A general high-stability POD control circuit and control method for ultrafast lasers

Abstract

The application provides a kind of general high-stability POD control circuit and control method of ultrafast laser, and the laser enters continuous release mode after starting pump, AOM1 output adjustable constant amplitude continuous analog control signal is in continuous release state, AOM2 is completely closed, and a certain residual energy is always maintained in amplification light path;When external trigger signal is input, switch to pulse release mode, the analog control signal of AOM1 is first pulled low to close, then pulled high for a short time to release a seed pulse after a fixed delay time, and AOM2 is synchronously opened to select output.The application maintains the energy stability of amplification light path through continuous release mode, cooperates with fixed delay design, ensures the stability of pulse energy, fixes the output time of external trigger signal to optical pulse, and significantly improves the processing efficiency.

Description

Technical Field

[0001] This invention relates to the field of ultrafast laser control technology, and more specifically, to a universal high-stability POD control circuit and control method for ultrafast lasers. Background Technology

[0002] Ultrafast lasers, with their high peak power, short duration, and minimal heat-affected zone, are the preferred light source for modern precision machining. However, in laser precision machining, the complexity of the machining trajectory means that using a fixed-frequency output can lead to pulse overlap at deceleration points, easily causing over-processing of the material and severely impacting machining quality. Therefore, POD (Pulse On Demand) functionality has become an indispensable core control function in high-end ultrafast laser processing systems.

[0003] POD (Positive Oxidation of Optimal Laser) requires the laser to respond precisely to external trigger signals, enabling it to emit single pulses on demand and maintain constant output energy to ensure consistent processing results. POD technology has demonstrated significant advantages in fields such as UV laser high-speed microstructure processing and femtosecond laser residual thermal effect management, effectively improving processing accuracy and efficiency.

[0004] Currently, most ultrafast lasers use a two-stage AOM (acousto-optic modulator) structure to achieve POD (Pulse On Demand) function control. To achieve POD function, most ultrafast lasers synchronously regenerate the AOM1 fundamental frequency and AOM2 select signal when an external trigger signal arrives, thereby achieving pulse output on demand.

[0005] However, due to the uncertainty of the timing of the external trigger signal, the energy of the first output pulse exhibits significant jitter: after the arrival of the external trigger signal, the interval between the newly generated AOM1 pulse and the previous AOM1 pulse is not fixed (there is a 0-T time jitter), causing changes in the energy storage time corresponding to the newly generated AOM1 pulse, which affects the single-pulse energy. In fiber optic amplification systems, due to their saturation amplification effect, the energy stored in the gain medium is much higher than the energy extracted by a single pulse, and the impact of pulse interval fluctuations on output energy can be suppressed to some extent by the saturation effect. However, in solid-state amplified lasers, because the energy storage characteristics of the gain medium are more sensitive to changes in the pulse interval, continuously pumped solid-state amplifiers exhibit gain fluctuations and bifurcation instability when the pulse repetition period is comparable to the gain relaxation time, resulting in particularly significant pulse energy fluctuations.

[0006] In summary, existing technical solutions have not proposed a simple, efficient, and universally applicable solution to the energy jitter problem in POD scenarios. There is an urgent need for a universal POD control method that can both ensure pulse energy stability and achieve low-latency, fast response. Summary of the Invention

[0007] This invention addresses the technical problems existing in the prior art by providing a universal high-stability POD control circuit and control method for ultrafast lasers, which reduces pulse energy jitter by changing the operating mode of the two-stage acousto-optic modulator (AOM).

[0008] According to a first aspect of the present invention, a universal high-stability POD control circuit for ultrafast lasers is provided, comprising a timing control circuit, a seed source, a first acousto-optic modulator AOM1, a second acousto-optic modulator AOM2, and an amplification optical path;

[0009] The seed source is connected to the timing control circuit and the AOM1 respectively, and is used to provide a seed synchronization clock to the timing control circuit and a seed pulse to the AOM1;

[0010] The timing control circuit is connected to the seed source, AOM1 and AOM2 respectively, and is used to receive external trigger signals and generate a first control signal for controlling AOM1 and a second control signal for controlling AOM2, using the seed synchronization clock as the working clock.

