Stacked beam pumping ultra-wideband optical parametric amplification device and method based on multi-parameter cooperative regulation and control

Abstract

The invention discloses a stacked beam pumping ultra-wideband optical parametric amplification device and method based on multi-parameter cooperative regulation and control, and the device comprises a wideband seed laser light source, a pumping laser group, a high-precision delay line array, a nonlinear optical crystal group, and a feedback control system. The multi-dimensional parameters such as the wavelength of each pump light, the space incident angle relative to the crystal and the time delay of the seed light are coordinated, optimized and regulated through the feedback system, so that the multiple beams of pump light respectively meet the phase matching conditions of different spectrum sections in the crystal, finally, the energy of the pump light is efficiently coupled to the same signal light, and spectrum splicing type amplification is realized. The phase matching bandwidth limit (generally relative bandwidth is less than 20%) in the optical parametric amplification process of traditional single-beam pumping is broken through, ultra-wideband phase matching is supported, and the optical parametric amplification device is suitable for few-optical-period pulse amplification; the output laser average power limitation of a single-beam pumping optical parametric amplification system is broken through, the energy of multiple beams of incoherent high repetition frequency intensity laser is transferred to a single beam of coherent signal laser, and high-power ultrafast laser output is supported.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ultrafast laser and nonlinear optics, and particularly relates to a superimposed-beam pumped ultra-wideband optical parametric amplification device and method based on multi-parameter coordinated regulation, which is suitable for the generation and amplification of few-optical-period pulsed intense laser and the generation and amplification of high-average-power pulsed laser and other high-power ultrafast laser application scenarios. BACKGROUND

[0002] The traditional optical parametric amplification (OPA) and optical parametric chirped pulse amplification (OPCPA) technologies have the following technical bottlenecks: ① The gain bandwidth of a single-beam pumped laser is limited by the phase matching condition in the three-wave interaction process, and the typical gain bandwidth is usually less than 25% (relative bandwidth Δλ / λ0, where Δλ is the full width at half maximum of the gain spectrum, and λ0 is the central wavelength); ② A multi-stage OPA / OPCPA cascade configuration is used to extend the gain bandwidth by designing the cut angle of each nonlinear optical crystal to achieve phase matching for different wavelengths of the seed laser, but there are problems such as system complexity, low energy conversion efficiency, and phase mismatch accumulation.

[0003] The main reason why the prior art cannot achieve high conversion efficiency and ultra-wideband laser amplification is that only a single dimension (such as only adjusting the wavelength of the pump light or only optimizing the crystal angle) of the regulation strategy is used, which is difficult to meet the time-space-spectrum multi-dimensional matching conditions required for ultra-wideband amplification.

[0004] For example, patent documents CN109387991A and CN108873558A, regardless of how they optimize the chirp, angle or crystal, are based on a single pump light. The gain bandwidth and output energy of the entire system are fundamentally limited by the performance (such as wavelength, bandwidth, and energy) of the single pump source.

[0005] Therefore, there is an urgent need for a new optical parametric amplification technology that can break through the limitations of traditional bandwidth and energy efficiency to meet the urgent needs of high-power, ultra-wideband, and few-period pulsed laser applications. SUMMARY

[0006] The purpose of the present application is to solve the problems of narrow gain bandwidth, low conversion efficiency, and complex system in the existing optical parametric amplification technology, and to provide a superimposed-beam pumped ultra-wideband optical parametric amplification device and method based on multi-parameter coordinated regulation. Through the synergistic effect of multiple degrees of freedom such as wavelength, spatial angle, and time delay of multiple pump lights, efficient phase matching and energy transfer are achieved in a wide spectral range, which significantly expands the gain bandwidth and improves the system performance.

[0007] The technical solution of the present application is as follows:

[0008] The application discloses a multi-parameter cooperative regulation based stacked-beam pumped ultra-wideband optical parametric amplification device.

[0009] A broadband seed laser source is used for generating a beam of ultra-wideband seed laser.

[0010] A multi-pump light source system comprises at least two independent pump laser sources, and is used for providing multiple pump lights. The wavelengths of the multiple pump lights are independently adjustable, and the multiple pump lights are incident on a nonlinear crystal in a non-collinear manner. x The incident angles (θ y ) are adjustable, and the adjustment accuracy is less than or equal to 1 mrad.

