A high-power fiber laser capable of suppressing space-induced mode instability.

Abstract

This invention discloses a high-power fiber laser capable of suppressing space-induced mode instability (SMI), comprising a seed source, an amplification-stage pump source, a forward combiner, a gain fiber, a reverse combiner consisting of a combiner region and a pigtail, a cladding stripper, a collimation output system, a temperature monitoring module located in the combiner region of the reverse combiner, a leakage power detection module located in the pigtail of the pump arm of the reverse combiner, a near-infrared photodetector, a time-domain / frequency-domain analysis module, a space-induced mode instability identification module, and a fiber laser electrical control module. This laser can efficiently suppress SMI, filling a gap in the field of high-power fiber lasers for space applications that effectively suppress SMI, and providing strong support for space missions.

Description

Technical Field

[0001] This invention relates to the field of laser technology and demonstrates a high-power fiber laser for space use that can effectively suppress the radiation-induced mode instability effect. It can effectively suppress the radiation-induced mode instability effect caused by space irradiation and fill the gap in the field of high-stability, long-life high-power fiber lasers for space use. Background Technology

[0002] High-power fiber lasers possess advantages such as good beam quality, high conversion efficiency, compact structure, and convenient thermal management, making them valuable in both civilian and military applications. However, fiber lasers suffer from mode instability. When the laser power exceeds the mode instability threshold, the laser exhibits drastic fluctuations in output power and mode degradation, severely impacting output performance and device safety. When a high-power fiber laser operates in an irradiated environment, irradiation loss lowers the mode instability threshold, a phenomenon known as radiation-induced mode instability.

[0003] When radiation-induced mode instability occurs, the fundamental and higher-order mode components of the laser periodically couple, causing a rapid increase in the power of the higher-order modes, which is then filtered out by the cladding optical stripper. This leads to drastic fluctuations and a significant decrease in the fundamental mode power, ultimately resulting in a rapid increase in the laser's thermal load and even a risk of burnout. Therefore, accurately assessing radiation-induced mode instability in fiber lasers is crucial and urgent to promptly limit pump power and prevent further increases in the laser's thermal load. Currently, research on radiation-induced mode instability in high-power fiber lasers for space applications has not been publicly published; this invention fills a gap in this field.

[0004] This invention incorporates the following innovative optimizations: It comprehensively assesses multiple factors, including the temperature of the reverse beam combining region, leakage power, and laser time / frequency domain characteristic signals, to accurately identify radiation-induced mode instability (RIM). Based on the current level of RIM instability in fiber lasers, it adjusts the laser's pump current accordingly, thereby protecting fiber laser devices and suppressing RIM through optical / thermal bleaching. Furthermore, this invention is based on a modular design, facilitating system debugging and maintenance. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a high-power fiber laser that can suppress the radiation-induced mode instability effect in space. This laser can efficiently suppress the radiation-induced mode instability effect, fill the gap in the field of high-power fiber lasers for space use that can effectively suppress the radiation-induced mode instability effect, and provide strong support for performing space missions.

[0006] The technical solution of the present invention is: a high-power fiber laser capable of suppressing spatial radiation-induced mode instability, comprising a seed source, an amplification-stage pump source, a forward combiner, a gain fiber, a reverse combiner composed of a combiner region and a pigtail, a cladding light stripper, a collimation output system, a temperature monitoring module located in the combiner region of the reverse combiner, a leakage light power detection module located in the pigtail of the pump arm of the reverse combiner, a near-infrared photodetector, a time-domain / frequency-domain analysis module, a spatial radiation-induced mode instability identification module, and a fiber laser electrical control module;

[0007] The seed light emitted from the seed source and the pump light emitted from the pump source are combined by a forward combiner and injected into the gain fiber to achieve laser amplification. The amplified laser then passes sequentially through a reverse combiner, a cladding stripper, and a collimation output system, ultimately outputting a collimated laser. The pump arm pigtail of the reverse combiner is used to monitor leakage power, and the cladding stripper is used to remove cladding light from the output laser. The temperature monitoring module monitors the temperature of the combining region of the reverse combiner, and the optical power detection module monitors leakage power in the pump arm pigtail of the reverse combiner. Exposed light power; the near-infrared photodetector is installed on the collimation output system to convert the scattered light signal of the collimated laser into an electrical signal; the time-domain / frequency-domain analysis module receives the electrical signal output by the near-infrared photodetector, analyzes the time-domain / frequency-domain characteristic signal of the collimated laser and sends it to the identification module; the identification module determines whether the laser has experienced radiation-induced mode instability based on the received time-domain / frequency-domain characteristic signal, and outputs a lock-in pump signal when it occurs; the fiber laser electrical control module is used to control the power and power supply timing of the seed source and the amplification stage pump source.

