All-fiber pulse laser device based on fiber saturable absorption amplification and generation method

Abstract

The invention discloses an all-fiber pulse laser device based on optical fiber saturable absorption amplification and a generation method. The pulse laser device is composed of a pumping module, an optical fiber circulator, a doped saturable absorption optical fiber amplifier and a main oscillator. The method comprises the steps that the pumping module outputs pumping light to the optical fiber circulator; the optical fiber circulator transmits the pump light to the doped saturable absorption optical fiber amplifier, and meanwhile, the main oscillator generates a seed pulse signal and inputs the seed pulse signal to the doped saturable absorption optical fiber amplifier; pump light is absorbed through the saturable absorption effect of the doped saturable absorption optical fiber amplifier, ground state ions absorb the pump light and suppress oscillation of a main oscillator under low pumping power, the ground state bleaching effect triggers release in a pulse along with enhancement of the pumping power, meanwhile, pulse energy is amplified through stimulated radiation, and therefore the pulse energy is amplified. And high-peak power pulse laser output is obtained. The device and the method can realize high peak power, high average power and stable pulse laser output.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, specifically relating to an all-fiber pulsed laser based on fiber saturable absorption amplification and its generation method. Background Technology

[0002] Compared to continuous-wave lasers, pulsed lasers, with their repetitive output frequency and high peak power, have attracted significant attention due to their importance in numerous practical applications, including medicine, spectral analysis, remote sensing, lidar systems, and materials processing. High-energy, short-duration lasers, conforming to the thermal confinement factors of biological tissues, result in less thermal damage, making them the preferred choice for tissue ablation. They offer significant advantages and broad application prospects in minimally invasive surgery, tumor resection, and cosmetic medicine, greatly expanding the application areas of lasers and representing a research hotspot in cutting-edge laser technology.

[0003] Compared to solid-state lasers, fiber lasers offer numerous advantages, including compact structure, high robustness, wide wavelength tuning range, convenient thermal management, good beam quality, and ease of maintenance. Therefore, all-fiber pulsed lasers represent a significant development trend. Common active modulators used to achieve pulsed laser operation include acousto-optic modulators (AOMs) and electro-optic modulators (EOMs). Passive modulation typically involves incorporating a saturable absorber (SA) or equivalent saturable absorber structure within the resonant cavity. Active modulation requires an active modulator and control system within the laser resonant cavity, complicating the laser system structure. Furthermore, the high cost of active modulators increases the overall laser cost and hinders integration. While semiconductor saturable absorber mirrors, commonly used in passive modulation, offer mature technology and allow for customized modulation depths, their high cost and complex fabrication process make them unsuitable. Other types of saturable absorber materials, although lower in cost and easier to fabricate, still require additional components within the system, increasing complexity and cost.

[0004] To address the above problems, this invention provides an all-fiber, high-performance pulsed laser generator based on the saturable absorption amplification of doped gain fiber, which is of great significance for the development of compact, efficient, simple and reliable laser systems. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an all-fiber pulsed laser device and generation method based on fiber saturable absorption amplification. The device has a simple structure, readily available materials, low manufacturing cost, adopts an all-fiber structure, has a stable output pulse sequence, high average power, high pulse energy, and is easy to control. It can obtain stable pulsed laser output with high average power and high peak power. The method is simple to implement and has low implementation cost. It can achieve high peak power, high average power, and stable pulsed laser output, and is suitable for pulsed laser application scenarios.

[0006] To achieve the above objectives, the present invention provides an all-fiber pulsed laser device based on fiber saturable absorber amplification, the pulsed laser device comprising a pump module, a fiber circulator, a doped saturable absorber fiber amplifier, and a master oscillator.

[0007] As a preferred embodiment, the output of the pump module is connected to port c of the fiber optic circulator, port b of the fiber optic circulator is connected to one end of the doped saturable absorber fiber amplifier, the other end of the doped saturable absorber fiber amplifier is connected to the output of the master oscillator, and port a of the fiber optic circulator serves as the output of the pulsed laser device.

