Multifunctional interface for repairing performance degradation of fiber laser and use method

Abstract

Aiming at the problem that the performance of an optical fiber laser is reduced due to photon darkening and radiation darkening, the invention provides a multifunctional interface for repairing the performance degradation of the optical fiber laser and a use method, the multifunctional interface is used for reliably connecting a bleaching light source with the optical fiber laser, and the multifunctional interface comprises a first interface and a second interface, the first interface is used for being connected with an output end of a bleaching light source, and the second interface is used for being connected with a bleaching light input port of the optical fiber laser. And the multifunctional interface for repairing the performance degradation of the fiber laser is used for repairing the fiber laser. The multifunctional interface for repairing the performance degradation of the fiber laser can inject bleaching light with a specific wavelength, and can directly repair the damaged gain fiber without replacing the fiber. According to the method, many defects of a traditional repairing method are avoided, the maintenance cost is remarkably reduced, the service life of the optical fiber laser is prolonged, and the stability of the optical fiber laser is improved.

Description

Technical Field

[0001] The present invention mainly relates to the field of fiber laser technology, and in particular to a multifunctional interface for repairing the performance degradation of fiber lasers and a usage method. Background Art

[0002] As an advanced laser technology, fiber lasers have many remarkable advantages. First of all, fiber lasers have a high optical-to-optical conversion efficiency, usually reaching more than 80%. Secondly, fiber lasers have excellent beam quality, can achieve high-power density output, and at the same time maintain tight focusing and minimum divergence. In addition, fiber lasers are compact in structure and light in weight, which is convenient for integration and use. Fiber lasers also have high stability and reliability and can work stably for a long time in harsh environments. Fiber lasers have been widely used in many fields. In ground applications, fiber lasers are widely used in industrial manufacturing, such as laser cutting, welding, and marking. Their high power density and high beam quality make the processing process more efficient and precise. In space applications, fiber lasers can be used for satellite communication, space exploration, and lidar, etc., providing high-precision measurement and communication support for space missions.

[0003] Despite the many advantages of fiber lasers, there are still some challenges in practical applications. When used for a long time, fiber lasers will be affected by the photon darkening effect, resulting in a decrease in output power and a deterioration of beam quality. In addition, fiber lasers in space applications will also be affected by the irradiation effect, further exacerbating the damage of the gain fiber. These damages not only reduce the performance of fiber lasers but also shorten their service life. Traditional repair methods usually involve replacing the damaged gain fiber. However, this method is not only costly but also may reduce the service life of passive devices. Additional splicing losses will also be introduced during the fiber splicing process, affecting the overall performance of the laser. In addition, the disassembly and reassembly process of fiber lasers is complex and may affect their stability.

[0004] Optical bleaching technology is an effective repair method that can significantly improve the performance degradation of fiber lasers caused by photon darkening and radiation-induced darkening. Optical bleaching irradiates the damaged optical fiber with light of a specific wavelength to repair the defects induced by radiation-induced darkening or photon darkening, thereby restoring the optical performance of the optical fiber. This technology has a significant effect on repairing photon darkening and radiation damage, and can effectively restore the output power and beam quality of fiber lasers. However, for fiber lasers with radiation damage or photon darkening, a special channel is required to couple the bleaching light in. Since fiber lasers for space applications usually have high requirements for quality and reliability, repairing irradiated fiber lasers on the ground is an ideal method. The traditional repair method is to fuse the output fiber of the bleaching light source with the output fiber of the beam combiner, but there are many problems with this method. Each fusion will reduce the length of the output fiber of the beam combiner. At the same time, the output fiber of the beam combiner is exposed and is extremely vulnerable to damage, which not only increases the repair cost but also reduces the service life and stability of the fiber laser. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention proposes a multi-functional interface and a usage method for repairing the performance degradation of fiber lasers. By injecting bleaching light into the fiber laser through the multi-functional interface, the problems of the degradation of the output power of the laser and the decrease of the mode instability threshold caused by photon darkening and radiation-induced darkening are overcome, and a repairable and reusable fiber laser is realized.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a multi-functional interface for repairing the performance degradation of fiber lasers, which is used to reliably connect the bleaching light source to the fiber laser. The multi-functional interface includes a first interface and a second interface. The first interface is used to connect to the output end of the bleaching light source, and the second interface is used to connect to the bleaching light input port of the fiber laser. The interface types of the first interface and the second interface include FC type interfaces and SMA905 type interfaces. The insertion loss of the multi-functional interface is ≤0.2 dB, and the operating temperature is between -25°C and +70°C.

