Composite pulse width laser

Abstract

The invention relates to the technical field of lasers, and discloses a composite pulse width laser which comprises a first laser seed source, a second laser seed source, an acousto-optic modulator, a polarization beam combiner and an amplification module, the output end of the first laser seed source is connected with the input end of the acousto-optic modulator, and the output end of the second laser seed source is connected with the input end of the polarization beam combiner. The output end of the acousto-optic modulator is connected with one input end of the polarization beam combiner, the output end of the second laser seed source is connected with the other input end of the polarization beam combiner, the output end of the polarization beam combiner is connected with the input end of the amplification module, and the first laser seed source is in a normally open state. The acousto-optic modulator is used for controlling on-off of laser output by the first laser seed source, the first laser seed source is used for outputting laser with the pulse width range of picosecond magnitude or smaller than picosecond magnitude, and the second laser seed source is used for outputting laser with the pulse width range of nanosecond magnitude or larger than nanosecond magnitude. According to the invention, the composite pulse width laser with a larger pulse width range can be obtained, and the method can adapt to more processing scenes.

Description

Technical Field

[0001] The invention relates to the technical field of lasers, and in particular to a composite pulse width laser. Background Art

[0002] Pulse lasers are widely used in many fields such as laser marking, cutting, and ranging due to their high power and short pulse width. Pulse lasers can be divided into nanosecond, picosecond, and femtosecond pulse lasers according to their pulse widths. They have unique application values ​​in their respective fields. For example, continuous lasers also have stable processing effects in laser welding, laser 3D printing, and other fields that pulse lasers cannot match due to their power stability.

[0003] However, most existing pulse lasers output in a single pulse width mode, such as sub-nanosecond lasers, nanosecond lasers, and picosecond lasers. There is no solution that can output both picosecond and nanosecond pulses at the same time, making it difficult to achieve composite processing in multiple scenarios. Summary of the invention

[0004] In view of this, the present invention provides a composite pulse width laser to solve or partially solve the technical problem that existing lasers cannot achieve composite processing in multiple scenarios.

[0005] The technical solution proposed by the present invention is as follows:

[0006] The invention provides a composite pulse width laser, comprising a first laser seed source, a second laser seed source, an acousto-optic modulator (AOM), a polarization beam combiner and an amplification module, wherein the output end of the first laser seed source is connected to the input end of the acousto-optic modulator, the output end of the acousto-optic modulator is connected to one input end of the polarization beam combiner, the output end of the second laser seed source is connected to the other input end of the polarization beam combiner, the output end of the polarization beam combiner is connected to the input end of the amplification module, the first laser seed source is in a normally open state, the acousto-optic modulator is used to control the on and off of the laser output by the first laser seed source, the first laser seed source is used to output a laser with a pulse width range of picoseconds or less, the second laser seed source is used to output a laser with a pulse width range of nanoseconds or greater than nanoseconds, the pulse width of the laser output by the second laser seed source is greater than the pulse width of the laser output by the first laser seed source, and the switching time of the acousto-optic modulator is nanoseconds.

[0007] In the composite pulse width laser of the embodiment of the present invention, the second laser seed source outputs a laser with a pulse width range of nanoseconds or greater, and the pulse width of the laser output by the second laser seed source is greater than the pulse width of the laser output by the first laser seed source. Considering the switching time interval between different laser seed sources, since the first laser seed source is in a normally open state, even if the first laser seed source is used to output a laser with a pulse width range of picoseconds or less than picoseconds, there will be no obvious time interval between the switching of the two laser seed sources, and instantaneous switching is achieved. The first laser seed source is controlled to be turned on and off by an acousto-optic modulator to ensure that the two laser seed sources are not turned on at the same time. At the same time, one laser seed source outputs a laser, which is output for processing after passing through a polarization beam combiner and an amplification module. The present invention combines the first laser seed source and the second laser seed source, and can output at least two types of pulse lasers, picoseconds and nanoseconds, to obtain a composite pulse width laser with a larger pulse width range, which can adapt to more processing scenarios. Since the switching time of the acousto-optic modulator is in the nanosecond order and is similar to the pulse width of the second laser seed source, there will be no obvious time interval between the switching of the two laser seed sources, and instantaneous switching is achieved.