[0008] As a preferred embodiment, the doped saturable absorber fiber amplifier is a single-clad fiber, a double-clad fiber, or a photonic crystal fiber, and the doped rare earth elements include cerium, praseodymium, neodymium, dysprosium, thulium, holmium, ytterbium, and erbium, or transition metal elements include one or more of chromium, iron, cobalt, and bismuth.

[0009] As a preferred embodiment, the doped saturable absorber fiber amplifier is replaced with a doped gain fiber with other doping characteristics that has both gain and saturable absorber properties.

[0010] As a preferred embodiment, the doped saturable absorber fiber amplifier not only acts as a saturable absorber, modulating the operating characteristics of the master oscillator through pump control to achieve a stable pulse output, but also acts as an amplifier to amplify the output pulse signal from the master oscillator.

[0011] As a preferred embodiment, the master oscillator and the doped saturable absorber fiber amplifier constitute a master oscillation and power amplification pulsed laser device; the doped saturable absorber fiber amplifier is independently placed outside the resonant cavity of the master oscillator.

[0012] As a preferred option, the fiber optic circulator can be replaced with other devices and apparatuses that have the same function.

[0013] As a preferred embodiment, by using an optical fiber circulator, the pump light is coupled into a doped saturable absorber fiber amplifier and a master oscillator through port c to achieve back-pumping. The pulse signal is amplified by the doped saturable absorber fiber amplifier and finally output from port a of the optical fiber circulator.

[0014] This invention aims to provide a high-performance pulsed laser device based on a doped saturable absorber amplification fiber amplifier (DOA) with an all-fiber master oscillator and power amplifier (MOPA). The DOA fiber amplifier combines amplification and saturable absorption functions. This invention offers advantages such as simple structure, easy control, readily available materials, and low cost. Furthermore, its all-fiber structure enables stable pulsed laser output with high average power and high peak power, significantly expanding the application scenarios of fiber lasers. The DOA technology presented in this invention achieves high average power, high peak power, high performance, and stable pulsed laser output while simultaneously ensuring the simplicity and reliability of the laser system. The principle involves using the saturable absorption of the input pump laser by the doped saturable absorber fiber amplifier to control the pump of the oscillator, thereby obtaining pulsed laser output. The amplifier then amplifies the output pulse of the master oscillator to achieve high-intensity pulse operation.

[0015] By leveraging the saturable absorption effect of the doped saturable absorber fiber amplifier (DAB) to achieve passive gain control of the pump, no external modulation element is required. This allows for a more compact and simpler laser system, reducing manufacturing costs while ensuring performance feasibility. At low input pump power, the DAB's saturable absorption strongly absorbs the pump light, resulting in a relatively weak pump reaching the master oscillator. As the input pump light intensity increases, more particles are pumped to higher energy levels, while the number of ground-state particles decreases, thus reducing the absorption coefficient of the pump light. The stronger the pump light, the smaller the actual absorption coefficient of the fiber, resulting in "ground-state bleaching." This characteristic allows the DAB to function not only as an amplifier but also as a saturable absorber in the invented laser system, used to control and amplify pulse generation. Compared to other types of saturable absorbers, utilizing doped gain fiber as both an amplifier and a saturable absorber offers advantages such as a high damage threshold, readily available materials, low cost, ease of all-fiber implementation, and a compact structure. Given the above advantages, using doped gain fiber as both an amplification and saturable absorber can realize a high-performance, high-stability all-fiber pulsed laser.

[0016] This device utilizes the saturable absorption characteristics of doped gain fiber to simultaneously function as a saturable absorption amplification device, realizing a low-cost, easily tunable, high-efficiency, and compact all-fiber pulsed laser. It can achieve high average power, high peak power, high performance, and stable pulsed laser output, which has significant academic research value and industrial application potential.

