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

Abstract

The invention discloses an optical fiber laser amplification system and a dynamic suppression method for a stimulated Brillouin scattering effect. Through spectral data obtained by the spectral analysis probe, the analysis control unit rapidly analyzes spectral characteristic data of backward Stokes light in the fiber laser amplification system so as to judge the severity of the stimulated Brillouin scattering effect in the system, and the data are transmitted to the main control unit in real time. The main control unit intelligently regulates and controls the intelligent signal generator to generate different types of signals, the signals are injected into the electro-optic phase modulator to modulate the fundamental frequency signal light at different modulation depths, the spectrum is broadened to different degrees, the information is collected by the spectrum analysis probe again and processed again, and the process is repeated, so that the spectrum analysis accuracy is improved. Finally, the peak gain of the SBS can be reduced, and the stimulated Brillouin scattering effect in the fiber laser amplification system is effectively inhibited, so that the system power is improved.

Description

Technical Field

[0001] The present application belongs to the field of laser technology, and in particular relates to a fiber laser amplification system and a method for dynamically suppressing stimulated Brillouin scattering effects. Background Art

[0002] During the amplification process, fiber lasers are limited by many factors such as thermal effects, mode instability, and nonlinear effects, and the output power of fiber lasers has certain bottlenecks. In related special fields, the brightness and power of single-channel output fiber lasers can no longer meet application requirements.

[0003] In order to obtain a fiber laser with higher power output, it is necessary to overcome the constraints that limit power increase during fiber amplification, among which nonlinear effects are the biggest constraint. Common nonlinear effects include stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), and self-phase modulation (SPM). Among the above main effects, the threshold of stimulated Brillouin scattering is the lowest, which has become the main factor limiting the power increase of single-frequency fiber lasers.

[0004] The method of increasing the SBS threshold can be achieved by reducing the peak gain coefficient of the SBS. Currently, the most effective means of reducing the peak gain of the SBS is to broaden the spectrum of the single-frequency light, thereby achieving the broadening of the SBS gain spectrum, thereby effectively reducing the peak gain of the SBS. However, the methods used in the related art are complex and single, and cannot intuitively reduce the peak gain of the SBS. Summary of the invention

[0005] The embodiments of the present application provide a fiber laser amplification system and a method for dynamically suppressing stimulated Brillouin scattering effect, which are used to at least solve the problem in the related art that stimulated Brillouin scattering effect limits the power increase of a single-frequency fiber laser.

[0006] In a first aspect, an embodiment of the present application provides a fiber laser amplification system, including a single-frequency seed source, a fiber pre-amplification stage, a fiber main amplifier stage, a spectrum analysis probe, an analysis control unit, a main control unit, an intelligent signal generator, and an electro-optical phase modulator;

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

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

[0010] The electro-optical phase modulator is connected to the single-frequency seed source, the optical fiber pre-amplifier stage and the intelligent signal generator respectively, and is used to perform phase modulation of the fundamental frequency signal light input by the single-frequency seed source at a modulation depth matching the target suppression signal according to the target suppression signal injected by the intelligent signal generator, so as to achieve broadening of the fundamental frequency light spectrum.

[0011] In a second aspect, an embodiment of the present application provides a method for dynamically suppressing stimulated Brillouin scattering effect, the method being applied to a fiber laser amplification system as described in any embodiment of the first aspect, the method comprising:

[0012] The spectrum analysis probe is used to detect the backward Stokes light generated during the optical fiber amplification process in real time to obtain spectrum data;

[0013] The analysis control unit analyzes the spectral data to obtain spectral characteristic data and a severity level of stimulated Brillouin scattering effect in the fiber laser amplification system;

[0014] The main control unit controls the intelligent signal generator to generate at least one type of matching target suppression signal according to the spectral characteristic data and the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system;

