WO2021243513A1

WO2021243513A1 - All-fiber high-energy pulse regenerative amplification apparatus and method based on 2×3 optical switch

Info

Publication number: WO2021243513A1
Application number: PCT/CN2020/093735
Authority: WO
Inventors: 崔玉栋; 刘雪明
Original assignee: 浙江大学
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2021-12-09

Abstract

Disclosed is an all-fiber high-energy pulse regenerative amplification apparatus based on a 2×3 optical switch. The apparatus comprises a 2×3 optical switch, an all-fiber regenerative amplification resonant cavity composed of the 2×3 optical switch, an ultrashort pulse laser seed source, a pulse broadening apparatus, a pulse compression apparatus and a detection and feedback control apparatus. The 2×3 optical switch selectively inputs a pulse of the regenerative amplification resonant cavity and outputs the pulse from different ports. The input pulse of the all-fiber regenerative amplification resonant cavity is circularly amplified multiple times in the resonant cavity. The locking of the repetition frequency of the ultrashort pulse laser seed source and the all-fiber regenerative amplification resonant cavity, and synchronization between a 2×3 optical switch control signal and the ultrashort pulse laser seed source are ensured by using the detection and feedback control apparatus. The high-energy pulse regenerative amplification apparatus can effectively replace a multi-stage amplification and frequency reduction structure in traditional high-power optical fiber laser amplification, such that the cost of a high-energy ultrafast laser is reduced, and research and application of an ultrafast laser can be promoted.

Description

An all-fiber high-energy pulse regenerative amplifying device and method based on 2×3 optical switch

Technical field

The present invention relates to the technical field of fiber laser amplification, in particular to a 2×3 optical switch realized by a large-mode field fiber, and an all-fiber high-energy pulse regenerative amplification device and method realized by using the same.

Background technique

Ultra-short laser pulses have extremely narrow time scales, ultra-wide spectral widths and ultra-high peak powers, especially for high-energy femtosecond laser pulses, in high-precision laser processing, biomedicine, high-precision measurement, ultra-fast diagnosis, etc. The field is widely used. However, under normal circumstances, the output power and pulse energy of the femtosecond laser oscillator are limited, and it is necessary to use an amplifier to increase the pulse energy. The amplification of the femtosecond laser is limited by the nonlinear effect of light and relies on the chirped pulse amplification technology. It first uses a dispersive element to expand the light pulse in the time domain, then uses the gain medium to amplify the pulse energy, and finally uses the opposite sign Dispersion compresses the pulse to the femtosecond level. Usually, bulk crystals are used to achieve pulsed laser amplification, which has a larger mode field area to achieve higher energy laser pulses, but its single gain efficiency is relatively low, and the use of multi-stage amplification will greatly increase the system’s Complexity and cost. In order to obtain a sufficiently high gain, the researchers proposed a technical solution for regenerative amplification. The pulse to be amplified is input into a low-loss resonant cavity with a gain medium, and the pulse will pass through the gain medium multiple times in the resonant cavity and be amplified. Several times, then output the amplified high-energy pulse. This method can not only use a relatively simple structure to achieve high-energy pulses, but also can reduce the frequency. However, for solid-state laser amplification, strict resonant cavity design requirements, instability of the spatial optical path, and limitations of gain conversion efficiency make it difficult for current regenerative amplifiers to work stably in environments outside the laboratory. The all-fiber structure regenerative amplifier will be a way to solve the above problems.

In fact, very little work has been carried out on the research of all-fiber structure regenerative amplifiers, mainly because the mode field area in the fiber is small, and the nonlinear effect is very strong. The long-distance transmission of high-energy pulses in the fiber will lead to comparison. Obvious non-linear phase shift. In fact, with the development of large-mode field fiber design and manufacturing technology, it has provided an opportunity for further development of the research and application of all-fiber regenerative amplifiers. So far, the reported fiber regenerative amplifiers usually only use gain fibers instead of laser crystals, and still contain a large number of spatial light structures. The few researches on all-fiber regenerative amplifiers mainly focus on the principle and stability. The fiber used is also ordinary single-mode fiber. There are many problems in the pulse input and output, frequency reduction, and synchronization of the regenerative cavity. , There is no solution to achieve high-energy ultra-fast laser output. Another technical limitation of the all-fiber regenerative amplifier lies in the input and output components used. The commonly used electro-optic or acousto-optic 2×2 optical switches not only have a relatively large insertion loss, but it is also difficult to directly obtain a large signal-to-noise ratio frequency reduction.