[0011] The AOM1 is connected to the seed source, the timing control circuit and the amplification optical path respectively, and is used to select pulses from the seed pulses according to the first control signal and release them to the amplification optical path;

[0012] The amplification optical path is connected to AOM1 and AOM2 respectively, and is used to amplify the pulse released by AOM1 and output the amplified pulse to AOM2;

[0013] The AOM2 is connected to the timing control circuit and the amplification optical path respectively, and is used to select, release or intercept the amplified pulse output by the amplification optical path according to the second control signal;

[0014] The timing control circuit is configured to: when there is no external trigger signal, control AOM1 to output a continuous analog signal with an adjustable constant amplitude to be in a continuous release state, so that the seed pulse continuously enters the amplified optical path to maintain energy steady state, and control AOM2 to be in a closed state; when an external trigger signal is received, control AOM1 to first turn off the continuous analog signal, wait for a preset fixed delay time, and then output a pulse release signal to release a single seed pulse, and then turn it off again and detect the fixed delay time. During this process, AOM2 is synchronously controlled to turn on to select and output the corresponding amplified pulse, wherein the fixed delay time is less than the fundamental frequency period of AOM1.

[0015] Based on the above technical solution, the present invention can also be improved as follows.

[0016] Optionally, the timing control circuit includes a microcontroller and a field-programmable gate array (FPGA), wherein the FPGA is connected to the AOM1 via a high-speed DAC;

[0017] The microcontroller is used to receive and store operating parameters through a communication interface, and to send the operating parameters to the FPGA.

[0018] The FPGA is used to determine the working mode according to the operating parameters, use the seed synchronization clock as the working clock, receive the external trigger signal, and output digital control signals.

[0019] The high-speed DAC is used to convert the digital control signal output by the FPGA into an analog waveform, which is then output to the AOM1 as the first control signal.

[0020] Optionally, the FPGA is connected to the AOM2, and the FPGA is also used to output a switch signal and an analog signal as the second control signal to the AOM2 according to the external trigger signal, so as to control the on and off of the AOM2 and the adjustment of the output laser power.

[0021] Optionally, the timing control circuit further includes a serial port and an external control interface;

[0022] The FPGA receives external TTL level trigger signals through the external control interface; and connects to external debugging equipment through the serial port to read and set operating parameters.

[0023] Optionally, after the pulse release ends, the timing control circuit is further configured to: within a preset detection time, if it is operating in TRIG mode and no new external trigger signal is detected, control AOM1 to switch back to the continuous release state and turn off AOM2; if it is operating in GATE mode and the external trigger signal is detected to be off, control AOM1 to switch back to the continuous release state and turn off AOM2.

[0024] Optionally, both the fixed delay time and the preset detection time are T / 2, where T is one AOM1 base frequency cycle.

[0025] According to a second aspect of the present invention, a universal high-stability POD control method for ultrafast lasers is provided, comprising:

[0026] After the laser is powered on, it enters the continuous release mode, controlling AOM1 to output a continuously analog signal with an adjustable constant amplitude to be in a continuous release state, so that the seed pulse continuously enters the amplification optical path to maintain energy steady state, and controlling AOM2 to be in the off state.

[0027] When an external trigger signal is received, the continuous release mode is switched to the pulse release mode: the AOM1 is controlled to first turn off the continuous analog signal, wait for a preset fixed delay time, and then output a pulse release signal to release a single seed pulse. Then it is turned off again and the fixed delay time is detected. During the fixed delay time, the AOM2 is synchronously controlled to turn on to select and output the corresponding amplified pulse.

[0028] Within a preset detection time after the release pulse, it is determined whether the backoff condition is met according to the working mode. If it is met, AOM1 is switched back to the continuous release mode and AOM2 is turned off.

[0029] Optionally, the preset fixed delay time is T / 2, where T is one AOM1 base frequency cycle.

[0030] Optionally, determining whether the rollback condition is met based on the working mode includes:

[0031] If operating in TRIG mode, when no new external trigger signal arrives within the preset detection time, it is determined that the rollback condition is met, and AOM1 is switched back to the continuous release mode and AOM2 is turned off; otherwise, in response to a new external trigger signal, the pulse release mode is re-executed.

