A steep-edge ultrafast pulse train laser control device and its usage method

Abstract

This invention proposes a steep-edge ultrafast pulse train laser control device and its usage method, relating to the field of laser technology. It includes an ultrafast seed source, a high-speed amplitude modulator, a pulse amplification module, a high-power amplitude modulation module, and a signal driving module. The ultrafast seed source is connected to the high-speed amplitude modulator, which performs first-stage amplitude modulation on the laser pulse output from the ultrafast seed source, generating a pre-pulse and a main pulse. The high-speed amplitude modulator is connected to the pulse amplification module. The pulse amplification module is connected to the high-power amplitude modulation module, which performs second-stage amplitude modulation on the amplified pre-pulse and main pulse, truncating the pre-pulse so that the high-power amplitude modulation module outputs only the main pulse. The signal driving module is electrically connected to both the high-speed amplitude modulator and the high-power amplitude modulation module. This invention helps ensure the pulse flatness and steep-edge characteristics of the output ultrafast pulse train laser.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a steep-edge ultrafast pulse train laser control device and its usage method. Background Technology

[0002] In fields such as particle accelerators and light-matter interaction research, amplified pulse trains need to possess both sharp edges (typically ≤1 ns, containing a complete micropulse) and flat pulse tops (amplitude fluctuation ≤5%). Typical long pulse trains (on the order of ns-µs) exhibit pulse leading-edge overshoot during power amplification due to the accumulation and depletion of inverted particle numbers. To obtain flat pulses, techniques such as pulse pre-shaping, pulse pumping, and back-end chopping can be used to control the pulse shape.

[0003] Chinese Patent Publication No. CN118472755A discloses a pulsed fiber laser with adjustable repetition rate, including a control module, a seed source, an injection source, at least one amplification module, a first circulator, and a second circulator. The control module controls the seed source to output a seed pulse with an adjustable repetition rate and controls the injection source to output an injection pulse with an adjustable repetition rate. The seed pulse output from the seed source is incident on the first end of the first circulator, and the injection pulse output from the injection source is incident on the first end of the second circulator. After passing through the first and second ends of the first circulator, the seed pulse is amplified by the amplification module and output after passing through the second and third ends of the second circulator. The injection pulse is injected back into the amplification module after passing through the first and second ends of the second circulator, and the amplified spontaneous emission generated is output from the third end of the first circulator. The above scheme has limited ability to correct overshoot through pulse pre-shaping, making it difficult to meet the high requirement of a flat pulse top. Pulse pumping is not suitable for high repetition rate pulses. The back-end chopper response bandwidth is low, making it difficult to achieve the modulation requirement of steep-edge pulse trains when the micro-pulse interval is less than 1 ns. Therefore, it is essential to provide a steep-edge ultrafast pulse train laser control device and its usage method to ensure the pulse flatness and steep edge characteristics of the output pulse. Summary of the Invention

[0004] In view of this, the present invention proposes a laser control device and method for a steep-edge ultrafast pulse train. A high-speed amplitude modulator performs first-stage amplitude modulation on the laser pulses output from the ultrafast seed source, generating a pulse train composed of a pre-pulse and a main pulse. Simultaneously, a high-power amplitude modulation module performs second-stage amplitude modulation on the amplified pulses, effectively eliminating the distortion of the pre-pulse generated during amplification. Combining the characteristics of the high-speed amplitude modulator ("high bandwidth, low power handling") and the high-power amplitude modulator ("low bandwidth, high power handling"), the pulse flatness and steep-edge characteristics of the output pulse are ensured.

[0005] In a first aspect, the present invention provides a steep-edge ultrafast pulse train laser control device, comprising an ultrafast seed source, a high-speed amplitude modulator, a pulse amplification module, a high-power amplitude modulation module, and a signal driving module, wherein...

[0006] The ultrafast seed source is connected to the high-speed amplitude modulator, which is used to perform first-order amplitude modulation on the laser pulse output by the ultrafast seed source. There is a certain time interval between the prepulse and the main pulse, and the prepulse and the main pulse form a pulse train.