[0008] Optionally, the pulse width of the laser output by the second laser seed source ranges from 1 nanosecond to 500 nanoseconds.

[0009] In this manner, the second laser seed source provides a pulse laser output with a pulse width ranging from 1 nanosecond to 500 nanoseconds, which can meet most nanosecond pulse laser processing requirements.

[0010] Optionally, the switching time of the AOM is from 2 nanoseconds to 200 nanoseconds.

[0011] In this manner, the fast switching time of the AOM is similar to the pulse width of the second laser seed source, and there is no obvious time interval between the switching of the two laser seed sources, which can improve the response speed of the laser.

[0012] Optionally, the first laser seed source is used to output laser light with a pulse width in the range of picoseconds or less.

[0013] In this manner, the first laser seed source provides a laser with a pulse width range of picoseconds or less, which can meet most high-precision laser processing requirements, making the composite pulse width laser of the present invention have a wider range of application scenarios.

[0014] Optionally, the laser output by the second laser seed source is a continuous laser.

[0015] In this way, continuous laser and picosecond pulse laser can be output, which can provide more diverse processing options.

[0016] Optionally, the lasers output by the first laser seed source and the second laser seed source have the same central wavelength and the same spectral width range.

[0017] In this way, the spectral consistency of the laser output from the two laser seed sources is guaranteed, which is beneficial to improving the processing quality.

[0018] Optionally, the central wavelengths of the lasers output by the first laser seed source and the second laser seed source are both 1030 nanometers or 1064 nanometers, and the spectral width ranges are both 0.5 nanometers±0.2 nanometers.

[0019] In this method, the central wavelength of the lasers output by the two laser seed sources are both infrared lasers of 1030 nanometers or 1064 nanometers, and the spectral width range is 0.5 nanometers ± 0.2 nanometers, which can meet the needs of rapid switching and fine processing in multiple scenarios.

[0020] Optionally, the amplification module includes a primary pre-amplification unit, a secondary pre-amplification unit and a main amplification unit; the primary pre-amplification unit includes a first optical isolator, a first gain fiber, a first wavelength division multiplexer, a second optical isolator and a first semiconductor pump source, one end of the first optical isolator is connected to the output end of the polarization combiner, the first optical isolator, the first gain fiber, the first wavelength division multiplexer and the second optical isolator are connected in sequence, and the output end of the first semiconductor pump source is connected to the first wavelength division multiplexer; the secondary pre-amplification unit includes a second gain fiber, a first fiber combiner, a second semiconductor pump source and a first three optical isolators, one end of the second gain fiber is connected to the second optical isolator, the second gain fiber, the first fiber combiner and the third optical isolator are connected in sequence, and the output end of the second semiconductor pump source is connected to the first fiber combiner; the main amplification unit includes a third semiconductor pump source, a second fiber combiner, a third gain fiber and a fourth optical isolator, one end of the second fiber combiner is connected to the third optical isolator, the second fiber combiner, the third gain fiber and the fourth optical isolator are connected in sequence, and the output end of the third semiconductor pump source is connected to the second fiber combiner.

[0021] In this manner, the output laser is amplified by the first-stage pre-amplification unit, the second-stage pre-amplification unit and the main amplification unit, so that high-power laser output can be achieved.

[0022] Optionally, the composite pulse width laser further includes a frequency doubling module, which is located behind the amplifying module and is used to double the frequency of the laser amplified by the amplifying module.

[0023] In this way, by setting a frequency doubling module, an output laser with a shorter wavelength can be obtained, which can adapt to more processing scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly express the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 Schematic diagram of the structure of the composite pulse width laser in an embodiment of the present invention.

