Fiber laser amplification system and dynamic suppression method for stimulated Brillouin scattering effect

Abstract

The application discloses an optical fiber laser amplification system and a dynamic suppression method of stimulated Brillouin scattering effect. Spectrum data obtained by a spectrum analysis probe is analyzed by a control unit to obtain spectrum characteristic data of backward Stokes light in the optical fiber laser amplification system, so as to determine the severity of the stimulated Brillouin scattering effect in the system. The data is transmitted to a main control unit in real time, the main control unit intelligently controls an intelligent signal generator to generate different types of signals, the signals are injected into an electro-optic phase modulator to modulate the base frequency signal light with different modulation depths, the spectrum is expanded with different degrees, the information is collected by the spectrum analysis probe again and processed again, and the process is repeated until the peak gain of SBS is reduced and the stimulated Brillouin scattering effect in the optical fiber laser amplification system is effectively suppressed, so that the system power is improved.

Description

Technical Field

[0001] This application belongs to the field of laser technology, and in particular relates to a fiber laser amplification system and a dynamic suppression method for stimulated Brillouin scattering effect. Background Technology

[0002] During the amplification process, fiber lasers are limited by factors such as thermal effects, mode instability, and nonlinear effects, resulting in a bottleneck in their output power. In certain specialized fields, the brightness and power of current single-output fiber lasers are insufficient to meet application requirements.

[0003] To achieve higher power output in fiber lasers, it is necessary to overcome the limiting factors that restrict power increase during fiber amplification, with nonlinear effects being the most significant constraint. Common nonlinear effects include stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), and self-phase modulation (SPM). Among these major effects, stimulated Brillouin scattering has the lowest threshold, making it the primary factor limiting the power increase of single-frequency fiber lasers.

[0004] Improving the SBS threshold can be achieved by reducing the SBS peak gain coefficient. Currently, the most effective method for reducing SBS peak gain is through spectral broadening of single-frequency light, thereby broadening the SBS gain spectrum and effectively reducing the SBS peak gain. However, the methods used in related technologies are complex and simplistic, and cannot directly reduce the SBS peak gain. Summary of the Invention

[0005] This application provides a fiber laser amplification system and a dynamic suppression method for stimulated Brillouin scattering, which at least solves the problem in the related art that stimulated Brillouin scattering limits the power enhancement of single-frequency fiber lasers.

[0006] In a first aspect, embodiments of this application provide a fiber laser amplification system, including a single-frequency seed source, a fiber pre-amplification stage, a fiber main amplification stage, a spectral analysis probe, an analysis control unit, a main control unit, an intelligent signal generator, and an electro-optic phase modulator;

[0007] The spectral analysis probe is connected to the fiber pre-amplification stage, the fiber main amplification stage and the analysis control unit respectively, and is used to detect the back Stokes light generated during the fiber amplification process in real time to obtain spectral data.

[0008] The analysis and control unit is used to analyze the spectral data to obtain spectral characteristic data and the severity level of stimulated Brillouin scattering in the fiber laser amplification system;

[0009] The main control unit is connected to the analysis control unit and the intelligent signal generator respectively, and is used to control the intelligent signal generator to generate at least one type of matching target suppression signal based on the spectral feature data and the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system.

[0010] The electro-optic phase modulator is connected to the single-frequency seed source, the fiber preamplifier stage, and the intelligent signal generator, respectively. It is used to perform phase modulation on the fundamental frequency signal light input from the single-frequency seed source with a modulation depth matching the target suppression signal according to the target suppression signal injected by the intelligent signal generator, thereby achieving broadening of the fundamental frequency light spectrum.

[0011] Secondly, embodiments of this application provide a dynamic suppression method for stimulated Brillouin scattering, the method being applied to a fiber laser amplification system as described in any embodiment of the first aspect, the method comprising:

[0012] Spectral data are obtained by real-time detection of the backward Stokes light generated during fiber amplification using a spectral analysis probe.

[0013] The spectral data is analyzed by the control unit to obtain spectral characteristic data and the severity level of stimulated Brillouin scattering in the fiber laser amplification system;

[0014] The main control unit controls the intelligent signal generator to generate at least one type of target suppression signal that matches the spectral feature data and the severity of the stimulated Brillouin scattering effect in the fiber laser amplification system.

