A hybrid MOPA laser system with tapered gain fiber pre-amplification

Abstract

This invention relates to the field of laser technology, specifically to a hybrid MOPA laser system with tapered gain fiber pre-amplification. The system, along its optical path, sequentially comprises: an all-fiber pulse seed source, a uniform gain fiber pre-amplification link, a tapered gain fiber pre-amplifier module, a free-space optical transmission processing module, and a solid-state main amplifier module. The tapered gain fiber pre-amplifier module includes a pump LD, a pump / signal combiner, and a tapered gain fiber. This invention utilizes a tapered gain fiber as the pre-amplification core, combining the high stability and high repetition rate capability of an all-fiber structure with the high nonlinear threshold and high power output capability resulting from mode field spreading. It overcomes the shortcomings of traditional solid-state regenerative pre-amplification, such as poor stability and low repetition rate, as well as the power limitations of traditional uniform fiber pre-amplification, providing a high-quality, high-power injection beam for the subsequent solid-state main amplifier, ultimately achieving high beam quality, high repetition rate, high average power, and high pulse energy laser output.

Description

Technical Field

[0001] This invention relates to the field of laser technology, specifically to a Master Oscillator Power Amplifier (MOPA) laser system, and more particularly to a hybrid MOPA laser system that uses tapered gain fiber as the core gain medium of the preamplifier, for achieving laser output with high repetition rate, high beam quality, high average power and high pulse energy. Background Technology

[0002] Master Oscillator Power Amplifier (MOPA) laser systems, due to their combination of the excellent spectral and temporal characteristics of seed sources and the high energy output capability of power amplifier stages, have wide applications in precision industrial processing (such as micro-drilling and cutting), lidar, spectroscopy, and scientific research. A MOPA system typically includes a seed source as an oscillator, one or more preamplifier stages, and a final main power amplifier. The preamplifier module plays a crucial role in boosting the energy of the weak seed pulse to a level sufficient to efficiently drive the subsequent high-power main amplifier.

[0003] Existing MOPA system pre-amplification schemes are mainly divided into two categories: solid-state regenerative amplification schemes and all-fiber amplification schemes.

[0004] Solid-state regenerative amplification schemes typically utilize electro-optic switches (such as Pockelsters) to control seed pulses to oscillate and amplify in a resonant cavity composed of polarization elements and a solid gain medium (such as Nd:YVO4, Yb:CaYAlO4 crystals). Once the energy accumulates to a set value, the output is generated. While this scheme can achieve a high single-pulse energy boost, it has significant drawbacks:

[0005] (1) Poor beam pointing stability: The beam inside the cavity needs to be reflected multiple times, and the optical path is extremely sensitive to mechanical vibration and temperature fluctuations, which easily causes pointing drift; the thermal lensing effect of the solid gain medium will further aggravate beam distortion and instability.

[0006] (2) Weak resistance to environmental interference: The complex free space optical cavity structure has strict requirements for laboratory environment (such as airflow, humidity and cleanliness), and it is difficult to operate stably in non-ideal environments such as industrial sites.

[0007] (3) Limited pulse repetition frequency: Due to the limited response speed and drive circuit bandwidth of electro-optic switches such as Pockel cells, it is difficult to achieve stable pulse amplification at repetition frequencies of hundreds of MHz or even higher.

[0008] All-fiber amplification schemes amplify seed pulses directly within rare-earth-doped gain fibers, offering advantages such as compact structure, all-fiber operation, strong anti-interference capabilities, and ease of achieving high repetition rate amplification. However, conventional single-mode or large-mode-area uniform gain fibers, limited by their finite mode area, are prone to inducing strong nonlinear effects, such as stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS), when increasing pulse energy and average power, severely limiting further increases in output power and energy. Therefore, traditional uniform gain fiber preamplifiers typically only function as low-power preamplifiers, requiring subsequent solid-state regenerative amplifiers or multi-stage solid-state amplifiers to achieve high-power output, thus failing to fully leverage the advantages of fiber optic systems.

