Burst mode high repetition rate tunable pulse cluster laser generation device

Abstract

The application provides a burst high-repetition-frequency tunable pulse cluster laser generating device, and belongs to the technical field of high-power microwave. The device comprises a pulse cluster laser seed module, an active optical fiber ring module, a multi-stage optical power amplification module and a multi-channel signal generation module. The technical scheme of the application realizes burst replication of the pulse cluster through the active optical fiber ring module, and outputs high-repetition-frequency tunable burst pulse cluster laser in combination with a pre-compensation technology. The output laser pulse is multi-parameter adjustable, the thermal accumulation effect of the high-repetition-frequency laser is reduced, and the continuous output problem of the instantaneous high-power laser in different application occasions is solved.

Description

Technical Field

[0001] This invention relates to the field of high-power microwave technology, and more specifically to a burst-type high-repetition-rate tunable pulse cluster laser generation device. Background Technology

[0002] In modern warfare, electromagnetic threats are diverse and their spectrum is becoming increasingly rich. High-power microwave systems need to possess multi-dimensional adaptive tuning capabilities in the time, frequency, and energy domains to enhance strike effectiveness. However, currently, high-power microwaves are mainly generated by "relativistic vacuum electronic devices," and due to limitations imposed by electron beams and high-frequency structural characteristics, the parameters of the output high-power microwaves are usually fixed or difficult to tune. Furthermore, the repetition rate of the output high-power microwaves typically does not exceed 100Hz, making it difficult to achieve repetition rates above 100kHz.

[0003] Microwave effect research results show that high-power microwave pulses with ultra-high repetition rate can significantly improve the combat effectiveness of electronic countermeasures equipment, providing a new technological means for electronic countermeasures under battlefield conditions.

[0004] Optical microwave technology utilizes a high-power tunable high-repetition-rate pulsed laser as the driving light source, which is incident on a wide-bandgap optical guide device and then amplified by a bias voltage to generate tunable high-power microwaves. The high-power tunable high-repetition-rate pulsed laser offers advantages in power capacity and wide parameter tuning, while the wide-bandgap optical guide device features high voltage resistance and good linearity. The synergistic operation of the high-power tunable high-repetition-rate pulsed laser and the wide-bandgap optical guide device enables continuously tunable microwave output over a wide frequency range. Furthermore, combining this with spectrum sensing technology can enhance the effectiveness of the microwave output.

[0005] In the prior art, Chinese invention patent CN110265854B discloses a photoguide-adaptive narrow-spectrum microwave generation method based on high-energy pulsed cluster laser. The microwave generator used in this method produces high-power microwaves with adjustable repetition rate, pulse width, and main frequency. However, because it relies on uniform and continuous high-repetition-rate pulsed laser output, it cannot adapt to application scenarios with special requirements for instantaneous high-power-density output or sudden concentrated energy release.

[0006] In addition, conventional techniques typically employ ultra-high repetition rate lasers with continuously chirped pulse amplification to drive wide-bandgap photoconductive semiconductor devices. However, because the light source used is a conventional MHz source, the thermal accumulation effect is quite severe when driving wide-bandgap semiconductors, affecting the lifespan of the photoconductive devices. Summary of the Invention

[0007] Based on this, the technical solution provided by the present invention replicates pulse clusters to form pulse train lasers with controllable width through an active fiber ring module, and combines multi-stage optical power amplification and pre-compensation technology to realize burst pulse cluster lasers in the MHz range, thus solving the thermal accumulation effect of existing technologies in high repetition rate scenarios.

[0008] To achieve the above objectives, the present invention provides a burst-type high repetition rate tunable pulse cluster laser generation device. The pulse cluster laser generation device includes: a pulse cluster laser seed module for outputting a seed laser, the seed laser comprising a plurality of pulse clusters, each pulse cluster comprising a plurality of sub-pulses, the envelope of the plurality of sub-pulses within the pulse cluster increasing over time, the repetition frequency of the plurality of pulse clusters being the repetition frequency, and the repetition frequency of the plurality of sub-pulses within the pulse cluster being the dominant frequency; an active fiber ring module for replicating the pulse clusters of the seed laser to output a burst-type pulse train laser, the burst-type pulse train laser comprising a plurality of pulse trains, each pulse train comprising a plurality of replicated pulse clusters, the repetition frequency of the pulse clusters within the pulse train being the burst repetition frequency; a multi-stage optical power amplification module for amplifying the power of the burst-type pulse train laser to output a burst-type pulse cluster laser; and a multi-channel signal generation module for sending synchronization control signals to the pulse cluster laser seed module, the active fiber ring module, and the multi-stage optical power amplification module to achieve synchronization control.

