A low repetition rate fiber laser amplifier pump light time division optical device

Abstract

The application discloses a low-repetition-frequency optical fiber laser amplifier pump light time-sharing and light-splitting device. The device comprises a pump source, a fiber acousto-optic modulator, a plurality of laser systems and a control unit. The pump source is used for generating pump light; the fiber acousto-optic modulator is connected with the output end of the pump source and is used for receiving the pump light and realizing time-sharing and light-splitting; the plurality of laser systems are respectively connected with the light-splitting output ends of the fiber acousto-optic modulator to form respective light-splitting branches and are used for receiving time-sharing pump light and performing laser amplification; and the control unit is connected with the fiber acousto-optic modulator and is used for controlling the time-sharing and light-splitting operation of the fiber acousto-optic modulator according to a preset time sequence. The device structure in the technical scheme of the application is relatively simple, easy to realize and integrate, the pump light is time-shared and light-split by the acousto-optic modulator, the ASE during the fiber laser amplification can be obviously inhibited, the beam quality and power stability of the laser output are improved, and the reasonable distribution and efficient utilization of the pump light in the plurality of laser systems can be realized.

Description

Technical Field

[0001] This application relates to the field of laser technology, and in particular to a time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier. Background Technology

[0002] Low repetition rate (LRFR) pulsed fiber laser amplifiers have wide applications in many fields. Due to their low repetition rate, the time interval between signal light pulses is relatively long, while the duration of the signal light pulses is relatively short, resulting in a low duty cycle. If continuous pumping is used, there is a significant amount of time without signal light to carry away the pump light energy, which often leads to amplified spontaneous emission (ASE). This results in limited laser output power and degraded beam quality, severely affecting the performance and application expansion of low repetition rate fiber lasers.

[0003] In existing technologies, the pumping method for such fiber amplifiers often employs electrically modulated pulse pumping, which achieves this by rapidly increasing or decreasing the pump source current. However, this method has significant drawbacks: firstly, it requires the pump source to complete the current increase or decrease within an extremely short time, placing extremely high demands on the precision and response speed of circuit control, thus increasing the difficulty and cost of circuit design and implementation; secondly, it fails to fully and rationally utilize the pump light in the time dimension, resulting in a waste of pump light resources.

[0004] Therefore, a new pump output method is urgently needed to solve these problems. Utility Model Content

[0005] This application provides a time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier, which aims to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this application proposes a time-division splitting device for the pump light of a low-repetition-rate fiber laser amplifier, the device comprising:

[0007] Pump source, used to generate pump light;

[0008] An optical fiber acousto-optic modulator is connected to the output of the pump source to receive pump light and achieve time-division splitting.

[0009] Multiple laser systems are respectively connected to the beam splitting output end of the fiber acousto-optic modulator to form each beam splitting branch, which is used to receive time-division pump light and perform laser amplification.

[0010] The control unit is connected to the fiber optic acousto-optic modulator and is used to control the time-division and beam splitting operation of the fiber optic acousto-optic modulator according to a preset timing sequence.

[0011] In some embodiments, the fiber optic acousto-optic modulator includes an acousto-optic crystal and a radio frequency driving module connected to the acousto-optic crystal. The radio frequency driving module is connected to the control unit to adjust the diffraction efficiency under the control signal of the control unit, thereby achieving dynamic adjustment of the beam splitting ratio.

[0012] In some embodiments, the spectral splitting ratio adjustment range is 10% to 90%, and the step accuracy is ≤1%.

[0013] In some embodiments, a temperature control component is further included, which is integrated with the fiber optic acousto-optic modulator to maintain the temperature of the acousto-optic crystal within a preset temperature range of ±0.1°C.

[0014] In some embodiments, a polarization controller is further included, which is disposed at the input end of the fiber optic acousto-optic modulator to optimize the polarization state of the pump light to improve diffraction efficiency.

[0015] In some embodiments, an optical isolator is also included, which is disposed between the pump source and the fiber optic acousto-optic modulator to suppress back-reflected light.