[0007] The usage method of the above multi-functional interface for repairing the performance degradation of fiber lasers, which is used for the repair of fiber lasers, includes: Obtain the initial output power P0 of the fiber laser before performance degradation; Obtain the output power P1 of the fiber laser affected by the photon darkening effect or the radiation-induced darkening effect; The first interface of the multi-functional interface is connected to the output end of the bleaching light source, and the second interface is connected to the bleaching light input port of the fiber laser. The bleaching light source and the fiber laser are turned on simultaneously, and the bleaching light source is injected into the fiber laser through the multi-functional interface. The current output power P2(t) of the fiber laser is collected and recorded in real time. Compare the current output power P2(t) of the fiber laser with the initial output power P0 before the performance degradation of the fiber laser to evaluate the repair effect on the fiber laser.

[0008] Preferably, to evaluate the repair effect on the fiber laser, it includes: if P1 = P2(t) < P0, it indicates that the bleaching light source is not helpful for restoring the output power of the fiber laser; if P1 < P2(t) < P0, it indicates that the bleaching light source can partially restore the output power of the fiber laser; if P2(t) = P0, it indicates that the bleaching light source can completely restore the output power of the fiber laser. Further, the repair effect of the fiber laser needs to be feedback-controlled and adjusted based on the evaluation result of the repair effect of the fiber laser. If the restoration of the output power of the fiber laser fails to meet the set expectation, the power of the bleaching light output by the bleaching light source is increased or the wavelength of the bleaching light is replaced for repair, and then the repair effect of the fiber laser is evaluated again until the restoration of the output power of the fiber laser reaches the set expectation.

[0009] Preferably, the fiber laser is a fiber laser oscillator, a fiber amplifier, or a cascaded structure of a fiber laser oscillator and a fiber amplifier.

[0010] Preferably, the fiber laser includes a pump module, a pump combiner, a high-reflectivity fiber grating, a gain fiber, and a low-reflectivity fiber grating. The fiber laser has at least one bleaching light input port, and each bleaching light input port is respectively connected to the first interface of the corresponding multi-functional interface.

[0011] The bleaching light input port of the fiber laser can be any pump arm of the pump combiner that is not connected to the pump module, or the signal arm of the pump combiner.

[0012] Compared with the prior art, the technical effects of the present invention: The present invention introduces a multifunctional interface for repairing the performance degradation of fiber lasers. By injecting bleaching light of a specific wavelength into the fiber laser through the multifunctional interface, the damaged gain fiber can be directly repaired. This method eliminates the need to replace the fiber, avoiding many drawbacks of traditional repair methods, such as fusion loss, reduction in fiber length, and vulnerability of the exposed fiber. This not only significantly reduces the maintenance cost but also improves the service life and stability of the fiber laser. This multifunctional interface also has multiple advantages. In addition to repairing the damaged fiber through photo-bleaching technology and restoring the output performance of the fiber laser, the multifunctional interface can be combined with a power meter at the output end of the laser to provide real-time feedback on the repair status, facilitating user monitoring and management. Moreover, by detecting the signal output from the multifunctional interface, the stability of the fiber laser can be monitored. This integrated solution significantly improves the maintenance efficiency and reliability of the fiber laser, providing strong support for the wide use of fiber lasers on the ground and in space. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0014] Figure 1 Schematic diagram of the structure of the multifunctional interface for repairing the performance degradation of the fiber laser provided in Embodiment 1; Figure 2 Schematic diagram of the structure of Embodiment 2; Figure 3 Schematic diagram of the structure of Embodiment 3; Figure 4 Schematic diagram of the structure of Embodiment 4; Figure 5 Schematic diagram of the structure of Embodiment 5; Figure 6 Schematic diagram of the structure of Embodiment 6; Figure 7 Schematic diagram of the structure of Embodiment 7; Reference Numerals: 100, First Interface; 200, Second Interface; 1, Bleaching Light Source; 2, Multifunctional Interface; 3, Pump Module; 4, Forward Pump Combiner; 5, High Reflectivity Fiber Grating; 6, Gain Fiber; 7, Low Reflectivity Fiber Grating; 8, Backward Pump Combiner; 9, Fiber End Cap; 10, Power Meter; 11, Computer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0016] Embodiment 1: Refer to Figure 1 , a multifunctional interface for repairing the performance degradation of a fiber laser is provided, which is used to reliably connect a bleaching light source to the fiber laser. The multifunctional interface includes a first interface 100 and a second interface 200. The first interface 100 is used to connect to the output end of the bleaching light source, and the second interface 200 is used to connect to the bleaching light input port of the fiber laser. The interface types of the first interface 100 and the second interface 200 include FC type interfaces and SMA905 type interfaces. The insertion loss of the multifunctional interface is ≤0.2 dB, and the operating temperature is between -25°C and +70°C.