[0026] Reference numerals:

[0027] 1-first laser seed source; 2-second laser seed source; 3-acoustic-optic modulator; 4-polarization combiner; 5-first optical isolator; 6-first gain fiber; 7-first wavelength division multiplexer; 8-second optical isolator; 9-first semiconductor pump source; 10-second gain fiber; 11-first fiber combiner; 12-second semiconductor pump source; 13-third optical isolator; 14-third semiconductor pump source; 15-second fiber combiner; 16-third gain fiber; 17-fourth optical isolator. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] At present, laser technology has become an indispensable tool in the fields of industrial manufacturing, medical surgery, scientific research and exploration. The high energy, high collimation and high focusing of lasers give them unique advantages in many applications.

[0033] Among them, pulse lasers are mostly output in a single pulse width mode, such as sub-nanosecond to nanosecond lasers and picosecond lasers. There is no solution for simultaneous output of both picosecond and nanosecond pulses, making it difficult to achieve composite processing in multiple scenarios.

[0034] In view of this, an embodiment of the present invention proposes a composite pulse width laser, which can output pulse lasers in the range of picoseconds to nanoseconds to achieve composite fine processing in multiple scenarios.

[0035] like Figure 1 As shown, the composite pulse width laser of the embodiment of the present invention comprises a first laser seed source 1, a second laser seed source 2, an acousto-optic modulator 3, a polarization beam combiner 4 and an amplification module, the output end of the first laser seed source 1 is connected to the input end of the acousto-optic modulator 3, the output end of the acousto-optic modulator 3 is connected to one input end of the polarization beam combiner 4, the output end of the second laser seed source 2 is connected to the other input end of the polarization beam combiner 4, the output end of the polarization beam combiner 4 is connected to the input end of the amplification module, the first laser seed source 1 is in a normally open state, the acousto-optic modulator 3 is used to control the on and off of the laser output by the first laser seed source 1, the second laser seed source 2 is used to output a laser with a pulse width range of nanoseconds or greater than nanoseconds, the pulse width of the laser output by the second laser seed source 2 is greater than the pulse width of the laser output by the first laser seed source 1, for example, the first laser seed source 1 is used to output a laser with a pulse width range of picoseconds or less than picoseconds, and the switching time of the acousto-optic modulator 3 is nanoseconds.

[0036] Specifically, the laser output by the first laser seed source 1 can be a continuous laser, or the pulse width of the first laser seed source 1 can be nanoseconds, picoseconds, femtoseconds, attoseconds, etc. The central wavelength can be 1030 nanometers or 1064 nanometers, the spectrum width range is 0.5 nanometers ± 0.2 nanometers, the power is generally in the range of 20mW-50mW, and it is in a normally open state. The acousto-optic modulator 3 controls the switch of the first laser seed source 1.

[0037] Preferably, the first laser seed source 1 uses an ultrafast pulse seed light source, and the pulse width of the output pulse laser is picosecond, femtosecond, attosecond, etc. The central wavelength can be 1030 nanometers or 1064 nanometers, the spectrum width range is 0.5 nanometer ± 0.2 nanometers, the power is generally in the range of 20mW-50mW, and it is in a normally open state. The acousto-optic modulator 3 controls the switch of the first laser seed source 1.

[0038] In one example, the pulse width of the laser output by the first laser seed source 1 ranges from 1 picosecond to 200 picoseconds. In this example, the first laser seed source 1 provides a pulse laser output with a pulse width range of 1 picosecond to 200 picoseconds, which can meet most high-precision laser processing requirements.

[0039] The second laser seed source 2 must be a nanosecond laser seed source or above, and the second laser seed source 2 can also be a continuous laser seed light source, and the pulse width of the pulsed laser output by the second laser seed source 2 ranges from 1 nanosecond to 500 nanoseconds, or the laser output by the second laser seed source 2 is a continuous laser. The central wavelength of the laser output by the second laser seed source 2 can be 1030 nanometers or 1064 nanometers, the spectrum width ranges from 0.5 nanometers to 20 nanometers, and the power is generally in the range of 5mW to 100mW.