[0009] Preferably, the active fiber optic ring module includes: an optical coupler for splitting the seed laser beam, so that one beam is combined with another beam after passing through the fiber optic ring; a passive fiber for providing a fixed optical path to set the time interval of pulse clusters within the pulse train; an adjustable optical delay line for providing a real-time continuously adjustable optical path to adjust the time interval of pulse clusters within the pulse train in real time; a fiber optic acousto-optic modulator for adjusting the transmission time of one of the beams in the fiber optic ring to adjust the time width of the pulse train; and a fiber optic power amplifier for adjusting the amplification factor according to the synchronization control signal to amplify the power of one of the beams to compensate for fiber power loss and enable the active fiber optic ring to stably replicate the pulse clusters.

[0010] Preferably, the pulse cluster laser seed module includes a laser diode, an electro-optic modulation module, and an acousto-optic modulation module. The laser diode is used to output a seed pulse, and the pulse repetition frequency of the seed pulse is equal to the repetition frequency. The electro-optic modulation module is used to generate several sub-pulses within the seed pulse to form the pulse cluster and output the pulse cluster laser. The acousto-optic modulation module is used to pre-compensate the time-domain waveform of the pulse cluster laser, causing the envelope of the several sub-pulses within the pulse cluster to increase over time, in order to pre-compensate for the waveform distortion caused by gain saturation during the subsequent amplification process of the pulse cluster laser, and output the seed laser.

[0011] Furthermore, the electro-optic modulation module includes a high-frequency signal generator, a high-speed electro-optic modulator driver, and a high-speed electro-optic modulator. The high-frequency signal generator is used to generate a high-frequency electrical oscillation signal. The high-speed electro-optic modulator driver is used to amplify the amplitude of the high-frequency electrical oscillation signal so that the driving voltage is greater than the half-wave voltage of the high-speed electro-optic modulator. The high-speed electro-optic modulator is used to load the high-frequency electrical oscillation signal onto the seed pulse to generate several sub-pulses, forming the pulse cluster laser.

[0012] Furthermore, the acousto-optic modulation module includes a waveform generator, an acousto-optic modulator driver, and an acousto-optic modulator. The acousto-optic modulator driver generates a radio frequency (RF) signal. The acousto-optic modulator controls the transmittance of the pulse cluster laser based on the RF signal, causing the envelope of the plurality of sub-pulses within the pulse cluster to increase over time, forming a waveform that is initially low and then increases in the time domain. This pre-compensates for waveform distortion caused by gain saturation during the subsequent amplification process of the pulse cluster laser. The waveform generator generates a trigger pre-compensation signal to the acousto-optic modulator driver based on the synchronization control signal to adjust the amplitude of the RF signal.

[0013] Furthermore, the signal source of the high-frequency signal generator is any one of a voltage-controlled frequency converter, a frequency synthesizer, an arbitrary waveform generator, or a function generator, or a combination of any one of the voltage-controlled frequency converter, the frequency synthesizer, the arbitrary waveform generator, or the function generator with a source power amplifier.

[0014] Specifically, the main frequency is continuously adjustable, and the adjustment range of the main frequency is determined by the bandwidth of the high-frequency signal generator and the high-speed electro-optic modulator.

[0015] Furthermore, the envelope of the trigger pre-compensation signal Satisfy the equation The real-time output gain G(t) of the waveform generator satisfies the following relationship: G0 is the small-signal gain, E sat For optical fiber to saturate absorb energy, I input E is the envelope of the input signal of the waveform generator. out (t) represents the output energy of the waveform generator.

[0016] Preferably, the multi-stage optical power amplifier module includes at least one stage of optical power amplifier, which is a fiber laser amplifier or a solid-state laser amplifier, or a cascade of the fiber power amplifier and the solid-state laser amplifier.

[0017] The technical solution provided by this invention has the following beneficial effects:

[0018] A burst-type cluster laser, comprising pulse trains, is generated by replicating pulse clusters using an active fiber ring. Due to the considerable adjustable time intervals between the laser pulse trains, compared to conventional MHz repetition rate lasers, the average power of the burst-type cluster laser output by the cluster laser generation device provided by this invention is significantly reduced at the same peak power output. This effectively reduces the heat accumulation effect during device operation, enabling continuous output in applications requiring instantaneous high power density output or concentrated burst energy release. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the pulse cluster laser generating device according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the active fiber optic ring module structure according to an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the pulse cluster laser seed module structure according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of a multi-stage optical power amplification module according to an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the laser signal waveform conversion process according to an embodiment of the present invention. Figure 5 (a) is a schematic diagram of the time-domain waveform of the seed pulse in an embodiment of the present invention. Figure 5 (b) is a schematic diagram of the time-domain waveform of the pulse cluster in an embodiment of the present invention. Figure 5 (c) is a schematic diagram of the time-domain waveform of the seed laser in an embodiment of the present invention. Figure 5 (d) is a schematic diagram of the time-domain waveform of the burst pulse train laser according to an embodiment of the present invention. Figure 5 (e) is a schematic diagram of the time-domain waveform of a burst-type pulse cluster laser according to an embodiment of the present invention.

