, ytterbium, phosphorus, cerium, and antimony co-doped quartz optical fibers obtained in the above examples and comparative examples were subjected to a fiber laser performance test: the optical fibers of the same length were applied to a fiber amplifier, fixedly operated under the conditions of 150 mW 1550 nm signal light and 2.9-11.5 W 940 nm reverse pump light, and the maximum output power and slope efficiency of the optical fibers were tested. The laser output power and slope efficiency of the erbium, ytterbium, phosphorus, cerium, and antimony co-doped quartz optical fibers described in Examples 1-3 and Comparative Examples 1-2 are shown in FIG. Figure 2 As shown; Optical fiber radiation resistance test: The same length of optical fiber is applied to the optical fiber amplifier, fixedly working under the conditions of 150mW 1550nm signal light and 11.5W 940nm reverse pump light, the optical fiber part is exposed to high-energy X-rays with a total irradiation dose of 100Gy and an irradiation dose rate of 60Gy / h, and the amplifier output gain is tested to change with the irradiation dose. The radiation-induced gain change of the erbium, ytterbium, phosphorus, cerium, and antimony co-doped quartz optical fiber described in Example 1-3 and Comparative Example 1-2 after X-ray irradiation with a dose rate of 60Gy / h and a total dose of 100Gy is shown in the figure. Figure 3 shown.
[0119] The core composition of the Er:Yb:P:C:Sb co-doped silica optical fiber obtained in the above examples and comparative examples is shown in Table 1.
[0120] Table 1
[0121]
[0122]
[0123] The results of the fiber laser performance test and fiber radiation resistance test of the Er-Yb-Ce-Sb co-doped quartz optical fiber obtained in the above embodiments and comparative examples are shown in Table 2. In Table 2, the higher the laser output power and slope efficiency of the optical fiber, the better the laser performance of the optical fiber; the greater the radiation-induced gain attenuation of the optical fiber, the worse the radiation resistance of the optical fiber.
[0124] Table 2
[0125]
[0126]
[0127] Combining Table 1 and Table 2, we can see that:
[0128] It can be seen from Examples 1 and 2 that increasing the content of variable valence ions in the core material (e.g. Ce 3+ / 4+ Increasing the content from 0.1wt% to 0.2wt%) will cause the laser performance of the optical fiber to decrease, but the radiation resistance performance will be improved. In order to ensure the best laser performance and radiation resistance performance, the content of variable valence ions needs to be controlled within a reasonable range (for example, Ce content ≤ 0.2wt%, Sb content ≤ 0.2wt%).
[0129] It can be seen from Example 1 and Comparative Examples 1-2 that the erbium, ytterbium, phosphorus, cerium, and antimony co-doped optical fiber of the present invention can be significantly improved in radiation resistance after deuterium infiltration, pre-irradiation, and vacuum treatment, especially pre-irradiation treatment, and has little effect on the output power and slope efficiency of laser performance, and the decline in laser performance is within an acceptable range;
[0130] It can be seen from Examples 3 and 4-5 that it is preferred that Sb is within a specific doping amount range (0.1-0.2wt%), so as to ensure that the laser performance (such as the laser efficiency of 33.3% in Example 3) and the radiation resistance performance (such as the radiation-induced gain attenuation of up to 1.81dB in Example 3) of the Er-Yb-Ce-Sb co-doped optical fiber are within an acceptable range; when the Sb content is ≤0.05wt%, the laser performance is better (such as the laser efficiency of 34.4% in Example 4), but the radiation resistance performance is poor (such as the radiation-induced gain attenuation of up to 3.42dB in Example 4); when the Sb content is ≥3wt%, the laser performance is poor (such as the laser efficiency of Example 5 is as low as 20.8%), but the radiation resistance performance is good (such as the radiation-induced gain attenuation of only 0.53dB in Example 5).