[0015] The fundamental frequency signal light input from the single-frequency seed source is phase-modulated by an electro-optic phase modulator according to the target suppression signal injected by the intelligent signal generator, with a modulation depth matching the target suppression signal, thereby achieving broadening of the fundamental frequency light spectrum.

[0016] The fiber laser amplification system and dynamic suppression method for stimulated Brillouin scattering (SBS) of this application utilize spectral data obtained by a spectral analysis probe. The analysis and control unit rapidly analyzes the spectral characteristics of the backscattered Stokes light in the fiber laser amplification system to determine the severity of the SBS effect. This data is transmitted to the main control unit in real time. The main control unit intelligently controls an intelligent signal generator to produce different types of signals. These signals are injected into an electro-optic phase modulator. The fundamental frequency signal light passing through the electro-optic phase modulator undergoes modulation at different depths, resulting in varying degrees of spectral broadening and suppression of the backscattered Stokes light. This information is then collected again by the spectral analysis probe and processed once more. This process is repeated until the peak gain of the SBS is reduced, effectively suppressing the SBS effect in the fiber laser amplification system and thus improving system power. Furthermore, this system requires no complex operation, greatly increasing efficiency and portability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a conventional optical fiber master oscillator power amplifier structure;

[0019] Figure 2 This is a schematic diagram of the structure of a fiber laser amplification system provided in an embodiment of this application;

[0020] Figure 3 This is a spectral image obtained by analyzing spectral data through an analysis control unit, as provided in the embodiments of this application;

[0021] Figure 4 This is a flowchart illustrating a dynamic suppression method for stimulated Brillouin scattering provided in an embodiment of this application.

[0022] Figure label:

[0023] Single-frequency seed source 100, fiber optic pre-amplifier stage 200, fiber optic main amplifier stage 300, spectral analysis probe 400, analysis control unit 500, main control unit 600, intelligent signal generator 700, electro-optic phase modulator 800, circulator 900. Detailed Implementation

[0024] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0026] Fiber lasers have undergone decades of rapid development and currently enjoy wide applications in scientific research, information communication, industrial processing, and specialized fields. However, different fields require different power levels for fiber lasers. During amplification, fiber lasers are limited by factors such as thermal effects, mode instability, and nonlinear effects, resulting in a bottleneck in their output power. In certain specialized fields, the brightness and power of current single-channel output fiber lasers are no longer sufficient to meet application demands.

[0027] To achieve higher combining power and better combining effect, using narrow-linewidth linearly polarized fiber lasers as the combining sub-lasers has become the preferred choice. However, during the fusion splicing process of polarization-maintaining fibers, in order to improve efficiency, the fusion splicer often uses a program to automatically identify the XY field of view to determine whether the fast and slow axes of the polarization-maintaining fiber are aligned. In some special fields, since the polarization-maintaining fiber used is not the common fiber available in the market, the fusion splicing program is not entirely applicable. Therefore, in many cases, the machine misidentifies the fiber but does not report the error in time and continues the fusion process, resulting in the fast and slow axes of the fiber not being completely aligned, ultimately causing the polarization state of the fiber output to rotate.

[0028] To achieve higher power output in fiber lasers, it is necessary to overcome the limiting factors that restrict power increase during fiber amplification, with nonlinear effects being the most significant constraint. Common nonlinear effects include stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), and self-phase modulation (SPM). Among these major effects, stimulated Brillouin scattering has the lowest threshold, making it the primary factor limiting the power increase of single-frequency fiber lasers.

[0029] The threshold formula for SBS can be approximated as:

[0030]

[0031] Among them, A eff g is the effective mode area of ​​the optical fiber. SBS L is the peak gain coefficient of SBS. eff Where is the effective length of the optical fiber, and K is a fixed factor.