[0008] The radiation-induced mode instability effect includes:

[0009] The temperature in the combining region of the reverse combiner rises by 10°C within 10 seconds.

[0010] The leakage optical power of the pump arm pigtail increased by 75W within 10 seconds;

[0011] Collimated lasers exhibit repetitive pulses on a millisecond scale in the time domain;

[0012] An envelope peak on a kilohertz scale appears in the frequency domain;

[0013] When all four conditions mentioned above occur simultaneously, the identification module determines that the laser has experienced radiative mode instability and then outputs a lock-in pump signal.

[0014] The center wavelength of the light output from the seed source is between 1030nm and 1100nm, and the seed light power is adjustable.

[0015] The pump wavelength of the amplification stage pump source is 915±10nm or 976±10nm, and it consists of multiple cascaded laser diodes with adjustable total pump power.

[0016] The temperature monitoring module is used to monitor the temperature of the beam combining area of ​​the reverse beam combiner. The monitored temperature range covers 0 to 90℃. The triggering and deactivation conditions are adjustable, as follows: when the temperature rises by 10℃ within 10 seconds, a temperature alarm signal is triggered; when the temperature drops to a stable value, i.e., the rate of change is less than 2% within 15 minutes, the temperature alarm signal is deactivated.

[0017] The optical power detection module is used to monitor the leakage optical power of the reverse combiner pump arm. The monitoring power range is greater than 600W@1030nm~1100nm. The triggering and de-alarm conditions are adjustable, as follows: when the leakage optical power increases by 75W within 10s, the power alarm signal is triggered; when the leakage optical power decreases to a stable value, that is, the change rate is less than 1.5% within 15 minutes, the power alarm signal is de-alarmed.

[0018] The time-domain / frequency-domain analysis module is used to analyze the time-domain / frequency-domain characteristics of the laser electrical signal. The triggering and de-alarm conditions are adjustable, and the conditions are as follows: when a repetitive pulse on the millisecond scale appears in the time domain and an envelope peak on the kilohertz scale appears in the frequency domain, the time-domain / frequency-domain alarm signal is triggered. When the above characteristic signals disappear, the time-domain / frequency-domain alarm signal is de-alarmed.

[0019] The identification module is used to accurately determine whether the radiation-induced mode instability effect has occurred. When the temperature monitoring module, the leakage power detection module, and the time-domain / frequency-domain analysis module simultaneously trigger alarm signals, it is determined that the laser has experienced the radiation-induced mode instability effect, and a pump current lockout command is issued. When the temperature monitoring module, the leakage power detection module, and the time-domain / frequency-domain analysis module all deactivate the alarm signals, it is determined that the radiation-induced mode instability effect of the laser has been effectively suppressed, and a pump current unlocking command is issued.

[0020] The near-infrared photodetector is installed on the collimation output system to collect the scattered light of the collimated laser and convert the scattered light signal into an electrical signal. The detection rate is not less than 100M / s and the bandwidth is not less than 100MHz.

[0021] The electronic control module is used to control the power supply timing and current of the laser seed source and pump source. When the electronic control module receives a pump current lock command from the identification module, it will not allow the pump current to continue to increase, thus protecting the laser module. When it receives a pump current unlock command, it will allow the pump current to continue to increase, thereby increasing the output power of the laser.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) This invention can accurately determine the radiation-induced mode instability (RIM) effect in fiber lasers. Experimental studies have shown that after RIM occurs in a fiber laser, the temperature in the reverse combining region rises rapidly, the leakage power of the reverse combiner pump arm increases rapidly, and the laser's time-domain / frequency-domain characteristic signals become obvious. With prolonged light output, based on the combined effects of optical bleaching and thermal bleaching, the radiation-induced loss in the laser gradually decreases, and the RIM effect is effectively suppressed. Ultimately, the temperature fluctuation in the reverse combining region decreases to a stable value, the leakage power fluctuation decreases to a stable value, and the time-domain / frequency-domain characteristic signals disappear. This invention combines these three characteristic signals to accurately determine whether a fiber laser has experienced RIM.