[0016] In some embodiments, the laser system includes:

[0017] The gain fiber is coupled to the beam splitting output of the fiber acousto-optic modulator and is used to receive time-division pump light to achieve population inversion.

[0018] A seed light source, coupled to the gain fiber, is used to inject seed light into the gain fiber to stimulate amplification and output working laser light.

[0019] A cladding stripper, located at the output end of the gain fiber, is used to remove residual pump light from the working laser.

[0020] In some embodiments, the time-division scheme of the control unit includes:

[0021] The periodic polling mode distributes pump light to each laser system sequentially at fixed time intervals;

[0022] Event-triggered mode: dynamically adjusts the spectral order in response to external trigger signals.

[0023] In some embodiments, a splitting ratio monitoring module is further included, used to monitor the power of each splitting branch in real time and feed it back to the control unit to form a closed-loop regulation; the splitting ratio monitoring module includes:

[0024] The beam splitter has its input end connected to each of the laser systems to couple a portion of the optical signal from each split branch;

[0025] A photodetector array, connected to the output of the beam splitter, is used to convert the optical signal into an electrical signal;

[0026] A signal processing circuit, connected to the photodetector array, is used to calculate the real-time spectral splitting ratio deviation.

[0027] In some embodiments, a fault protection module is also included, which automatically cuts off the corresponding beam splitter and redistributes the pump light when an abnormality is detected in one of the laser systems.

[0028] This application proposes a time-division splitting device for the pump light of a low-repetition-rate fiber laser amplifier. The device includes a pump source, a fiber acousto-optic modulator, multiple laser systems, and a control unit. The pump source generates pump light; the fiber acousto-optic modulator is connected to the output of the pump source to receive the pump light and perform time-division splitting; the multiple laser systems are each connected to the splitting output of the fiber acousto-optic modulator to form a splitting branch, which receives the time-division pump light and performs laser amplification; the control unit is connected to the fiber acousto-optic modulator to control the time-division splitting operation of the fiber acousto-optic modulator according to a preset timing sequence. The device structure in this application is relatively simple, easy to implement and integrate. The acousto-optic modulator performs time-division splitting of the pump light, which can significantly suppress ASE (associated acoustic wave propagation) during fiber laser amplification, improve the beam quality and power stability of the laser output, and achieve reasonable allocation and efficient utilization of the pump light among multiple laser systems, thereby improving the utilization rate of the pump light and reducing the operating cost of the laser. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0030] Figure 1 This is a schematic diagram of a module of a low repetition rate fiber laser amplifier pump light time-division and beam splitting device according to an embodiment of this application. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] It should be noted that, unless otherwise stated or limited, all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0033] It should also be noted that, unless otherwise stated or limited, when an element is referred to as "fixed to" or "set on" another element, it may be directly on the other element or there may be an intervening element present. When an element is referred to as "connected to" another element, it may be directly connected to the other element or there may be an intervening element present.

[0034] Furthermore, unless otherwise stated or limited, the descriptions involving "first," "second," etc., in this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0035] See Figure 1 As shown, this application proposes a time-division splitting device for pump light of a low repetition rate fiber laser amplifier. The device includes a pump source 10, a fiber acousto-optic modulator 20, multiple laser systems 30, and a control unit 40. The pump source 10 is used to generate pump light. The fiber acousto-optic modulator 20 is connected to the output end of the pump source 10 and is used to receive the pump light and perform time-division splitting. The multiple laser systems 30 are respectively connected to the splitting output end of the fiber acousto-optic modulator 20 to form a splitting branch, which is used to receive the time-division pump light and perform laser amplification. The control unit 40 is connected to the fiber acousto-optic modulator 20 and is used to control the time-division splitting operation of the fiber acousto-optic modulator 20 according to a preset timing sequence.