[0017] The core function of the multifunctional interface for repairing the performance degradation of a fiber laser is to reliably connect the bleaching light source to the fiber laser, ensure the smooth transmission of optical signals, and at the same time minimize the loss of optical signals at the connection point. The types of the first interface and the second interface in the multifunctional interface mainly include two types: Fiber Connector (FC type) and SubMiniatureversion A 905 (SMA905 type). If both the first interface and the second interface of the multifunctional interface are FC type interfaces, then FC type fiber - FC type fiber connection can be achieved. If both the first interface and the second interface of the multifunctional interface are SMA905 type interfaces, then SMA905 type fiber - SMA905 type fiber connection can be achieved. If the first interface and the second interface of the multifunctional interface are FC type interface and SMA905 type interface respectively, then FC type fiber - SMA905 type fiber connection can be achieved, and the transmission loss of the fiber connection is ≤0.2 dB.

[0018] Furthermore, the optical fiber connected to the first interface and the second interface should be selected as the optical fiber with a smaller transmission loss in the visible light region than the insertion loss of the multifunctional interface to reduce the transmission loss of the bleaching light. The size of the optical fiber connected to the first interface should be less than or equal to the optical fiber connected to the second interface to reduce the loss of the bleaching light at the multifunctional interface.

[0019] After a fiber laser is affected by the photon darkening effect or radiation-induced darkening effect, defects will be generated in the gain fiber, resulting in a decrease in the output power and the instability threshold of the mode of the fiber laser. These defects can be restored by a bleaching laser source, so as to achieve the purpose that the output power and the instability threshold of the mode can be restored. Through a multifunctional interface for repairing the performance degradation of a fiber laser, bleaching light of a specific wavelength can be injected, and the damaged gain fiber can be directly repaired without replacing the fiber. This method avoids many drawbacks of traditional repair methods, significantly reduces the maintenance cost, and improves the service life and stability of the fiber laser.

[0020] The usage method of the above-mentioned multifunctional interface for repairing the performance degradation of a fiber laser, which is used for repairing a fiber laser, includes: Obtain the initial output power P0 of the fiber laser before its performance degrades; Obtain the output power P1 of the fiber laser after being affected by the photon darkening effect or radiation-induced darkening effect; Connect the first interface of the multifunctional interface to the output end of the bleaching light source, and connect the second interface to the bleaching light input port of the fiber laser. At the same time, turn on the bleaching light source and the fiber laser, inject the bleaching light source into the fiber laser through the multifunctional interface, and collect and record the current output power P2(t) of the fiber laser in real time; Compare the current output power P2(t) of the fiber laser with the initial output power P0 of the fiber laser before its performance degrades, and evaluate the repair effect on the fiber laser, including: if P1 = P2(t) < P0, it indicates that the bleaching light source is not helpful for restoring the output power of the fiber laser; if P1 < P2(t) < P0, it indicates that the bleaching light source can partially restore the output power of the fiber laser; if P2(t) = P0, it indicates that the bleaching light source can completely restore the output power of the fiber laser.

[0021] Furthermore, the repair effect of the fiber laser needs to be feedback-controlled and adjusted based on the evaluation result of the repair effect of the fiber laser. If the restoration of the output power of the fiber laser fails to meet the set expectation, increase the power of the bleaching light output by the bleaching light source or replace the wavelength of the bleaching light for repair and then evaluate the repair effect of the fiber laser again until the restoration of the output power of the fiber laser reaches the set expectation.