[0007] The high-speed amplitude modulator is connected to the pulse amplification module, which amplifies the pulse train.

[0008] The pulse amplification module is connected to the high-power amplitude modulation module. The high-power amplitude modulation module is used to perform secondary amplitude modulation on the amplified pulse train and cut off the pre-pulse so that the high-power amplitude modulation module only outputs the main pulse.

[0009] The signal driving module is electrically connected to the high-speed amplitude modulator and the high-power amplitude modulation module, respectively. The signal driving module is used to provide radio frequency driving signals to control the delay of the chopping signals of the high-speed amplitude modulator and the high-power amplitude modulation module, respectively.

[0010] Based on the above technical solutions, preferably, the high-power amplitude modulation module includes a half-wave plate, a Pockel cell, and a polarization beam splitter. The half-wave plate is connected to the Pockel cell, and the Pockel cell is connected to both the signal driving module and the polarization beam splitter.

[0011] Based on the above technical solutions, preferably, the signal driving module includes a first radio frequency driver, a second radio frequency driver, and a clock source. The first radio frequency driver is electrically connected to the clock source and the high-speed amplitude modulator, respectively, and the second radio frequency driver is electrically connected to the clock source and the Pockel cell, respectively.

[0012] More preferably, the first RF driver receives a clock signal from the clock source and controls the shaping of the input laser pulse into a pre-pulse and a main pulse based on the clock signal, and the second RF driver controls the polarization rotation of the Pockel cell to remove the overshoot characteristics of the pre-pulse during amplitude modulation.

[0013] More preferably, when the phase difference bias of the high-speed amplitude modulator is located at the π phase, the output mode of the high-speed amplitude modulator is specifically as follows:

[0014] When there is no radio frequency pulse signal input to the high-speed amplitude modulator, the continuous output power of the high-speed amplitude modulator is at its minimum value;

[0015] When a radio frequency pulse signal is input to the high-speed amplitude modulator, the high-speed amplitude modulator outputs a corresponding optical pulse signal according to the pulse width and amplitude of the radio frequency pulse signal.

[0016] More preferably, when the phase difference bias of the high-speed amplitude modulator is set to 0 phase, the output mode of the high-speed amplitude modulator is specifically as follows:

[0017] When there is no radio frequency signal input to the high-speed amplitude modulator, the continuous power output of the high-speed amplitude modulation is at its maximum value;

[0018] When a radio frequency pulse signal is input to the high-speed amplitude modulator, the high-speed amplitude modulator cuts off the corresponding waveform on the laser pulse output from the ultrafast seed source according to the pulse width and amplitude of the radio frequency pulse signal.

[0019] More preferably, the high-speed amplitude modulator is a high-bandwidth lithium niobate waveguide modulator or a lithium niobate thin-film modulator, and the Pockel cell is a spatial electro-optic modulator.

[0020] More preferably, the prepulse width, the time interval between the prepulse and the main pulse, and the amplitude ratio between the prepulse and the main pulse can all be controlled by the radio frequency drive signal output by the first radio frequency driver.

[0021] More preferably, the repetition frequency of the ultrafast seed source does not exceed 2 GHz, the micropulse width does not exceed 100 ps, ​​and the interval between adjacent micropulses is not less than 400 ps.

[0022] Secondly, the present invention provides a method for using a steep-edge ultrafast pulse train laser control device, comprising the following steps:

[0023] The laser pulses output from the ultrafast seed source are shaped into a pulse train consisting of a pre-pulse and a main pulse by a high-speed amplitude modulator driven by a first radio frequency drive signal. The first radio frequency drive signal is generated by a signal drive module.

[0024] The pulse train is amplified by the pulse amplification module, and the amplified pulse train is then driven by the second radio frequency drive signal to drive the high-power amplitude modulation module to perform secondary amplitude modulation on the amplified pulse train. The pre-pulse is removed so that the high-power amplitude modulation module outputs only the main pulse. The second radio frequency drive signal is generated by the signal drive module.