[0032] If operating in GATE mode, when the external trigger signal is turned off within the preset detection time, it is determined that the rollback condition is met, and AOM1 is switched back to the continuous release mode and AOM2 is turned off; otherwise, the pulse release mode continues to be executed.

[0033] Optionally, in the continuous release mode, the energy absorbed by the seed pulse entering the amplified optical path is changed by adjusting the amplitude of the continuous analog signal of the AOM1, thereby adjusting the residual energy level maintained in the amplified optical path.

[0034] The present invention provides a universal high-stability POD control circuit and control method for ultrafast lasers, which has the following beneficial effects:

[0035] (1) By setting AOM1 to continuous release mode in continuous release mode, the present invention maintains a certain amount of residual energy in the amplification optical path. After switching to pulse release mode, only T / 2 time optical pulse is needed to achieve normal output energy, which fundamentally eliminates the energy storage fluctuation caused by the uncertainty of the phase relationship between the external trigger signal and the seed pulse, and greatly reduces the energy jitter of the first output pulse and subsequent pulses.

[0036] (2) By adjusting the pulse release control of AOM1 and cooperating with AOM2 to intercept unexpected pulses, this invention ensures the stability of pulse energy and fixes the time from external trigger signal to optical pulse output to T / 2. Compared with the shielding of the first pulse in the prior art (release time not less than T), the output delay is reduced by 1 / 2, which significantly improves the processing efficiency.

[0037] (3) The present invention uses the mechanism of detecting the T / 2 time window after releasing the pulse. In TRIG mode, it can follow the external trigger signal to output at a frequency higher than AOM1. In GATE mode, it can realize single or multiple laser pulse output, which improves control flexibility.

[0038] (4) The hardware architecture of the present invention is basically the same as that of existing products. Only the driving method of AOM1 needs to be changed to high-speed DAC analog signal driving. The modification cost is low and it is easy to implement.

[0039] (5) The present invention provides a scheme for maintaining the steady state of energy in the amplified optical path through a continuous release mode. It is applicable to both fiber amplification and solid-state amplification ultrafast lasers and is not limited by the type of amplification medium. In fiber amplification, the energy stability can be further enhanced by the saturation amplification effect. In solid-state amplification, it can effectively compensate for the energy jitter caused by the energy storage fluctuation of the gain medium. It has wide applicability. Attached Figure Description

[0040] Figure 1 A schematic diagram of a universal high-stability POD control circuit for ultrafast lasers provided in one embodiment of the present invention;

[0041] Figure 2 This is a flowchart illustrating a universal high-stability POD control method for ultrafast lasers according to an embodiment of the present invention;

[0042] Figure 3 This is a timing diagram illustrating the implementation of the POD function in this invention;

[0043] Figure 4 This is the timing diagram of the external low-frequency trigger signal for the TRIG mode of this invention;

[0044] Figure 5 This is the timing diagram of the external trigger signal in the GATE mode of this invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined with each other to form feasible technical solutions. Such combinations are not constrained by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0046] To overcome the problem of large output pulse energy jitter caused by the random phase of the external trigger signal in existing POD control technology, and to solve the problem of excessive time from external trigger signal to optical pulse output in existing improvement technologies, a universal high-stability POD control method and circuit for ultrafast lasers is provided. It is applicable to fiber amplification and solid-state amplification ultrafast lasers. By adjusting the pulse release control mechanism of AOM1 and cooperating with AOM2 to intercept unexpected pulses, the time from external trigger signal to optical pulse output is fixed at T / 2 while ensuring pulse energy stability, effectively improving processing efficiency and stability.

[0047] Figure 1 The diagram shows a schematic of a universal high-stability POD control circuit for an ultrafast laser according to an embodiment of the present invention. The control circuit mainly includes a timing control circuit, a seed source, a first acousto-optic modulator AOM1, a second acousto-optic modulator AOM2, and an amplification optical path.