[0131] It can be seen from Example 3 and Examples 6-8 that the total dose of pre-irradiation of the present invention will affect the performance of the optical fiber, preferably within a specific range (1500-2400Gy), so as to ensure that the laser performance (such as the laser efficiency of 33.3% in Example 3) and the radiation resistance performance (such as the radiation-induced gain attenuation of 1.81dB in Example 3) of the erbium ytterbium phosphide cerium antimony co-doped optical fiber are within an acceptable range. When the pre-irradiation dose is ≤500Gy, the laser performance is better (such as the laser efficiency of 34.2% in Example 8), but the radiation resistance performance is weaker (such as the radiation-induced gain attenuation of 2.43dB in Example 8); when the pre-irradiation dose is ≥3000Gy, the laser performance is poor (such as the laser efficiency of 32.6% in Example 6), but the radiation resistance performance is better (such as the radiation-induced gain attenuation of 1.52dB in Example 6).
[0132] It can be seen from Examples 3 and 9-10 that the vacuuming time of the present invention will also affect the laser performance and radiation resistance of the optical fiber. The preferred vacuuming time is 150-200 hours, the purpose of which is to ensure that the laser performance (such as the laser efficiency of 33.3% in Example 3) and the radiation resistance (such as the radiation-induced gain attenuation of 1.81 dB in Example 3) of the erbium ytterbium phosphide cerium antimony co-doped optical fiber are within an acceptable range. When the vacuuming time is ≤100h, the laser performance of the erbium, ytterbium, phosphorus, cerium, and antimony co-doped optical fiber is low (such as the laser efficiency of 32.8% in Example 9), but the radiation resistance is very good (such as the radiation-induced gain attenuation of only 0.56dB in Example 9). This is because there is still deuterium gas residual in the optical fiber. The presence of deuterium gas leads to very good radiation resistance of the optical fiber, but the absorption loss of deuterium gas will lead to low laser efficiency of the optical fiber. Moreover, in a vacuum environment such as space, deuterium gas will diffuse from the optical fiber, causing defects such as bubbles in the optical fiber laser, affecting the power stability of the laser. When the vacuuming time is ≥250h (Example 10), the laser performance and radiation resistance of the erbium, ytterbium, phosphorus, cerium, and antimony co-doped optical fiber doped with erbium, ytterbium, phosphorus, cerium, and antimony doped optical fiber do not change significantly compared with the case of vacuuming for only 200h (Example 3). The longer the vacuuming time, the lower the preparation efficiency of the optical fiber.
[0133] In summary, the present invention provides a radiation-resistant erbium, ytterbium, phosphorus, cerium, and antimony co-doped quartz optical fiber, and a preparation method and application thereof. By co-doping variable-valence ions and using erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica as the fiber core, combined with optical fiber deuterium doping-pre-irradiation-vacuum pretreatment, it not only does not have a significant negative impact on the original laser performance and mechanical properties of the optical fiber, but also can simply and quickly improve the radiation resistance of the optical fiber.
[0134] The radiation-resistant Erbium, Ytterbium, Phosphorus, Ce-Antimony co-doped quartz optical fiber of the present invention is mainly used in optical fiber lasers for space applications, for example, it can be used as a core gain medium of a space laser radar.
[0135] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.
Claims
1. A radiation-resistant Er:Yb:Ce:Sb co-doped silica optical fiber, characterized in that: The radiation-resistant Er / Yb / Ce / Sb co-doped silica optical fiber comprises a coating layer, an outer cladding layer, an inner cladding layer and a doped core, wherein the inner cladding layer covers the surface of the doped core layer, the outer cladding layer covers the surface of the inner cladding layer, the coating layer covers the surface of the outer cladding layer, and the doped core layer is Er / Yb / Ce / Sb co-doped silica glass; The doping ions in the Er-Yb-Ce-Sb co-doped silica glass include Er 3+ , Yb 3+ , P 5+ 、Ce 3+ / 4+ and Sb 3+ / 5+ .