[0025] The steep-edge ultrafast pulse train laser control device and its usage method provided by this invention have the following advantages over the prior art:

[0026] (1) The laser pulse output from the ultrafast seed source is subjected to first-stage amplitude modulation by a high-speed amplitude modulator, which can accurately generate pre-pulse and main pulse, ensuring steep pulse edges to meet the requirements of high-precision applications. The pulse amplification module amplifies the pre-pulse and main pulse, significantly improving the energy of the laser pulse. At the same time, the high-power amplitude modulation module performs second-stage amplitude modulation on the amplified pulse, which can remove the overshoot of the amplified pre-pulse and, based on the sufficient time interval between the pre-pulse and the main pulse, ensure that the main pulse maintains good steep edge characteristics. The radio frequency drive signal provided by the signal drive module can accurately control the waveform and timing of the output pulses of the high-speed amplitude modulator and the high-power amplitude modulation module, thereby ensuring the pulse flatness and steep edge characteristics of the output pulse.

[0027] (2) The waveform and timing of the output pulses of the high-speed amplitude modulator and the high-power amplitude modulation module are controlled by the first and second RF drivers respectively to achieve precise pulse synchronization. The first RF driver shapes the laser pulse into a pre-pulse and a main pulse according to the clock signal to ensure that the shape of the pulse is stable before and after. The second RF driver regulates the electric field of the Pockel cell to effectively remove the overshoot characteristics of the pre-pulse and reduce signal distortion. Through precise RF drive signal control, the stability and response speed of the amplitude modulation process are enhanced, and the overall modulation accuracy is improved. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of the structure of the steep-edge ultrafast pulse train laser control device provided by the present invention;

[0030] Figure 2 This is a schematic diagram of the pulse waveform modulation process provided by the present invention.

[0031] Explanation of reference numerals in the attached diagram: 1. Ultrafast seed source; 2. High-speed amplitude modulator; 3. Pulse amplifier module; 4. High-power amplitude modulation module; 41. Half-wave plate; 42. Pockels cell; 43. Polarization beam splitter; 5. Signal drive module. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, this invention provides a steep-edge ultrafast pulse train laser control device and user, including an ultrafast seed source 1, a high-speed amplitude modulator 2, a pulse amplification module 3, a high-power amplitude modulation module 4, and a signal driving module 5, wherein...

[0034] The ultrafast seed source 1 is connected to the high-speed amplitude modulator 2, which is used to perform first-order amplitude modulation on the laser pulses output from the ultrafast seed source 1 to generate a pulse train consisting of a pre-pulse and a main pulse. The high-speed amplitude modulator 2 is a high-bandwidth lithium niobate waveguide modulator.

[0035] The repetition frequency of the output pulses of the ultrafast seed source 1 does not exceed 2 GHz, the pulse width does not exceed 100 ps, ​​and the pulse interval between adjacent pulses is not less than 400 ps. The ultrafast seed source 1 is a high repetition rate picosecond mode-locked pulsed laser. The repetition frequency of the high repetition rate picosecond mode-locked pulsed laser is 1 GHz, the pulse width of the high repetition rate picosecond mode-locked laser is 15 ps, and the pulse interval between adjacent pulses of the high repetition rate picosecond mode-locked laser is about 1 ns.

[0036] The high-speed amplitude modulator 2 has two chopping modes. When the phase difference of the high-speed amplitude modulator 2 is biased to the π phase, the output mode of the high-speed amplitude modulator 2 is as follows: when there is no radio frequency pulse signal input to the high-speed amplitude modulator 2, the continuous power output of the high-speed amplitude modulator 2 is at its minimum value; when a radio frequency pulse signal is input to the high-speed amplitude modulator 2, the high-speed amplitude modulator 2 outputs a corresponding optical pulse signal according to the pulse width and amplitude of the radio frequency pulse signal.