[0009] In summary, existing pre-amplification techniques struggle to simultaneously achieve key performance indicators such as high beam quality and pointing stability, strong resistance to environmental interference, high repetition rate operation, and high power / energy output, exhibiting significant technical shortcomings. Therefore, there is an urgent need to develop a novel pre-amplification technique to overcome these deficiencies and meet the growing demands of high-performance laser applications. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a hybrid MOPA laser system with tapered gain fiber pre-amplification. This system cleverly combines the advantages of fiber amplifiers and solid-state amplifiers by introducing tapered gain fiber as the core gain medium for pre-amplification, aiming to simultaneously achieve high beam quality and pointing stability, strong resistance to environmental interference, high repetition rate operation, and high-power, high-energy laser output.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] A hybrid MOPA laser system with tapered gain fiber pre-amplification, comprising, along the laser propagation direction, the following:

[0013] All-fiber structure pulse seed source module;

[0014] A uniform gain fiber preamplifier link, the input of which is connected to the seed source module;

[0015] A tapered gain fiber preamplifier module, the input end of which is connected to the output end of the uniform gain fiber preamplifier link; the tapered gain fiber preamplifier module includes a pump source and a tapered gain fiber, used to amplify the power of the laser from the fiber preamplifier link and directly output a free space laser beam;

[0016] The free-space optical transmission processing module is used to receive and collimate and match the free-space laser beam output from the tapered gain fiber.

[0017] The solid-state main amplifier module is used to receive the laser beam processed by the free space light transmission processing module and amplify its power.

[0018] As a further aspect of the present invention: the tapered gain fiber preamplifier module further includes a pump / signal combiner, wherein the pump light emitted from the pump source and the signal light from the uniform gain fiber preamplifier link are combined by the pump / signal combiner and injected into the tapered gain fiber.

[0019] As a further aspect of the present invention: the tapered gain fiber is a rare-earth ion-doped fiber, the mode field area at its input end is matched with the mode field area of ​​the final stage output fiber of the uniform gain fiber pre-amplification link, and the mode field area at its output end is greater than the mode field area at its input end. The rare-earth ions are selected from at least one of ytterbium ions (Yb3+), erbium ions (Er3+), thulium ions (Tm3+), holmium ions (Ho3+), or neodymium ions (Nd3+).

[0020] As a further aspect of the present invention: the uniform gain fiber preamplifier link includes at least one stage of uniform gain fiber preamplifier.

[0021] As a further aspect of the present invention, the uniform gain fiber preamplifier link further includes a bandpass filter and / or an optical isolator disposed between the seed source module and the at least one stage of the preamplifier, and / or between each stage of the preamplifier.

[0022] As a further aspect of the present invention: the free space optical transmission processing module includes:

[0023] A laser beam collimation system is used to collimate the diverging laser beam output from the tapered gain fiber into parallel light;

[0024] A laser beam matching system, located after the laser beam collimation system, is used to adjust the diameter of the laser beam to match the input requirements of the solid-state main amplifier module.

[0025] As a further aspect of the present invention, the free-space light transmission processing module further includes a free-space light isolator disposed between the laser beam collimation system and the laser beam matching system for blocking reverse-transmitted light.

[0026] As a further aspect of the present invention: the solid-state main amplifier module adopts one or more combinations of end-pumped solid-state amplifier, side-pumped solid-state amplifier, slab amplifier, thin-film amplifier, regenerative amplifier or multi-pass amplifier.

[0027] As a further aspect of the present invention: the laser pulse repetition frequency output by the system is greater than 1MHz, and the beam quality factor M2 is less than 1.5.

[0028] A laser amplification method, employing a hybrid MOPA laser system with pre-amplification using a tapered gain fiber as described above, includes the following steps:

[0029] The initial pulsed laser seed is generated by the all-fiber structure pulsed seed source module;

[0030] The pulsed laser seed is initially amplified via the uniform gain fiber pre-amplification link;

[0031] The initially amplified laser beam and the pump light emitted by the pump laser diode are combined by the pump / signal combiner and injected into the tapered gain fiber for power amplification, and a free space laser beam is output from its output end.

[0032] The free-space laser beam is collimated, isolated, and beam-matched by the free-space light transmission and processing module.

[0033] The matched laser beam is injected into the solid-state main amplifier module for final power amplification and output.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. High stability and strong anti-interference: The main body of the pre-amplification stage is an all-fiber structure (up to the tapered fiber output end), which avoids complex free space optical cavities, greatly reduces the system's sensitivity to mechanical vibration, temperature changes and environmental airflow disturbances, and achieves superior beam pointing stability and environmental adaptability.