[0017] This invention also provides a method for generating an all-fiber pulsed laser based on fiber saturable absorption amplification, employing an all-fiber pulsed laser device based on fiber saturable absorption amplification, comprising the following steps: Step 1: Output pump light from the pump module to the fiber optic circulator; Step 2: The pump light is transmitted unidirectionally to the doped saturable absorber fiber amplifier through the fiber optic circulator. The master oscillator generates a seed pulse signal and inputs it into the doped saturable absorber fiber amplifier. Step 3: The pump light is absorbed by the saturable absorption effect of the doped saturable absorber fiber amplifier. At low pump power, the ground-state ions of the doped saturable absorber fiber amplifier absorb the pump light and suppress the oscillation of the master oscillator. As the pump power increases, the doped saturable absorber fiber amplifier generates a ground-state bleaching effect, which triggers the master oscillator to generate a pulse signal. The pulse energy is amplified by stimulated emission of the doped saturable absorber fiber amplifier. Finally, a high peak power pulsed laser is obtained and output through port a of the fiber circulator.

[0018] This method is simple to implement and has low implementation cost. It utilizes the saturable absorption and amplification characteristics, high damage threshold features and dynamic control flexibility of doped gain fiber, combined with the oscillation characteristics of the master oscillator, to achieve modulation of the core laser parameters such as the repetition frequency, pulse energy and pulse width of the output pulsed laser. Ultimately, it can achieve high peak power, high average power and stable pulsed laser output, which is suitable for pulsed laser application scenarios. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the pulsed laser device in Embodiment 1 of the present invention; Figure 2 This is a diagram showing the main energy level structure of thulium ions and a schematic diagram of the main pumping and ion transition processes in this invention. Figure 3 This is the theoretical simulation result of the pulse operation characteristics of the thulium-doped laser based on the fiber optic saturable absorption amplification mechanism in this invention.

[0020] Figure 4 This is a schematic diagram of the pulsed laser device in Embodiment 2 of the present invention; Figure 5 The laser pulse sequence of Embodiment 2 of the present invention is shown when the average output power is 12.18 W; Figure 6 This is a single-pulse time-domain diagram of Embodiment 2 of the present invention when the average output power is 12.18 W.

[0021] In the diagram: 1. Pump module, 1-1. Semiconductor laser pump source, 1-2. Pump combiner, 1-3. High reflectivity Bragg grating A, 1-4. Thulium-doped gain fiber A, 1-5. Low reflectivity Bragg grating A, 1-6. Pump light stripper; 2. Fiber circulator, 3. Doped saturable absorber fiber amplifier, 4. Master oscillator, 4-1. Low reflectivity Bragg grating B, 4-2. Thulium-doped gain fiber B, 4-3. High reflectivity Bragg grating B. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-6 The embodiments of the present invention will be further described in detail below, but are not limited to the following embodiments. The terms "first," "second," etc., appearing in the embodiments of this application are only for illustration and to distinguish the objects being described, and have no order, nor do they indicate a special limitation on the number of devices in the embodiments of this application, and cannot constitute any limitation on the embodiments of this application.

[0023] Example 1: This embodiment describes an all-fiber pulsed laser device based on fiber saturable absorption amplification, such as... Figure 1 As shown, the pulsed laser device consists of a pump module 1, an optical fiber circulator 2, a doped saturable absorber optical fiber amplifier 3, and a master oscillator 4.

[0024] The output end of the pump module 1 is connected to port c of the fiber optic circulator 2. Port b of the fiber optic circulator 2 is connected to one end of the doped saturable absorber fiber amplifier 3. The other end of the doped saturable absorber fiber amplifier 3 is connected to the output end of the master oscillator 4. Port a of the fiber optic circulator 3 serves as the output end of the pulsed laser device.

[0025] Preferably, the master oscillator 4 and the doped saturable absorber fiber amplifier 3 constitute a master oscillation and power amplification pulsed laser device; the master oscillator 4 is used to generate seed pulse signals; the doped saturable absorber fiber amplifier 3 is independently placed outside the resonant cavity of the master oscillator 4. The doped saturable absorber fiber amplifier 3 has both pump light saturable absorption and signal amplification functions. The doped saturable absorber fiber amplifier 3 not only acts as a saturable absorber, modulating the operating characteristics of the master oscillator 4 through pump control to enable the master oscillator 4 to obtain stable pulse output, but also acts as an amplifier to amplify the output pulse signal from the master oscillator 4.