[0024] Figure 6 This is a diagram of a pre-compensated electrical signal generated by the arbitrary waveform generator in Embodiment 2 of the present invention.

[0025] Figure 7 This is a diagram of the pre-compensated electrical signal generated by the arbitrary waveform generator in Embodiment 3 of the present invention.

[0026] Figure 8 This is a diagram of the pre-compensated electrical signal generated by the arbitrary waveform generator in Embodiment 4 of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] Example 1

[0029] Please see the appendix Figure 1 , Figure 1 The diagram illustrates the structure of a pulse cluster laser generating device according to an embodiment of the present invention. As shown in the diagram, the pulse cluster laser generating device includes: a pulse cluster laser seed module for generating a seed laser, the seed laser being output to an active fiber optic ring module connected to the pulse cluster laser seed module; an active fiber optic ring module for performing pulse cluster replication on the seed laser into a burst pulse train laser, the burst pulse train laser being output to a multi-stage optical power amplification module connected to the active fiber optic ring module; a multi-stage optical power amplification module for amplifying the power of the burst pulse train laser and outputting a burst pulse cluster laser; and a multi-channel signal generation module connected to the pulse cluster laser seed module, the active fiber optic ring module, and the multi-stage optical power amplification module, respectively, for sending synchronization control signals to the pulse cluster laser seed module, the active fiber optic ring module, and the multi-stage optical power amplification module to achieve synchronization control.

[0030] Please see the appendix Figure 2 , Figure 2 This is a schematic diagram of an active fiber optic ring module structure provided in an embodiment of the present invention. As shown in the figure, the active fiber optic ring module includes: an optical coupler, a passive optical fiber, a tunable optical delay line, a fiber optic acousto-optic modulator, and a fiber optic power amplifier. The optical coupler includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal. The first input terminal and the output terminal of the pulse cluster laser seed module are connected via fiber optic fusion splicing, and the first output terminal and the input terminal of the multi-stage optical power amplifier module are connected via fiber optic fusion splicing. The second output terminal and the input terminal of the tunable optical delay line are connected via fiber optic fusion splicing, the output terminal of the tunable optical delay line and the fiber optic input terminal of the fiber optic acousto-optic modulator are connected via fiber optic fusion splicing, the fiber optic output terminal of the fiber optic acousto-optic modulator and the input terminal of the passive optical fiber are connected via fiber optic fusion splicing, the output terminal of the passive optical fiber and the input terminal of the fiber optic power amplifier are connected via fiber optic fusion splicing, and the output terminal of the fiber optic power amplifier and the second input terminal of the optical coupler are connected via fiber optic fusion splicing, forming an overall fiber optic ring. In one or other embodiments of the present invention, the passive optical fiber, the tunable optical delay line, the fiber optic acousto-optic modulator, and the fiber optic power amplifier may also have other connection orders and connection methods.

[0031] In one embodiment of the present invention, an optical coupler is used to split the seed laser beam. The seed laser is input through the first input terminal of the optical coupler. After splitting, two beams of light with the same intensity (splitting ratio of 1:1) are output from the first and second output terminals of the optical coupler. One beam of light from the second output terminal of the optical coupler enters the active fiber ring, then re-enters the optical coupler through the second input terminal. After being split again by the optical coupler according to the same ratio, it is combined with the seed laser from the first input terminal. The first and second output terminals of the optical coupler then output two beams of light respectively, and the above process is repeated. A passive optical fiber is used to provide a fixed optical path to set the time interval of pulse clusters within the pulse train. In this embodiment of the present invention, the passive optical fiber in the active fiber ring is used to coarsely set the time interval of pulse clusters within the pulse train, and the optical path error can be controlled at the centimeter level. An adjustable optical delay line is used to provide a real-time continuously adjustable optical path to adjust the time interval of pulse clusters within the pulse train in real time. In this embodiment of the invention, the tunable optical delay line provides a continuously adjustable optical path for the active fiber ring, so as to finely adjust the time interval between pulse clusters within the pulse train on the picosecond scale.

[0032] The fiber optic acousto-optic modulator is used to adjust the transmission time of the light beam through the active fiber optic ring, thereby adjusting the time width of the pulse train, i.e., adjusting the number of pulse clusters within a pulse train. The fiber optic power amplifier is used to adjust the amplification factor according to the synchronization control signal to amplify the power of the light beam passing through the active fiber optic ring, compensating for the power loss caused by the active fiber optic ring, and enabling the active fiber optic ring to stably replicate pulse cluster laser.

[0033] For example, the seed laser output from the pulse cluster laser seed module is split into two beams by an optical coupler at a 1:1 intensity ratio. One beam is output through the second output terminal of the optical coupler and enters the tunable optical delay line, fiber acousto-optic modulator, passive fiber, and fiber power amplifier of the active fiber ring. Finally, it re-enters the optical coupler through the second input terminal. The fiber acousto-optic modulator controls the number of pulse clusters within the pulse train, i.e., the time width of the pulse train, by controlling the time of laser transmission.