[0040] In some embodiments, the pulse width of the laser output by the second laser seed source 2 is in the range of 1 nanosecond to 500 nanoseconds. The pulse laser output with a pulse width in the range of 1 nanosecond to 500 nanoseconds can meet most nanosecond pulse laser processing requirements.

[0041] According to the above embodiments, the composite pulse width laser can output ultrafast pulse lasers with a pulse width range covering attoseconds, femtoseconds and picoseconds, as well as lasers covering nanoseconds or continuous pulse widths.

[0042] In some embodiments, the pulse width of the pulse laser output by the first laser seed source 1 is 6ps-1000ps, and the pulse width of the pulse laser output by the second laser seed source 2 is 1ns-500ns. The composite pulse width laser can obtain a pulse laser with a pulse width of 6ps-500ns and an output power of about 2mW-100mW.

[0043] In other embodiments, the pulse width of the pulse laser output by the first laser seed source 1 is a nanosecond laser of 1ns-500ns, and the pulse width of the pulse laser output by the second laser seed source 2 is 500ns-100us, or even the laser output by the second laser seed source 2 is a continuous laser. That is, as long as the second laser seed source 2 outputs a laser with a pulse width range of nanoseconds or greater, and the second laser seed source 2 outputs a pulse width greater than the pulse width of the pulse laser output by the first laser seed source 1, it is not necessary that the pulse width of the pulse laser output by the first laser seed source 1 must be less than the nanosecond laser.

[0044] For example, when the pulse width of the pulse laser output by the first laser seed source 1 is in the nanosecond range and the continuous laser output by the second laser seed source 2 is used, there are many application scenarios for laser composite processing, such as laser marking, cutting, and ranging, as well as laser welding or 3D printing.

[0045] Furthermore, the lasers output by the first laser seed source 1 and the second laser seed source 2 have the same central wavelength and the same spectral width range.

[0046] For example, the central wavelengths of the lasers output by the first laser seed source 1 and the second laser seed source 2 are both 1030 nanometers, and the spectral width ranges are both 0.5 nanometers ± 0.2 nanometers.

[0047] Alternatively, the central wavelengths of the lasers output by the first laser seed source 1 and the second laser seed source 2 are both 1064 nanometers, and the spectral width ranges are both 0.5 nanometers±0.2 nanometers.

[0048] By using two laser seed sources with the same central wavelength and the same spectral width range, the spectral consistency of the laser output by the two laser seed sources is ensured, which is beneficial to improving the processing quality.

[0049] In some embodiments, in order to avoid the two laser seed sources being turned on at the same time and affecting the subsequent individual amplification, an acousto-optic modulator 3 is used to control the on and off of the laser output by the first laser seed source 1. This control mechanism is precise and efficient because the acousto-optic modulator 3 is based on the acousto-optic effect, that is, the refractive index of certain crystal or glass materials is changed by the oscillating mechanical strain of the sound wave, thereby changing the properties of the laser beam passing through the material, including its intensity, frequency or direction.

[0050] The switching time of the AOM 3 is one of the key parameters of its performance, which refers to the time required for the AOM 3 to switch from a fully closed state to a fully open state, or vice versa.

[0051] In some embodiments, the switching time of the AOM 3 is set between 2 nanoseconds and 200 nanoseconds. Such a fast response time can ensure that the two laser seed sources are not turned on at the same time, thereby avoiding mutual interference. For example, a specific switching time of 2 nanoseconds, 100 nanoseconds or 200 nanoseconds can be used, and these parameters can be adjusted according to specific application requirements.

[0052] It is worth noting that the switching time of the AOM 3 needs to match the pulse width of the second laser seed source 2 to ensure that there is no obvious time interval between the switching of the two laser seed sources. This matching can improve the response speed of the laser, allowing the system to switch from one laser source to another more quickly without affecting the amplification and output quality of the laser.