[0026] As a preferred embodiment, the pump module 1, fiber optic circulator 2, doped saturable absorber fiber amplifier 3, and master oscillator 4 are connected in pairs by fiber optic fusion splicing, and the fusion loss must be less than or equal to 0.1dB during each fusion splicing process. The pump module 1 is used to provide pump light; furthermore, the pump module 1 is not limited to fiber lasers, fiber-coupled output or free-space output semiconductor lasers, solid-state lasers, etc., but can also be other types of lasers with different coupling methods.

[0027] Furthermore, the doped saturable absorber fiber amplifier 3 can be a single-clad fiber or a double-clad fiber or photonic crystal fiber with a core diameter-to-clad area ratio tailored to the design requirements of the fiber laser. The doped rare earth or transition metal elements include one or more of cerium (Ce), praseodymium (Pr), neodymium (Nd), dysprosium (Dy), thulium (Tm), holmium (Ho), ytterbium (Yb), erbium (Er), chromium (Cr), iron (Fe), cobalt (Co), and bismuth (Bi). As an alternative, other ion-doped fibers that combine laser gain and saturable absorption characteristics can be used to replace the doped saturable absorption fiber amplifier 3.

[0028] As a further preferred option, the doped saturable absorbable fiber amplifier 3 is based on the saturable absorption characteristics of pump light by doped gain fiber. By selecting different device parameters, such as the length of doped gain fiber, doping concentration, fiber core diameter to cladding area ratio (core-cladding ratio), doping ions and matrix material types and pump parameters, different modulation characteristics and output laser pulse operation characteristics (output laser repetition frequency, pulse energy, pulse width, etc.) can be controlled. The fiber circulator 2 is used to unidirectionally input pump light into the doped saturable absorber fiber amplifier 3; as a preferred option, the fiber circulator 2 can be replaced with other devices and apparatuses with the same function.

[0029] As a preferred embodiment, by using fiber optic circulator 2, the pump light is coupled into the doped saturable absorber fiber amplifier 3 and the master oscillator 4 through port c to achieve backward pumping. The pulse signal is amplified by the doped saturable absorber fiber amplifier 3 and finally output from port a of fiber optic circulator 2.

[0030] This invention provides a novel all-fiber pulsed laser generation technology. This approach is low-cost, simple in system structure, employs an all-fiber architecture, and produces stable output pulse sequences with high average power and high pulse energy. Utilizing the saturable absorption and high damage threshold characteristics of doped gain fibers, the repetition frequency, pulse energy, and pulse width of the output pulsed laser can be modulated. The fiber saturable absorption amplifier in this invention is independent of the main oscillator and is easily adjustable. By changing the saturable absorption amplifier parameters, such as the length and concentration of the doped fiber, the core-to-cladding area ratio (core-to-cladding ratio), and the types of dopant ions and matrix materials, its saturable absorption characteristics can be altered, enabling high-power, stable pulsed fiber laser operation suitable for pulsed laser applications. Therefore, it has significant advantages over other active and passive Q-switching schemes, and this invention has significant application value and great development potential in both academic and industrial fields.

[0031] Example 2: Example 2 is a specific implementation of the structure in Example 1 using thulium-doped fiber. Theoretical and experimental verification is performed on it. The simulation uses a resonant-pumped thulium-doped fiber system as an example, Tm 3+ The relevant energy level structure and transition processes of ions are as follows: Figure 2 As shown. The rate equations for the change in particle population at each energy level with time are shown in equations (1), (2), (3), and (4): (1); (2); (3); (4); In the formula, The rate at which the CR1 and ETU1 processes affect the population of the relevant energy levels. The rates of influence of the CR2 and ETU2 processes on the population of the relevant energy levels are expressed by equations (5) and (6), respectively: (5); (6); In the formula, ( , =1, 2, 3, 4) represents i→ j Spontaneous emission lifetime of energy level transitions; express Energy level particle lifetime; express Particle number density at energy levels; , , , Let pump rate, pump band emission rate, signal laser absorption rate, and signal laser emission rate be respectively expressed by formulas (7), (8), (9), and (10): (7); (8); (9); (10); In the formula, The pump light power fill factor is approximately the ratio of the fiber core area to the cladding area. is the signal optical power fill factor, whose value can be approximated as a constant under certain laser wavelength and fiber structure conditions; The pump light wavelength, The wavelength of the signal light; It is Planck's constant; and The effective absorption and emission cross section at the pump wavelength, and The effective absorption and emission cross sections corresponding to the laser oscillation wavelength; and These represent the power of the pump light and the signal light in the optical fiber, respectively, with the superscripts "+" and "-" indicating the forward and reverse propagation directions.