[0036] Therefore, the laser amplification process in the technical solution of this application is as follows:

[0037] Pump source 10 (such as a semiconductor laser) generates continuous pump light (typical wavelength 976nm / 915nm), which is output to fiber acousto-optic modulator 20 (AOM). Control unit 40 applies radio frequency signal to AOM to excite acoustic diffraction grating, thereby distributing pump light to different diffraction orders (such as 0th order and ±1st order) according to a preset time sequence. Each diffraction order corresponds to a beam splitting branch. For example, pump light is directed to laser system 1 during time period T1 (0-50μs) and switched to laser system 2 during time period T2 (0-50μs), and the cycle repeats. Then, each laser system 30 achieves particle inversion under the action of time-division pump light, and the synchronously injected seed light is amplified to output high-power working laser.

[0038] The device structure in this application is relatively simple, and it is easy to implement and integrate based on AOM. Furthermore, after time-division splitting the pump light using AOM, the pump light can enter different laser systems 30 at different times. This effectively avoids the concentrated action of pump light when there is no seed light, which would lead to a large amount of ASE (associated lasing) in the laser amplification system, significantly suppressing ASE during fiber laser amplification and improving the beam quality and power stability of the laser output. In addition, it achieves reasonable allocation and efficient utilization of pump light among multiple laser systems 30, avoiding pump light waste, improving pump light utilization, reducing laser operating costs, and simultaneously improving the overall performance and operating efficiency of the fiber laser.

[0039] In some embodiments, the fiber optic acousto-optic modulator 20 includes an acousto-optic crystal and a radio frequency driving module connected to the acousto-optic crystal. The radio frequency driving module is connected to the control unit 40 to adjust the diffraction efficiency under the control signal of the control unit 40, thereby realizing dynamic adjustment of the beam splitting ratio.

[0040] In this embodiment, the input of the RF drive module is connected to the control unit 40 via a digital bus, and the output is connected to the piezoelectric transducer on the acousto-optic crystal via a coaxial cable. Furthermore, the RF drive module receives analog / digital signals from the control unit 40 and outputs them to the piezoelectric transducer to excite acoustic waves. Under the action of the acoustic waves excited by the RF drive module, a periodic refractive index change is formed inside the crystal, causing the pump light to diffract and precisely distribute to each laser system 30 according to a preset timing sequence.

[0041] The radio frequency (RF) drive module can change the acoustic wave intensity within the acousto-optic crystal by adjusting the power (amplitude) and frequency of the output signal, thereby dynamically controlling the diffraction efficiency (splitting ratio) of the light. For example: increasing RF power → increasing acoustic wave amplitude → increasing diffracted light intensity.

[0042] Furthermore, the acousto-optic crystal uses high figure of merit materials, such as TeO2 or PbMoO4 crystals, to ensure that 10% diffraction efficiency can be achieved at low RF power and more than 90% at high power. That is, the beam splitting ratio adjustment range is 10% to 90%, and the step accuracy is set to ≤1%, which makes the AOM both highly flexible and reliable, and more suitable for scenarios with stringent requirements for light energy distribution.

[0043] In some embodiments, the device further includes a temperature control component integrated with the fiber optic acousto-optic modulator 20 for maintaining the temperature stability of the acousto-optic crystal within a preset temperature range of ±0.1°C.

[0044] It is understandable that the refractive index, sound velocity and other parameters of acousto-optic crystals change with temperature, which can cause the diffraction efficiency to drift. Temperature control of ±0.1℃ can ensure that the diffraction efficiency fluctuation is <±0.5%, avoid the misalignment of the beam splitting ratio and ensure the precise distribution of the beam.

[0045] For example, the temperature control component includes a high-precision temperature sensor and a temperature control actuator (TEC) connected to the control unit 40. The high-precision temperature sensor, such as a platinum resistance thermometer or a thermocouple, is directly attached to the surface of the acousto-optic crystal or embedded in the crystal support for real-time temperature monitoring. The sensor signal is transmitted to the control unit 40 with a resolution of 0.01°C. The thermoelectric cooler is integrated between the housing and the crystal to achieve heating or cooling. The control unit 40 dynamically adjusts the TEC current based on temperature feedback to achieve ±0.1°C stability, ensuring a constant temperature of the acousto-optic crystal.

[0046] In some embodiments, the device further includes a polarization controller 50, which is disposed at the input end of the fiber optic acousto-optic modulator 20 and is used to optimize the polarization state of the pump light to improve diffraction efficiency.