[0022] Example 2 Referring to Example 2, provide a method using Figure 1A method for realizing the repair of a fiber laser by a multifunctional interface for repairing the performance degradation of the fiber laser. First, a repair optical path is built, including a bleaching light source 1, a multifunctional interface 2, a pump module 3, a forward pump combiner 4, a high-reflectivity fiber grating 5, a gain fiber 6, a low-reflectivity fiber grating 7, a backward pump combiner 8, and a fiber end cap 9. Among them, the high-reflectivity fiber grating 5, the gain fiber 6, and the low-reflectivity fiber grating 7 form a resonant cavity. The pump module 3, the forward pump combiner 4, the high-reflectivity fiber grating 5, the gain fiber 6, the low-reflectivity fiber grating 7, the backward pump combiner 8, and the fiber end cap 9 form a fiber laser oscillator.

[0023] Among them, the signal arm of the forward pump combiner 4 serves as the bleaching light input port of the fiber laser oscillator. The output fiber connector of the bleaching light source 1 and the signal arm connector of the forward pump combiner 4 are connected through the multifunctional interface 2.

[0024] The output fiber of the pump module 3 is fusion spliced with the pump arm of the forward pump combiner 4; the output fiber of the forward pump combiner 4 is fusion spliced with the input end of the high-reflectivity fiber grating 5; both ends of the gain fiber 6 are respectively fusion spliced with the output end of the high-reflectivity fiber grating 5 and the output end of the low-reflectivity fiber grating 7; the output end of the backward pump combiner 8 is fusion spliced with the fiber end cap 9.

[0025] The above-mentioned gain fiber 6 is a double-clad fiber, where the core diameter ranges from 10μm to 60μm, and the cladding diameter ranges from 130μm to 600μm. The doping type of the gain fiber is ytterbium-doped, erbium-doped, thulium-doped, etc.

[0026] The above-mentioned forward pump combiner 4 is an (N + 1)×1 forward pump combiner, 2 ≤ N ≤ 18, having N pump arms, one signal arm, and one combined output end; The above-mentioned backward pump combiner 8 is an (N + 1)×1 backward pump combiner, 2 ≤ N ≤ 18, having N pump arms, one signal arm, and one combined output end.

[0027] The above-mentioned bleaching light source is a semiconductor laser with a central wavelength located between 300nm and 808nm, and a power greater than 10mW.

[0028] Using the multifunctional interface for repairing the performance degradation of the fiber laser for the repair of the fiber laser oscillator includes the following steps: (1) Obtain the initial output power P0 of the fiber laser oscillator before performance degradation; (2) Darken the fiber laser oscillator, which can be divided into the following three methods according to different application scenarios: First, the fiber laser oscillator is photon-darkened during long-term operation; Second, irradiate the fiber laser oscillator with an irradiation source to artificially accelerate the darkening; Third, the fiber laser oscillator performs a space mission or is used in a nuclear radiation environment for a period of time for irradiation darkening. Test the output power P1 of the fiber laser after being affected by the photon darkening effect or the radiation-induced darkening effect (the bleaching light source is not turned on during the whole process); (3) Turn on the bleaching light source 1 and the fiber laser oscillator at the same time. Inject the bleaching light source 1 into the fiber laser oscillator through the multi-functional interface 2, and collect and record the current output power P2(t) of the fiber laser oscillator in real time. Compare the current output power P2(t) of the fiber laser oscillator with the initial output power P0 before the performance degradation of the fiber laser oscillator, and evaluate the repair effect on the fiber laser oscillator, including: If P1 = P2(t) < P0, it indicates that the bleaching light source is not helpful for restoring the output power of the fiber laser oscillator; If P1 < P2(t) < P0, it indicates that the bleaching light source can partially restore the output power of the fiber laser oscillator; If P2(t) = P0, it indicates that the bleaching light source can completely restore the output power of the fiber laser oscillator.

[0029] After the fiber laser oscillator is restored, steps (2) to (3) can be repeated for operation.

[0030] Embodiment 3 Figure 1 The multi-functional interface for repairing the performance degradation of the fiber laser shown can, in addition to Figure 2 repairing the bidirectionally pumped fiber laser oscillator shown, also repair the forward-pumped or backward-pumped fiber laser oscillator. Refer to Figure 3 , and use Figure 1 the multi-functional interface for repairing the performance degradation of the fiber laser shown to repair the forward-pumped fiber laser oscillator.

[0031] Specifically, it includes a bleaching light source 1, a multi-functional interface 2, a pump module 3, a forward-pumping coupler 4, a high-reflectivity fiber grating 5, a gain fiber 6, a low-reflectivity fiber grating 7, and a fiber end cap 9. Among them, the high-reflectivity fiber grating 5, the gain fiber 6, and the low-reflectivity fiber grating 7 form a resonant cavity. The pump module 3, the forward-pumping coupler 4, the high-reflectivity fiber grating 5, the gain fiber 6, the low-reflectivity fiber grating 7, and the fiber end cap 9 form a forward-pumped fiber laser oscillator.