[0032] As can be seen from the formula, increasing the SBS threshold can be achieved by increasing the mode area of ​​the fiber or decreasing the fiber length. However, increasing the mode area leads to an increase in modes, while decreasing the fiber length results in insufficient gain. Therefore, the most effective method is to reduce the peak gain coefficient of the SBS. In existing reports, the most effective method for reducing the peak gain of the SBS is to broaden the spectrum of the single-frequency light, thereby broadening the SBS gain spectrum and effectively reducing the peak gain of the SBS.

[0033] Patent CN115395362A introduces a method for suppressing stimulated Brillouin scattering (SBS), but its system is relatively complex and not conducive to engineering. Patent CN109378687B adopts a method of increasing the SBS loss, but its structure is complex and the devices are easily damaged, which has a significant impact on the signal light. Patent CN117728278A adopts a novel approach, which reduces the SBS effect by effectively controlling the driving power supply. However, the methods used in the above patents are complex and singular, and a single device can only generate one type of signal, which cannot directly reduce the peak gain of SBS.

[0034] To address the problems in the related technologies, this application provides a fiber laser amplification system and a dynamic suppression method for stimulated Brillouin scattering, which can intelligently suppress the stimulated Brillouin scattering effect that restricts the power enhancement of the fiber laser amplification system.

[0035] Currently, the master oscillator power amplifier (MOPA) structure is generally used in common 1-2μm fiber laser amplification systems. Figure 1 The conventional fiber optic master oscillator power amplifier structure is shown. For example... Figure 1As shown, its structure can be simplified into three stages: a low-power single-frequency seed source, a medium-power fiber pre-amplification stage, and a high-power fiber main amplification stage, followed by system output. However, this traditional fiber laser can only generate one signal, and the complexity of the equipment for suppressing stimulated Brillouin scattering also increases. In contrast, the embodiments of this application can dynamically control the signal, determining in real-time what kind of signal to generate based on real-time monitoring, thereby autonomously outputting different types of signals and possessing multiple integrated functions.

[0036] The fiber laser amplification system provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0037] refer to Figure 2 This is a schematic diagram of the structure of a fiber laser amplification system according to an embodiment of this application. Figure 2 As shown, the fiber laser amplification system includes a single-frequency seed source 100, a fiber pre-amplification stage 200, a fiber main amplification stage 300, a spectral analysis probe (SAPD) 400, an analysis control unit (ACU) 500, a main control unit (MCU) 600, an intelligent signal generator (ISG) 700, and an electro-optic phase modulator (EOM) 800.

[0038] It is understood that the fiber laser amplification system of this application mainly consists of two parts: an SBS detection region and an SBS intelligent suppression region. The SBS detection region includes a high-speed response spectral analysis probe 400 and an analysis and control unit 500. The SBS intelligent suppression region includes an electro-optic phase modulator 800, an intelligent signal generator 700, and a main control unit 600.

[0039] Among them, the spectral analysis probe 400 is connected to the fiber optic pre-amplification stage 200, the fiber optic main amplification stage 300 and the analysis control unit 500 respectively; the main control unit 600 is connected to the analysis control unit 500 and the intelligent signal generator 700 respectively; and the electro-optic phase modulator 800 is connected to the single-frequency seed source 100, the fiber optic pre-amplification stage 200 and the intelligent signal generator 700 respectively.

[0040] Specifically, the single-frequency seed source 100 has an extremely narrow linewidth and good single-frequency performance; the fiber pre-amplification stage 200 is used for seamless transition during amplification; the fiber main amplification stage 300 is used for high-power amplification of the fundamental frequency light; the spectral analysis probe 400 is used to detect the back-stokes light generated during fiber amplification in real time and obtain spectral data; the analysis control unit 500 is used to analyze the spectral data to obtain spectral characteristic data and the severity level of stimulated Brillouin scattering in the fiber laser amplification system; the main control unit 600 is used to control the intelligent signal generator 700 to generate at least one type of matching target suppression signal based on the spectral characteristic data and the severity level of stimulated Brillouin scattering in the fiber laser amplification system; and the electro-optic phase modulator 800 is used to perform phase modulation on the fundamental frequency signal light input from the single-frequency seed source 100 with a modulation depth matching the target suppression signal based on the target suppression signal injected by the intelligent signal generator 700, thereby achieving spectral broadening of the fundamental frequency light.