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

[0016] The fiber laser amplification system and the method for dynamically suppressing the stimulated Brillouin scattering effect of the embodiment of the present application, through the spectrum data obtained by the spectrum analysis probe, the analysis control unit quickly analyzes the spectrum characteristic data of the backward Stokes light in the fiber laser amplification system to judge the severity of the stimulated Brillouin scattering effect in the system, these data are transmitted to the main control unit in real time, the main control unit intelligently controls the intelligent signal generator to generate different types of signals, these signals are injected into the electro-optical phase modulator, the baseband signal light of the electro-optical phase modulator is modulated with different modulation depths, the spectrum is broadened to different degrees, the backward Stokes light is suppressed to a certain extent, this information is collected by the spectrum analysis probe again, the information is processed again, and the cycle repeats, and finally the peak gain of SBS can be reduced, and the stimulated Brillouin scattering effect in the fiber laser amplification system can be effectively suppressed, thereby improving the system power. In addition, the system does not need to perform complex operations, which greatly increases efficiency and portability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

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

[0019] Figure 2 It is a structural schematic diagram of a fiber laser amplification system provided in an embodiment of the present application;

[0020] Figure 3 It is a spectrum graph obtained by analyzing the spectrum data by the analysis control unit provided in the embodiment of the present application;

[0021] Figure 4 It is a flow chart of a method for dynamically suppressing stimulated Brillouin scattering effect provided in an embodiment of the present application.

[0022] Reference numerals:

[0023] A single-frequency seed source 100, an optical fiber pre-amplifier stage 200, an optical fiber main amplifier stage 300, a spectrum analysis probe 400, an analysis control unit 500, a main control unit 600, an intelligent signal generator 700, an electro-optical phase modulator 800, and a circulator 900. DETAILED DESCRIPTION

[0024] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0025] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0026] Fiber lasers have experienced decades of rapid development and are now widely used in scientific research, information communication, industrial processing and special fields. However, different fields require different powers for fiber lasers. During the amplification process, fiber lasers are limited by many factors such as thermal effects, mode instability and nonlinear effects. The output power of fiber lasers has certain bottlenecks. In relevant special fields, the brightness and power of single-channel output fiber lasers can no longer meet application requirements.

[0027] In order to obtain higher synthetic power and better synthetic effect, the use of narrow linewidth linear polarization fiber laser as the synthetic sub-laser becomes the first choice. However, in the process of polarization-maintaining fiber fusion splicing, in order to improve efficiency, the fusion splicer automatically identifies the image of the XY field of view through the program 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 ordinary civilian fiber on the market, the fusion splicing program is not completely applicable. Therefore, in many cases, there are cases of machine misidentification, but the error is not reported in time to continue the fusion splicing process, resulting in the fast and slow axes of the fiber not being fully aligned, which ultimately leads to the rotation of the polarization state of the fiber output.

[0028] In order to obtain a fiber laser with higher power output, it is necessary to overcome the constraints that limit power increase during fiber amplification, among which nonlinear effects are the biggest constraint. Common nonlinear effects include stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), and self-phase modulation (SPM). Among the above main effects, the threshold of stimulated Brillouin scattering is the lowest, which has become the main factor limiting the power increase of single-frequency fiber lasers.

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

[0030]

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

[0032] As can be seen from the formula, the method to increase the SBS threshold can be to increase the mode field area of ​​the optical fiber or reduce the length of the optical fiber, but increasing the mode field area will lead to more modes, and reducing the length of the optical fiber will result in insufficient gain. Therefore, the most effective method is to reduce the peak gain coefficient of SBS. In the existing known reports, the most effective means to reduce the peak gain of SBS is to broaden the spectrum of single-frequency light, thereby achieving the broadening of the SBS gain spectrum, thereby effectively reducing the peak gain of SBS.

[0033] Patent CN115395362A introduces a method for suppressing stimulated Brillouin scattering, but its system is relatively complex and not conducive to engineering; Patent CN109378687B adopts a method of increasing stimulated Brillouin scattering loss, but its structure is complex and the device is easy to wear, which has a great impact on the signal light; Patent CN117728278A adopts a new method to achieve the purpose of reducing the stimulated Brillouin scattering effect by effectively controlling the driving power supply. However, the methods adopted by the above patents are complex and single, and one device can only generate one signal, which cannot intuitively reduce the peak gain of SBS.