[0011] An adjustable delay control system comprises delay line units arranged on the light paths of the multiple pump lights respectively, and is used for independently adjusting the relative time delays Δt1, Δt2,... Δt n between the multiple pump lights and the seed light.

[0012] A spatial angle regulation and combination system is used for receiving the multiple pump lights and the seed light after delay regulation, and is used for guiding the multiple pump lights and the seed light into a nonlinear optical crystal in a non-collinear manner.

[0013] The nonlinear optical crystal is used for optical parametric amplification interaction between the seed light and the multiple pump lights.

[0014] A feedback control system comprises an output performance monitoring unit used for monitoring at least one performance parameter of the amplified output laser in real time, and a central control unit in communication connection with the output performance monitoring unit, the multi-pump light source system, the delay control system and the spatial angle regulation and combination system.

[0015] At least two pump lights in the multi-pump light source system have different central wavelengths, and the wavelength combination comprises a short-wavelength pump light and a long-wavelength pump light.

[0016] The two independent pump laser sources in the multi-pump light source system are high-power and narrow-line-width (less than or equal to 1 nm) solid-state lasers, and the output wavelengths are selected from the following combinations: the fundamental frequency 1030 nm of Yb:YAG laser, the second harmonic frequency 515 nm, the third harmonic frequency 343 nm, or the fundamental frequency 1064 nm of Nd:YAG laser, the second harmonic frequency 532 nm, and the third harmonic frequency 355 nm.

[0017] The nonlinear optical crystal adopts a nonlinear material with a wide transparent window, including BBO (β-BaB2O4), YCOB (YCa4O(BO3)3), or LBO (LiB3O5).

[0018] The initial spatial incident angles (θ x ,θ γ ) of the pump lights relative to the nonlinear optical crystal and the included angle between adjacent two pump lights are ≥7 mrad.

[0019] A super-wideband light parametric amplification method using the above device, characterized in that the method comprises the following steps:

[0020] S1. Parameter initialization: selecting the type and cutting angle of the nonlinear optical crystal according to the target gain bandwidth, determining the initial wavelength combination (λ p1 ,λ p2 ,…,λ pn ) of the pump light source based on the dispersion characteristics of the nonlinear optical crystal, and calculating the initial spatial incident angles (θ x ,θ γ ) and the initial time delays (Δt1, Δt2,…, Δt n ) of the pump lights relative to the nonlinear optical crystal;

[0021] S2. Beam combining and incident: through the beam combining and angle control assembly, the multiple pump lights after delay control and the seed laser are jointly incident to the nonlinear optical crystal at a preset non-collinear angle relationship;

[0022] S3. Phase matching optimization: adjusting the spatial incident angles (θ x ,θ γ ) of the pump lights to reduce the phase mismatching amount of each channel;

[0023] S4. Time-domain synchronization: adjusting the time delays (Δt1, Δt2,…, Δt n ) of the pump lights to match the seed laser after chirp processing in the time domain, and realizing time-sharing injection amplification;

[0024] S5. Iterative feedback optimization: using the feedback control system to monitor the spectrum and power of the output laser in real time, taking the gain bandwidth and conversion efficiency as multi-objectives, feeding back and controlling the wavelength, spatial incident angle, and time delay parameters of the pump lights, and through iterative calculation, the final output laser meets the performance indicators of gain bandwidth ≥400 nm and energy conversion efficiency ≥35%.

[0025] In the time-domain synchronization step, the optimal injection time and pulse width of each pump light are dynamically calculated and matched according to the chirp rate (0.25 ps / nm) of the seed laser and the distribution of the target gain spectrum.

[0026] The iterative feedback optimization step continues until the central control unit determines that the output laser spectrum continuously covers at least a 400 nm bandwidth, and the energy conversion efficiency is stabilized at more than 35%.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1) Multiple beams (≥2) of independently controllable pump light are used, and the wavelength (spectral dimension), spatial incident angle (spatial dimension), and time delay (time dimension) are adjusted, that is, three key degrees of freedom are adjusted, and a closed loop optimization is formed through real-time feedback. The multiple beams of pump light are incident at non-collinear angles into the same nonlinear crystal, and each beam of pump light interacts with the seed light to form an independent gain channel. Each pump light is responsible for amplifying a different sub-band in the seed spectrum through angle tuning, and through the "spectral splicing" effect, the gain bandwidths of multiple sub-channels are combined into a continuous ultra-wideband spectrum (≥400 nm) far exceeding the limit of a single channel. The energy of multiple high-energy pump lights is converted into the same signal light through nonlinear interaction, realizing "parallel-serial conversion" of energy, thereby significantly improving the output power and conversion efficiency (≥35%) while improving the output bandwidth, and avoiding the problems of efficiency and complexity caused by multi-stage cascading.