Summary of the invention

The purpose of the present invention is to address the shortcomings of the prior art, propose a 2×3 fiber optic switch, and use it to realize an ultra-fast ultra-fast switch with an all-fiber structure, a more compact structure, more convenient implementation, and better environmental stability. The laser pulse regenerative amplification device and method can provide an environmentally stable high-energy ultra-short pulse source for industrial processing, medical, national defense and military fields.

The purpose of the present invention is achieved through the following technical solutions: an all-fiber high-energy pulse regenerative amplifying device based on a 2×3 optical switch, which includes a 2×3 optical switch and an all-fiber regenerative amplifying resonant cavity composed of the 2×3 optical switch , Pulse laser seed source, pulse compression device, detection and feedback control device;

The 2×3 optical switch includes 2 input ports a and b and 3 output ports c, d, e, and has two working states: on and off: in the off state, the input light of port a is output from port c, and port b The input light is output from port d; in the open state, the input light of port a is converted to port d output, and the input light of port b is converted to port e output; the a port of the 2×3 optical switch is connected to the pulse laser seed source, c The and e ports are the output ports of the all-fiber regenerative amplifier resonator, and the b and d ports are connected to the all-fiber regenerative amplifier resonator.

The all-fiber regenerative amplifying resonant cavity is composed of optical fibers, including 2×3 optical switches, a combiner, and a gain fiber that are sequentially connected through the optical fiber. The pump source couples the pump light into the gain fiber through the combiner; The fiber regenerative amplifier resonant cavity also contains a coupler and an isolator.

The pulsed laser seed source and the all-fiber regenerative amplifying resonator are connected by an optical fiber. The laser output of the all-fiber regenerative amplifying resonant cavity from the e port of the 2×3 optical switch is a spatial collimated output, and the output laser enters the pulse compression device.

The output signal of the coupler in the all-fiber regenerative amplifying cavity or the c-port output signal of the 2×3 optical switch enters the detection and feedback control device to obtain the repetition frequency of the all-fiber regenerative amplifying cavity, and the feedback signal controls the pulse laser seed source The repetition frequency adjustment device ensures that the repetition frequency of the all-fiber regenerative amplification resonant cavity is in an integer proportional relationship with the repetition frequency of the pulsed laser seed source.

Further, the pump source in the all-fiber regenerative amplifier resonant cavity is a multimode semiconductor laser, the gain fiber is a rare-earth ion doped fiber, and the coupler couples less than 1% of the energy out of the resonant cavity.

Further, the optical fibers used in the all-fiber regenerative amplification resonant cavity are all large-mode field fibers.

Further, the pulsed laser seed source is a standard mode-locked fiber laser, used to generate femtosecond or picosecond pulsed laser, and includes a repetition frequency adjustment device. And 5% of the output light is incident on the detection and feedback control device.

Further, the all-fiber high-energy pulse regenerative amplifying device may also include a pulse stretching device. When the all-fiber regenerative amplifying resonator includes a pulse stretching device, the pulse of the pulse laser seed source is first input into the pulse stretching device through the optical fiber, and then Enter the a port of the all-fiber regenerative amplification resonant cavity; the pulse stretching device and the pulse compression device are composed of dispersive elements, which are used to provide dispersion and stretch and compress the pulse. Fiber gratings, grating pairs, dispersive fibers, photonic crystal fibers or micro Nanofiber, pulse stretching device and pulse compression device have the same dispersion value but opposite signs.

Further, the amplification of the laser pulse can also be achieved by controlling the evolution of the pulse by changing the pump power. The pulse evolution performance is: in the initial stage, the pump power is small, and the pulse energy slowly increases with time. The pulse is broadened by the dispersion of the fiber in the regenerative amplifying cavity while maintaining the suppression of nonlinear effects, and then the pump power is increased to achieve the pulse Amplification; or, in the normal dispersion regenerative amplification resonator, set a suitable pump power to make the pulse evolution meet the conditions of self-similar amplification evolution, and realize the simultaneous increase of the pulse width and the spectral width during the amplification process.

Further, the detection and feedback control device includes a photodetector, a controller and a regulator. The detector respectively detects the signal repetition frequency in the pulsed laser seed source and the all-fiber regenerative amplification resonant cavity; the controller provides a feedback signal for the regulator by comparing the differences between the two, and the regulator and the repetition frequency adjustment device are implemented together The frequency of the seed source and the amplifying cavity is locked.