[0053] The polarization beam combiner 4 (Polarization Beam Combiner, PBC) is mainly used to couple the laser output from the first laser seed source 1 and the second laser seed source 2 into an optical fiber, and then amplify the laser through a subsequent amplification module to increase the power of the output laser.

[0054] The amplification module uses a fiber amplifier. Furthermore, an optical isolator can be arranged between the amplification module and the polarization combiner 4 to prevent return light.

[0055] Taking the case where the pulse width of the pulse laser output by the first laser seed source 1 is a picosecond pulse laser of 6ps-1000ps and the pulse width of the nanosecond pulse laser output by the second laser seed source 2 is 1ns-500ns as an example, when the composite pulse width laser of the embodiment of the present invention is in operation, the first laser seed source 1 is in a normally open state, and the on and off of the laser output by the first laser seed source 1 is controlled by the acousto-optic modulator 3. At the same time, the pulse and on and off of the laser output by the second laser seed source 2 are controlled by an external controller. When the second laser seed source 2 does not output the nanosecond pulse laser, the acousto-optic modulator 3 controls the first laser seed source 1 to output the picosecond pulse laser. When the second laser seed source 2 starts to output the nanosecond pulse laser, the acousto-optic modulator 3 controls the picosecond pulse laser output by the first laser seed source 1 to be turned off, thereby realizing the output of the pulse laser in the range of picoseconds to nanoseconds.

[0056] The composite pulse width laser of the embodiment of the present invention outputs a laser with a pulse width range of picoseconds or less than picoseconds through the first laser seed source 1, and the second laser seed source 2 outputs a laser with a pulse width range of nanoseconds or greater than nanoseconds. Considering the switching time interval between different laser seed sources, the first laser seed source 1 is in a normally open state, and the acousto-optic modulator 3 is used to control the on and off of the laser output of the first laser seed source 1, thereby ensuring that the two laser seed sources are not turned on at the same time. At the same time, one laser seed source outputs laser, which is output for processing after passing through the polarization beam combiner 4 and the amplification module. The present invention combines the first laser seed source 1 and the second laser seed source 2, and can output both picosecond and nanosecond pulse lasers to obtain a composite pulse width laser with a larger pulse width range, which can adapt to more processing scenarios. Moreover, since the switching time of the acousto-optic modulator 3 is in the nanosecond order, which is similar to the pulse width of the second laser seed source 2, there will be no obvious time interval in the switching of the two laser seed sources, thereby achieving instantaneous switching.

[0057] In some embodiments, the amplification module includes a primary pre-amplification unit, a secondary pre-amplification unit and a main amplification unit; the primary pre-amplification unit includes a first optical isolator 5, a first gain fiber 6, a first wavelength division multiplexer 7, a second optical isolator 8 and a first semiconductor pump source 9, one end of the first optical isolator 5 is connected to the output end of the polarization combiner 4, the first optical isolator 5, the first gain fiber 6, the first wavelength division multiplexer 7 and the second optical isolator 8 are connected in sequence, and the output end of the first semiconductor pump source 9 is connected to the first wavelength division multiplexer 7; the secondary pre-amplification unit includes a second gain fiber 10, a first fiber combiner 11, a second semiconductor pump source 12 and a third optical The main amplifying unit comprises a third semiconductor pump source 14, a second fiber combiner 15, a third gain fiber 16 and a fourth optical isolator 17, one end of the second fiber combiner 15 is connected to the third optical isolator 13, the second gain fiber 10 is connected to the second optical isolator 8, the second gain fiber 10, the first fiber combiner 11 and the third optical isolator 13 are connected in sequence, and the output end of the second semiconductor pump source 12 is connected to the first fiber combiner 11; the main amplifying unit comprises a third semiconductor pump source 14, a second fiber combiner 15, a third gain fiber 16 and a fourth optical isolator 17, one end of the second fiber combiner 15 is connected to the third optical isolator 13, the second fiber combiner 15, the third gain fiber 16 and the fourth optical isolator 17 are connected in sequence, and the output end of the third semiconductor pump source 14 is connected to the second fiber combiner 15.