[0041] In some alternative embodiments, such as Figure 2 As shown, the fiber preamplifier stage 200 and the fiber main amplifier stage 300 are connected by a circulator 900, and the circulator 900 is provided with an optical fiber for detection, and the spectral analysis probe 400 is provided on the optical fiber arm.

[0042] Optionally, the spectral characteristic data includes at least the spectral power of the backward Stokes light in the fiber laser amplification system within a preset frequency band and the ratio of its spectral peak value to the peak value of the central main peak, as well as the peak fluctuation of the backward Stokes light within a preset time range.

[0043] In some embodiments, the analysis control unit 500 is specifically used to: calculate, based on spectral data and with the backscattering wavelength as the center, the spectral power of the backscattering Stokes light in the fiber laser amplification system within a preset frequency band and the ratio of its spectral peak value to the peak value of the central main peak, as well as the peak fluctuation of the backscattering Stokes light within a preset time range; and to perform comprehensive analysis of the spectral characteristic data to obtain the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system.

[0044] It should be understood that in such an amplification system structure, the Brillouin frequency shift is mostly in the range of 10-30 GHz. Therefore, the data collected by the high-speed response spectral analysis probe 400 can be analyzed in real time. That is, the data detected by the probe is transmitted to the ACU in real time and calculated inside it. Taking the backscattering wavelength as the center, the spectral power and the ratio of the spectral peak to the peak value of the central main peak in the range of 10-30 GHz, or the ratio of the area occupied by it in a certain range, the peak fluctuation in a certain time range, etc.

[0045] More specifically, the proportion of backward Stokes light in the fiber laser amplification system is determined based on the ratio of the peak value of the backward Stokes light to the peak value of the central main peak; the power flatness of the backward Stokes light is determined based on the spectral power of the backward Stokes light within a preset frequency band; and the severity of stimulated Brillouin scattering in the fiber amplification system is inferred by comprehensively analyzing the fluctuation stability of the backward light power and the proportion of Stokes light in the backward reflected light.

[0046] In other words, by quickly analyzing the proportion of backward Stokes light in the system and using the pre-implanted criteria for judging the proportion of backward Stokes light, the ACU will feed back different data to the intelligent suppression region of SBS based on the situation. These data are used to characterize the severity of SBS in the system. Through the preset SBS criteria, the intelligent suppression region of SBS will respond differently according to the real-time severity, thereby achieving the purpose of intelligently suppressing SBS.

[0047] refer to Figure 3 This is a spectral graph obtained by analyzing spectral data through the analysis control unit 500. For example... Figure 3 As shown, the back-stokes beam and the fundamental frequency beam are spaced 10-30 GHz apart. The horizontal axis represents frequency, the vertical axis represents intensity, and the area formed by the dashed line indicates the region where the peak value is generated within the preset detection area.

[0048] In some embodiments, the main control unit 600 is specifically configured to: determine the degree of suppression of stimulated Brillouin scattering based on spectral characteristic data and the severity level of stimulated Brillouin scattering in the fiber laser amplification system; determine at least one matching target suppression signal, as well as the target bandwidth and target power corresponding to the target suppression signal, from several types of candidate suppression signals built into the intelligent signal generator 700, based on the degree of suppression; generate control commands based on the target suppression signal and its corresponding target bandwidth and target power, and send the control commands to the intelligent signal generator 700, so that the intelligent signal generator 700 generates the corresponding target suppression signal according to the control commands.

[0049] In some optional embodiments, the intelligent signal generator 700 can output high-power signals. The signal types of several types of alternative suppression signals cover mainstream and special-requirement signals such as sinusoidal signals (Sin), white noise signals (WNS), pseudo-random binary sequence signals (PRBS), arbitrary waveform signals (AWG), piecewise parabolic signals (PPS), and custom special program signals (CSPS). The signal power range covers -20dBm to +40dBm, and the signal bandwidth supports arbitrary adjustment from DC to 100GHz.