Further, there is an integer proportional relationship between the switching frequency of the 2×3 optical switch and the repetition frequency of the seed source, and the on-state time of the optical switch is less than the pulse interval time of the seed source.

An all-fiber high-energy pulse regenerative amplification method based on 2×3 optical switches. The specific steps of the method are as follows:

(1) The pulsed laser seed source produces femtosecond or picosecond laser. After the laser passes through the pulse stretching device, the pulse width is increased to the order of hundreds of picoseconds or nanoseconds, and it is input into the all-fiber regenerative amplifier resonator;

(2) If the optical switch is in the on state, the pulse of the amplified cavity enters the a port of the 2×3 optical switch, and the pulse is output from the d port into the all-fiber regenerative amplifier resonator; at the same time, the pulse of the all-fiber regenerative amplifier resonator is from the light Enter the b port of the switch and output it from the e port to obtain a higher energy pulse; the output pulse finally passes through a pulse compression device to obtain an ultra-short pulse output. If the optical switch is off, the pulse in the regenerative amplifying cavity enters the optical switch from port b, and returns to the cavity from port d, and then passes through the gain medium for multiple times for amplification until the next optical switch is in the on state时 output. The repetition frequency of the output pulse depends on the switching frequency of the optical switch.

The beneficial effects of the present invention are:

1. The high-energy pulse regenerative amplification device can not only achieve high-magnification amplification of pulse energy, but also reduce the pulse repetition frequency, which effectively replaces the structure of multi-stage amplification and frequency reduction in traditional high-power fiber laser amplification. The cost of high-energy ultrafast lasers can promote the research and application of ultrafast lasers.

2. The high-energy pulse regenerative amplifier device is an all-fiber structure, which overcomes the difficulties of traditional regenerative amplifiers in the design and adjustment of the spatial optical path. It has excellent environmental stability and compact structure design. It is a small size for high-energy ultrafast lasers. Provides a way.

3. The all-fiber high-energy pulse regenerative amplifier device adopts large-mode field optical fiber, combined with chirped pulse amplification technology, which can effectively reduce the nonlinear effect in the optical fiber and increase the pulse energy.

4. The 2×3 optical switch can isolate the seed laser from the resonant cavity in the off state, which improves the signal-to-noise ratio of the regenerative amplifier.

5. The detection and feedback control device locks the frequency of the seed source, the all-fiber regenerative amplifier resonator and the 2×3 optical switch, which improves the working stability of the all-fiber regenerative amplifier resonator and reduces the nonlinear evolution caused by detuning Unstable.

Description of the drawings

Figure 1 is a schematic diagram of the overall structure of the present invention;

Figure 2 is a schematic diagram of the implementation of the all-fiber regenerative amplification resonant cavity in the present invention;

Figure 3 is a schematic diagram of the implementation of the 2×3 optical switch in the present invention;

Figure 4 is a schematic diagram of signals in the working process of the present invention;

In the figure, 101—ultrashort pulse laser seed source; 102—pulse stretching device; 103—all-fiber regenerative amplifier resonator; 104—detection and feedback control device; 105—pulse compression device; 201-2×3 optical switch; 202 —Combiner; 203—gain fiber; 204—coupler; 205—pump source; 206—isolator; 301-2×2 optical switch; 302-1×2 optical switch; 401—ultrashort pulse laser seed source Output pulse sequence; 401-2×3 optical switch control signal; 403—all-fiber regenerative amplifier resonator output signal from 2×3 optical switch e-port; 404—all-fiber regenerative amplifier resonator self-coupler output signal .

detailed description

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

The present invention provides an all-fiber high-energy pulse regenerative amplifying device based on a 2×3 optical switch, which includes a 2×3 optical switch and an all-fiber regenerative amplifying resonator composed of the 2×3 optical switch, a pulse laser seed source, and a pulse compression device , Detection and feedback control device;

The all-fiber regenerative amplifying resonant cavity is composed of a large-mode field fiber, including a 2×3 optical switch, a combiner, and a gain fiber that are sequentially connected through the fiber, and the pump source couples the pump light into the gain fiber through the combiner; The all-fiber regenerative amplification resonant cavity also includes a coupler and an isolator. The pump source in the all-fiber regenerative amplifier resonant cavity is a multimode semiconductor laser, the gain fiber is a rare-earth ion doped fiber, and the coupler couples less than 1% of the energy out of the resonant cavity.