[0029] 2) The "multiple pump channel" parallel amplification architecture used in the present application solves the traditional contradiction between bandwidth and energy. The "spatial-time-spectral" multi-parameter full-active, closed-loop collaborative adjustment upgrades the system from an open-loop manual debugging mode to a closed-loop intelligent optimization mode. High average power, ultra-wideband laser output can be generated, and after compression, high-energy, few-cycle (<10 fs) laser pulses can be obtained. This will greatly promote the research process in the fields of ultrafast science, strong field physics, precision spectroscopy, and attosecond science, and also has potential application prospects in the fields of industrial processing and medical treatment. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural schematic diagram of a multi-parameter controlled nonlinear beam superposition ultra-wideband amplification device embodiment of the present application.

[0031] Figure 2 is a gain angle spectrum when the present application implements spectral regulation.

[0032] Figure 3 is a relationship between the single beam output spectrum and the phase matching angle when the present application implements spectral expansion.

[0033] Figure 4 is a gain spectrum of a small-angle spliced pump light beam when the present application implements spectral expansion.

[0034] Figure 5 is the gain spectrum of the larger included angle pump beam spliced when the present application is implemented to expand the spectrum.

[0035] Figure 6 is the relationship between the single beam pump light output spectrum and the phase matching angle of different wavelengths when the present application is implemented to pump with different wavelengths.

[0036] Figure 7 is the bandwidth spectrum amplification obtained by time-sharing injection when the present application is implemented to optimize the time domain matching. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be particularly noted that the described embodiments are only used to illustrate the technical solutions of the present application and do not constitute a limitation on the scope of protection.

[0038] Device part:

[0039] As shown in the figure, the device of the present application comprises the following core modules: Figure 1

[0040] a) Seed laser module: broadband seed laser light source 1, spectral range covering 600-1000nm, Fourier transform limit pulse width 3fs; pulse stretcher can be added to expand the seed laser to chirped pulses, the pulse width used in the technical verification below is 5ps, and when time domain matching optimization is performed, the chirped pulse can be expanded to 100ps with a chirp rate of 0.25ps / nm;

[0041] b) Beam superposition pumping system:

[0042] ① First pump laser source 2: frequency-doubled light of Yb:YAG laser, center wavelength 515nm,

[0043] pulse width 3ps, single pulse energy 1mJ;

[0044] ② First delay line 3: electrically driven translation stage, resolution 5μm (corresponding to time delay accuracy 33fs),

[0045] stroke ≥100mm;

[0046] ③ Second pump laser source 4: frequency-doubled light of Yb:YAG laser (center wavelength 515nm) or frequency-doubled light of Nd:YAG (center wavelength 532nm), wavelength 355nm, pulse width 3ps;

[0047] ④ Second delay line 5: same model as the first delay line, independently controlled.

[0048] c) Optical parametric amplification module:

[0049] ​① Nonlinear optical crystal 6: YCOB crystal, size 10x10x5mm 3 cutting angle

[0050] θ = 24.5° ± 0.5°;

[0051] ② Electrically controlled precision adjustment frame: angle adjustment resolution 0.001°, repeat positioning accuracy ± 0.005°;

[0052] ③ Pump light separator: dichroic mirror, reflectivity of pump light > 99%, transmittance of signal light > 95%.

[0053] d) Output monitoring system:

[0054] Spectrometer: resolution range 0.7-1.1nm, wavelength range 200-1100nm;

[0055] Power meter: measurement uncertainty ≤ ± 3%.

[0056] Method part:

[0057] The regulation method of the application comprises the following steps:

[0058] a) Parameter initialization stage:

[0059] ① Set the target gain bandwidth (such as center wavelength 800nm, bandwidth ≥ 200nm);

[0060] ② Select the pump light wavelength combination (such as nm+nm);

[0061] ③ Calculate the initial crystal angle and pump light incidence angle based on the Sellmeier equation.