[0058] Specifically, the first optical isolator 5, the second optical isolator 8, the third optical isolator 13 and the fourth optical isolator 17 are all bandpass filter isolators with a bandwidth of 5 nm. The fourth isolator carries a stripper.

[0059] The wavelength of the pumping light output by the first semiconductor pump source 9, the second semiconductor pump source 12 and the third semiconductor pump source 14 is 980 nm. The pumping mode may be forward pumping or reverse pumping.

[0060] Correspondingly, the multiplexing wavelengths of the first wavelength division multiplexer 7 are 980 nm and 1064 nm or 980 nm and 1030 nm.

[0061] The first gain optical fiber 6 is a single-mode gain optical fiber.

[0062] The second gain optical fiber 10 is a 10 / 130 double-clad gain optical fiber.

[0063] The third gain optical fiber 16 is a double-clad gain optical fiber such as 25 / 250, 30 / 250 or T-DCF.

[0064] The first optical fiber combiner 11 is a (2+1)×1 optical fiber combiner.

[0065] The second optical fiber combiner 15 is a (6+1)×1 optical fiber combiner.

[0066] In an embodiment of the present invention, the first-stage pre-amplification unit is responsible for receiving the initial laser signal, such as a nanosecond pulse laser or a picosecond pulse laser, and performing preliminary amplification on it. Subsequently, the laser enters the second-stage pre-amplification unit, and the power of the laser is further enhanced by the second-stage pre-amplification unit while maintaining the quality and stability of the light beam. The second-stage pre-amplification unit needs to handle higher-power lasers, and thermal management issues must also be considered to prevent the laser from overheating and causing performance degradation. The laser that has been amplified in the first two stages enters the main amplification unit. The main amplification unit usually uses a high-efficiency gain fiber to be able to continuously and stably output high-power lasers.

[0067] Furthermore, the composite pulse width laser also includes a frequency doubling module, which is located behind the amplifying module and is used to double the frequency of the laser amplified by the amplifying module.

[0068] For example, the frequency doubling module is a double frequency doubling module, which is used to convert lasers with central wavelengths of 1030 nanometers or 1064 nanometers into lasers with central wavelengths of 515 nanometers or 532 nanometers. By setting the frequency doubling module, an output laser with a shorter wavelength can be obtained, which can adapt to more processing scenarios.

[0069] The composite pulse width laser of the embodiment of the present invention has the following advantages:

[0070] 1. The embodiment of the present invention combines a first laser seed source 1 and a second laser seed source 2. In one mode, the second laser seed source 2 does not output, while the first laser seed source 1 outputs. At this time, it can output a laser of the picosecond level or less than the picosecond level, for example, it can output a picosecond, femtosecond or even attosecond ultrafast laser. In another mode, the first laser seed source 1 is controlled to pause output by an acousto-optic modulator 3, and the second laser seed source 2 is turned on to output a nanosecond pulse width seed source or above, for example, outputting a nanosecond pulse width or a continuous laser with an adjustable pulse width of 2ns-500ns, thereby obtaining a composite pulse width laser with a wider pulse width. The composite pulse width laser covers attoseconds, femtoseconds, picoseconds, nanoseconds and even larger pulse widths, and can adapt to more application scenarios.

[0071] 2. Considering the switching time interval between different laser seed sources, the first pulse laser seed source of the embodiment of the present invention is in a normally open state, and the on and off of the laser output by the first pulse laser seed source is controlled by the acousto-optic modulator 3, thereby ensuring that the two laser seed sources are not turned on at the same time to avoid affecting the subsequent separate amplification.

[0072] 3. The switching time of the acousto-optic modulator 3 is between 2ns and 200ns. There is no obvious time interval between the switching of the two laser seed sources, that is, the switching is instantaneous.