[0037] When the phase difference bias of the high-speed amplitude modulator 2 is set to 0 phase, the output mode of the high-speed amplitude modulator 2 is as follows: when there is no radio frequency signal input to the high-speed amplitude modulator 2, the continuous power of the high-speed amplitude modulation output is at its maximum value; when a radio frequency pulse signal is input to the high-speed amplitude modulator 2, the high-speed amplitude modulator 2 cuts off the corresponding waveform on the laser pulse output by the ultrafast seed source 1 according to the pulse width and amplitude of the radio frequency pulse signal.

[0038] In this embodiment, when the phase bias is set to π phase, the modulator output power is at its minimum when there is no RF pulse signal input, which is suitable for applications with higher pulse signal-to-noise ratio requirements. After an RF pulse signal is input, it can output a corresponding optical pulse signal according to the pulse width and amplitude, achieving precise modulation. Conversely, with a 0 phase bias, the modulator output power is at its maximum when there is no RF signal input, which is suitable for applications with higher requirements for pulse top flatness. After an RF pulse signal is input, it can cut off the corresponding waveform on the laser pulse, precisely controlling the laser output. This flexible modulation method enhances the adaptability of the pulsed laser control device, meeting the requirements for laser pulse characteristics in different scenarios.

[0039] The high-speed amplitude modulator 2 is connected to the pulse amplification module 3, which is used to amplify the pulse train. The pulse amplification module 3 can be an optical fiber, solid-state, or hybrid optical-solid-state amplification system.

[0040] The pulse amplification module 3 is connected to the high-power amplitude modulation module 4. The high-power amplitude modulation module 4 is used to perform two-stage amplitude modulation on the amplified pre-pulse and main pulse, and to cut off the pre-pulse so that the high-power amplitude modulation module 4 only outputs the main pulse.

[0041] Furthermore, the high-power amplitude modulation module 4 includes a half-wave plate 41, a Pockel cell 42, and a polarization beam splitter 43. The half-wave plate 41 is connected to the Pockel cell 42, and the Pockel cell 42 is connected to both the signal driving module 5 and the polarization beam splitter 43. The Pockel cell 42 is a lithium niobate (LN) or barium borate (BBO) spatial electro-optic modulator.

[0042] In this embodiment, the pulse amplification module 3 is connected to the high-power amplitude modulation module 4. The high-power amplitude modulation module 4 includes a half-wave plate 41, a Pockel cell 42, and a polarization beam splitter 43. The Pockel cell 42, as a spatial electro-optic modulator, is connected to the signal driving module 5 and the polarization beam splitter 43. The high-power amplitude modulation module 4 performs two-stage amplitude modulation on the amplified pre-pulse and the main pulse, effectively separating the main pulse from the pre-pulse, ensuring that only the main pulse is output, and without affecting the leading and trailing edges of the main pulse. This improves the stability and accuracy of the pulse output and enhances the performance of the pulsed laser control device in high-power and high-precision pulse control.

[0043] The signal driving module 5 is electrically connected to the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4, respectively. The signal driving module 5 is used to provide radio frequency driving signals to control the waveform and timing of the output pulses of the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4, respectively. The signal driving module 5 includes a first radio frequency driver, a second radio frequency driver, and a clock source. The first radio frequency driver is electrically connected to the clock source and the high-speed amplitude modulator 2, respectively. The second radio frequency driver is electrically connected to the clock source and the Pockel cell 42, respectively.

[0044] The first RF driver receives a clock signal from a clock source and shapes the input laser pulse into a pre-pulse and a main pulse based on the clock signal. The second RF driver controls the electric field of the Pockel cell 42 to remove the overshoot characteristics of the pre-pulse during amplitude modulation. The timing of the drive signals output by the first and second RF drivers can be adjusted.