[0034] For example, in this embodiment of the invention, the active fiber optic ring module includes a fiber optic acousto-optic modulator driver. The input terminal of the fiber optic acousto-optic modulator driver and the output terminal of the multi-channel signal generation module are connected via a coaxial cable, and the output terminal of the fiber optic acousto-optic modulator driver and the radio frequency input terminal of the fiber optic acousto-optic modulator are connected via a coaxial cable. The fiber optic acousto-optic modulator driver is used to receive synchronization control signals to control the fiber optic acousto-optic modulator.

[0035] For example, in this embodiment of the invention, the input / output optical fibers of the fiber optic acousto-optic modulator are both polarization-maintaining fibers with a working bandwidth greater than 100MHz.

[0036] For example, in an embodiment of the present invention, the operating wavelength range of the passive optical fiber is 970–1550 nm, and the core numerical aperture is 0.120.

[0037] For example, in an embodiment of the present invention, the operating wavelength of the tunable optical delay line is 1064nm, the adjustable delay range is 0 to 700ps, and the adjustable accuracy is less than 1ps.

[0038] For example, in this embodiment of the invention, the optical power amplifier is selected as a single-stage forward-pumped fiber-core amplifier, comprising a gain fiber, a pump source, and a wavelength division multiplexer. The output end of the pump source and the pump end of the wavelength division multiplexer are connected by fiber fusion splicing; the output end of the passive fiber and the signal end of the wavelength division multiplexer are connected by fiber fusion splicing; the output end of the wavelength division multiplexer and the input end of the gain fiber are connected by fiber fusion splicing; and the output end of the gain fiber and the second input end of the optical coupler are connected by fiber fusion splicing. The gain fiber includes rare-earth doped particles to provide inverted particles. The pump source provides energy to excite the rare-earth doped particles in the gain fiber to a high energy level. The wavelength division multiplexer efficiently couples the pump light and the signal light into the gain fiber.

[0039] Please see the appendix Figure 3 , Figure 3 This is a schematic diagram of a pulse cluster laser seed module provided in an embodiment of the present invention. The pulse cluster laser seed module includes a laser diode, an electro-optic modulation module, and an acousto-optic modulation module. The laser diode generates a seed pulse according to a synchronization control signal, and the seed pulse is output to the electro-optic modulation module connected to the laser diode. The electro-optic modulation module modulates the seed pulse to generate several sub-pulses, forming a pulse cluster laser which is output to the acousto-optic modulation module connected to the electro-optic modulation module. The acousto-optic modulation module is used to pre-compensate the time-domain waveform of the pulse cluster laser, so that the envelope of the several sub-pulses within the pulse cluster increases with time, in order to pre-compensate for the waveform distortion caused by gain saturation effect during the subsequent amplification process of the pulse cluster laser, and output the seed laser.

[0040] For example, the electro-optic modulation module includes a high-frequency signal generator, a high-speed electro-optic modulator driver, and a high-speed electro-optic modulator. The output terminal of the high-frequency signal generator and the input terminal of the high-speed electro-optic modulator driver are connected via a high-frequency cable, the output terminal of the high-speed electro-optic modulator driver and the radio frequency input terminal of the high-speed electro-optic modulator are connected via a high-frequency cable, and the input terminal of the high-speed electro-optic modulator and the optical fiber output terminal of the laser diode are connected via optical fiber fusion splicing.

[0041] In this embodiment of the invention, a high-frequency signal generator is used to generate a high-frequency electrical oscillation signal, which is then output to a high-speed electro-optic modulator. The high-speed electro-optic modulator driver amplifies the amplitude of the high-frequency electrical oscillation signal so that the driving voltage is greater than the half-wave voltage of the high-speed electro-optic modulator. The high-speed electro-optic modulator is used to load the high-frequency electrical oscillation signal onto the seed pulse to generate several sub-pulses, forming the pulse cluster laser.

[0042] The acousto-optic modulation module includes a waveform generator, an acousto-optic modulator driver, and an acousto-optic modulator. The output of the waveform generator and the input of the acousto-optic modulator driver are connected by a high-frequency cable, the output of the acousto-optic modulator driver and the radio frequency input of the acousto-optic modulator are connected by a high-frequency cable, and the output of the high-speed electro-optic modulator and the optical fiber input of the acousto-optic modulator are connected by optical fiber fusion splicing.

[0043] A waveform generator is used to generate a trigger pre-compensation signal based on the synchronization control signal and send it to the acousto-optic modulator driver to adjust the amplitude of the radio frequency signal. The acousto-optic modulator driver is used to receive the trigger pre-compensation signal, generate a radio frequency signal, and transmit the radio frequency signal to the acousto-optic modulator. The acousto-optic modulator is used to control the transmittance of the pulse cluster laser based on the radio frequency signal, so that the envelope of the plurality of sub-pulses within the pulse cluster increases over time.