[0024] (2) The optical path structure of the present invention is simple and easy to implement, and effectively solves the problem of radiative mode instability faced by high-power fiber lasers in space.

[0025] (3) The present invention is based on modular design. The fiber laser module adopts a mature optical path structure, and the monitoring module, identification module and electrical control module all adopt mature modules, which are easy to test and maintain. Attached Figure Description

[0026] Figure 1 A schematic diagram of a high-power fiber laser capable of suppressing spatial radiation-induced mode instability provided by the present invention;

[0027] Figure 2 This is a schematic diagram showing the changes in laser power, leakage light power, and reverse beam combining region temperature with the switching time after radiation-induced mode instability occurs. Detailed Implementation

[0028] The present invention discloses a high-power fiber laser capable of suppressing spatial radiation-induced mode instability, comprising a seed source 101, an amplification-stage pump source 102, a forward combiner 103, a gain fiber 104, a reverse combiner 105 composed of a combiner region and a pigtail, a cladding light stripper 106, a collimation output system 107, a temperature monitoring module 108 located in the combiner region of the reverse combiner 105, a leakage light power detection module 109 located in the pigtail of the pump arm of the reverse combiner 105, a near-infrared photodetector 110, a time-domain / frequency-domain analysis module 111, a spatial radiation-induced mode instability identification module 112, and a fiber laser electrical control module 113.

[0029] The seed light emitted from seed source 101 and the pump light emitted from pump source 102 are combined by forward combiner 103 and injected into gain fiber 104 for laser amplification. The amplified laser then passes through reverse combiner 105, cladding stripper 106, and collimation output system 107 in sequence before finally outputting collimated laser light. The pump arm pigtail of reverse combiner 105 is used to monitor leakage power, and cladding stripper 106 is used to remove cladding light from the output laser. Temperature monitoring module 108 is used to monitor the temperature of the combining region of reverse combiner 105. Optical power detection module 109 is used to monitor the pump power of reverse combiner 105. The leakage light power of the pump arm pigtail; the near-infrared photodetector 110 is installed on the collimation output system 107 to convert the scattered light signal of the collimated laser into an electrical signal; the time-domain / frequency-domain analysis module 111 receives the electrical signal output by the near-infrared photodetector 110, analyzes the time-domain / frequency-domain characteristic signal of the collimated laser and sends it to the identification module 112; the identification module 112 determines whether the laser has a radiation mode instability effect based on the received time-domain / frequency-domain characteristic signal, and outputs a lock-in pump signal when it occurs; the fiber laser electrical control module 113 is used to control the power and power supply timing of the seed source 101 and the amplification stage pump source 102.

[0030] After the fiber laser operates at its current locked pump power for a period of time, the radiation-induced loss in the laser gradually decreases due to the combined effects of photobleaching and thermal bleaching, and the radiation-induced mode instability threshold gradually increases. At the same time, the rate of change of the output power of the fiber laser rising to a stable value within 15 minutes is less than 1.5%, the rate of change of the temperature in the reverse beam combining region falling to a stable value within 15 minutes is less than 2%, the rate of change of the leakage light power falling to a stable value within 15 minutes is less than 1.5%, the millisecond-scale repetitive pulses in the time domain disappear, and the kilohertz-scale envelope peak in the frequency domain disappears. The identification module 112 determines that the radiation-induced mode instability effect of the laser has been effectively suppressed, and at the same time, the locking of the pump source current by the electrical control module 113 is released.

[0031] The radiation-induced mode instability effect includes:

[0032] The temperature in the combining region of the reverse combiner 105 rises by 10°C within 10 seconds.

[0033] The leakage optical power of the pump arm pigtail increased by 75W within 10 seconds;

[0034] Collimated lasers exhibit repetitive pulses on a millisecond scale in the time domain;

[0035] An envelope peak on a kilohertz scale appears in the frequency domain;

[0036] When the above four situations occur simultaneously, the identification module 112 determines that the laser has now experienced a radiative mode instability effect, and then outputs a lock-in pump signal.

[0037] The center wavelength of the output light from the seed source 101 is between 1030nm and 1100nm, and the seed light power is adjustable.

[0038] The pump wavelength of the amplification stage pump source 102 is 915±10nm or 976±10nm, and it consists of multiple cascaded laser diodes with adjustable total pump power.