[0050] As an optional embodiment, the intelligent signal generator 700 internally includes a signal combiner. Figure 2 (Not shown in the image). This signal combiner is used to combine several types of target suppression signals and transmit them to the electro-optic phase modulator 800, based on the target bandwidth and target power corresponding to each type of target suppression signal, when there is more than one type of target suppression signal.

[0051] In other words, the generation and power of the target suppression signal are controlled by the main control unit 600. Based on the data fed back from the ACU and referring to the severity of SBS, the MCU dynamically and randomly allocates the intelligent signal generator 700 to generate different types of combined signals and dynamically allocates the power of each signal. Under a reasonable ratio, multiple signals are integrated through a signal combiner. The integrated signal is injected into the electro-optic phase modulator 800. The electro-optic phase modulator 800 modulates the input signal light with different modulation depths according to the magnitude of the injected signal power, thereby broadening the fundamental frequency light spectrum, reducing the peak gain of SBS, and suppressing SBS.

[0052] It should be noted that in the embodiments of this application, the operations used to detect SBS and suppress SBS in the fiber laser amplification system are all executed by the host computer issuing instructions. This can improve the control accuracy, avoid errors caused by human operation, and increase the safety of personnel.

[0053] Therefore, the spectral data obtained by the high-speed response spectral analysis probe 400 in the SBS detection area is quickly analyzed by the analysis control unit 500 to determine the proportion and fluctuation of backward Stokes light in the fiber laser amplification system. This data is used to determine the severity of SBS in the fiber laser amplification system. This data is transmitted in real time to the main control unit 600 in the intelligent suppression area of ​​SBS. According to the preset judgment criteria, the main control unit 600 intelligently controls the intelligent signal generator 700 to generate different types of signals. The bandwidth and power of these signals are intelligently and dynamically allocated and controlled by the MCU. The controlled signals are integrated by the signal combiner and injected into the electro-optic phase modulator 800 with a certain bandwidth. The fundamental frequency signal light of the electro-optic phase modulator 800 is modulated at different modulation depths, and the spectrum is broadened to different degrees. Backward Stokes light is suppressed to a certain extent. This information is again collected by the high-speed response spectral analysis probe 400 in the detection area, processed again, and transmitted back to the intelligent suppression area of ​​SBS... This cycle repeats until intelligent suppression of SBS in the fiber laser amplification system is finally achieved.

[0054] Furthermore, this application also provides a dynamic suppression method for stimulated Brillouin scattering. It should be noted that the dynamic suppression method for stimulated Brillouin scattering can be applied to fiber laser amplification systems as described in any of the above embodiments.

[0055] Figure 4 A flowchart illustrating a dynamic suppression method for stimulated Brillouin scattering according to an embodiment of this application is shown. Figure 4 As shown, the dynamic suppression method for stimulated Brillouin scattering may specifically include the following steps:

[0056] S401. Spectral data is obtained by real-time detection of the backward Stokes light generated during fiber amplification using a spectral analysis probe.

[0057] S402. The spectral data is analyzed by the analysis and control unit to obtain spectral characteristic data and the severity level of stimulated Brillouin scattering in the fiber laser amplification system;

[0058] S403. The main control unit controls the intelligent signal generator to generate at least one type of target suppression signal that matches the spectral feature data and the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system.

[0059] S404. The fundamental frequency signal light input from the single-frequency seed source is phase-modulated by an electro-optic phase modulator according to the target suppression signal injected by the intelligent signal generator, with a modulation depth matching the target suppression signal, thereby achieving broadening of the fundamental frequency light spectrum.

[0060] In some embodiments, after S404, the phase-modulated fundamental frequency signal light is amplified by the fiber optic main amplifier stage and then output.

[0061] In some embodiments, in S402, the data collected by the spectral analysis probe is transmitted back to the analysis and control unit in the detection area in real time. The analysis and control unit determines the power flatness and stability of the back Stokes light by analyzing the power of the back Stokes light over a period of time; it determines the proportion of Stokes light in the back reflection light by analyzing the ratio between the peak value of the back Stokes light and the peak value of the main peak of the signal light; and it infers the severity of SBS in the fiber laser amplification system by comprehensively analyzing the fluctuation stability of the back light power and the proportion of Stokes light in the back reflection light. This data is transmitted to the main control unit in the SBS intelligent suppression area in real time.