[0045] In this embodiment, precise pulse synchronization is achieved by controlling the time delay of the output pulses of the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4 through the first and second RF drivers, respectively. The first RF driver shapes the laser pulse into a pre-pulse and a main pulse according to the clock signal, ensuring the stability of the pulse shape before and after. The second RF driver modulates the electric field of the Pockel cell 42 to effectively remove the overshoot characteristics of the pre-pulse and reduce signal distortion. Through precise RF drive signal control, the stability and response speed of the amplitude modulation process are enhanced, and the overall modulation accuracy is improved. The optimized pulse control and shape adjustment improve the working efficiency and consistency of the entire pulsed laser control device, thereby ensuring the stable operation of the pulsed laser control device under high power and high-speed modulation conditions.

[0046] Furthermore, the width of the pre-pulse and the main pulse, the interval between the pre-pulse and the main pulse, and the amplitude ratio of the pre-pulse and the main pulse can all be controlled by the radio frequency drive signals output by the first radio frequency driver and the second radio frequency driver.

[0047] This invention uses a high-speed amplitude modulator 2 to perform first-level amplitude modulation on the laser pulse output from the ultrafast seed source 1, which can accurately generate pre-pulse and main pulse, ensuring steep pulse edges to meet the requirements of high-precision applications. Furthermore, the pulse amplification module 3 amplifies the pulse train, significantly increasing the energy of the laser pulse. The high-power amplitude modulation module 4 performs second-level amplitude modulation on the amplified pulse, which can remove the pre-pulse and ensure that the high-power amplitude modulation module 4 only outputs the main pulse, reducing unnecessary overshoot signal interference. The radio frequency drive signal provided by the signal drive module 5 can accurately control the output pulse delay of the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4, thereby ensuring the pulse flatness and steep edge characteristics of the output pulse.

[0048] In one example, such as Figure 2 As shown in (a) above, the steps of the pulse train amplification generation method of the present invention are as follows:

[0049] A1: The seed source uses a high repetition rate picosecond mode-locked pulsed laser with a repetition rate of 1 GHz, a micropulse width of 15 ps, and an interval of about 1 ns between adjacent pulses.

[0050] A2: The picosecond seed source first employs a high-speed amplitude modulation chopping stage, using a 20GHz bandwidth lithium niobate electro-optic modulator as the chopping device. The rise and fall times are on the order of hundreds of ps, with a pulse period of less than 1 ns, ensuring the integrity of the micropulse. After chopping, the pre-pulse width is approximately 10μs, containing 10,000 micropulse cycles (the pre-pulse width can be adjusted according to the actual amplification system; the number of pulses is simplified in the diagram). After a 20ns interval (20 micropulse cycles) of pre-pulse, the main pulse follows, with a main pulse width of approximately 100μs containing 100,000 micropulse cycles. The pulse train frequency after chopping is 1kHz.

[0051] A3: After the pulse train following the first-stage chopping passes through a first-stage fiber amplifier (gain approximately 10dB), an overshoot occurs at the leading edge of the prepulse;

[0052] A4: The amplified laser beam is chopped by a spatial BBO Pockel cell 42 and a polarization beam splitter 43 (PBS) to remove the overshoot pre-pulse portion, resulting in a main pulse portion with a flat top. The rise time of the Pockel cell 42 is approximately 10 ns, located in the timing gap between the pre-pulse and the main pulse, thus preserving the steep edge characteristics of the main pulse. This ultimately achieves a pulse train laser output with sub-ps rise and fall times, a micropulse repetition rate of 1 GHz, a macropulse repetition rate of 1 kHz, a macropulse width of 100 μs, and amplitude fluctuations within the macropulse not exceeding 5%.

[0053] In contrast, conventional pulse train amplification methods, such as Figure 2 As shown in (b) above, the steps are as follows:

[0054] B1: The seed source uses a high-repetition-rate picosecond mode-locked pulsed laser with a repetition rate of 1 GHz, a micro-pulse width of 15 ps, and an interval of about 1 ns between adjacent pulses.