[0044] For example, in this embodiment of the invention, the laser diode is a polarization-maintaining semiconductor pulsed laser diode, which can generate seed pulses with flexibly adjustable repetition rate and pulse width according to different application requirements. The center wavelength range of the laser diode is 1000nm to 1065nm, the pulse width range is 2ns to 1ms, and the repetition rate range is 10Hz to 200MHz.

[0045] For example, in this embodiment of the invention, the high-speed electro-optic modulator is a polarization-maintaining fiber-coupled electro-optic modulator with a working bandwidth of 10 GHz or greater.

[0046] For example, in an embodiment of the present invention, the signal source of the high-frequency signal generator is any one of a voltage-controlled frequency converter, a frequency synthesizer, an arbitrary waveform generator, and a function generator. In one or other embodiments of the present invention, the signal source of the high-frequency signal generator is a combination of any one of the voltage-controlled frequency converter, the frequency synthesizer, the arbitrary waveform generator, and the function generator with a source power amplifier.

[0047] For example, in this embodiment of the invention, the high-frequency electrical oscillation signal is a sinusoidal signal, and the frequency of the sinusoidal signal is flexibly adjustable, with the adjustment range covering the GHz level.

[0048] For example, in an embodiment of the present invention, the main frequency is continuously adjustable, and the adjustment range of the main frequency is determined by the bandwidth of the high-frequency signal generator and the high-speed electro-optic modulator.

[0049] For example, in this embodiment of the invention, the acousto-optic modulator of the pulse cluster laser seed module is a fiber-coupled acousto-optic modulator, and both the input and output fibers are polarization-maintaining fibers with a working bandwidth greater than 100MHz.

[0050] For example, in an embodiment of the present invention, the envelope I of the trigger pre-compensation signal output Satisfy the equation The real-time output gain G(t) of the waveform generator satisfies the following relationship: G0 is the small-signal gain, E sat For optical fiber to saturate absorb energy, I input E is the envelope of the input signal to the waveform generator. out (t) represents the output energy of the waveform generator, G0 and E sat It was measured through experiments.

[0051] Please see the appendix Figure 4 , Figure 4 This is a schematic diagram of a multi-stage optical power amplification module according to an embodiment of the present invention. In this embodiment, the multi-stage optical power amplification module includes a multi-stage optical power amplifier for amplifying the power of the burst laser pulse train. In one or other embodiments of the present invention, the multi-stage optical power amplification module may also be a single-stage optical power amplifier. Exemplarily, the optical power amplifier is a fiber optic power amplifier, a solid-state laser amplifier, or a cascaded fiber optic power amplifier with a solid-state laser amplifier. The fiber optic power amplifiers at each stage are connected by fiber optic fusion splicing, and the solid-state laser amplifiers at each stage are connected by spatial optical connection. The output of the fiber optic power amplifier is collimated and coupled to the solid-state laser amplifier via a lens.

[0052] For example, in an embodiment of the present invention, the output terminal of the last stage optical power amplifier is provided with an isolator and a beam splitter, wherein the isolator is used to prevent backlight from damaging the laser system, and the beam splitter is used to split a small portion of the light to monitor the output waveform of the multi-stage optical power amplifier module.

[0053] For example, in an embodiment of the present invention, the output end of the pulse cluster laser seed module (i.e., the fiber optic output end of the acousto-optic modulator) and the input end of the active fiber optic ring module (i.e., the first input end of the optical coupler) are connected by fiber optic fusion splicing, and the first output end of the optical coupler in the active fiber optic ring module and the input end of the multi-stage optical power amplifier module (i.e., the input end of the first stage optical power amplifier of the optical power amplifier) ​​are connected by fiber optic fusion splicing.

[0054] For example, in this embodiment of the invention, the output terminal of the multi-channel signal generation module and the input terminal of the laser diode are connected via a coaxial cable; the output terminal of the multi-channel signal generation module and the input terminal of the waveform generator are connected via a high-frequency cable; and the output terminal of the multi-channel signal generation module and the driver input terminal of the fiber optic acousto-optic modulator are connected via a coaxial cable. The output terminal of the multi-channel signal generation module and the pump source control terminal in the fiber optic power amplifier are connected via a coaxial cable. The output terminal of the multi-channel signal generation module and the pump source control terminals of several optical power amplifiers in the multi-stage optical power amplifier module are all connected via coaxial cables.

[0055] For example, in this embodiment of the invention, the time accuracy of the multi-channel signal generation module is less than 10 ns. It can not only generate digital signals to synchronously trigger the acousto-optic modulator driver and waveform generator, but also generate analog signals with adjustable amplitude and pulse width to control several optical power amplifiers in the fiber optic acousto-optic modulator driver, fiber optic power amplifier, and multi-stage optical power amplifier module.