2. The radiation-resistant Er:Yb:P:Ce:Sb:co-doped silica optical fiber according to claim 1, characterized in that: In the erbium, ytterbium, phosphorus, cerium and antimony co-doped silica glass, the content of Er element is 0.20-0.21wt%, the content of Yb element is 3.9-4.0wt%, the content of P element is 12-13wt%, the content of Ce element is 0.1-0.2wt%, the content of Sb element is 0.1-0.2wt%, and the total content of Si element and O element is 82.39-83.7wt%.
3. The radiation-resistant Er:Yb:Ce:Sb co-doped silica optical fiber according to claim 1 or 2, characterized in that: The radiation-resistant Er / Yb / P / Ce / Sb co-doped quartz optical fiber has a laser efficiency of more than 33% and a laser output power of more than 3.6 watts.
4. A method for preparing the radiation-resistant Er:Yb:Ce:Sb co-doped silica optical fiber according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) preparing untreated Er / Yb / Ce / Sb co-doped silica optical fiber; (2) The untreated erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica optical fiber of step (1) is subjected to deuterium infiltration treatment, X-ray irradiation treatment, and vacuum treatment in sequence to obtain the radiation-resistant erbium, ytterbium, phosphorus, cerium, and antimony co-doped silica optical fiber.
5. The preparation method according to claim 4, characterized in that: In the X-ray irradiation treatment in step (2), the total irradiation dose is 200-2400 Gy, preferably 500-2400 Gy, and more preferably 1500-2400 Gy; Preferably, during the X-ray irradiation treatment in step (2), the irradiation dose rate is 500-1000 Gy / h.
6. The preparation method according to claim 4 or 5, characterized in that: The atmosphere of the deuterium treatment in step (2) comprises a mixed gas of nitrogen and deuterium; Preferably, in the mixed gas of nitrogen and deuterium, the volume content of deuterium is 5-20%; Preferably, the deuterium treatment in step (2) is carried out under a pressure of 4.0-8.0 MPa, at a temperature of 40-70° C., for a time of 24-120 h.
7. The preparation method according to any one of claims 4 to 6, characterized in that: The vacuum treatment time in step (2) is 150-200 hours; Preferably, the temperature of the vacuum treatment in step (2) is 50-60°C, and the vacuum degree is <10Pa.
8. The preparation method according to any one of claims 4 to 7, characterized in that: The method for preparing untreated Er / Yb / Ce / Sb co-doped silica optical fiber in step (1) comprises MCVD combined with solution doping method; Preferably, the MCVD combined with solution doping method comprises: (i) chemically polishing the inner wall of the liner, and then depositing 3 to 7 layers of phosphosilicate loose bodies by MCVD method; (ii) soaking the phosphosilicate loose body in Er 3+ , Yb 3+ 、Ce 3+ , Sb 5+ After the immersion is completed, the mixture is dried to obtain a doped loose body; (iii) dehydroxylating the doped loose body obtained in step (ii), and then heat treating the body to prepare a solid rod; (iv) The solid rod obtained in step (iii) is subjected to rod sleeve and octagon optical processing, and then drawn into an optical fiber to obtain the untreated Erbium Ytterbium Phosphorus Ce Antimony co-doped silica optical fiber.
9. The preparation method according to claim 8, characterized in that: Chemically polishing the inner wall of the liner in step (i) using sulfur hexafluoride; Preferably, during the MCVD deposition in step (i), phosphorus oxychloride and silicon tetrachloride are introduced; Preferably, the soaking time in step (ii) is 1-2 hours; Preferably, the drying method in step (ii) comprises nitrogen purging; Preferably, chlorine gas is introduced during the dehydroxylation treatment in step (iii), and the heating temperature of the liner is 1000-1050° C.; Preferably, the heat treatment in step (iii) comprises first depositing at a temperature above 1600°C and then depositing at a temperature above 2200°C.
10. An application of the radiation-resistant Er / Yb / P / Ce / Sb co-doped silica optical fiber according to any one of claims 1 to 3, characterized in that: The application will be in fiber lasers for space applications.