The pulsed laser seed source and the all-fiber regenerative amplifying resonator are connected by an optical fiber. The laser output of the all-fiber regenerative amplifying resonant cavity from the e port of the 2×3 optical switch is a spatial collimated output, and the output laser enters the pulse compression device. The pulsed laser seed source is a standard mode-locked fiber laser, used to generate femtosecond or picosecond pulsed laser, and contains a repetition frequency adjustment device. And 5% of the output light is incident on the detection and feedback control device.

The output signal of the coupler in the all-fiber regenerative amplifying cavity or the c-port output signal of the 2×3 optical switch enters the detection and feedback control device to obtain the repetition frequency of the all-fiber regenerative amplifying cavity, and the feedback signal controls the pulse laser seed source The repetition frequency adjustment device ensures that the repetition frequency of the all-fiber regenerative amplification resonant cavity is in an integer proportional relationship with the repetition frequency of the pulsed laser seed source. The detection and feedback control device includes a photodetector, a controller and a regulator. The detector respectively detects the signal repetition frequency in the pulsed laser seed source and the all-fiber regenerative amplification resonant cavity; the controller provides a feedback signal for the regulator by comparing the differences between the two, and the regulator and the repetition frequency adjustment device are implemented together The frequency of the seed source and the amplifying cavity is locked.

The all-fiber high-energy pulse regenerative amplifying device may further include a pulse stretching device. When the all-fiber regenerative amplifying resonator includes a pulse stretching device, the pulse of the pulse laser seed source is first input into the pulse stretching device through the optical fiber, and then enters the all-fiber The a port of the regenerative amplifying cavity; the pulse stretching device and the pulse compression device are composed of dispersive elements, which are used to provide dispersion and stretch and compress the pulse. Fiber gratings, grating pairs, dispersive fibers, photonic crystal fibers or micro-nano fibers can be used. The dispersion values of the pulse stretching device and the pulse compression device are the same, but the signs are opposite.

The amplification of the laser pulse can also be achieved by controlling the evolution of the pulse by changing the pump power. The pulse evolution performance is: in the initial stage, the pump power is small, and the pulse energy slowly increases with time. The pulse is broadened by the dispersion of the fiber in the regenerative amplifying cavity while maintaining the suppression of nonlinear effects, and then the pump power is increased to achieve the pulse Amplification; or, in the normal dispersion regenerative amplification resonator, set a suitable pump power to make the pulse evolution meet the conditions of self-similar amplification evolution, and realize the simultaneous increase of the pulse width and the spectral width during the amplification process. There is an integer proportional relationship between the switching frequency of the 2×3 optical switch and the repetition frequency of the seed source, and the on-state time of the optical switch is less than the pulse interval time of the seed source.

The present invention also provides an all-fiber high-energy pulse regenerative amplification method based on a 2×3 optical switch. The specific steps of the method are as follows:

Specific examples of the present invention are as follows:

As shown in Figure 1(a), the present invention provides a 2×3 optical switch and an all-fiber high-energy pulse regenerative amplifying device realized by using it, including an ultra-short pulse laser seed source 101 connected in sequence through an optical fiber, and pulse stretching The device 102 and the all-fiber regenerative amplifying resonator 103, the all-fiber regenerative amplifying resonant cavity 103 outputs laser light as a spatially collimated output, and the output laser enters the pulse compression device 105. It is also possible not to include the pulse stretching device 102, and directly use the optical fiber to input the seed source pulse into the all-fiber regenerative amplifying resonator 103, as shown in FIG. 1(b).

The ultrashort pulse laser seed source 101 can use a typical mode-locked fiber laser, and a cavity length adjuster based on a PZT crystal is placed on the fiber in the resonant cavity. 5% of the energy of the output signal of the ultrashort pulse laser seed source 101 is split into the feedback control device 104, the photodetector is used to obtain the signal repetition frequency, and a feedback signal is provided to adjust the ultrashort pulse laser seed source 101 repeat frequency. The pulse stretching device 102 is a dispersive fiber with positive dispersion, which stretches the pulse width to the order of nanoseconds; the pulse compression device 105 is a grating pair that provides negative dispersion, and the gap between the grating pair is precisely adjusted to make the dispersion value and pulse broaden The device 102 is consistent.