[0032] The signal arm of the forward-pumping coupler 4 serves as the bleaching light input port of the forward-pumped fiber laser oscillator. The output fiber connector of the bleaching light source 1 and the signal arm connector of the forward-pumping coupler 4 are connected through the multi-functional interface 2.

[0033] The preferred forward pumping combiner 4 is specifically an (N + 1)×1 forward pumping combiner, where 2 ≤ N ≤ 18, having N pumping arms, one seed end, and one output end. The preferred backward pumping combiner is specifically an (N + 1)×1 backward pumping combiner, where 2 ≤ N ≤ 18, having N pumping arms, one signal arm, and one combined output end.

[0034] The above-mentioned bleaching light source is a semiconductor laser with a central wavelength in the range of 300 nm - 808 nm and a power greater than 10 mW.

[0035] Use the multifunctional interface for repairing the performance degradation of the repair fiber laser in the repair of the fiber laser oscillator. The specific repair process is the same as that in Embodiment 2 above and will not be elaborated here.

[0036] Embodiment 4 A multifunctional interface for repairing the performance degradation of a fiber laser can repair the optically darkened fiber laser amplifier at different positions. As Figure 4 shown, the fiber laser includes a seed part and an amplification part. The optical path of the seed part adopts a bidirectional pumped fiber laser oscillator. In the seed part, it includes multiple multifunctional interfaces. Figure 4 Among them, there are 3 multifunctional interfaces. The first multifunctional interface 2-1 is connected to the signal arm of the forward pumping combiner 4, the second multifunctional interface 2-2 is connected to the pumping arm of the forward pumping combiner 4, and the third multifunctional interface 2-3 is connected to the pumping arm of the backward pumping combiner 4. The bleaching light source 1 is injected into the gain fiber 6 of the optical path of the seed part from multiple positions. In the amplification part, the multifunctional interface also includes multiple. Figure 4 Among them, the amplification part includes 2 multifunctional interfaces. The fourth multifunctional interface 2-4 is connected to the signal arm of the forward pumping combiner of the amplification part, and the fifth multifunctional interface 2-5 is connected to the pumping arm of the backward pumping combiner of the amplification part. The bleaching light source 1 is injected from different positions. Each bleaching light source 1 is a semiconductor laser with a central wavelength in the range of 300 nm - 808 nm and a power greater than 10 mW. When repairing the performance degradation of the fiber laser, if the fiber laser in Embodiment 4 is connected to more than one bleaching light source, the bleaching light source can be a single-wavelength semiconductor laser or a combination of multiple-wavelength semiconductor lasers.

[0037] Embodiment 5 Based on the multifunctional interface for repairing the performance degradation of the fiber laser provided by the present invention, the repair status of the fiber laser can be fed back in real time. A structural schematic diagram of an embodiment is as Figure 5As shown in the figure, the fiber laser includes a bleaching light source 1, a multi-functional interface 2, a pump module 3, a forward pump combiner 4, a high-reflectivity fiber grating 5, a gain fiber 6, a low-reflectivity fiber grating 7, a fiber end cap 9, a power meter 10, and a computer 12. Among them, the high-reflectivity fiber grating 5, the gain fiber 6, and the low-reflectivity fiber grating 7 form a resonant cavity. The pump module 3, the forward pump combiner 4, the high-reflectivity fiber grating 5, the gain fiber 6, the low-reflectivity fiber grating 7, and the fiber end cap 9 form a forward pump fiber laser oscillator. The power meter 10 is used to monitor the power of the laser output from the fiber end cap 9 in real time and feedback the monitoring results to the computer 11.

[0038] The signal arm of the forward pump combiner 4 serves as the bleaching light input port of the forward pump fiber laser oscillator. The output fiber connector of the bleaching light source 1 is connected to the signal arm connector of the forward pump combiner 4 through the multi-functional interface 2.

[0039] The preferred forward pump combiner 4 is specifically an (N + 1)×1 forward pump combiner, where 2 ≤ N ≤ 18, having N pump arms, one seed end, and one output end. The preferred backward pump combiner is specifically an (N + 1)×1 backward pump combiner, where 2 ≤ N ≤ 18, having N pump arms, one signal arm, and one combined output end.