[0036] 2. Supports ultra-high repetition frequency: The system's operating repetition frequency mainly depends on the power amplification of the seed source and fiber amplifier, completely eliminating the response frequency limitation of the Pockels cell in solid-state regenerative amplifiers, and can easily achieve stable amplification of high repetition frequency pulses from kHz to hundreds of MHz and even GHz.

[0037] 3. High power and high energy output potential: The unique structure of the tapered gain fiber causes its mode field area to gradually increase from the input end to the output end, which effectively reduces the power density in the gain fiber and significantly suppresses nonlinear effects such as Kerr self-focusing and stimulated Raman scattering. This allows for the injection of higher pump power, achieving pulse energy and average power output that are tens to hundreds of times higher than those of traditional single-mode gain fibers, providing a sufficient and high-quality injection beam for subsequent solid-state main amplifiers.

[0038] 4. Excellent beam quality: Tapered optical fiber has good waveguide characteristics, which can maintain single-mode or near-single-mode transmission at high power. The beam quality factor M² of the output laser can approach 1.3, which lays the foundation for efficient and high beam quality amplification of subsequent solid-state amplification stages.

[0039] 5. Strong system flexibility and scalability: The architecture proposed in this invention is universal. The tapered gain fiber can be doped with different rare earth ions as needed. The solid-state main amplifier can flexibly choose from various technical routes such as end pump, side pump, slab, and thin sheet according to the requirements of final output power, pulse energy, etc. The system is easy to integrate with other pulse compression, nonlinear frequency conversion and other technical modules. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of the hybrid MOPA laser system with tapered gain fiber pre-amplification provided in an embodiment of the present invention.

[0041] Figure 2 This is a graph showing the output power of the ytterbium-doped tapered gain fiber preamplifier as a function of pump power in an embodiment of the present invention.

[0042] Figure 3 This is an autocorrelation trace diagram of the output pulsed laser from the ytterbium-doped tapered gain fiber preamplifier in an embodiment of the present invention.

[0043] Figure 4 This is a spectrum diagram of the output pulsed laser from the ytterbium-doped tapered gain fiber preamplifier in an embodiment of the present invention.

[0044] Figure 5 This is a beam quality analysis diagram of the output pulsed laser from the ytterbium-doped tapered gain fiber preamplifier in an embodiment of the present invention.

[0045] Figure 6 This is a graph showing the output power of the solid-state main amplifier (side pump module) as a function of pump current in an embodiment of the present invention.

[0046] In the diagram: 1. All-fiber structure pulsed seed source; 2. Single-mode fiber; 3a. Bandpass filter after seed source; 3b. Bandpass filter after first-stage uniform gain fiber preamplifier; 3c. Bandpass filter after second-stage uniform gain fiber preamplifier; 4a. Isolator after seed source; 4b. Isolator after first-stage uniform gain fiber preamplifier; 4c. Isolator after second-stage uniform gain fiber preamplifier; 5a. First-stage uniform gain fiber preamplifier; 5b. Second-stage uniform gain fiber preamplifier; 6. Tapered gain fiber preamplifier pump LD; 7. Tapered gain fiber preamplifier pump / signal combiner; 8. Tapered gain fiber preamplifier; 9. Output of tapered gain fiber preamplifier. 10. Diverging laser beam; 11. Laser beam collimation system; 12. Collimated laser beam; 13. Free-space high-power optical isolator; 14a. Collimated laser beam after isolation; 14b. Collimated laser beam requiring beam contraction; 15. Laser beam contraction system; 15a. Plano-convex lens one; 15b. Converging beam; 15c. Plano-concave lens one; 16. Laser beam expansion system; 16a. Plano-concave lens two; 16b. Diverging beam; 16c. Plano-convex lens two; 17a. Collimated laser beam output by the beam contraction system; 17b. Collimated laser beam output by the beam expansion system; 18. Solid-state main amplifier; 19. Final output beam of the solid-state main amplifier. Detailed Implementation

[0047] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0048] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0049] Please see Figure 1 In one embodiment of the present invention, a hybrid MOPA laser system with tapered gain fiber pre-amplification is specifically configured as follows:

[0050] 1. All-fiber structure pulse seed source module:

[0051] A polarization-maintaining "9" cavity mode-locked laser was used as the all-fiber structure pulse seed source 1. Its output laser center wavelength was approximately 1064 nm, the pulse repetition frequency was 42.896 MHz, and the initial average output power was 3.37 mW.