[0032] The pump light and signal laser power at any point along the fiber direction can be described by the power transfer equations, specifically expressed as formulas (11) and (12): (11); (12); In the formula, and These are the loss factors of the pump light and signal light in the optical fiber, respectively, which represent the loss per unit length.

[0033] According to thulium (Tm 3+ The energy level structure of thulium-doped fiber lasers can be determined by using resonant pumping technology to directly pump ground-state ions to the upper energy level of the laser. Since the pump light wavelength is similar to the laser wavelength, the quantum efficiency is high, which can effectively reduce the heat deposition per unit length in the fiber. This is an important technology for improving the output power and efficiency of thulium-doped fiber lasers.

[0034] In the simulation, the gain fiber used in the doped saturable absorber fiber amplifier (3) and the master oscillator (4) is a single-mode thulium-doped fiber of the same specification. By solving the four energy level particle number equations and the eight differential equations of the pump light and signal light transmission in both directions simultaneously, the pulse output characteristics of the laser device under given fiber parameters can be obtained. Figure 3 As shown, the pulse sequence at the output of the master oscillator (4) (blue short line) and after amplification by the saturable absorber fiber amplifier (3) (red solid line) is given.

[0035] Simulation results clearly show that, through the selection of appropriate fiber optic parameters, Figure 3 The saturable absorption amplification master oscillator-power amplification laser device based on doped gain fiber shown can generate stable pulsed laser output.

[0036] like Figure 4 The diagram shows a specific implementation of the structure in Example 1, using thulium-doped fiber as the gain fiber. The specific structure of the all-fiber pulsed laser device based on fiber saturable absorption amplification is as follows: As a preferred embodiment, the pump module 1 includes a semiconductor laser pump source 1-1, a pump combiner 1-2, a high-reflectivity Bragg grating A1-3, a thulium-doped gain fiber A1-4, a low-reflectivity Bragg grating A1-5, and a pump light stripper 1-6; the input end of the pump combiner 1-2 is connected to the output end of the semiconductor laser pump source 1-1; one end of the high-reflectivity Bragg grating A1-3 is connected to the output end of the pump combiner 1-2; one end of the thulium-doped gain fiber A1-4 is connected to the other end of the high-reflectivity Bragg grating A1-3; one end of the low-reflectivity Bragg grating A1-5 is connected to the other end of the thulium-doped gain fiber A1-4; the input end of the pump light stripper 1-6 is connected to the other end of the low-reflectivity Bragg grating A1-5, and the output end of the pump light stripper 1-6 serves as the output end of the pump module 1; more preferably, the high-reflectivity Bragg grating A1-3 is 1940 The high-reflectivity Bragg grating has a reflectivity of 99.8% (HR) and a full width at half maximum (FWHM) of 1.5 nm. The thulium-doped gain fiber A1-4 has a length of 3.6 m and an absorption coefficient of approximately 3 dB / m at 793 nm. The thulium-doped gain fiber A1-4 can be a domestically produced single-mode thulium-doped gain fiber with a specification of (10 / 130). The low-reflectivity Bragg grating A1-5 is a 1940 nm low-reflectivity Bragg grating with a reflectivity of 10% (LR) and a FWHM of 0.5 nm. The output of pump module 1 is connected to port c of fiber optic circulator 2, port b of fiber optic circulator 2 is connected to one end of doped saturable absorber fiber amplifier 3, and port a of fiber optic circulator 3 serves as the output of pulsed laser device.