[0056] The multi-channel signal generation module provides synchronization control signals to the laser diode, which generates seed lasers with corresponding repetition rates and pulse widths based on the synchronization control signals. It also provides amplitude- and pulse-width-adjustable synchronization control signals to the fiber optic acousto-optic modulator driver, which controls the light transmission time of the modulator based on these signals. Furthermore, the multi-channel signal generation module provides synchronization control signals to the pump source, which controls the power of the fiber optic power amplifier based on these signals. Finally, it transmits synchronization trigger signals to a waveform generator, which sends trigger electrical signals to the acousto-optic modulator driver based on the synchronization signals. Finally, the multi-channel signal generation module provides synchronization control signals to multiple pump sources to control the power of the optical power amplifier.

[0057] Please see the appendix Figure 5 , Figure 5 This is a schematic diagram of the laser signal waveform conversion process in an embodiment of the present invention. The working process of the present invention is as follows: the laser diode generates a seed pulse (time-domain waveform as shown in the diagram) based on the synchronization control signal issued by the multi-channel signal generation module, where the repetition rate (1 / T0) and pulse width (D) are flexibly adjustable. Figure 5 (a) shows that the pulse repetition frequency of the seed pulse is equal to the repetition frequency. The electro-optic modulation module is used to generate several sub-pulses within the pulse of the seed pulse to form the pulse cluster, generating a time-domain waveform as shown. Figure 5 (b) shows a cluster laser pulse, with a dominant frequency of 1 / T1. An acousto-optic modulation module is used to correct the time-domain waveform of the cluster laser, so that a seed laser with a lower initial time-domain waveform and a higher initial time-domain waveform is formed within the cluster (time-domain waveform as shown in image). Figure 5(c) shows the seed laser. The seed laser comprises several pulse clusters, each pulse cluster comprising several sub-pulses. The repetition frequency of the pulse clusters is the repetition frequency (1 / T0), and the repetition frequency of the sub-pulses within each pulse cluster is the main frequency (1 / T1). The active fiber ring module is used to replicate the pulse clusters of the seed laser to output burst laser pulse trains (time-domain waveform as shown in figure). Figure 5 (d) shows that the burst pulse train laser includes several pulse trains, each pulse train including several replicated pulse clusters, and the repetition frequency of the pulse clusters within each pulse train is the burst repetition frequency (RRF). The RRF is determined by the optical path length of the active fiber loop module and is 1 / T2. The RRF can be adjusted by regulating the passive fiber and the tunable optical delay line. Adjusting the turn-off time of the fiber optic modulator to adjust the time width of the pulse train allows for adjustment of the number of pulse clusters in the pulse train, i.e., T3 is adjustable. A multi-stage optical power amplification module is used to amplify the power of the burst pulse train laser, outputting a burst pulse cluster laser (time-domain waveform as shown in the figure). Figure 5 (e) shows that the pulse width, repetition rate, main frequency, and burst repetition rate of the burst pulse cluster laser can all be adjusted.

[0058] Example 2

[0059] This invention provides a pulse cluster laser generating device, which aims to achieve the following output performance: a center wavelength of 1064nm, a pulse cluster width of 100ns, a repetition rate of 100Hz, a pulse cluster interval (T2-D) of 100ns (corresponding to a burst repetition rate of 5MHz), 10 pulse trains, a main frequency that is continuously adjustable from 0.1 to 10GHz, a peak power of 100kW, and an average power of 5W.

[0060] For example, the pulse cluster laser seed module includes: a laser diode employing a directly electrically modulated polarization-maintaining semiconductor laser with an output center wavelength of 1064 nm, a pulse width of 100 ns, a repetition frequency of 100 Hz, and an output fiber of PM980; a high-speed electro-optic modulator, fiber-coupled type, with a bandwidth of 10 GHz, a half-wave voltage of 4.5 V, and both input and output fibers of PM980; a high-frequency signal generator, an arbitrary waveform generator with an analog bandwidth of 25 GHz; a high-speed electro-optic modulator driver for amplifying the output voltage of the high-frequency signal generator to exceed the half-wave voltage of the high-speed electro-optic modulator; a waveform generator for receiving a synchronization control signal in external trigger mode and sending a trigger electrical signal to the acousto-optic modulator driver; and an acousto-optic modulator driver for generating an RF signal matching the acousto-optic modulator based on the trigger electrical signal. The acousto-optic modulator is fiber-coupled, with an operating bandwidth of 200MHz and an extinction ratio of 20dB. The input / output fiber is PM980. The acousto-optic modulator receives the RF signal and generates a pre-compensated waveform based on the waveform generator output (see appendix). Figure 6 , Figure 6 (This is a schematic diagram of the pre-compensated electrical signal generated by the arbitrary waveform generator in Embodiment 2 of the present invention) Adjusting the transmittance and controlling the time-domain waveform.