[0048] The seed source is connected to both the timing control circuit and AOM1, providing a seed synchronization clock for the timing control circuit and a seed pulse for AOM1. The timing control circuit is connected to the seed source, AOM2, and a high-speed DAC connected to AOM1. It receives external trigger signals and generates RF drive signals based on the seed synchronization clock to control the switching of AOM1 and AOM2. The timing control circuit is a control core composed of a microcontroller and an FPGA. The microcontroller is responsible for serial data transmission, reception, and storage, and sends operating parameters to the FPGA via the SPI interface. The FPGA determines the operating mode based on the operating parameters, uses the seed synchronization clock as the operating clock, receives external trigger signals, drives the high-speed DAC to output analog waveforms to AOM1, and outputs switching signals and analog signals to AOM2. AOM1 and AOM2 are controlled by the AOM1 driver circuit and AOM2 driver circuit, respectively. The microcontroller can connect to debugging software via an RS232 interface for parameter reading and setting.

[0049] The AOM1 is connected to the seed source, timing control circuit, and amplification optical path, respectively, and is used to release the seed pulses into the amplification optical path after screening. The AOM1 adopts a high-speed DAC analog signal driving method. The high-speed DAC converts the digital signal output by the FPGA into an analog waveform, which is then converted into an RF signal to drive the AOM1 by the AOM1 driving circuit. In continuous release mode, the high-speed DAC outputs a continuous analog signal with an adjustable constant amplitude; in pulse release mode, the high-speed DAC outputs a rapidly changing analog waveform.

[0050] The amplification optical path is connected to AOM1 and AOM2 respectively, and is used to amplify the filtered pulses.

[0051] AOM2 is connected to both the timing control circuit and the amplification optical path, and is used to intercept or release the amplified pulse in response to the control signal from the timing control circuit. The AOM2 driver circuit controls the on / off state of AOM2 according to the switching signal output by the FPGA, and adjusts the output laser power according to the analog signal output by the FPGA. Specifically, each time an external trigger signal arrives, the counter is reset to zero and a new control signal is generated, AOM2 is turned on for single-pulse gating, and AOM2 is turned off after T / 2 time. In GATE mode, the above single-pulse gating process is repeatedly executed during the valid period of the external trigger signal. In TRIG mode, the above single-pulse gating process is executed on each rising edge of the external trigger signal.

[0052] This invention also provides a general high-stability POD control method for ultrafast lasers based on control circuits, applicable to fiber-amplified and solid-state-amplified ultrafast lasers. By adjusting the pulse release control mechanism of AOM1 and cooperating with AOM2 to intercept unexpected pulses, the time from the external trigger signal to the optical pulse output is fixed at T / 2 while ensuring pulse energy stability. This overcomes the problem of large output pulse energy jitter caused by the random phase of the external trigger signal in existing POD control technologies, and also solves the problem of excessively long time from the external trigger signal to the optical pulse output in existing improvement technologies, effectively improving processing efficiency and stability.

[0053] See Figure 2 The universal high-stability POD control method for ultrafast lasers based on control circuits provided in this embodiment of the invention includes the following steps:

[0054] Step 1: After the laser is powered on, it enters the continuous release mode. The AOM1 is controlled to output a continuous analog signal with an adjustable constant amplitude to be in the continuous release state, so that the seed pulse continues to enter the amplification optical path to maintain the energy steady state, and the AOM2 is controlled to be in the off state.

[0055] Step 2: When an external trigger signal is received, switch from the continuous release mode to the pulse release mode: control the AOM1 to first turn off the continuous analog signal, wait for a preset fixed delay time, and then output a pulse release signal to release a single seed pulse. Then turn it off again and detect the fixed delay time. During this process, control the AOM2 to turn on to select and output the corresponding amplified pulse.

[0056] Step 3: Within the preset detection time after the release pulse, determine whether the rollback condition is met according to the working mode. If it is met, switch AOM1 back to the continuous release mode and turn off AOM2.

[0057] in, Figure 3 The timing diagram of the POD function implementation in an embodiment of the present invention is shown. The following describes in detail the various working modes involved in the embodiments of the present invention.

[0058] S1: Continuous release mode.

[0059] After the laser is powered on and the pump is activated, it enters continuous release mode. In this mode, AOM1 is controlled by a continuously analog signal with adjustable constant amplitude output from a high-speed DAC and is in continuous release state, while AOM2 is completely turned off.