[0047] Understandably, the diffraction efficiency of acousto-optic effects (such as Bragg diffraction) is highly dependent on the polarization direction of the incident light. For example, TeO2 crystals have the highest diffraction efficiency for light polarized along the crystal axis, and deviations from the optimal polarization state can lead to an efficiency decrease of more than 30%. Furthermore, stress, bending, or temperature changes during fiber transmission can randomly alter the polarization state (SOP) of the pump light, requiring real-time correction.

[0048] Therefore, a polarization controller 50 can be installed at the input of the AOM. This polarization controller 50 includes a polarization detection module and a polarization adjuster. The polarization detection module is an online polarization analyzer that monitors the polarization extinction ratio in real time. The control unit 40 drives the polarization adjuster to the optimal state based on the monitored data to ensure maximum diffraction efficiency. The polarization controller 50 uses piezoelectric ceramic or liquid crystal materials, which offer fast response and high adjustment accuracy.

[0049] In some embodiments, the device further includes an optical isolator 60 disposed between the pump source 10 and the fiber optic acousto-optic modulator 20 for suppressing back-reflected light.

[0050] Understandably, directional reflected light can cause output power fluctuations (above ±5%) in semiconductor lasers (pump sources), even mode switching, and re-entry into the gain fiber, exacerbating amplified spontaneous emission (ASE). Furthermore, high-power reflected light can damage the end face of pump source 10 (e.g., the COMD effect). Therefore, by incorporating an optical isolator 60 for suppression, the stability of pump source 10 can be improved, reducing power fluctuations from ±5% to ±0.5% and wavelength drift to <0.1nm; system efficiency is improved, avoiding energy loss from reflected light (traditional systems can lose 3-5% of pump light); reliability is enhanced, pump source 10 lifetime is increased, and the AOM crystal is protected from reverse light thermal load interference, improving diffraction efficiency stability to ±0.5%.

[0051] The optical isolator 60 can be an all-fiber isolator, fused together with the output fiber of the pump source 10 and the input fiber of the AOM to avoid connector reflection. Preferably, the optical isolator 60 is positioned close to the output end of the pump source 10 to maximize the effect of suppressing reflected light.

[0052] In some embodiments, the laser system 30 includes a gain fiber, a seed source, and a cladding light stripper. The gain fiber is coupled to the beam splitting output of the fiber optic acousto-optic modulator 20 and is used to receive time-division pump light to achieve population inversion; the seed source is coupled to the gain fiber and is used to inject signal light into the gain fiber to stimulate amplification of the pump light; the cladding light stripper is disposed at the output of the gain fiber and is used to remove residual pump light.

[0053] In this embodiment, efficient and pure laser amplification is achieved only through the synergistic design of gain fiber + seed light source + cladding optical stripper.

[0054] Among them, the gain fiber can be selected from ytterbium-doped fiber (Yb). 3+ (Wavelength range 1030-1080nm) is suitable for high power; and erbium-doped fiber (Er 3+ The pump light (1550nm) is suitable for the communication band; and the structure is a double-clad fiber (such as ytterbium-doped Yb-DCF), with the pump light propagating in the cladding and the signal light amplified in the core. The seed light source can be a semiconductor laser or a fiber laser. The seed pulse (e.g., 10ns@1064nm) is injected synchronously with the pump light and amplified by stimulated emission. A cladding stripper removes unabsorbed pump light (typically a residual ratio of 5-10%).

[0055] Furthermore, the AOM, according to the timing sequence of the control unit 40, guides the pump light into different gain fibers in a time-division manner (e.g., switching one fiber every millisecond). The pump light is absorbed by the gain fiber, and doped with ions (such as Yb). 3+ The energy transitions to the upper energy level, forming an inverted distribution. When the seed light passes through the gain fiber, it triggers stimulated emission, transferring energy to the signal light and amplifying it. Finally, the cladding stripper removes unabsorbed pump light to prevent it from interfering with subsequent optical components or causing thermal effects.