[0061] Exemplarily, the active fiber optic ring module includes: an optical coupler, which is a 1:1 fiber optic coupler, with both input and output fibers being PM980; a fiber optic acousto-optic modulator driver, used to receive the synchronization control signal to control the fiber optic acousto-optic modulator; the fiber optic acousto-optic modulator, which is fiber-coupled, with both input and output fibers being PM980 fibers, and an operating bandwidth of 200MHz, used to control the on / off state of the active fiber optic ring module to achieve an iteration time (T3) of 2μs, corresponding to a pulse train width of 2μs (10 pulses); and a passive fiber, approximately equal to 20m minus the total length of the input and output fibers of the optical coupler, minus the total length of the input and output fibers of the fiber optic acousto-optic modulator, minus the fiber length of the fiber power amplifier, and minus the total length of the input and output fibers of the adjustable optical delay line. The passive fiber provides a fixed optical path to set the time interval of pulse clusters within the pulse train. In this embodiment of the invention, the fixed optical path provided by the passive fiber makes the pulse cluster interval (T2-D) within the pulse train 100ns. The tunable optical delay line is used for fine tuning of the pulse cluster spacing (T2-D) within the pulse train. The fiber power amplifier is a single-stage bidirectional pumped fiber core amplifier that achieves near-balanced loop gain and loss in the active fiber loop module, ensuring stable replication of the output sampled pulse train while minimizing sampled pulse train distortion.

[0062] The multi-stage optical power amplification module includes: a first-stage bidirectional pumped fiber core amplifier and a third-stage forward pumped cladding amplifier. The core diameters of the gain fibers in the forward pumped cladding amplifier are 15μm, 30μm, and 50μm, respectively. The last stage has a 50μm core doped fiber followed by a section of passive fiber and a fiber end cap, and finally outputs laser light through the end cap.

[0063] The multi-channel signal generation module is used to send synchronization control signals to the pulse cluster laser seed module, the active fiber ring module, and the multi-stage optical power amplification module to achieve synchronous control of each module.

[0064] The final output laser parameters are: center wavelength 1064nm, pulse cluster width 100ns, repetition rate 100Hz, pulse cluster interval (T2-D) within the pulse train (corresponding to burst repetition frequency 5MHz), number of pulse trains 10, main frequency 0.1-10GHz continuously adjustable, average power 5W, corresponding peak power 100kW.

[0065] Example 3

[0066] This invention provides a pulse cluster laser generating device, which aims to achieve the following output performance: center wavelength of 1064nm, pulse cluster width of 5ns, repetition rate of 100Hz, pulse cluster interval (T2-D) of 2μs (corresponding to burst repetition rate of 500kHz), number of pulse trains of 10, main frequency continuously adjustable from 0.1-10GHz, peak power of 100kW, and average power of 0.25W.

[0067] The technical configuration is the same as in Embodiment 2, with the following differences:

[0068] The laser diode output pulse width is 5 ns. The iteration time (T3) of the active fiber loop module is set to 20 μs, corresponding to a total pulse train width of 20 μs. The passive fiber length is adjusted to approximately 400 m minus the fiber lengths of other components in Example 2. The adjustable delay line finely tunes the pulse cluster spacing (T2-D) within the pulse train, ensuring a total optical path length of 2 μs within the active fiber loop. The pre-compensated waveform output by the waveform generator (see Appendix) Figure 7 , Figure 7 (A schematic diagram of the pre-compensated electrical signal generated by the arbitrary waveform generator in Embodiment 3 of the present invention) is used to adjust the time-domain waveform.

[0069] Final output laser parameters: center wavelength 1064nm, pulse cluster width 5ns, repetition rate 100Hz, pulse cluster interval (T2-D) within the pulse train is 2μs (corresponding to burst repetition rate 500kHz), number of pulse trains 10, main frequency continuously adjustable from 0.1-10GHz, average power 0.25W, corresponding to peak power 100kW.

[0070] Example 4

[0071] This invention provides a pulse cluster laser generating device, which aims to achieve the following output performance: center wavelength of 1064nm, pulse cluster width of 1μs, repetition rate of 100Hz, pulse cluster interval (T2-D) of 1μs (corresponding to burst repetition rate of 500kHz), number of pulse trains of 10, main frequency continuously adjustable from 0.1-10GHz, peak power of 10kW, and average power of 5W.

[0072] The technical configuration is the same as in Embodiment 2, with the following differences:

[0073] The laser diode output pulse width is 1 ns. The iteration time (T3) of the active fiber loop module is set to 20 μs, corresponding to a total pulse train width of 20 μs. The passive fiber length is adjusted to approximately 400 m minus the fiber lengths of other components in Example 2. The adjustable delay line finely tunes the pulse cluster spacing (T2-D) within the pulse train, ensuring a total optical path length of 2 μs within the active fiber loop. The pre-compensated waveform output by the waveform generator (see Appendix) is shown below. Figure 8 , Figure 8The pre-compensated electrical signal diagram generated by the arbitrary waveform generator in Embodiment 4 of the present invention is used to adjust the time-domain waveform.