[0060] The AOM1 is driven and controlled by a high-speed DAC analog signal. The so-called continuous release state refers to the AOM1 continuously releasing seed pulses by adjusting the amplitude of the continuous analog signal output from the high-speed DAC. These seed pulses continuously enter the amplification optical path with decreasing energy. Each seed pulse entering the amplification optical path absorbs controllable energy, ensuring that a certain amount of residual energy is always maintained in the amplification optical path, maintaining an energy steady state.

[0061] By adjusting the amplitude of the AOM1 continuous signal in continuous release mode, the energy absorbed by the seed pulse can be changed, thereby altering the residual energy level in the amplified optical path. This residual energy level directly affects the energy of the first output pulse in subsequent pulse release modes, thus allowing for fine-tuning of the energy of the first pulse released upon external triggering.

[0062] The fundamental difference from existing technologies lies in the following: In existing technologies, the AOM1 continuously releases pulses into the amplification optical path according to the fundamental frequency. However, the phase relationship of the external trigger signal is uncertain, causing fluctuations in the interval between two pulses. Even if the energy stability is ensured by optimizing and adjusting to release a second pulse, the pulse release time is simultaneously lengthened, affecting processing efficiency. In contrast, this invention switches the AOM1 to a continuous release mode, keeping the residual energy in the amplification optical path stable at all times. While ensuring a fast response to the output optical pulse, it suppresses the fluctuation of pulse energy to a range equivalent to the energy difference of only one seed pulse cycle.

[0063] S2: Pulse release mode.

[0064] When an external trigger signal is input, the laser automatically switches from continuous release mode to pulse release mode.

[0065] In this mode, the analog control signal of AOM1 is first pulled low from a continuous level to turn off, and then pulled high for a short time (duration not exceeding one seed pulse cycle) after T / 2 time to release a seed pulse into the amplified optical path, and then pulled low to turn off and detect T / 2 time.

[0066] The technical principle behind selecting the T / 2 waiting time is as follows: Since a certain amount of residual energy is maintained in the amplified optical path during continuous release mode, after AOM1 is turned off and a T / 2 time is waited, the first released seed pulse can utilize the residual energy plus the T / 2 energy storage time to reach the normal output energy level. The T / 2 waiting times before and after effectively ensure that the pulse energy at any given time corresponds to a total energy storage time of T. Furthermore, the T / 2 waiting time ensures that the time from the external trigger signal to the optical pulse output is T. delay =T / 2 fixed delay + T jitterThe synchronization jitter time (less than one seed clock cycle, without considering the optical pulse propagation delay) also facilitates alignment with AOM2 (ensuring output after the rise time of AOM2). Compared with the shielded first pulse scheme, the output delay is reduced by 1 / 2, which can significantly improve processing efficiency.

[0067] After the seed pulse released by AOM1 enters the amplified optical path, AOM2 is simultaneously turned on for gating during this process. AOM2 maintains its existing control mode, and after an external trigger signal is input, a new pulse signal is generated to turn on AOM2, and AOM2 is turned off after a time of T / 2.

[0068] S3: Mode rollback.

[0069] After the laser pulse is released, the laser continuously monitors time T / 2 and performs mode backoff judgment based on the laser's operating mode and the status of the external trigger signal, as detailed below:

[0070] Figure 4 This is the timing diagram of the external trigger signal in the TRIG mode of this invention. If the laser is operating in TRIG mode, the time T / 2 is continuously monitored after the pulse is released:

[0071] 1. If the next external trigger signal arrives within T / 2 time, then in response to the next external trigger signal, AOM1 will restart counting T / 2 time and output the next pulse, thereby following the external trigger signal and outputting at a frequency higher than AOM1.

[0072] 2. If no next external trigger signal arrives within T / 2 time, the current light emission process is judged to be over, AOM1 is switched back to continuous release mode, and AOM2 is turned off simultaneously.

[0073] Figure 5 This is the timing diagram of the external trigger signal in GATE mode of the present invention. If the laser is operating in GATE mode, the time T / 2 is continuously monitored after the pulse is released:

[0074] 1. If the external trigger signal is turned off within T / 2 time, it is determined that the current light emission process has ended, AOM1 is switched back to continuous release mode, AOM2 is turned off simultaneously, and the process waits for the next external trigger process.