[0040] The above-mentioned bleaching light source is a semiconductor laser with a central wavelength located between 300 nm and 808 nm and a power greater than 10 mW.

[0041] The actual operation of this embodiment includes the following steps: (1) In the initial stage, the fiber laser is not darkened. Start the bleaching light source 1, and let the bleaching light pass through the multi-functional interface 2, the forward pump combiner 4, the high-reflectivity fiber grating 5, the gain fiber 6, the low-reflectivity fiber grating 7, and the backward pump combiner 8 in sequence, and output at the fiber end cap 9. Use the power meter 10 to measure the output power K0 of the bleaching light source 1 passing through the non-darkened fiber laser.

[0042] (2) The fiber laser is darkened, which can be divided into the following three methods according to different application scenarios: the fiber laser undergoes photon darkening during long-term operation; the fiber laser is artificially accelerated to darken using an irradiation source; the fiber laser performs space missions or is used for a period of time in a nuclear radiation environment for irradiation darkening.

[0043] Start the bleaching light source 1 and test the initial output power K1 of the bleaching light output by the bleaching light source 1 passing through the darkened fiber laser.

[0044] (3) Continuously start the bleaching light source 1, use the power meter 10 to measure in real time the current output power K2(t) of the fiber laser after the bleaching light output by the bleaching light source 1 passes through the darkening process, and collect and record it in real time by the computer 11. Compare the current output power value K2(t) with the initial output power K1 of the fiber laser after the bleaching light passes through the darkening process. If K1 = K2(t) < K0, it indicates that the bleaching light source 1 is not helpful for the recovery of the output power of the fiber laser; if K1 < K2(t) < K0, it indicates that the bleaching light source can partially recover the output power of the fiber laser; if K2(t) = K0, it indicates that the bleaching light source can completely recover the output power of the laser.

[0045] Example 6 A multifunctional interface for repairing the performance degradation of a fiber laser. In addition to being able to repair the optically darkened fiber laser, this multifunctional interface can also provide real-time feedback on the operating state of the fiber laser, such as Figure 6 shown. The output power of this multifunctional interface can be measured in real time using the power meter 10 and collected and recorded in real time by the computer 11. The stability of the fiber laser is monitored by evaluating the fluctuations in the output power.

[0046] Example 7 A multifunctional interface for repairing the performance degradation of a fiber laser. This multifunctional interface connects the bleaching light source 1 to the fiber laser. The bleaching light output by the bleaching light source 1 passes through devices such as the multifunctional interface 2, the forward pumping coupler 4, the high reflectivity fiber grating 5, the gain fiber 6, and the low reflectivity fiber grating 7 in sequence, as Figure 7 shown. The bleaching light and the signal light propagate together in the optical fiber and in the same propagation direction. The signal light is a near-infrared invisible light, while the bleaching light is a visible light. Due to the visible characteristics of the bleaching light, the bleaching light can be used as an indicator light to ensure the correct transmission path and output direction of the laser beam, and it can play an important role in the subsequent spatial optical path auxiliary alignment process, such as helping technicians to more conveniently perform tasks such as optical path alignment and adjustment. In addition, the bleaching light connected to the fiber laser can also be used for fault detection, which can detect fiber breaks, optimize mechanical splices, etc., and help the staff quickly locate fiber faults.

[0047] Generally speaking, the present invention effectively solves the problem of the performance degradation of the fiber laser under the influence of photodarkening and radiation-induced darkening by introducing the optical bleaching repair technology and combining the innovative design of the multifunctional interface.

[0048] Compared with the prior art, the present invention does not require replacing the damaged gain fiber, avoiding problems such as high cost, splicing loss, and decreased system stability brought by traditional repair methods. By injecting bleaching light of a specific wavelength through a multi-functional interface, the damaged optical fiber can be directly repaired, significantly reducing the maintenance cost, extending the service life of the fiber laser, and improving its reliability in ground and space applications. In addition, this multi-functional interface also has the functions of real-time feedback of the repair status and monitoring the stability of the laser, providing strong support for the efficient maintenance and wide application of the fiber laser.

[0049] Matters not described in the present invention are well-known technologies.