[0034] In order to solve the problems of related technologies, the embodiments of the present application provide a fiber laser amplification system and a method for dynamically suppressing stimulated Brillouin scattering effect, which can realize intelligent suppression of stimulated Brillouin scattering effect that restricts power increase in the fiber laser amplification system.

[0035] At present, for common 1-2μm fiber laser amplification systems, a master oscillator power amplifier (MOPA) structure is generally used. Figure 1 FIG. 2 shows a conventional optical fiber master oscillator power amplifier structure. Figure 1As shown, its structure can be simplified into three stages: low-power single-frequency seed source, medium-power fiber pre-amplifier stage, and high-power fiber main amplifier stage, and then the system outputs. However, this traditional fiber laser can only generate one signal, and the complexity of the equipment to suppress the stimulated Brillouin scattering effect is also increased. The embodiment of the present application can dynamically control the signal, and determine what kind of signal to generate through real-time monitoring as needed, so that different types of signals can be output autonomously, and it has multiple integrated functions.

[0036] The fiber laser amplification system provided in the embodiment of the present application is described in detail below through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0037] refer to Figure 2 , is a schematic diagram of the structure of a fiber laser amplification system according to an embodiment of the present application. Figure 2 As shown, the fiber laser amplification system includes a single-frequency seed source 100, a fiber pre-amplifier stage 200, a fiber main amplifier stage 300, a spectrum 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-optical phase modulator (EOM) 800.

[0038] It can be understood that the fiber laser amplification system of the embodiment of the present application is mainly composed of two parts, one part is the SBS detection area, and the other part is the SBS intelligent suppression area. In the SBS detection area, a high-speed response spectrum analysis probe 400 and an analysis control unit 500 are included. In the SBS intelligent suppression area, an electro-optical phase modulator 800, an intelligent signal generator 700 and a main control unit 600 are included.

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

[0040] Specifically, the single-frequency seed source 100 has an extremely narrow linewidth and good single-frequency performance; the optical fiber pre-amplifier stage 200 is used for transition during the amplification process; the optical fiber main amplifier stage 300 is used for high-power amplification of the fundamental frequency light; the spectral analysis probe 400 is used to detect the backward Stokes light generated during the optical fiber amplification process in real time to 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 the stimulated Brillouin scattering effect in the optical 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 according to the spectral characteristic data and the severity level of the stimulated Brillouin scattering effect in the optical fiber laser amplification system; the electro-optical phase modulator 800 is used to perform phase modulation of the fundamental frequency signal light input by the single-frequency seed source 100 at a modulation depth matching the target suppression signal according to the target suppression signal injected by the intelligent signal generator 700, so as to achieve the broadening of the fundamental frequency light spectrum.

[0041] In some optional embodiments, such as Figure 2 As shown, the optical fiber pre-amplifier stage 200 is connected to the optical fiber main amplifier stage 300 via a circulator 900, and the circulator 900 is provided with an optical fiber for detection, and the spectrum analysis probe 400 is arranged 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 to 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 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 to the central main peak, as well as the peak fluctuation of the backward Stokes light within a preset time range based on the spectral data and with the backward scattering wavelength as the center; perform a comprehensive analysis of the spectral feature 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, so 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 calculations are performed internally therein, with the backscattered wavelength as the center, to calculate the spectral power within the range of 10-30 GHz and the ratio of the spectral peak to the central main peak, or the ratio of the area occupied within a certain range, the peak fluctuation within a certain time range, etc.

[0045] More specifically, the proportion of backward Stokes light in the fiber laser amplification system is determined according to 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 according to the spectral power of the backward Stokes light within a preset frequency band; and the severity of the stimulated Brillouin scattering effect in the fiber amplification system is inferred through a comprehensive analysis of the fluctuation stability of the backward light optical power and the proportion of Stokes light in the backward reflected light.

[0046] In other words, the proportion of backward Stokes light in the system is quickly analyzed, and by pre-implanting the judgment standard of the proportion of backward Stokes light internally, the ACU will feedback different data to the SBS intelligent suppression area according to the situation. These data are used to characterize the severity of SBS in the system. Through the preset SBS standard, the SBS intelligent suppression area will make different responses according to the real-time severity, so as to achieve the purpose of intelligently suppressing SBS.