[0055] B2: The picosecond seed source first undergoes a high-speed amplitude modulation chopping process, and the pulse train formed by the chopping is continuous without intervals. In some scenarios, step B2 can be omitted to directly amplify and generate continuous output micropulses.

[0056] B3: After the pulse train following the first-stage chopping passes through the first-stage amplifier, an overshoot occurs at the leading edge of the pre-pulse;

[0057] B4: In order to obtain a flat pulse leading edge, the overshoot is cut off by a high-power amplitude modulator. However, due to the limited bandwidth and long rise time of the high-power amplitude modulator, the amplitude of the micropulse at the edge of the pulse train will be incomplete. The same problem is faced in the application scenario where the process of skipping B2 and directly amplifying is performed.

[0058] As can be seen from the comparison, the device and method described in this invention can effectively produce pulse trains with flat tops and steep edges compared to conventional pulse train amplification methods.

[0059] Secondly, the present invention provides a method for using a steep-edge ultrafast pulse train laser control device, comprising the following steps:

[0060] Step S1: The laser pulse output by the ultrafast seed source 1 is shaped into a pre-pulse and a main pulse by the high-speed amplitude modulator 2 driven by the first radio frequency driving signal. The first radio frequency driving signal is generated by the signal driving module 5.

[0061] Step S2: The pre-pulse and main pulse are amplified by the input pulse amplification module 3, and the amplified pre-pulse and main pulse are input by the second radio frequency drive signal to drive the high-power amplitude modulation module 4 to perform secondary amplitude modulation on the amplified pre-pulse and main pulse, separating the main pulse from the pre-pulse, so that the high-power amplitude modulation module 4 only outputs the main pulse. The second radio frequency drive signal is generated by the signal drive module 5.

[0062] In this embodiment, the laser pulse is shaped into a pre-pulse and a main pulse by a high-speed amplitude modulator 2, ensuring the shape and sharp edges of the laser pulse. Simultaneously, the pre-pulse and main pulse are amplified by the pulse amplification module 3, increasing the energy of the laser pulse. The amplified pulse is then subjected to two-stage amplitude modulation by a high-power amplitude modulation module 4, effectively separating the main pulse from the pre-pulse. This ensures that the high-power amplitude modulation module 4 outputs only the main pulse, avoiding unnecessary signal interference. The radio frequency drive signal generated by the signal drive module 5 ensures the synchronization and stability of the entire process, reducing fluctuations and uncertainties during pulse output. By precisely controlling the shaping and amplification of the pulse, the final output main pulse has better time characteristics and energy distribution, making it suitable for demanding laser processing and measurement applications.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A steep-edge ultrafast pulse train laser control device, characterized in that, It includes an ultrafast seed source (1), a high-speed amplitude modulator (2), a pulse amplification module (3), a high-power amplitude modulation module (4), and a signal driving module (5), among which, The ultrafast seed source (1) is connected to the high-speed amplitude modulator (2). The high-speed amplitude modulator (2) is used to perform first-level amplitude modulation on the laser pulse output by the ultrafast seed source (1) to generate a pre-pulse and a main pulse respectively. There is a certain time interval between the pre-pulse and the main pulse. The pre-pulse and the main pulse form a pulse train. The high-speed amplitude modulator (2) is connected to the pulse amplification module (3), which is used to amplify the pulse train; The pulse amplification module (3) is connected to the high-power amplitude modulation module (4). The high-power amplitude modulation module (4) is used to perform secondary amplitude modulation on the amplified pulse train and cut off the pre-pulse so that the high-power amplitude modulation module (4) only outputs the main pulse. The signal driving module (5) is electrically connected to the high-speed amplitude modulator (2) and the high-power amplitude modulation module (4) respectively. The signal driving module (5) is used to provide radio frequency driving signals to control the waveform and timing of the output pulses of the high-speed amplitude modulator (2) and the high-power amplitude modulation module (4) respectively.