[0073] Although example embodiments and their advantages have been described in detail, those skilled in the art may make various changes, substitutions and modifications to these embodiments without departing from the spirit and defined scope of the present invention, and such modifications and variations are all within the defined scope.

Claims

1. A composite pulse width laser, characterized in that: The invention comprises a first laser seed source (1), a second laser seed source (2), an acousto-optic modulator (3), a polarization beam combiner (4) and an amplification module, wherein the output end of the first laser seed source (1) is connected to the input end of the acousto-optic modulator (3), the output end of the acousto-optic modulator (3) is connected to one input end of the polarization beam combiner (4), the output end of the second laser seed source (2) is connected to the other input end of the polarization beam combiner (4), the output end of the polarization beam combiner (4) is connected to the input end of the amplification module, the first laser seed source (1) is in a normally open state, the acousto-optic modulator (3) is used to control the on and off of the laser output by the first laser seed source (1), the second laser seed source (2) is used to output laser light with a pulse width range of nanoseconds or greater, the pulse width of the laser light output by the second laser seed source (2) is greater than the pulse width of the laser light output by the first laser seed source (1), and the switching time of the acousto-optic modulator (3) is in the nanoseconds.

2. The composite pulse width laser according to claim 1, characterized in that: The pulse width of the laser output by the second laser seed source (2) is in the range of 1 nanosecond to 500 nanoseconds.

3. The composite pulse width laser according to claim 1 or 2, characterized in that: The switching time of the acousto-optic modulator (3) is 2 nanoseconds to 200 nanoseconds.

4. The composite pulse width laser according to claim 3, characterized in that: The first laser seed source (1) is used to output laser light with a pulse width in the range of picoseconds or less.

5. The composite pulse width laser according to claim 1, characterized in that: The laser output by the second laser seed source (2) is continuous laser.

6. The composite pulse width laser according to claim 1, characterized in that: The lasers output by the first laser seed source (1) and the second laser seed source (2) have the same central wavelength and the same spectral width range.

7. The composite pulse width laser according to claim 6, characterized in that: The central wavelengths of the lasers output by the first laser seed source (1) and the second laser seed source (2) are both 1030 nanometers or 1064 nanometers, and the spectral width ranges are both 0.5 nanometers ± 0.2 nanometers.

8. The composite pulse width laser according to claim 1, characterized in that: The amplification module includes a primary pre-amplification unit, a secondary pre-amplification unit and a main amplification unit; The first-stage pre-amplification unit comprises a first optical isolator (5), a first gain fiber (6), a first wavelength division multiplexer (7), a second optical isolator (8) and a first semiconductor pump source (9); one end of the first optical isolator (5) is connected to the output end of the polarization beam combiner (4); the first optical isolator (5), the first gain fiber (6), the first wavelength division multiplexer (7) and the second optical isolator (8) are connected in sequence; and the output end of the first semiconductor pump source (9) is connected to the first wavelength division multiplexer (7); The secondary pre-amplification unit comprises a second gain fiber (10), a first fiber combiner (11), a second semiconductor pump source (12) and a third optical isolator (13); one end of the second gain fiber (10) is connected to the second optical isolator (8); the second gain fiber (10), the first fiber combiner (11) and the third optical isolator (13) are connected in sequence; and the output end of the second semiconductor pump source (12) is connected to the first fiber combiner (11); The main amplification unit comprises a third semiconductor pump source (14), a second optical fiber combiner (15), a third gain fiber (16) and a fourth optical isolator (17); one end of the second optical fiber combiner (15) is connected to the third optical isolator (13); the second optical fiber combiner (15), the third gain fiber (16) and the fourth optical isolator (17) are connected in sequence; and the output end of the third semiconductor pump source (14) is connected to the second optical fiber combiner (15).

9. The composite pulse width laser according to claim 1, characterized in that: It also includes a frequency doubling module, which is located behind the amplifying module and is used to double the frequency of the laser amplified by the amplifying module.

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