As shown in Figure 2(a), the all-fiber regenerative amplifier resonator 103 includes a 2×3 optical switch 201, a beam combiner 202, a gain fiber 203, and a pump source 205. The length of the resonant cavity and the ultrashort pulse laser seed source The length of the resonant cavity is an integer multiple. The pulse enters the port a of the 2×3 optical switch 201. When the optical switch 201 is in the off state, the pulse is directly output from the c port; when the optical switch 201 is in the on state, the pulse is output from the d port into the all-fiber regenerative amplifier resonator 103 middle. The combiner 202 is an N+1 pump combiner, which is composed of N multimode pump input fibers and a large-mode single-mode fiber as a signal fiber bundle, and the output is a large-mode double-clad fiber, and The large-mode field double-clad rare-earth ion doped gain fiber 203 is matched; the input pump source 205 is a multi-mode semiconductor laser, and multiple pump sources can be used to achieve higher power laser through the beam combiner 202. The all-fiber regenerative amplifier resonator 103 can also include a coupler 204 and an isolator 206. As shown in Figure 2(b), the coupler 204 and the isolator 206 realize the functions of coupling split beam output and laser unidirectional operation, respectively. The beam splitting ratio of the device 204 is less than 5%, which can monitor the working status of the all-fiber regenerative amplifier resonator 103; the laser beam output by the coupler 204 or the laser output from the port c of the 2×3 optical switch 201 is incident on the feedback In the control device 104, the photodetector therein is used to obtain the repetition frequency of the regenerative amplification resonant cavity 103.

The 2×3 optical switch 201 can be composed of a 2×2 optical switch 301 and a 1×2 optical switch 302 in series, as shown in Figure 3, that is, the input port of the 1×2 optical switch 302 and one of the 2×2 optical switch 301 The output port is connected, and the two optical switches are turned on or off at the same time during operation; the 2×2 optical switch 301 and the 1×2 optical switch 302 can be realized by acousto-optical, electro-optical or magneto-optical switches. The 2×2 optical switch 301 and the 1×2 optical switch 302 can be connected in two ways, as shown in Fig. 3(a) and Fig. 3(b).

The working process of the present invention is shown in Fig. 4: the output laser sequence 401 of the ultrashort pulse laser seed source 101 enters the pulse stretching device 102, the pulse width is stretched, and then the pulse enters the a port of the all-fiber regenerative amplification resonator 103. The feedback control device 104 uses the control electrical signal 402 to control the switching time of the 2×3 optical switch 201 according to the signal of the seed source 101, and only one pulse is allowed to enter the port d in each cycle. When the optical switch 201 is in the off state, the pulse circulates through the gain fiber in the regenerative amplifying cavity 103 multiple times to obtain amplification. When the optical switch 201 is in the on state next time, the regenerative amplifier resonant cavity 103 outputs a pulse 403 through the e port, and another pulse enters the resonant cavity 103 at the same time. The output pulse sequence 404 of the coupler in the regenerative amplifier resonant cavity 103 enters the feedback control device 104. By comparing the repetition frequency of the seed source 101 and the resonant cavity 103, the adjustment device in the seed source 101 is controlled to keep the repetition frequency of the two locked.

Claims

An all-fiber high-energy pulse regenerative amplifying device based on a 2×3 optical switch, which is characterized in that: the device includes a 2×3 optical switch and an all-fiber regenerative amplifying resonant cavity composed of the 2×3 optical switch, a pulse laser seed source, and a pulse compression device , Detection and feedback control device;

The 2×3 optical switch includes 2 input ports a and b and 3 output ports c, d, e, and has two working states: on and off: in the off state, the input light of port a is output from port c, and port b The input light is output from port d; in the open state, the input light of port a is converted to port d output, and the input light of port b is converted to port e output; the a port of the 2×3 optical switch is connected to the pulse laser seed source, c The and e ports are the output ports of the all-fiber regenerative amplifier resonator, and the b and d ports are connected to the all-fiber regenerative amplifier resonator.

The all-fiber regenerative amplifying resonant cavity is composed of optical fibers, including 2×3 optical switches, a combiner, and a gain fiber that are sequentially connected through the optical fiber. The pump source couples the pump light into the gain fiber through the combiner; The fiber regenerative amplifier resonant cavity also contains a coupler and an isolator.

The amplification of the laser pulse is achieved by controlling the evolution of the pulse by changing the pump power. The pulse evolution performance is: in the initial stage, the pump power is small, and the pulse energy slowly increases with time. The pulse is broadened by the dispersion of the fiber in the regenerative amplifying cavity while maintaining the suppression of nonlinear effects, and then the pump power is increased to achieve the pulse Amplification; or, in the normal dispersion regenerative amplification resonator, set a suitable pump power to make the pulse evolution meet the conditions of self-similar amplification evolution, and realize the simultaneous increase of the pulse width and the spectral width during the amplification process.