[0037] As a preferred embodiment, the master oscillator 4 includes a high-reflectivity Bragg grating B4-3, a thulium-doped gain fiber B4-2, and a low-reflectivity Bragg grating B4-1. One end of the thulium-doped gain fiber B4-2 is connected to the high-reflectivity Bragg grating B4-3, and one end of the low-reflectivity Bragg grating B4-1 is connected to the other end of the thulium-doped gain fiber B4-2. The other end of the low-reflectivity Bragg grating B4-1 serves as the output end of the master oscillator 4. More preferably, the low-reflectivity Bragg grating B4-1 is a 1980 nm low-reflectivity Bragg grating with a reflectivity of 15% (LR); the thulium-doped gain fiber B4-2 has a length of 2.6 m and can be a domestically produced single-mode thulium-doped gain fiber of specification (10 / 130); the high-reflectivity Bragg grating B4-3 is a 1980 nm high-reflectivity Bragg grating with a reflectivity of 99.8% (HR).

[0038] The other end of the doped saturable absorber fiber amplifier 3 is connected to the output end of the main oscillator 4; as a preferred embodiment, the length of the doped saturable absorber fiber amplifier 3 is 6m; the doped saturable absorber fiber amplifier 3 not only acts as a saturable absorber for pumping lasers to perform pulse modulation, but also acts as an amplifier for the output laser signal of the oscillator to amplify the pulse signal.

[0039] As a preferred embodiment, the semiconductor laser pump source 1-1 is a semiconductor laser pump source with a center wavelength of 793 nm; as a further preferred embodiment, the semiconductor laser pump source 1-1 is composed of two 30 W semiconductor lasers with a center wavelength of 793 nm and fiber-coupled output.

[0040] The all-fiber pulsed laser generation method based on fiber saturable absorption amplification in Embodiment 2 above includes the following steps: Step 1: Output pump light from pump module 1 to fiber optic circulator 2; Specifically, the semiconductor laser pump source 1-1 is started and outputs 793nm pump light, which is coupled to the thulium-doped gain fiber A1-4 through the pump fiber of the pump combiner 1-2. It is then used in conjunction with the oscillation cavity composed of a high-reflectivity Bragg grating A1-3 and a low-reflectivity Bragg grating A1-5. The pump light at the output end is stripped of the residual pump light in the cladding by the pump light stripper 1-6, and finally outputs 1940nm pump light to port C of the fiber circulator 2. Step 2: The pump light is transmitted unidirectionally to the doped saturable absorber fiber amplifier 3 through port b of the fiber optic circulator 2. The seed pulse signal is generated by the master oscillator 4, which consists of a high reflectivity Bragg grating B4-3, a thulium-doped gain fiber B4-2, and a low reflectivity Bragg grating B4-1, and then input into the doped saturable absorber fiber amplifier 3. Step 3: The pump light is absorbed using the saturable absorption effect of the doped saturable absorber fiber amplifier 3. At low pump power, the ground-state ions of the doped saturable absorber fiber amplifier 3 absorb the pump light, suppressing the oscillation of the master oscillator 4. As the 1940 nm pump power increases, the doped saturable absorber fiber amplifier 3 generates a ground-state bleaching effect, triggering the master oscillator 4 to generate a pulse signal. The pulse energy is amplified through stimulated emission of the doped saturable absorber fiber amplifier 3. Finally, a high peak power pulsed laser with an average power of 12.18 W, a repetition rate of 153 kHz, a pulse energy of 79.2 μJ, and a peak power of 213 W is obtained and output through port a of the fiber circulator 2.

[0041] Figure 5 , 6 The images show the pulsed laser sequence and single-pulse diagram corresponding to an average output power of 12.18 W, with a pulse width of 372 ns.

[0042] The all-fiber pulsed laser device based on fiber saturable absorber amplification provided in this application can achieve stable high-energy pulsed laser output with high average power and high peak power. The thulium-doped gain fiber serves simultaneously as the saturable absorber of the pump light and the amplifier of the signal laser, simplifying the laser structure and improving its stability, compactness, and reliability. These advantages make it of great significance in both basic research and industrial applications.