[0047] refer to Figure 3 , is a spectrum diagram obtained by analyzing the spectrum data by the analysis control unit 500. Figure 3 As shown, the interval between the backward Stokes light and the fundamental frequency light is in the range of 10-30 GHz. The horizontal axis is the frequency, the vertical axis is the intensity, and the range area formed by the dotted line represents the area where the peak value is generated within the preset detection area.

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

[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-need signals such as sinusoidal signals (Sin), white noise signals (WNS), pseudo-random binary sequence signals (PRBS), arbitrary waveform signals (AWG), segmented 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 is internally provided with a signal combiner ( Figure 2 The signal combiner is used to combine several types of target suppression signals according to the target bandwidths and target powers corresponding to the several types of target suppression signals and transmit them to the electro-optical phase modulator 800 when there is more than one type of target suppression signal.

[0051] That is to say, the generation and power of the target suppression signal are controlled by the main control unit 600. The MCU dynamically and randomly allocates the intelligent signal generator 700 to generate signals of different types of combinations based on the data fed back by the ACU and the severity of the SBS, and dynamically allocates the power of each signal. Under a reasonable ratio, multiple signals are integrated through a signal combiner, and the integrated signal is injected into the electro-optical phase modulator 800. The electro-optical phase modulator 800 performs phase modulation of the input signal light with different modulation depths according to the size of the injected signal power, so as to achieve the broadening of the fundamental frequency light spectrum, thereby reducing the peak gain of the SBS and achieving the suppression of the SBS.

[0052] It should be noted that in the embodiments of the present application, the operations for detecting SBS and suppressing SBS in the fiber laser amplification system are all instructed and executed by the host computer throughout the process, which can improve the control accuracy while avoiding errors caused by human operation and increasing the safety of personnel.

[0053] Thus, the analysis control unit 500 quickly analyzes the proportion and fluctuation of the backward Stokes light in the fiber laser amplification system through the spectrum data obtained by the high-speed response spectrum analysis probe 400 in the SBS detection area. These data are used to judge the severity of SBS in the fiber laser amplification system. These data are transmitted to the main control unit 600 in the intelligent suppression area of ​​SBS in real time. According to the preset judgment standard, the main control unit 600 intelligently adjusts the intelligent signal generator 700 to generate different types of signals. The bandwidth and power of these signals are intelligently and dynamically allocated and regulated by the MCU. The regulated signals are integrated through the signal combiner and injected into the electro-optical phase modulator 800 with a certain bandwidth. The baseband signal light of the electro-optical phase modulator 800 is modulated with different modulation depths, and the spectrum is broadened to different degrees, and the backward Stokes light is suppressed to a certain extent. These information are collected again by the high-speed response spectrum analysis probe 400 in the detection area, and the information is processed again and transmitted back to the intelligent suppression area of ​​SBS... Repeatedly, the intelligent suppression of SBS in the fiber laser amplification system is finally achieved.

[0054] Furthermore, the present application also provides a method for dynamically suppressing stimulated Brillouin scattering effect. It should be noted that the method for dynamically suppressing stimulated Brillouin scattering effect can be applied to the fiber laser amplification system of any of the above embodiments.

[0055] Figure 4 FIG. 2 is a flow chart showing a method for dynamically suppressing the stimulated Brillouin scattering effect according to an embodiment of the present application. Figure 4 As shown, the method for dynamically suppressing the stimulated Brillouin scattering effect may specifically include the following steps:

[0056] S401, detecting the backward Stokes light generated in the process of optical fiber amplification in real time by a spectrum analysis probe to obtain spectrum data;

[0057] S402, analyzing the spectral data by an analysis control unit to obtain spectral characteristic data and a severity level of stimulated Brillouin scattering effect in the fiber laser amplification system;

[0058] S403, controlling the intelligent signal generator to generate at least one type of matching target suppression signal according to the spectral feature data and the severity level of stimulated Brillouin scattering effect in the fiber laser amplification system through the main control unit;

[0059] S404, performing phase modulation of the baseband signal light input by the single-frequency seed source at a modulation depth matching the target suppression signal injected by the intelligent signal generator through an electro-optic phase modulator, so as to achieve spectrum broadening of the baseband light.