[0056] In some embodiments, the time-division scheme of the control unit 40 includes:

[0057] The periodic polling mode distributes pump light to each laser system 30 sequentially at fixed time intervals. Each laser system 30 is allocated an equal or adjustable pump period, and non-uniform energy distribution is achieved by adjusting the RF drive power or period length of each branch. This mode allows multiple processing heads to work in turn, avoiding heat accumulation, and enables each laser system 30 to receive pump energy in a time-sharing manner, generating alternating pulse sequences. It offers high temporal stability and is suitable for low-repetition-rate repetitive tasks such as laser cutting.

[0058] The event-triggered mode dynamically adjusts the beam splitting order in response to external trigger signals. For example, seed laser triggering or sensor feedback allows for real-time adjustment of the beam splitting order and duration. It supports interrupting the current polling process to prioritize high-priority tasks. For instance, in the default polling mode, when a high-priority task is triggered, the control unit 40 immediately interrupts the current pumping period and reallocates the pump light to the designated laser system 30, ensuring timely task response and optimizing processing efficiency. This mode can also meet specific needs, such as lidar target tracking, improving pump utilization.

[0059] Furthermore, in further configurations, a collaborative strategy of basic polling plus trigger coverage can be used. The default allocation is polling, and time-driven allocation is temporarily inserted upon receiving a trigger signal. For example, in a 300μs cycle, laser system 1 normally occupies 0–100μs; at t=50μs, a trigger is received from laser system 3, and the system immediately switches to laser system 3 for 20μs; the remaining 30μs of system 1 are deferred to 70–100μs for execution. When time-triggered, the subsequent polling duration is proportionally compressed to maintain the total cycle time.

[0060] Through the above control, the device can meet the requirements of stable repetitive tasks and flexibly respond to dynamic scenarios, becoming the core guarantee for the efficient operation of the low repetition rate optical front laser system 30.

[0061] In some embodiments, the device further includes a beam splitting ratio monitoring module 70, used to monitor the power of each beam splitting branch in real time and feed it back to the control unit 40 to form a closed-loop regulation; the beam splitting ratio monitoring module 70 includes a beam splitter, a photodetector array, and a signal processing circuit. The input end of the beam splitter is connected to each laser system 30 to couple a portion of the optical signal from each beam splitting branch; the photodetector array is connected to the output end of the beam splitter to convert the optical signal into an electrical signal; the signal processing circuit is connected to the photodetector array to calculate the real-time beam splitting ratio deviation.

[0062] In this embodiment, the beam splitter is an optical fiber coupled type, with a splitting ratio of 1%-5% for each branch (for monitoring) and a main optical path transmittance >95%. It is positioned between the AOM splitting output and each laser system 30, coupling out a small amount of optical signal for monitoring. The photodetector array is selected as an InGaAs PIN photodiode, suitable for the 900-1700nm band; response time <10ns, matching the repetition rate of the laser system 30, such as 10kHz; and each splitting branch corresponds to one detector to ensure synchronous monitoring. The signal processing circuit includes the following functional modules: transimpedance amplifier (TIA): converts photocurrent into a voltage signal (adjustable gain); ADC module (16-bit resolution): sampling rate ≥1MSa / s; DSP / FPGA: calculates the power ratio in real time and generates a deviation signal. Therefore, the closed-loop adjustment workflow is as follows:

[0063] Each branch beam splitter couples 1% of the optical signal to the detector, converts it into a voltage signal, and uses this voltage signal to calculate the real-time beam splitting ratio. This ratio is compared with a preset ratio to generate an error signal. The control unit 40 then dynamically adjusts the RF drive power of the AOM to correct the beam splitting ratio. The time from monitoring to adjustment completion is less than 100 μs.

[0064] Therefore, the real-time monitoring-calculation-feedback chain of this closed-loop system significantly improves the splitting accuracy and stability, becoming a key technology for the highly reliable fiber laser system 30.

[0065] In some embodiments, a fault protection module 80 is also included, which is used to automatically cut off the corresponding beam splitter and redistribute the pump light when an abnormality is detected in a certain laser system 30.