[0062] In some embodiments, in S403, the main control unit receives data transmitted by the analysis control unit and, based on pre-set internal judgment criteria, quickly classifies and locates the SBS severity level in the fiber laser amplification system, sending different instructions to the intelligent signal generator according to the severity. The preset judgment criteria include, but are not limited to, a preset proportion threshold. Thus, the SBS severity level in the system can be determined by comparing the preset proportion threshold with the proportion of Stokes light in the back-reflected light.

[0063] In another embodiment, upon receiving an instruction, the intelligent signal generator automatically modulates the signal accordingly. For example, when the SBS effect is weak, the intelligent signal generator prioritizes allocating sinusoidal and white noise signals, which have a weaker SBS suppression effect; when the SBS effect is strong, it prioritizes allocating pseudo-random binary sequence signals and arbitrary waveform signals, which have a stronger SBS suppression effect. Thus, based on the strength of the SBS effect in the system, the intelligent signal generator 6 selects to generate suppression signals of different degrees. Furthermore, it intelligently allocates power and different combinations of these suppression signals, and transmits the combined signals to the electro-optic phase modulator through its built-in signal combiner.

[0064] Furthermore, in some embodiments, in S404, the electro-optic phase modulator modulates the fundamental frequency signal light passing through it with different modulation depths according to the waveform and power of its injected signal, so that the spectral width of the fundamental frequency signal light is broadened to a certain extent after being phase modulated, thereby broadening the SBS gain spectrum and effectively reducing the peak gain of SBS.

[0065] In addition, in some embodiments, the high-speed response spectral analysis probe in the monitoring area continues to monitor the back-reflected Stokes light generated during fiber amplification in real time. The monitored data is still transmitted to the analysis and control unit in real time. The unit quickly locates the severity of SBS in the system by analyzing important information such as the fluctuation stability of the back-reflected light power and the proportion of Stokes light in the back-reflected light. The analysis and control unit sends the results to the main control unit of the intelligent suppression area of ​​SBS, which sends a command to the intelligent signal generator. The intelligent signal generator quickly and intelligently matches different built-in suppression signals according to the severity of SBS, and then sends them to the electro-optic phase modulator... This cycle repeats until the purpose of intelligent suppression of SBS in the fiber laser amplification system is achieved.

[0066] As can be seen, the dynamic suppression method for stimulated Brillouin scattering (SBS) in this embodiment places a high-speed response spectral analysis probe in the SBS detection area between the fiber pre-amplification stage and the main amplification stage to monitor data. The analysis control unit analyzes the collected data and feeds the results back to the main control unit in the intelligent suppression area of ​​SBS. The main control unit sends commands to the intelligent signal generator based on the results, causing it to intelligently generate different signals and intelligently adjust the bandwidth and power of each signal. These signals are then transmitted to the electro-optic phase modulator through a signal combiner, resulting in broadening of the single-frequency optical spectrum and reducing the peak gain of SBS. This information is again collected by the high-speed response spectral analysis probe in the detection area, processed again, and transmitted back to the intelligent suppression area of ​​SBS. This process repeats continuously, ultimately reducing the peak gain of SBS, effectively suppressing the stimulated Brillouin scattering effect in the fiber laser amplification system, and thus improving the power of the fiber laser amplification system.

[0067] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0068] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0069] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0070] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0071] In this application, "multiple" means two or more (including two).

[0072] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0073] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0074] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A fiber laser amplification system, characterized by, The system comprises a single-frequency seed source, a fiber pre-amplification stage, a fiber main amplification stage, a spectrum analysis probe, an analysis control unit, a main control unit, an intelligent signal generator and an electro-optical phase modulator. The spectrum analysis probe is connected with the fiber pre-amplification stage, the fiber main amplification stage and the analysis control unit respectively, and is used for detecting backward Stokes light generated in the fiber amplification process in real time to obtain spectrum data. The analysis control unit is used for analyzing the spectrum data to obtain spectrum feature data and a severity level of stimulated Brillouin scattering effect in the fiber laser amplification system. The main control unit is connected with the analysis control unit and the intelligent signal generator respectively, and is used for controlling the intelligent signal generator to generate at least one type of target suppression signal matched with the spectrum feature data and the severity level of stimulated Brillouin scattering effect in the fiber laser amplification system. The electro-optical phase modulator is connected with the single-frequency seed source, the fiber pre-amplification stage and the intelligent signal generator respectively, and is used for performing phase modulation on the fundamental frequency signal light input by the single-frequency seed source according to the target suppression signal injected by the intelligent signal generator, so as to realize spectrum widening of the fundamental frequency light.