[0060] In some embodiments, after S404, the baseband signal light after phase modulation is power amplified by the optical fiber 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 control unit in the detection area in real time, and the analysis control unit determines the power flatness and stability of the backward Stokes light by analyzing the power of the backward Stokes light for a period of time; determines the proportion of the Stokes light in the backward reflected light by analyzing the ratio between the peak value of the backward Stokes light and the main peak value of the signal light; and infers the severity of the SBS in the fiber laser amplification system by comprehensively analyzing the fluctuation stability of the backward light power and the proportion of the Stokes light in the backward reflected light. These data will be 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 the data transmitted by the analysis control unit, and quickly classifies and locates the SBS degree in the fiber laser amplification system according to the internal pre-set judgment criteria, and sends different instructions to the intelligent signal generator according to the severity. Among them, for the preset judgment criteria, for example but not limited to: a preset ratio threshold. In this way, the SBS degree level in the system can be determined by comparing the preset ratio threshold with the proportion of Stokes light in the back-reflected light in the system.

[0063] In another embodiment, after receiving the instruction, the intelligent signal generator automatically regulates the signal according to the instruction. For example, when the SBS effect is weak, the intelligent signal generator gives priority to allocating sinusoidal signals and white noise signals with weaker SBS suppression; when the SBS effect is strong, it gives priority to allocating pseudo-random binary sequence signals and arbitrary waveform signals with stronger SBS suppression. In this way, according to the strength of the SBS effect in the system, the intelligent signal generator 6 will choose to generate suppression signals of different degrees. Furthermore, the power and different number combinations of these suppression signals are intelligently allocated, and the combined signals are transmitted to the electro-optical phase modulator through its built-in signal combiner.

[0064] Furthermore, in some embodiments, in S404, the electro-optical phase modulator performs phase modulation with different modulation depths on the baseband signal light passing through it according to the waveform and power of its injected signal, so that the spectrum width of the baseband signal light is widened to a certain extent after being phase modulated, thereby achieving the widening of the SBS gain spectrum, thereby effectively reducing the peak gain of the SBS.

[0065] In addition, in some embodiments, the high-speed response spectrum analysis probe in the monitoring area is still monitoring the backward Stokes light generated in the fiber amplification process in real time, and the monitoring data is still transmitted to the analysis and control unit in real time, which quickly locates the severity of SBS in the system by analyzing important information such as the fluctuation stability of the backward light optical power and the proportion of Stokes light in the backward reflected light. The analysis and control unit sends the result to the main control unit of the SBS intelligent suppression area, 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 transmits them to the electro-optical phase modulator... This cycle repeats itself, and ultimately achieves the purpose of intelligently suppressing SBS in the fiber laser amplification system.

[0066] It can be seen that the dynamic suppression method of the stimulated Brillouin scattering effect in the embodiment of the present application is to place a high-speed response spectrum analysis probe contained in the SBS detection area between the optical fiber pre-amplification stage and the main amplifier 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 ​​the SBS; the main control unit sends a command to the intelligent signal generator based on the results, so that it intelligently generates different signals, intelligently adjusts the bandwidth and power of each signal, and transmits them to the electro-optical phase modulator through the signal combiner, so that the single-frequency light spectrum is broadened and the peak gain of the SBS is reduced. This information is again collected by the high-speed response spectrum analysis probe in the detection area, and the information is once again processed and transmitted back to the intelligent suppression area of ​​the SBS... Repeating the process, it is finally possible to reduce the peak gain of the SBS, effectively suppress the stimulated Brillouin scattering effect in the optical fiber laser amplification system, and thus improve the power of the optical fiber laser amplification system.

[0067] It should be noted that the above describes some embodiments of the present 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 an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

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

[0069] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0070] In the embodiments of the present application, the same reference numerals represent 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 the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0071] The term "plurality" used in the present application refers to two or more (including two).