[0062] b) Phase matching optimization stage:

[0063] ① Optimize the pump light incidence angle through the electrically controlled precision adjustment frame (adjustment accuracy 0.001°);

[0064] ② Use gradient descent method to make the phase mismatch Δk ≤ 0.5 rad / mm.

[0065] c) Time domain synchronization stage:

[0066] ① Adjust the pump light time delay through the delay line (the step length of the electrically controlled translation stage is μm, that is, the time resolution of the time delay is fs);

[0067] d) Iterative optimization stage:

[0068] Multi-objective optimization, finally simultaneously meet the gain bandwidth ≥ 200nm; conversion efficiency ≥ 35%.

[0069] Example 1:

[0070] Referring to Figure 1 As shown in the embodiment, the superimposed beam pumping ultra-wideband optical parametric amplification device comprises a single wideband seed laser 1 amplified by two pump beams.

[0071] 1. Device structure and working principle

[0072] Referring to Figure 1 As shown in the embodiment, the superimposed beam pumping ultra-wideband optical parametric amplification device comprises a single wideband seed laser 1 amplified by two pump beams. The first pump beam 2 and the second pump beam 4 are incident to the nonlinear crystal 6 at different angles, respectively corresponding to one optical parametric amplification channel, and each generates one idler beam. The idler beam generated by the interaction of the pump beam 2 and the seed laser 1 is the first idler beam 7; the idler beam generated by the interaction of the pump beam 4 and the seed laser 1 is the second idler beam 8.

[0073] The pump beam control system comprises a delay line 3 of the first pump beam and a delay line 5 of the second pump beam, for adjusting the time delay between the corresponding pump beam and the signal beam, respectively. At the same time, the incident angle and the wavelength of the pump beam act in conjunction to meet the phase matching condition, so as to realize the accurate control of the amplification band.

[0074] Nonlinear crystal: YCOB crystal (crystal thickness, XOZ plane cut, cut angle 24.55°, effective nonlinear coefficient 1.349 pm / V), supporting ~200 nm gain bandwidth when pumped by a single beam.

[0075] First pump beam 2: narrowband laser with center wavelength 515 nm (second harmonic output of high-power Yb:YAG laser), light intensity 10 GW / cm 2 .

[0076] Second pump beam 4: narrowband laser with center wavelength 515 nm (second harmonic output of high-power Yb:YAG laser) as shown in the embodiments of Figure 4 and Figure 5 , light intensity 10 GW / cm 2 ; in the embodiment of Figure 6 , narrowband laser with center wavelength 532 nm (second harmonic output of high-power Yb:YAG laser) is used, light intensity 10 GW / cm 2 .

[0077] Gain spectrum characteristics of the optical parametric process pumped by a single beam Figure 2 , 3 : narrowband laser with center wavelength 515 nm is used for pumping, and when the incident angle θ p = 24.54° (the incident angle is the included angle between the wave vector and the optical axis), the output spectrum presents a wideband gain characteristic. Reducing θ pThis will cause a redshift in the gain spectrum, indicating that the gain spectrum of the system has angle-tunable characteristics.

[0078] Spectral splicing effect under the same wavelength laser beam-pumping scheme ( Figure 4 , 5 ):

[0079] ① Small angular difference mode (spectral overlap stitching): such as Figure 4 As shown, both pump beams are set to a wavelength of 515nm, and their non-collinear angle Δθ is adjusted to 0.14°. Under this configuration: the gain curve of the first pump beam (incident angle θ1) is centered at 825nm, with a bandwidth (FWHM) of approximately 150nm, covering the 700-950nm band. The gain curve of the second pump beam (incident angle θ2 = θ1 + Δθ) is redshifted to 905nm, with a bandwidth of approximately 140nm, covering the 860-1000nm band. Significant overlap exists between the two gain spectra in the 860-950nm range. By fine-tuning the energy ratio and precise angle of the two pump beams through a feedback control system, gain ripple in the overlapping region can be suppressed, ultimately achieving a continuous, flat, ultra-wideband output spectrum covering 700-1000nm (bandwidth 300nm).