[0039] The temperature monitoring module 108 is used to monitor the temperature of the beam combining area of ​​the reverse beam combiner. The monitoring temperature range covers 0 to 90℃. The triggering and deactivation conditions are adjustable. The conditions are as follows: when the temperature rises by 10℃ within 10 seconds, the temperature alarm signal is triggered. When the temperature drops to a stable value, that is, the change rate is less than 2% within 15 minutes, the temperature alarm signal is deactivated.

[0040] The optical power detection module 109 is used to monitor the leakage optical power of the pump arm of the reverse combiner. The monitoring power range is greater than 600W@1030nm~1100nm. The triggering and de-alarm conditions are adjustable, as follows: when the leakage optical power rises by 75W within 10s, the power alarm signal is triggered; when the leakage optical power drops to a stable value, that is, the change rate is less than 1.5% within 15 minutes, the power alarm signal is de-alarmed.

[0041] The time-domain / frequency-domain analysis module 111 is used to analyze the time-domain / frequency-domain characteristics of the laser electrical signal. The triggering and de-alarm conditions are adjustable, and the conditions are as follows: when a repetitive pulse on the millisecond scale appears in the time domain and an envelope peak on the kilohertz scale appears in the frequency domain, the time-domain / frequency-domain alarm signal is triggered. When the above characteristic signals disappear, the time-domain / frequency-domain alarm signal is de-alarmed.

[0042] The identification module 112 is used to accurately determine whether the radiative mode instability effect has occurred. When the temperature monitoring module 108, the leakage light power detection module 109, and the time-domain / frequency-domain analysis module 111 simultaneously trigger alarm signals, it is determined that the laser has experienced the radiative mode instability effect, and then a pump current lockout command is issued. When the temperature monitoring module 108, the leakage light power detection module 109, and the time-domain / frequency-domain analysis module 111 all deactivate the alarm signals, it is determined that the radiative mode instability effect of the laser has been effectively suppressed, and then a pump current unlocking command is issued.

[0043] The near-infrared photoelectric probe 110 is installed on the collimation output system 107 to collect the scattered light of the collimated laser and convert the scattered light signal into an electrical signal. The detection rate is not less than 100M / s and the bandwidth is not less than 100MHz.

[0044] The electronic control module 113 is used to control the power supply timing and power supply current of the laser seed source 101 and the pump source 102. When the electronic control module 113 receives a pump current lock command issued by the identification module 112, it will not allow the pump current to continue to increase, which is used to protect the laser module. When it receives a pump current unlock command, it will allow the pump current to continue to increase, which can improve the output power of the laser.

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with the appendix. Figure 1 The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0046] Please refer to Figure 1 The high-power fiber laser module is responsible for outputting high-power laser light. In this embodiment, ytterbium-doped fiber is used as the gain fiber, with a core / clasp size of 20 / 400 μm. The laser output power is approximately 2000 W, the slope efficiency is approximately 80%, the laser center wavelength is 1064 nm, and the mode instability threshold is approximately 2200 W. Due to space irradiation, radiation-induced losses occur in the ytterbium-doped fiber, and the thermal load of these losses lowers the mode instability threshold to 1000 W. With a pump power of 1200 W, the laser output power before irradiation is 1000 W, but after irradiation, the laser exhibits radiation-induced mode instability.

[0047] Please see Figure 2 After radiation-induced mode instability occurs, the changes in laser power, leakage light power, and reverse beam combining region temperature with the switching time are as follows:

[0048] T1 is the first stage after the laser power exceeds the radiation-induced mode instability threshold. It is mainly characterized by a rapid decrease in output power followed by a slight rebound, a rapid increase in leakage power followed by a slight decrease, and a rapid increase in temperature in the reverse beam combining region. Typically, the output power decreases by about 200W within 10 seconds, the leakage power increases by about 75W within 10 seconds, and the temperature rises by about 10℃ within 10 seconds.

[0049] T2 is the second stage after the radiation-induced mode instability effect occurs. The laser power is relatively stable but still lower than the original value, the leakage light power is relatively stable, and the temperature in the reverse beam combining region rises slightly.

[0050] T3 is the third stage after the radiation-induced mode instability effect occurs. The laser power decreases significantly again and then gradually stabilizes, the leakage light power increases significantly again and then gradually stabilizes, and the temperature in the reverse beam combining region rises slowly.