[0072] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present 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 some methods or systems based on a series of steps or devices. 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 embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0074] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A fiber laser amplification system, characterized in that: It includes a single-frequency seed source, an optical fiber pre-amplifier stage, an optical fiber main amplifier 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 to the optical fiber pre-amplification stage, the optical fiber main amplifier stage and the analysis control unit respectively, and is used to detect the backward Stokes light generated during the optical fiber amplification process in real time to obtain spectrum data; The analysis control unit is used to analyze the spectral data to obtain spectral characteristic data and a severity level of stimulated Brillouin scattering effect in the fiber laser amplification system; 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 according to the spectral characteristic data and the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system; The electro-optical phase modulator is connected to the single-frequency seed source, the optical fiber pre-amplifier stage and the intelligent signal generator respectively, and is used to perform phase modulation of the fundamental frequency signal light input by the single-frequency seed source at a modulation depth matching the target suppression signal according to the target suppression signal injected by the intelligent signal generator, so as to achieve broadening of the fundamental frequency light spectrum.

2. The fiber laser amplification system according to claim 1, characterized in that: The main control unit is specifically used for: Determining the degree of suppression of the stimulated Brillouin scattering effect according to the spectral characteristic data and the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system; According to the suppression degree, determining at least one matching target suppression signal from several types of candidate suppression signals built into the intelligent signal generator and a target bandwidth and a target power corresponding to the target suppression signal; According to the target suppression signal and its corresponding target bandwidth and target power, a control instruction is generated and sent 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 according to claim 1, characterized in that: The spectral characteristic data at least includes the spectral power of the backward Stokes light in the fiber laser amplification system within a preset frequency band, the ratio of its spectral peak to the central main peak, and the peak fluctuation of the backward Stokes light within a preset time range; The analysis control unit is specifically used for: According to the spectral data, with the backward scattering wavelength as the center, 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 to the central main peak, as well as the peak fluctuation of the backward Stokes light within a preset time range are calculated; The spectral characteristic data are comprehensively analyzed to obtain the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system.

4. The fiber laser amplification system according to claim 1, characterized in that: A signal combiner is provided inside the intelligent signal generator; The signal combiner is used to integrate several types of target suppression signals and transmit them to the electro-optical phase modulator according to the target bandwidths and target powers corresponding to the several types of target suppression signals when there is more than one type of target suppression signal.

5. The fiber laser amplification system according to claim 1, characterized in that: The optical fiber pre-amplification stage is connected to the optical fiber main amplifier stage via a circulator, the circulator is provided with an optical fiber for detection, and the spectrum analysis probe is arranged on the optical fiber arm.

6. The fiber laser amplification system according to claim 2, characterized in that: The several types of candidate suppression signals include at least: a sinusoidal signal, a white noise signal, a pseudo-random binary sequence signal, an arbitrary waveform signal, a segmented parabola signal, and a user-defined special program signal.

7. The fiber laser amplification system according to claim 2, characterized in that: The power range of the alternative suppression signal covers -20dBm to +40dBm, and the signal bandwidth supports arbitrary adjustment from DC to 100GHz.

8. A method for dynamic suppression of stimulated Brillouin scattering effect, characterized in that: The method is applied to the fiber laser amplification system according to any one of claims 1 to 7, and the method comprises: The spectrum analysis probe is used to detect the backward Stokes light generated during the optical fiber amplification process in real time to obtain spectrum data; The analysis control unit analyzes the spectral data to obtain spectral characteristic data and a severity level of stimulated Brillouin scattering effect in the fiber laser amplification system; The main control unit controls the intelligent signal generator to generate at least one type of matching target suppression signal according to the spectral characteristic data and the severity level of the stimulated Brillouin scattering effect in the fiber laser amplification system; The baseband signal light input by the single-frequency seed source is phase-modulated by an electro-optical phase modulator according to the target suppression signal injected by the intelligent signal generator to a modulation depth matching the target suppression signal, thereby achieving broadening of the baseband light spectrum.

9. The method according to claim 8, characterized in that The method further comprises: The baseband signal light after phase modulation is power amplified by the optical fiber main amplifier stage and then output.

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