[0080] ② Large angular difference mode (spectral broadening and stitching): such as Figure 5 As shown, dual 515nm pumps are still used, but the spatial angle Δθ is increased to 4.05°. At this point: the gain spectrum of the first pump light covers 700-950nm. The gain spectrum of the second pump light undergoes a significant redshift due to angle tuning, covering 900-1150nm. The two spectra overlap in the 900-950nm region. Through optimized control, a supercontinuum spectrum with a full width at half maximum (FWHM) exceeding 400nm (covering 700-1150nm) can ultimately be stitched together. This mode fully demonstrates the strong correlation between spatial angle and gain spectrum, breaking through the bandwidth limit of single pumping.

[0081] Spectral splicing effect under multi-wavelength laser synergistic pumping scheme ( Figure 6 )

[0082] By adjusting the pump light wavelength to match the available positional conditions, the output spectral range can be further optimized. Based on the large angle difference mode described above, it can be seen that under the same wavelength pumping condition, two broadband spectral segments can be obtained to achieve spectral splicing (taking 515nm pumping as an example, the two broadband spectral segments are 700-950nm and 900-1150nm). Figure 6 As shown, the effect of spectral splicing is achieved by changing the pump wavelength. It can be seen that the long-wavelength spectral range (900-1150nm) does not exhibit a redshift or blueshift with changes in pump wavelength, but the pump gain bandwidth narrows as the pump wavelength decreases. In addition, the short-wavelength spectral range exhibits a redshift as the pump wavelength decreases, and there is more overlap with the long-wavelength spectral range.

[0083] Time-domain matching optimization, such as Figure 7 As shown, for a chirped seed pulse of 100 ps, ​​in order to achieve efficient amplification of the entire broadband, the pump light needs to be matched in the time domain to the arrival time of different spectral components of the seed pulse at the crystal.

[0084] Based on the gain bandwidth, to achieve efficient amplification, the pump light needs to be injected in a time-division manner, with its delay time dynamically adjusted according to the chirp characteristics of the signal light. To match the gain bandwidth, the pump pulse width also needs to be adjusted accordingly. Based on the chirp rate of the seed light (0.25 ps / nm), the time difference between the beginning and end of a pulse with a spectral range from 700 nm to 1150 nm is approximately 112.5 ps. Therefore, multiple pump beams need to be time-divisionally spaced. The central control unit controls a high-precision delay linear array, sequentially injecting five pump beams (in this example) into the crystal according to calculated delay times (Δt1 = 35 ps, Δτp1 = 50 ps; Δt2 = -10 ps, ​​Δτp2 = 13 ps; Δt3 = -27 ps, Δτp3 = 10 ps; Δt4 = -42 ps, Δτp4 = 10 ps; Δt5 = -57 ps, Δτp4 = 10 ps, ​​with the arrival time of the seed light's center wavelength as zero). Simultaneously, the pulse width is dynamically adjusted based on the spectral bandwidth amplified by each pump beam to ensure sufficient temporal overlap and high energy extraction efficiency. The feedback system monitors the output spectral shape and energy, fine-tuning the delay time and pulse width of each pump beam to ensure sufficient and uniform amplification across all spectral bands, ultimately outputting a high-energy, ultra-wideband chirped pulse. This pulse, after compression, yields a short-period pulse of less than 10 fs.

[0085] This invention achieves spatiotemporal-spectral multi-dimensional parameter matching by organically combining and synergistically controlling a seed light source, a multi-beam pump light source, a high-precision delay line array, a multi-dimensional parameter beam combining and control component, a nonlinear optical crystal, and a feedback control system. This effectively solves the technical problem of balancing gain bandwidth and conversion efficiency in traditional OPA / OPCPA technology.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention. Those skilled in the art can make modifications or equivalent substitutions without departing from the core idea of ​​the present invention, and these variations should all be covered within the scope of the claims of the present invention.