[0051] T4 is the fourth stage after the radiation-induced mode instability effect occurs. The laser power increases and gradually stabilizes, exceeding the original value. The leakage light power decreases and gradually stabilizes (the change rate is less than 1.5% within 15 minutes). The temperature of the reverse beam combining region gradually decreases to a stable value (the change rate is less than 2.0% within 15 minutes).

[0052] During the T' stage, after a long period of light emission, the laser's radiation loss gradually decreases due to the combined effects of photobleaching and thermal bleaching. At this point, the radiation mode instability effect is suppressed, and the laser's various parameters return to normal.

[0053] Specifically, in this embodiment, the temperature monitoring module detected a 10°C increase in temperature in the reverse beam combining region within 10 seconds; the optical power detection module detected a 75W increase in leakage optical power in the pump arm of the reverse beam combiner within 10 seconds; the near-infrared photodetector and the time / frequency domain analysis module detected repetitive pulses on a millisecond scale in the time domain and envelope peaks on a kilohertz scale in the frequency domain, simultaneously triggering temperature alarm, leakage optical power alarm, and time / frequency domain alarm signals; the identification module determined that a radiation-induced mode instability effect had occurred, and to protect the safety of the fiber laser, the electronic control... The module executed a pump power limiting command, at which point the pump current value could be reduced but not allowed to increase further. After two hours of continuous light output, the temperature of the reverse beam combiner region had decreased and gradually stabilized (the rate of change was less than 1.5% within 15 minutes), the leakage power of the reverse beam combiner pump arm had decreased and gradually stabilized (the rate of change was less than 2.0% within 15 minutes), and the time / frequency domain characteristic signal of the collimated laser had disappeared. At this point, the radiation-induced mode instability effect of the laser had been effectively suppressed. The identification module judged this, and the electronic control module released the pump power limitation, allowing the pump current value to continue to increase. Due to radiation loss, the laser's output power stabilized at 900W, still lower than the 1000W before irradiation, but the radiation-induced mode instability effect had been effectively suppressed.

[0054] The experimental results of this embodiment demonstrate that the present invention can accurately determine whether a fiber laser has experienced radiation-induced mode instability based on multiple characteristic signals and execute corresponding operations. While ensuring the safety of the fiber laser, it further achieves effective suppression of radiation-induced mode instability. The present invention has advantages such as accurate judgment, simple optical path, and modular design, filling the gap in the field of high-power fiber lasers for space applications that effectively suppress radiation-induced mode instability, and providing strong support for space missions.

[0055] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A high-power fiber laser capable of suppressing spatially induced mode instability, characterized in that: It includes a seed source (101), an amplification pump source (102), a forward combiner (103), a gain fiber (104), a reverse combiner (105) composed of a combiner region and a pigtail, a cladding light stripper (106), a collimation output system (107), a temperature monitoring module (108) located in the combiner region of the reverse combiner (105), a leakage light power detection module (109) located in the pigtail of the pump arm of the reverse combiner (105), a near-infrared photodetector (110), a time-domain / frequency-domain analysis module (111), a spatial radiation-induced mode instability effect identification module (112), and a fiber laser electrical control module (113). The seed light emitted from the seed source (101) and the pump light emitted from the pump source (102) are combined by the forward combiner (103) and injected into the gain fiber (104) to achieve laser amplification. The amplified laser then passes through the reverse combiner (105), the cladding stripper (106), and the collimation output system (107) in sequence to finally output collimated laser. The pump arm pigtail of the reverse combiner (105) is used to monitor the leakage light power, and the cladding stripper (106) is used to remove the cladding light from the output laser. The temperature monitoring module (108) is used to monitor the temperature of the combining area of ​​the reverse combiner (105). The optical power detection module (109) is used to monitor the temperature of the reverse combiner (105). 05) Leakage power of pump arm pigtail; The near-infrared photodetector (110) is installed on the collimation output system (107) and is used to convert the scattered light signal of the collimated laser into an electrical signal; The time-domain / frequency-domain analysis module (111) receives the electrical signal output by the near-infrared photodetector (110), analyzes the time-domain / frequency-domain characteristic signal of the collimated laser and sends it to the identification module (112); The identification module (112) determines whether the laser has a radiation-induced mode instability effect based on the received time-domain / frequency-domain characteristic signal, and outputs a lock pump signal when it occurs; The fiber laser electrical control module (113) is used to control the power and power supply timing of the seed source (101) and the amplification stage pump source (102).