2. The fiber laser amplification system of claim 1, wherein, The main control unit is specifically used for: determining a suppression degree for the stimulated Brillouin scattering effect according to the spectrum feature data and the severity level of stimulated Brillouin scattering effect in the fiber laser amplification system; determining at least one type of target suppression signal matched with the suppression degree from a plurality of types of candidate suppression signals in the intelligent signal generator, and determining a target bandwidth and a target power corresponding to the target suppression signal; generating a control instruction according to the target suppression signal and the target bandwidth and the target power corresponding to the target suppression signal, and sending the control instruction to the intelligent signal generator, so that the intelligent signal generator generates the corresponding target suppression signal according to the control instruction.

3. The fiber laser amplification system of claim 1, wherein, The spectrum feature data at least comprises spectrum power of the backward Stokes light in the fiber laser amplification system in a preset frequency range, a ratio relationship between a spectrum peak value and a central main peak value, and a peak fluctuation of the backward Stokes light in a preset time range. The analysis control unit is specifically used for: calculating, according to the spectrum data, spectrum power of the backward Stokes light in the fiber laser amplification system in a preset frequency range, a ratio relationship between a spectrum peak value and a central main peak value, and a peak fluctuation of the backward Stokes light in a preset time range, with the backward scattering wavelength as the center; comprehensively analyzing the spectrum feature data to obtain the severity level of stimulated Brillouin scattering effect in the fiber laser amplification system.

4. The fiber laser amplification system of claim 1, wherein, The intelligent signal generator is internally provided with a signal combiner. The signal combiner is used for, in the case that the target suppression signal is of more than one type, integrating the plurality of types of target suppression signals according to the target bandwidth and the target power corresponding to each type of target suppression signal, and then transmitting the integrated target suppression signals to the electro-optical phase modulator.

5. The fiber laser amplification system of claim 1, wherein, The optical fiber pre-amplification stage and the optical fiber main amplification stage are connected through a circulator, the circulator is provided with an optical fiber for detection, and the optical spectrum analysis probe is arranged on the optical fiber arm.

6. The fiber laser amplification system of claim 2, wherein, The several types of alternative suppression signals at least include: a sine signal, a white noise signal, a pseudo-random binary sequence signal, an arbitrary waveform signal, a segmented parabolic signal, and a self-defined special program signal.

7. The fiber laser amplification system of claim 2, wherein, The power range of the alternative suppression signal covers -20dBm~+40dBm, and the signal bandwidth supports DC-100GHz arbitrary adjustment.

8. A method of dynamic suppression of stimulated Brillouin scattering effect, characterized in that, The method is applied to the optical fiber laser amplification system as claimed in any one of claims 1-7, and the method comprises: Real-time detection of backward Stokes light generated in the optical fiber amplification process by the optical spectrum analysis probe to obtain spectrum data; Analysis of the spectrum data by the analysis control unit to obtain spectrum feature data and the severity level of stimulated Brillouin scattering effect in the optical fiber laser amplification system; Generation of at least one type of target suppression signal matched by the intelligent signal generator according to the spectrum feature data and the severity level of stimulated Brillouin scattering effect in the optical fiber laser amplification system by the main control unit; Phase modulation of the fundamental frequency signal light input by the single-frequency seed source by the electro-optic phase modulator according to the target suppression signal injected by the intelligent signal generator to achieve the broadening of the spectrum of the fundamental frequency light.

9. The method of claim 8, wherein, The method further comprises: Power amplification of the phase-modulated fundamental frequency signal light by the optical fiber main amplification stage and then output.

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