[0050] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0051] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

[0052] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multifunctional interface for repairing the performance degradation of a fiber laser, characterized in that, For reliably connecting a bleaching light source to a fiber laser, the multifunctional interface includes a first interface and a second interface. The first interface is used to connect to the output end of the bleaching light source, and the second interface is used to connect to the bleaching light input port of the fiber laser. The interface types of the first interface and the second interface include FC type interfaces and SMA905 type interfaces. The insertion loss of the multifunctional interface is ≤0.2 dB, and the operating temperature is between -25°C and +70°C.

2. The method of using the multifunctional interface for repairing the performance degradation of the fiber laser according to claim 1, characterized in that Using the multifunctional interface for repairing the performance degradation of the fiber laser includes: Obtaining the initial output power P0 of the fiber laser before performance degradation; Obtaining the output power P1 of the fiber laser after being affected by the photon darkening effect or the radiation-induced darkening effect; Connecting the first interface of the multifunctional interface to the output end of the bleaching light source, and connecting the second interface to the bleaching light input port of the fiber laser. At the same time, turn on the bleaching light source and the fiber laser, inject the bleaching light source into the fiber laser through the multifunctional interface, and collect and record the current output power P2(t) of the fiber laser in real time; Comparing the current output power P2(t) of the fiber laser with the initial output power P0 of the fiber laser before performance degradation to evaluate the repair effect on the fiber laser.

3. The method of using the multifunctional interface for repairing the performance degradation of the fiber laser according to claim 2, characterized in that Evaluating the repair effect on the fiber laser includes: If P1 = P2(t) < P0, it indicates that the bleaching light source is not helpful for restoring the output power of the fiber laser; if P1 < P2(t) < P0, it indicates that the bleaching light source can partially restore the output power of the fiber laser; if P2(t) = P0, it indicates that the bleaching light source can completely restore the output power of the fiber laser; The repair effect of the fiber laser needs to be feedback-controlled and adjusted based on the evaluation result of the repair effect of the fiber laser. If the restoration of the output power of the fiber laser fails to meet the set expectation, increase the power of the bleaching light output by the bleaching light source or change the wavelength of the bleaching light for repair and then evaluate the repair effect of the fiber laser again until the restoration of the output power of the fiber laser reaches the set expectation.

4. The method for using the multifunctional interface for repairing the performance degradation of the fiber laser according to claim 2 or 3, characterized in that The fiber laser is a fiber laser oscillator, a fiber amplifier, or a cascaded structure of a fiber laser oscillator and a fiber amplifier.

5. The method of using the multi-functional interface for repairing the performance degradation of a fiber laser according to claim 4, characterized in that, The fiber laser includes a pump module, a pump combiner, a high-reflectivity fiber grating, a gain fiber, and a low-reflectivity fiber grating. The fiber laser has at least one bleaching light input port, and each bleaching light input port is respectively connected to the first interface of the corresponding multifunctional interface; The bleaching light input ports of the fiber laser include any pump arm of the pump combiner that is not connected to the pump module, and the signal arm of the pump combiner.

6. The method of using the multifunctional interface for repairing the performance degradation of a fiber laser according to claim 5, characterized in that, The gain fiber is a double-clad doped fiber, where the core diameter ranges from 10 μm to 60 μm, and the cladding diameter ranges from 130 μm to 600 μm.

7. The method of using the multi-functional interface for repairing the performance degradation of a fiber laser according to claim 6, characterized in that, The doping type of the gain fiber is ytterbium-doped, erbium-doped, or thulium-doped.

8. The method of using the multifunctional interface for repairing the performance degradation of a fiber laser according to claim 5 or 6 or 7, characterized in that, The pump combiner includes a forward pump combiner and a backward pump combiner; Among them, the forward pump combiner is an (N + 1) × 1 forward pump combiner, 2 ≤ N ≤ 18, having N pump arms, one signal arm, and one combined output end; The backward pumping combiner is an (N + 1) × 1 forward pumping combiner, where 2 ≤ N ≤ 18, having N pumping arms, one signal arm, and one combined output end.

9. The method of using the multifunctional interface for repairing the performance degradation of the fiber laser according to claim 8, characterized in that, The bleaching light source is a semiconductor laser with a central wavelength in the range of 300 nm - 808 nm and a power greater than 10 mW.

10. The method of using the multifunctional interface for repairing the performance degradation of a fiber laser according to claim 8, characterized in that, The bleaching light source accessed by the fiber laser is a single-wavelength semiconductor laser or a combination of multiple-wavelength semiconductor lasers.

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