[0043] The technical means disclosed in this application are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

[0044] The foregoing has provided a detailed description of an all-fiber pulsed laser based on saturable absorption amplification of doped gain fiber, as provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A fully fiber pulsed laser device based on fiber saturable absorption amplification, characterized in that, The pulsed laser device consists of a pump module (1), an optical fiber circulator (2), a doped saturable absorber optical fiber amplifier (3), and a master oscillator (4).

2. The all-fiber pulsed laser device based on fiber optic saturable absorption amplification according to claim 1, characterized in that, The output end of the pump module (1) is connected to port c of the fiber optic circulator (2), port b of the fiber optic circulator (2) is connected to one end of the doped saturable absorber fiber amplifier (3), and the other end of the doped saturable absorber fiber amplifier (3) is connected to the output end of the master oscillator (4). Port a of the fiber optic circulator (3) serves as the output end of the pulsed laser device.

3. The all-fiber pulsed laser device based on fiber optic saturable absorption amplification according to claim 1, characterized in that, The doped saturable absorber fiber amplifier (3) is a single-clad fiber, a double-clad fiber, or a photonic crystal fiber. The rare earth elements doped with it include cerium, praseodymium, neodymium, dysprosium, thulium, holmium, ytterbium, and erbium, or transition metal elements include one or more of chromium, iron, cobalt, and bismuth.

4. The all-fiber pulsed laser device based on fiber saturable absorption amplification according to claim 1, characterized in that, The doped saturable absorber fiber amplifier (3) is replaced with a doped gain fiber with other doping characteristics that has both gain and saturable absorber properties.

5. The all-fiber pulsed laser device based on fiber optic saturable absorption amplification according to claim 1, characterized in that, The doped saturable absorber fiber amplifier (3) not only acts as a saturable absorber, modulating the operating characteristics of the main oscillator (4) through pump control to enable the main oscillator (4) to obtain a stable pulse output, but also acts as an amplifier to amplify the output pulse signal from the main oscillator (4).

6. The all-fiber pulsed laser device based on fiber saturable absorption amplification according to claim 1, characterized in that, The main oscillator (4) and the doped saturable absorber fiber amplifier (3) constitute a main oscillation and power amplification pulsed laser device; the doped saturable absorber fiber amplifier (3) is independently placed outside the resonant cavity of the main oscillator (4).

7. The all-fiber pulsed laser device based on fiber saturable absorption amplification according to claim 1, characterized in that, The fiber optic circulator (2) is replaced with other devices and apparatuses that have the same function.

8. The all-fiber pulsed laser device based on fiber saturable absorption amplification according to claim 1, characterized in that, By using an optical fiber circulator (2), the pump light is coupled into the doped saturable absorber fiber amplifier (3) and the master oscillator (4) through port c to achieve backward pumping. The pulse signal is amplified by the doped saturable absorber fiber amplifier (3) and finally output from port a of the optical fiber circulator (2).

9. A method for generating an all-fiber pulsed laser based on fiber saturable absorption amplification, comprising using an all-fiber pulsed laser device based on fiber saturable absorption amplification as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Step 1: Output pump light from the pump module (1) to the fiber optic circulator (2); Step 2: The pump light is transmitted unidirectionally to the doped saturable absorber fiber amplifier (3) through the fiber optic circulator (2). The master oscillator (4) generates a seed pulse signal and inputs it into the doped saturable absorber fiber amplifier (3). Step 3: The pump light is absorbed by the saturable absorption effect of the doped saturable absorber fiber amplifier (3). Under low pump power, the ground state ions of the doped saturable absorber fiber amplifier (3) absorb the pump light and suppress the oscillation of the master oscillator (4). As the pump power increases, the doped saturable absorber fiber amplifier (3) generates a ground state bleaching effect, triggering the master oscillator (4) to generate a pulse signal. The pulse energy is amplified by stimulated emission of the doped saturable absorber fiber amplifier (3). Finally, a high peak power pulse laser is obtained and output through port a of the fiber circulator (2).

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