Claims

1. A beam-pumped ultrawideband optical parametric amplifier based on multi-parameter coordinated control, characterized in that, include: A broadband seed laser source is used to generate an ultra-wideband seed laser beam. A multi-pump light source system comprises at least two independent pump laser sources to provide multiple pump beams, each with a wavelength of... Independently adjustable, and incident on the nonlinear crystal in a non-collinear manner, at an incident angle (θ) x ,θ y Adjustable, with an adjustment accuracy of ≤1mrad; The adjustable delay control system includes delay line units (3,5) respectively disposed on each pump light path, for independently adjusting the relative time delay Δt1, Δt2, ... Δt between each pump light beam and the seed light. n ; A spatial angle control and beam combining system is used to receive multiple pump beams after delay control and the seed laser, and to guide the multiple pump beams and the seed laser into a nonlinear optical crystal in a non-collinear incident manner, and to independently adjust the spatial propagation direction of each pump beam within the crystal. A nonlinear optical crystal is used to allow the seed laser and multiple pump beams to undergo optical parametric amplification interaction therein; The feedback control system includes: an output performance monitoring unit for real-time monitoring of at least one performance parameter of the amplified output laser; The central control unit is communicatively connected to the output performance monitoring unit, the multi-pump light source system, the delay control system, and the spatial angle adjustment and beam combining system. It is configured to coordinately adjust the wavelength, spatial incident angle, and time delay parameter combination of each pump light based on the monitored performance parameters in order to achieve the predetermined output laser performance target.

2. The beam-pumped ultrawideband optical parametric amplifier based on multi-parameter coordinated control according to claim 1, characterized in that, In the multi-pump light source system, at least two pump beams have different center wavelengths, and their wavelength combination includes a short-wavelength pump beam and a long-wavelength pump beam.

3. The beam-pumped ultrawideband optical parametric amplifier based on multi-parameter coordinated control according to claim 1 or 2, characterized in that, The two independent pump laser sources (2,4) in the multi-pump light source system are high-power, narrow-linewidth (≤1nm) solid-state lasers, and their output wavelengths are selected from the following combinations: the fundamental frequency of Yb:YAG laser at 1030nm, the second harmonic at 515nm, and the third harmonic at 343nm, or the fundamental frequency of Nd:YAG laser at 1064nm, the second harmonic at 532nm, and the third harmonic at 355nm, and the linewidth of each pump light source is ≤1nm.

4. The beam-pumped ultrawideband optical parametric amplifier based on multi-parameter coordinated control according to claim 1, characterized in that, The nonlinear optical crystal uses a nonlinear material with a wide transparent window, including BBO (β-BaB2O4), YCOB (YCa4O(BO3)3) or LBO (LiB3O5).

5. The beam-pumped ultrawideband optical parametric amplifier based on multi-parameter coordinated control according to claim 1, characterized in that, The initial spatial incident angle (θ) of each pump light relative to the nonlinear optical crystal x ,θ γ And the angle between two adjacent pump beams is ≥7mrad.

6. A method for beam-pumped ultrawideband optical parametric amplification using the apparatus according to any one of claims 1-5, characterized in that, The method includes the following steps: S1. Parameter Initialization: Select the type and cut angle of the nonlinear optical crystal based on the target gain bandwidth, and determine the initial wavelength combination of the pump source based on the dispersion characteristics of the nonlinear optical crystal. And calculate the initial spatial incident angle (θ) of each pump light relative to the nonlinear optical crystal. x ,θ γ ) and initial time delay (Δt1, Δt2, ..., Δt) n ); S2. Beam combining and incident: The multiple pump beams after delay control and the seed laser are incident on the nonlinear optical crystal (6) together with the beam combining and angle control components at a preset non-collinear angle relationship. S3. Position Matching Optimization: Adjusting the spatial incident angle (θ) of each pump light. x ,θ γ This reduces the phase mismatch in each channel; S4. Time Domain Synchronization: Adjust the time delay (Δt1, Δt2, ..., Δt) of each pump light. n This allows it to be time-domain matched with the chirped seed laser, enabling time-division injection amplification; S5. Iterative Feedback Optimization: The feedback control system is used to monitor the spectrum and power of the output laser in real time. With gain bandwidth and conversion efficiency as multiple objectives, the wavelength, spatial incident angle and time delay parameters of each pump light are adjusted by feedback. Through iterative calculation, the final output laser can simultaneously meet the performance indicators of gain bandwidth ≥400nm and energy conversion efficiency ≥35%.

7. The method according to claim 6, characterized in that, In the time-domain synchronization step, the optimal injection time and pulse width of each pump light are dynamically calculated and matched based on the chirp rate (0.25 ps / nm) of the seed laser and the distribution of the target gain spectrum.

8. The method according to claim 6, characterized in that, The iterative feedback optimization steps continue until the central control unit determines that the output laser spectrum continuously covers a bandwidth of at least 400nm and the energy conversion efficiency is stable at 35% or higher.

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