[0066] In this embodiment, the fault protection module can monitor parameters through the anomaly detection unit, such as laser output power, temperature, and reflected light power. The signal processing circuit continuously compares the power / temperature of each branch with a preset threshold. When a condition is met, an anomaly determination is triggered. Such conditions could be any one of the following: power continuously below the threshold for 5ms (to prevent false triggering), temperature exceeding 50°C for 1ms, or reflected light power >10mW (pump source 10 protection). After the control unit determines an anomaly, the pump light originally allocated to the faulty branch is proportionally allocated to the normal branch. For example, before the fault: the allocation ratios of laser system 1, laser system 2, and laser system 3 are 50%, 30%, and 20%, respectively; after the fault, if laser system 2 is abnormal: laser system 1 receives 20% of the original 30%, increasing its share to 70%; laser system 3 receives 10% of the original 30%, increasing its share to 30%.

[0067] In this way, the fault protection module 80 maximizes resource utilization while ensuring safety through a three-stage mechanism of real-time monitoring, rapid disconnection, and intelligent redistribution, making the high-end fiber laser system 30 intelligent.

[0068] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier, characterized in that, include: Pump source, used to generate pump light; An optical fiber acousto-optic modulator is connected to the output of the pump source to receive pump light and achieve time-division splitting. Multiple laser systems are respectively connected to the beam splitting output end of the fiber acousto-optic modulator to form each beam splitting branch, which is used to receive time-division pump light and perform laser amplification. The control unit is connected to the fiber optic acousto-optic modulator and is used to control the time-division and beam splitting operation of the fiber optic acousto-optic modulator according to a preset timing sequence.

2. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 1, characterized in that, The fiber optic acousto-optic modulator includes an acousto-optic crystal and a radio frequency driving module connected to the acousto-optic crystal. The radio frequency driving module is connected to the control unit to adjust the diffraction efficiency under the control signal of the control unit, thereby realizing dynamic adjustment of the beam splitting ratio.

3. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 2, characterized in that, The spectral splitting ratio adjustment range is 10% to 90%, with a step accuracy of ≤1%.

4. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 2, characterized in that, It also includes a temperature control component, which is integrated with the fiber optic acousto-optic modulator to maintain the temperature of the acousto-optic crystal within a preset temperature range of ±0.1℃.

5. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 4, characterized in that, It also includes a polarization controller, which is disposed at the input end of the fiber optic acousto-optic modulator and is used to optimize the polarization state of the pump light to improve diffraction efficiency.

6. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 5, characterized in that, It also includes an optical isolator, which is disposed between the pump source and the fiber optic acousto-optic modulator to suppress back-reflected light.

7. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 1, characterized in that, The laser system includes: The gain fiber is coupled to the beam splitting output of the fiber acousto-optic modulator and is used to receive time-division pump light to achieve population inversion. A seed light source, coupled to the gain fiber, is used to inject seed light into the gain fiber to stimulate amplification and output working laser light. A cladding stripper, located at the output end of the gain fiber, is used to remove residual pump light from the working laser.

8. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 1, characterized in that, The time-division scheme of the control unit includes: The periodic polling mode distributes pump light to each laser system sequentially at fixed time intervals; Event-triggered mode: dynamically adjusts the spectral order in response to external trigger signals.

9. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 8, characterized in that, It also includes a beam splitting ratio monitoring module, used to monitor the power of each beam splitting branch in real time and feed it back to the control unit to form a closed-loop regulation; the beam splitting ratio monitoring module includes: The beam splitter has its input end connected to each of the laser systems to couple a portion of the optical signal from each split branch; A photodetector array, connected to the output of the beam splitter, is used to convert the optical signal into an electrical signal; A signal processing circuit, connected to the photodetector array, is used to calculate the real-time spectral splitting ratio deviation.

10. The time-division and beam-splitting device for the pump light of a low-repetition-rate fiber laser amplifier according to claim 1, characterized in that, It also includes a fault protection module, which automatically cuts off the corresponding beam splitter and redistributes the pump light when an abnormality is detected in one of the laser systems.

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