The pulsed laser seed source and the all-fiber regenerative amplifying resonator are connected by an optical fiber. The laser output of the all-fiber regenerative amplifying resonant cavity from the e port of the 2×3 optical switch is a spatial collimated output, and the output laser enters the pulse compression device.

The output signal of the coupler in the all-fiber regenerative amplifying cavity or the c-port output signal of the 2×3 optical switch enters the detection and feedback control device to obtain the repetition frequency of the all-fiber regenerative amplifying cavity, and the feedback signal controls the pulse laser seed source The repetition frequency adjustment device ensures that the repetition frequency of the all-fiber regenerative amplification resonant cavity is in an integer proportional relationship with the repetition frequency of the pulsed laser seed source.
An all-fiber high-energy pulse regenerative amplifier device based on a 2×3 optical switch according to claim 1, wherein the pump source in the all-fiber regenerative amplifier resonator is a multimode semiconductor laser, and the gain fiber is a rare earth ion With doped fiber, the coupler couples less than 1% of the energy to the outside of the resonant cavity.
An all-fiber high-energy pulse regenerative amplifier device based on a 2×3 optical switch according to claim 1, wherein the optical fibers used in the all-fiber regenerative amplifier resonator are all large-mode field fibers.
An all-fiber high-energy pulse regenerative amplification device based on 2×3 optical switches according to claim 1, wherein the pulse laser seed source is a standard mode-locked fiber laser, which is used to generate femtosecond or picosecond pulsed laser , And includes a repetition frequency adjustment device. And 5% of the output light is incident on the detection and feedback control device.
The all-fiber high-energy pulse regenerative amplifying device based on 2×3 optical switches according to claim 1, characterized in that: the all-fiber high-energy pulse regenerative amplifying device may further include a pulse stretching device, and the all-fiber When the regenerative amplifier resonator includes a pulse stretching device, the pulse laser seed source pulse is first input into the pulse stretching device through an optical fiber, and then enters the a port of the all-fiber regenerative amplifier resonator; the pulse stretching device and the pulse compression device are composed of dispersive elements. In order to provide dispersion, pulse broadening and compression, fiber grating, grating pair, dispersive fiber, photonic crystal fiber or micro-nano fiber can be used. The dispersion value of the pulse stretching device and the pulse compression device are the same, but the signs are opposite.
An all-fiber high-energy pulse regenerative amplification device based on a 2×3 optical switch according to claim 1, wherein the detection and feedback control device includes a photodetector, a controller, and a regulator. The detector respectively detects the signal repetition frequency in the pulsed laser seed source and the all-fiber regenerative amplification resonant cavity; the controller provides a feedback signal for the regulator by comparing the differences between the two, and the regulator and the repetition frequency adjustment device are implemented together The frequency of the seed source and the amplifying cavity is locked.
An all-fiber high-energy pulse regenerative amplifier device based on a 2×3 optical switch according to claim 1, wherein the switching frequency of the 2×3 optical switch and the repetition frequency of the seed source have an integer ratio. Relationship, the on-state time of the optical switch is less than the pulse interval time of the seed source.
An all-fiber high-energy pulse regenerative amplification method based on 2×3 optical switches is characterized in that the specific steps of the method are as follows:

(1) The pulsed laser seed source produces femtosecond or picosecond laser. After the laser passes through the pulse stretching device, the pulse width is increased to the order of hundreds of picoseconds or nanoseconds, and it is input into the all-fiber regenerative amplifier resonator;

(2) If the optical switch is in the on state, the pulse of the amplified cavity enters the a port of the 2×3 optical switch, and the pulse is output from the d port into the all-fiber regenerative amplifier resonator; at the same time, the pulse of the all-fiber regenerative amplifier resonator is from the light Enter the b port of the switch and output it from the e port to obtain a higher energy pulse; the output pulse finally passes through a pulse compression device to obtain an ultra-short pulse output. If the optical switch is off, the pulse in the regenerative amplifying cavity enters the optical switch from port b, and returns to the cavity from port d, and then passes through the gain medium for multiple times for amplification until the next optical switch is in the on state时 output. The repetition frequency of the output pulse depends on the switching frequency of the optical switch.