[0052] 2. Uniform gain fiber pre-amplification link:

[0053] The seed light first passes through a single-mode polarization-maintaining fiber 2 into a seed source post-bandpass filter 3a (bandwidth approximately 2nm, center 1064nm) for spectral purification to remove spontaneous emission noise. It then passes through a seed source post-isolator 4a to prevent backlighting from subsequent amplification stages from affecting the seed source's stability.

[0054] The purified seed light enters the first-stage uniform-gain fiber preamplifier 5a. This preamplifier uses a 3-meter-long ytterbium-doped single-mode fiber as the gain medium and is forward-pumped by a 975nm wavelength pump LD through a wavelength division multiplexer. The amplified pulse then passes through the first-stage uniform-gain fiber preamplifier 5a again, followed by a bandpass filter 3b and an isolator 4b, before entering the second-stage uniform-gain fiber preamplifier 5b. The second-stage uniform-gain fiber preamplifier 5b uses a 2-meter-long double-clad uniformly ytterbium-doped fiber and is clad-pumped by another 975nm pump LD to further enhance the pulse energy.

[0055] After the second-stage amplification, the optical signal passes through the second-stage preamplifier, the bandpass filter 3c, and the second-stage preamplifier isolator 4c. Then, it enters the signal input terminal of the core component of the tapered gain fiber preamplifier module—the tapered gain fiber preamplifier pump / signal combiner 7—through the single-mode fiber 2.

[0056] 3. Tapered gain fiber optic preamplifier module:

[0057] Pump light from the pump LD6 of a high-power tapered gain fiber preamplifier is injected into the pump end of the tapered gain fiber preamplifier pump / signal combiner 7. The pump light and the signal light from the second-stage preamplifier are combined in the tapered gain fiber preamplifier pump / signal combiner 7 and then injected together into a section of ytterbium-doped tapered gain fiber (the core gain medium in this embodiment, located within the tapered gain fiber preamplifier 8). The selected tapered fiber is specifically model Yb-MCOF-35 / 250-56 / 400-07-2.2-T0.7-PM. Its input end (narrow end) core diameter / cladding diameter is approximately 35 / 250 μm, and its mode field area matches that of single-mode fiber 2, facilitating low-loss splicing; its output end (thick end) core diameter / cladding diameter is approximately 56 / 400 μm, providing a larger mode field area. The tapered fiber is 7 meters long, with a taper transition region length of 2.2 meters.

[0058] With sufficient pump power, the signal pulse undergoes strong amplification in the tapered fiber. Because the fiber mode field area gradually increases along the transmission direction, nonlinear effects are effectively suppressed. The amplified laser is output from the thick end face of the tapered fiber, becoming the divergent laser output from the tapered gain fiber preamplifier.

[0059] 4. Free-space optical transmission and processing module:

[0060] The diverging laser 9 output from the tapered gain fiber preamplifier first passes through the laser beam collimation system 10, which is a collimating lens (e.g., a plano-convex lens or lens group) with a suitable focal length, and is collimated into an approximately parallel collimated laser beam 11.

[0061] The collimated laser beam 11 then passes through a free-space high-power optical isolator 12. Designed for a wavelength of 1064nm, the isolator has an isolation greater than 35dB and can effectively block strong laser light reflected from subsequent solid-state amplifiers, protecting the fragile fiber optic devices in the preceding stage.

[0062] After isolation, the collimated laser beam 13 enters the laser beam matching system according to the input beam size requirements of the subsequent solid-state main amplifier 18. In this embodiment, the solid-state main amplifier 18 is a side-pumped module, and its gain crystal (Nd:YAG) typically has a small beam size requirement, so the laser beam shrinking system 15 is selected.