2. A high-power fiber laser capable of suppressing spatial radiation-induced mode instability according to claim 1, characterized in that: The radiation-induced mode instability effect includes: The temperature in the combining region of the reverse combiner (105) rises by 10°C within 10 seconds; The leakage optical power of the pump arm pigtail increased by 75W within 10 seconds; Collimated lasers exhibit repetitive pulses on a millisecond scale in the time domain; An envelope peak on a kilohertz scale appears in the frequency domain; When the above four situations occur simultaneously, the identification module (112) determines that the laser has now experienced a radiative mode instability effect, and then outputs a lock-in pump signal.

3. A high-power fiber laser capable of suppressing spatial radiation-induced mode instability according to claim 1, characterized in that: The center wavelength of the light output by the seed source (101) is between 1030nm and 1100nm, and the seed light power is adjustable.

4. A high-power fiber laser capable of suppressing spatial radiation-induced mode instability according to claim 1, characterized in that: The pump wavelength of the amplification stage pump source (102) is 915±10nm or 976±10nm, and it consists of multiple cascaded laser diodes with adjustable total pump power.

5. A high-power fiber laser capable of suppressing spatial radiation-induced mode instability according to claim 1, characterized in that: The temperature monitoring module (108) is used to monitor the temperature of the beam combining area of ​​the reverse beam combiner. The temperature monitoring range covers 0 to 90°C. The triggering and deactivation conditions are adjustable. The conditions are as follows: when the temperature rises by 10°C within 10 seconds, the temperature alarm signal is triggered. When the temperature drops to a stable value, i.e., the change rate is less than 2% within 15 minutes, the temperature alarm signal is deactivated.

6. A high-power fiber laser capable of suppressing spatial radiation-induced mode instability according to claim 1, characterized in that: The optical power detection module (109) is used to monitor the leakage optical power of the pump arm of the reverse combiner. The monitoring power range is greater than 600W@1030nm~1100nm. The triggering and de-alarm conditions are adjustable. The conditions are as follows: when the leakage optical power rises by 75W within 10s, the power alarm signal is triggered. When the leakage optical power drops to a stable value, that is, the change rate is less than 1.5% within 15 minutes, the power alarm signal is de-alarmed.

7. A high-power fiber laser capable of suppressing spatially induced mode instability according to claim 1, characterized in that: The time-domain / frequency-domain analysis module (111) is used to analyze the time-domain / frequency-domain characteristics of the laser electrical signal. The triggering and de-alarm conditions are adjustable, and the conditions are as follows: when a repetitive pulse on the millisecond scale appears in the time domain and an envelope peak on the kilohertz scale appears in the frequency domain, the time-domain / frequency-domain alarm signal is triggered. When the above characteristic signals disappear, the time-domain / frequency-domain alarm signal is de-alarmed.

8. A high-power fiber laser capable of suppressing spatial radiation-induced mode instability according to claim 1, characterized in that: The identification module (112) is used to accurately determine whether the radiation-induced mode instability effect has occurred. When the temperature monitoring module (108), the leakage light power detection module (109), and the time-domain / frequency-domain analysis module (111) simultaneously trigger alarm signals, it is determined that the laser has now experienced the radiation-induced mode instability effect, and then a pump current lockout command is issued. When the temperature monitoring module (108), the leakage light power detection module (109), and the time-domain / frequency-domain analysis module (111) all deactivate the alarm signals, it is determined that the radiation-induced mode instability effect of the laser has been effectively suppressed, and then a pump current unlocking command is issued.

9. A high-power fiber laser capable of suppressing spatial radiation-induced mode instability according to claim 1, characterized in that: The near-infrared photoelectric probe (110) is installed on the collimation output system (107) to collect the scattered light of the collimated laser and convert the scattered light signal into an electrical signal. The detection rate is not less than 100M / s and the bandwidth is not less than 100MHz.

10. A high-power fiber laser capable of suppressing spatially induced mode instability according to claim 1, characterized in that: The power control module (113) is used to control the power supply timing and power supply current of the laser seed source (101) and pump source (102). When the power control module (113) receives a pump current lock command issued by the identification module (112), it does not allow the pump current to continue to increase, which is used to protect the laser module. When it receives a pump current unlock command, it allows the pump current to continue to increase, which can improve the output power of the laser.

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