2. The steep-edge ultrafast pulse train laser control device as described in claim 1, characterized in that, The high-power amplitude modulation module (4) includes a half-wave plate (41), a Pockel cell (42), and a polarization beam splitter (43). The half-wave plate (41) is connected to the Pockel cell (42), and the Pockel cell (42) is connected to the signal driving module (5) and the polarization beam splitter (43) respectively.

3. The steep-edge ultrafast pulse train laser control device as described in claim 2, characterized in that, The signal driving module (5) includes a first radio frequency driver, a second radio frequency driver and a clock source. The first radio frequency driver is electrically connected to the clock source and the high-speed amplitude modulator (2) respectively, and the second radio frequency driver is electrically connected to the clock source and the Pockel cell (42) respectively.

4. The steep-edge ultrafast pulse train laser control device as described in claim 3, characterized in that, The first radio frequency driver receives the clock signal sent by the clock source and controls the shaping of the input laser pulse into a pre-pulse and a main pulse based on the clock signal. The second radio frequency driver is used to control the polarization rotation of the Pockel cell (42) to remove the overshoot characteristics of the pre-pulse during amplitude modulation.

5. The steep-edge ultrafast pulse train laser control device as described in claim 1, characterized in that, When the phase difference of the high-speed amplitude modulator (2) is biased at the π phase, the output mode of the high-speed amplitude modulator (2) is as follows: When there is no radio frequency pulse signal input to the high-speed amplitude modulator (2), the continuous output power of the high-speed amplitude modulator (2) is at its minimum value; When a radio frequency pulse signal is input to the high-speed amplitude modulator (2), the high-speed amplitude modulator (2) outputs a corresponding optical pulse signal according to the pulse width and amplitude of the radio frequency pulse signal.

6. The steep-edge ultrafast pulse train laser control device as described in claim 5, characterized in that, When the phase difference bias of the high-speed amplitude modulator (2) is set to 0 phase, the output mode of the high-speed amplitude modulator (2) is as follows: When the high-speed amplitude modulator (2) has no radio frequency signal input, the continuous power output of the high-speed amplitude modulator is at its maximum value; When a radio frequency pulse signal is input to the high-speed amplitude modulator (2), the high-speed amplitude modulator (2) cuts off the corresponding waveform on the laser pulse output by the ultrafast seed source (1) according to the pulse width and amplitude of the radio frequency pulse signal.

7. The steep-edge ultrafast pulse train laser control device as described in claim 2, characterized in that, The high-speed amplitude modulator (2) is a high-bandwidth lithium niobate waveguide modulator or a lithium niobate thin film modulator, and the Pockel cell (42) is a spatial electro-optic modulator.

8. The steep-edge ultrafast pulse train laser control device as described in claim 4, characterized in that, The pre-pulse width, the time interval between the pre-pulse and the main pulse, and the amplitude ratio between the pre-pulse and the main pulse can all be controlled by the radio frequency drive signal output by the first radio frequency driver.

9. The steep-edge ultrafast pulse train laser control device as described in claim 1, characterized in that, The ultrafast seed source (1) outputs pulses with a repetition frequency not exceeding 2 GHz, a micro-pulse width not exceeding 100 ps, ​​and an interval between adjacent micro-pulses not less than 400 ps.

10. The method of using the steep-edge ultrafast pulse train laser control device according to any one of claims 1 to 9, characterized in that, Includes the following steps: The laser pulse output by the ultrafast seed source (1) is shaped into a pulse train consisting of a pre-pulse and a main pulse by a high-speed amplitude modulator (2) driven by a first radio frequency drive signal. The first radio frequency drive signal is generated by the signal drive module (5). The pulse train is amplified by the pulse amplification module (3), and the amplified pulse train is driven by the second radio frequency drive signal to drive the high power amplitude modulation module (4) to perform secondary amplitude modulation on the amplified pre-pulse and the main pulse, and the pre-pulse is cut off so that the high power amplitude modulation module (4) only outputs the main pulse. The second radio frequency drive signal is generated by the signal drive module (5).

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