[0063] The collimated laser beam 14a, which needs to be beam-shrunk, is first incident on the plano-convex lens 15a of the beam-shrunk system and is focused to form a converging beam 15b. The converging beam 15b is then incident on the plano-concave lens 15c and is re-collimated, but the beam diameter is effectively reduced. By adjusting the lens focal length and spacing, a collimated laser beam 17a with a diameter of approximately 5 mm is finally output from the beam-shrunk system.

[0064] Similarly, when the typical beam size requirement of the solid-state main amplifier 18 is large, a laser beam expander system 16 is selected. The collimated laser beam 14b that needs to be expanded is first incident on the plano-concave lens 16a of the beam expander system and is focused to form a diverging beam 16b. The diverging beam 16b is then incident on the plano-convex lens 16c and is re-collimated, but the beam diameter is effectively increased, and finally the collimated laser beam 17b output by the beam expander system is output.

[0065] 5. Solid-state main amplifier module:

[0066] In this embodiment, the solid-state main amplifier 18 is a side-pumped Nd:YAG module. The Nd:YAG crystal has a doping concentration of 0.6%, is a cylinder with a diameter of 5 mm and a length of 167 mm, and has 1064 nm anti-reflection coatings at both ends. The collimated laser beam 17a output from the matched beam-shrinking system is precisely guided into the crystal. Multiple laser diode bars surround the crystal for side pumping.

[0067] When the solid-state main amplifier pump is not activated, the laser power injected into the crystal is measured to be 60.21 W. By gradually increasing the drive current of the side-pumped LD, the system achieves its highest output power when the pump current reaches 24 A. Finally, a final output beam 19 with an average power of 119.4 W was obtained from the output of the solid-state main amplifier 18, achieving nearly double the gain compared to the injected power, thus verifying the ability of the pre-amplification stage to provide sufficiently high-quality injected light.

[0068] Testing and Characterization:

[0069] Figure 2 The curve showing the output power of the tapered gain fiber preamplifier 8 as a function of the pump LD6 power is displayed. At maximum pump, an output power of 90.06 W was obtained, with a slope efficiency of approximately 70%.

[0070] Figure 3 The output pulse autocorrelation trace measured using an autocorrelation meter (APE pulse Check 150) was fitted with Sech², yielding a pulse width of approximately 15.7 ps.

[0071] Figure 4 The spectrum was obtained using a spectrometer (Yokogawa AQ6370D). The center wavelength is around 1064 nm. The spectrum is clean and there is no obvious nonlinear broadening.

[0072] Figure 5 The beam quality measured using a beam quality analyzer (OPHIR-Spiricon BSQ-SP920) is Mx²≈1.28, My²≈1.31, indicating that the output beam quality is close to the diffraction limit.

[0073] Figure 6 The output power of the solid-state main amplifier 18 is shown as a function of its pump current, reaching a peak power of 119.4 W at a pump of 24 A.

[0074] This embodiment successfully demonstrates the technical approach of "tapered ytterbium-doped fiber pre-amplification + single-pass side-pumped solid-state main amplification," which completely replaces the traditional "solid-state regeneration pre-amplification + single-pass solid-state main amplification" scheme. The system exhibits comprehensive advantages in high stability, high repetition rate, high beam quality, and high output power.

[0075] Other implementation methods

[0076] Those skilled in the art will understand that various modifications and substitutions can be made without departing from the core concept of this invention:

[0077] Tapered gain fiber can be replaced with erbium-doped fiber (Er). 3+ ~1550nm), thulium-doped (Tm 3+~2μm), holmium doping (Ho) 3+ Other rare earth ion doping types, such as ~2.1μm, are used to cover different laser wavelengths.

[0078] The solid-state main amplifier 18 is not limited to side-pumped modules; it can also use end-pumped modules to obtain better beam quality, or use slab amplifiers or sheet amplifiers to obtain higher average power and heat dissipation capabilities. It can also use regenerative amplifier structures to obtain higher single-pulse energy.

[0079] The laser beam shrinking system 15 and the laser beam expanding system 16 can be designed to be more complex according to actual optical path requirements, such as using lens groups or telescope systems to achieve more precise beam transformation.

[0080] After the all-fiber structure pulse seed light source 1 or between each stage of amplifier, a pulse selector (such as an acousto-optic modulator) can be added as needed to reduce the repetition frequency, or a pulse stretcher / compressor can be added to achieve chirped pulse amplification (CPA).