[0075] 2. If the external trigger signal is not turned off after T / 2 time, the next AOM1 pulse will be output after T / 2 time is counted again. This process is repeated to achieve single or multiple laser pulse output in GATE mode.

[0076] After reverting to continuous release mode, the residual energy in the amplified optical path returns to a steady state, preparing for the arrival of the next external trigger signal.

[0077] The workflow of GATE mode and TRIG mode is explained below.

[0078] In GATE mode, the external trigger signal is high while a laser pulse is continuously output. The specific process is as follows:

[0079] 1. When the rising edge of the external trigger signal arrives, the laser switches from continuous release mode to pulse release mode. The analog control signal of AOM1 is first pulled low to turn off, and after waiting for T / 2, it is pulled high for a short time to release the first seed pulse. AOM2 turns on synchronously.

[0080] 2. After releasing the pulse, continuously monitor the T / 2 time. If the external trigger signal is not turned off after T / 2 time, the count will restart after T / 2 time and the next AOM1 pulse will be output. AOM2 will synchronously perform single pulse gating (i.e., it will be turned on and then turned off after T / 2 time). This process is repeated to continuously output laser pulses with the set repetition frequency.

[0081] 3. If the external trigger signal is turned off within T / 2 time, it is determined that the current light emission process has ended, AOM1 is switched back to continuous release mode, AOM2 is turned off simultaneously, and the process waits for the next external trigger process.

[0082] Since the time from the external trigger signal to the output of the optical pulse is fixed at T / 2, and the mechanism of detecting the T / 2 time window after the pulse is released ensures the consistency of the continuous pulse gaps and prevents fluctuations in the gaps between adjacent pulses.

[0083] In TRIG mode, the frequency of the output laser pulse is consistent with the frequency of the external trigger signal. One laser pulse is output each time the signal is triggered, and it can follow the external trigger signal to output at a frequency higher than AOM1. The specific process is as follows:

[0084] 1. When the rising edge of the external trigger signal arrives, the laser switches from continuous release mode to pulse release mode. The analog control signal of AOM1 is first pulled low to turn off, and after waiting for T / 2, it is pulled high for a short time to release a seed pulse. AOM2 is simultaneously turned on to select and output a laser pulse.

[0085] 2. After releasing the pulse, continuously monitor time T / 2. If a second external trigger signal arrives within T / 2 time, AOM1 will restart counting time T / 2 and output the next pulse. If no second external trigger signal arrives after time T / 2, AOM1 will switch back to continuous release mode, and AOM2 will be turned off synchronously.

[0086] 3. Wait for the next external trigger signal to arrive, and repeat the above process.

[0087] Because the amplification optical path is in a steady-state energy state of continuous release mode before each trigger, and the T / 2 waiting time ensures the consistency of the energy storage and recovery process, the energy of each output laser pulse is highly consistent. Simultaneously, in TRIG mode, it can follow an external trigger signal to output at a frequency higher than AOM1, improving control flexibility.

[0088] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0089] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0090] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A universal high-stability POD control circuit for ultrafast lasers, characterized in that, It includes a timing control circuit, a seed source, a first acousto-optic modulator AOM1, a second acousto-optic modulator AOM2, and an amplification optical path; The seed source is connected to the timing control circuit and the AOM1 respectively, and is used to provide a seed synchronization clock to the timing control circuit and a seed pulse to the AOM1; The timing control circuit is connected to the seed source, AOM1 and AOM2 respectively, and is used to receive external trigger signals and generate a first control signal for controlling AOM1 and a second control signal for controlling AOM2, using the seed synchronization clock as the working clock. The AOM1 is connected to the seed source, the timing control circuit and the amplification optical path respectively, and is used to select pulses from the seed pulses according to the first control signal and release them to the amplification optical path; The amplification optical path is connected to AOM1 and AOM2 respectively, and is used to amplify the pulse released by AOM1 and output the amplified pulse to AOM2; The AOM2 is connected to the timing control circuit and the amplification optical path respectively, and is used to select, release or intercept the amplified pulse output by the amplification optical path according to the second control signal; The timing control circuit is configured to: when there is no external trigger signal, control AOM1 to output a continuous analog signal with an adjustable constant amplitude to be in a continuous release state, so that the seed pulse continuously enters the amplified optical path to maintain energy steady state, and control AOM2 to be in a closed state; when an external trigger signal is received, control AOM1 to first turn off the continuous analog signal, wait for a preset fixed delay time, and then output a pulse release signal to release a single seed pulse, and then turn it off again and detect the fixed delay time. During this process, AOM2 is synchronously controlled to turn on to select and output the corresponding amplified pulse, wherein the fixed delay time is less than one AOM1 fundamental frequency period.