[0081] This hybrid MOPA laser system with tapered gain fiber pre-amplification replaces traditional solid-state regenerative pre-amplification, improving the laser system's beam pointing stability and resistance to environmental interference. Simultaneously, it enables pulse amplification with higher repetition rates, overcoming the frequency limitation of the Pockels cell response in solid-state regenerative amplifiers. This tapered fiber pre-amplification technology can be applied to fiber amplifiers of various wavelengths and rare-earth doped fibers, including erbium-doped, ytterbium-doped, thulium-doped, and holmium-doped fibers. Further solid-state amplification stages can be extended to various types of main amplification modules, such as end-pumped, side-pumped, slab, and wafer-type amplification modules.

[0082] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these should also be considered within the scope of protection of the present invention. These will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A hybrid MOPA laser system with tapered gain fiber pre-amplification, characterized in that, Along the laser transmission direction, the following are included in sequence: All-fiber structure pulse seed source module; A uniform gain fiber preamplifier link, the input of which is connected to the seed source module; A tapered gain fiber preamplifier module, the input end of which is connected to the output end of the fiber preamplification link; the tapered gain fiber preamplifier module includes a pump source and a tapered gain fiber, used to amplify the power of the laser from the uniform gain fiber preamplification link and directly output a free space laser beam; The free-space optical transmission processing module is used to receive and collimate and match the free-space laser beam output from the tapered gain fiber. The solid-state main amplifier module is used to receive the laser beam processed by the free space light transmission processing module and amplify its power.

2. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 1, characterized in that, The tapered gain fiber preamplifier module further includes a pump / signal combiner, whereby the pump light emitted from the pump source and the signal light from the uniform gain fiber preamplifier link are combined by the pump / signal combiner and injected into the tapered gain fiber.

3. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 1, characterized in that, The tapered gain fiber is a rare-earth ion-doped fiber, and its input end mode field area matches the mode field area of ​​the final stage output fiber of the uniform gain fiber pre-amplification link. Its output end mode field area is larger than its input end mode field area. The rare-earth ions are selected from at least one of ytterbium ions (Yb3+), erbium ions (Er3+), thulium ions (Tm3+), holmium ions (Ho3+), or neodymium ions (Nd3+).

4. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 1, characterized in that, The fiber optic preamplifier link includes at least one stage of uniform gain fiber optic preamplifier.

5. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 4, characterized in that, The fiber optic preamplifier link further includes a bandpass filter and / or an optical isolator disposed between the seed source module and the at least one stage of uniform gain fiber optic preamplifier, and / or between each stage of uniform gain fiber optic preamplifier.

6. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 1, characterized in that, The free-space optical transmission processing module includes: A laser beam collimation system is used to collimate the diverging laser beam output from the tapered gain fiber into parallel light; A laser beam matching system, located after the laser beam collimation system, is used to adjust the diameter of the laser beam to match the input requirements of the solid-state main amplifier module.

7. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 6, characterized in that, The free-space light transmission processing module also includes a free-space light isolator located between the laser beam collimation system and the laser beam matching system to block reverse-transmitted light.

8. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 1, characterized in that, The solid-state main amplifier module employs one or more combinations of end-pumped solid-state amplifiers, side-pumped solid-state amplifiers, slab amplifiers, sheet amplifiers, regenerative amplifiers, or multi-pass amplifiers.

9. The hybrid MOPA laser system with tapered gain fiber pre-amplification according to claim 1, characterized in that, The system outputs laser pulses with a repetition frequency greater than 1 MHz and a beam quality factor M. 2 Less than 1.

5.

10. A laser amplification method, characterized in that, The hybrid MOPA laser system employing tapered gain fiber pre-amplification as described in any one of claims 1 to 9 includes the following steps: The initial pulsed laser seed is generated by the all-fiber structure pulsed seed source module; The pulsed laser seed is initially amplified via the uniform gain fiber pre-amplification link; The initially amplified laser beam and the pump light emitted by the pump laser diode are combined by the pump / signal combiner and injected into the tapered gain fiber for power amplification, and a free space laser beam is output from its output end. The free-space laser beam is collimated, isolated, and beam-matched by the free-space light transmission and processing module. The matched laser beam is injected into the solid-state main amplifier module for final power amplification and output.

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