2. The control circuit according to claim 1, characterized in that, The timing control circuit includes a microcontroller and a field-programmable gate array (FPGA), and the FPGA is connected to the AOM1 via a high-speed DAC. The microcontroller is used to receive and store operating parameters through a communication interface, and to send the operating parameters to the FPGA. The FPGA is used to determine the working mode according to the operating parameters, use the seed synchronization clock as the working clock, receive the external trigger signal, and output digital control signals. The high-speed DAC is used to convert the digital control signal output by the FPGA into an analog waveform, which is then output to the AOM1 as the first control signal.

3. The control circuit according to claim 2, characterized in that, The FPGA is connected to the AOM2. The FPGA is also used to output a switch signal and an analog signal as the second control signal to the AOM2 according to the external trigger signal, so as to control the on and off of the AOM2 and the adjustment of the output laser power.

4. The control circuit according to claim 2, characterized in that, The timing control circuit also includes a serial port and an external control interface; The FPGA receives external TTL level trigger signals through the external control interface; and connects to external debugging equipment through the serial port to read and set operating parameters.

5. The control circuit according to claim 1, characterized in that, After the pulse release ends, the timing control circuit is further configured to: within a preset detection time, if it is operating in TRIG mode and no new external trigger signal is detected, control AOM1 to switch back to the continuous release state and turn off AOM2; if it is operating in GATE mode and the external trigger signal is detected to be off, control AOM1 to switch back to the continuous release state and turn off AOM2.

6. The control circuit according to claim 5, characterized in that, The fixed delay time and the preset detection time are both T / 2, where T is one AOM1 base frequency cycle.

7. A universal high-stability POD control method for ultrafast lasers, applied to the control circuit as described in any one of claims 1 to 6, characterized in that, include: After the laser is powered on, it enters the continuous release mode, controlling AOM1 to output a continuously analog signal with an adjustable constant amplitude to be in a continuous release state, so that the seed pulse continuously enters the amplification optical path to maintain energy steady state, and controlling AOM2 to be in the off state. When an external trigger signal is received, the system switches from the continuous release mode to the pulse release mode: the AOM1 is controlled to first turn off the continuous analog signal, wait for a preset fixed delay time, and then output a pulse release signal to release a single seed pulse. The system then turns off the signal again and detects the fixed delay time. During this process, the AOM2 is simultaneously opened to select the corresponding amplified pulse for output; Within a preset detection time after the release pulse, it is determined whether the backoff condition is met according to the working mode. If it is met, AOM1 is switched back to the continuous release mode and AOM2 is turned off.

8. The method according to claim 7, characterized in that, The preset fixed delay time is T / 2, where T is one AOM1 base frequency cycle.

9. The method according to claim 7, characterized in that, The step of determining whether the rollback conditions are met based on the working mode includes: If operating in TRIG mode, when no new external trigger signal arrives within the preset detection time, it is determined that the rollback condition is met, and AOM1 is switched back to the continuous release mode and AOM2 is turned off; otherwise, in response to a new external trigger signal, the pulse release mode is re-executed. If operating in GATE mode, when the external trigger signal is turned off within the preset detection time, it is determined that the rollback condition is met, and AOM1 is switched back to the continuous release mode and AOM2 is turned off; otherwise, the pulse release mode continues to be executed.

10. The method according to claim 7, characterized in that, In the continuous release mode, by adjusting the amplitude of the continuous analog signal of the AOM1, the energy absorbed by the seed pulse entering the amplified optical path is changed, thereby adjusting the residual energy level maintained in the amplified optical path.

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