[0074] Final output laser parameters: center wavelength 1064nm, pulse cluster width 1ns, repetition rate 100Hz, pulse cluster interval (T2-D) within the pulse train is 1μs (corresponding to burst repetition rate 500kHz), number of pulse trains 10, main frequency continuously adjustable from 0.1-10GHz, average power 5W, corresponding to peak power of 10kW.

[0075] All the above embodiments are based on the pulse cluster laser generation device proposed in this invention. Utilizing the high integration and stability of fiber optic devices, combined with optical path control, amplification link design, time-domain modulation, and feedback adjustment, a high repetition rate, high power, and low distortion light source output is achieved. For those skilled in the art, appropriate adjustments can be made to parameter configurations, component models, etc., without departing from the principles of this invention; such modifications should also be covered within the scope of protection of this invention.

[0076] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A burst-type high-repetition-rate tunable pulse cluster laser generation device, characterized in that, The pulse cluster laser generating device includes: A pulse cluster laser seed module is used to output a seed laser. The seed laser includes several pulse clusters, each pulse cluster includes several sub-pulses, the envelope of the several sub-pulses in the pulse cluster increases with time, the repetition frequency of the several pulse clusters is the repetition frequency, and the repetition frequency of the several sub-pulses in the pulse cluster is the main frequency. An active fiber optic ring module is used to replicate the pulse clusters of the seed laser to output burst pulse train laser. The burst pulse train laser includes several pulse trains, and each pulse train includes several replicated pulse clusters. The repetition frequency of the pulse clusters within the pulse train is the burst repetition frequency. A multi-stage optical power amplifier module is used to amplify the power of the burst pulse train laser and output a burst pulse cluster laser; and A multi-channel signal generation module is used to send synchronization control signals to the pulse cluster laser seed module, the active fiber optic ring module, and the multi-stage optical power amplification module to achieve synchronization control.

2. The pulse cluster laser generating device according to claim 1, characterized in that, The active fiber optic ring module includes: An optical coupler is used to split the seed laser beam, so that one beam passes through an optical fiber loop and is then combined with another beam. Passive optical fiber is used to provide a fixed optical path to set the time interval of pulse clusters within the pulse train; A tunable optical delay line is used to provide a real-time continuously adjustable optical path to adjust the time interval of pulse clusters within the pulse train in real time; An optical fiber acousto-optic modulator is used to adjust the transmission time of one of the light beams in the optical fiber loop, thereby adjusting the time width of the pulse train. An optical fiber power amplifier is used to adjust the amplification factor according to the synchronization control signal to amplify the power of one of the light beams, so as to compensate for the power loss of the optical fiber and enable the active optical fiber ring to stably replicate the pulse cluster.

3. The pulse cluster laser generating device according to claim 1, characterized in that, The pulse cluster laser seed module includes a laser diode, an electro-optic modulation module, and an acousto-optic modulation module; The laser diode is used to output a seed pulse, and the pulse repetition frequency of the seed pulse is equal to the repetition frequency. The electro-optic modulation module is used to generate several sub-pulses within the seed pulse to form the pulse cluster and output pulse cluster laser. The acousto-optic modulation module is used to pre-compensate the time-domain waveform of the pulse cluster laser, so that the envelope of the plurality of sub-pulses in the pulse cluster increases with time, in order to pre-compensate the waveform distortion caused by the gain saturation effect during the subsequent amplification process of the pulse cluster laser, and output the seed laser.

4. The pulse cluster laser generating device according to claim 3, characterized in that, The electro-optic modulation module includes a high-frequency signal generator, a high-speed electro-optic modulator driver, and a high-speed electro-optic modulator. The high-frequency signal generator is used to generate high-frequency electrical oscillation signals; The high-speed electro-optic modulator driver is used to amplify the amplitude of the high-frequency electro-oscillation signal so that the driving voltage is greater than the half-wave voltage of the high-speed electro-optic modulator. The high-speed electro-optic modulator is used to load the high-frequency electro-oscillation signal onto the seed pulse to generate several sub-pulses, forming the pulse cluster laser.

5. The pulse cluster laser generating device according to claim 3, characterized in that, The acousto-optic modulation module includes a waveform generator, an acousto-optic modulator driver, and an acousto-optic modulator. The acousto-optic modulator driver is used to generate radio frequency signals; The acousto-optic modulator is used to control the transmittance of the pulse cluster laser according to the radio frequency signal, so that the envelope of the plurality of sub-pulses in the pulse cluster increases with time. The waveform generator is used to generate a trigger pre-compensation signal based on the synchronization control signal and drive the acousto-optic modulator to adjust the amplitude of the radio frequency signal.

6. The pulse cluster laser generating device according to claim 4, characterized in that, The signal source of the high-frequency signal generator is any one of a voltage-controlled frequency converter, a frequency synthesizer, an arbitrary waveform generator, or a function generator, or a combination of any one of the voltage-controlled frequency converter, the frequency synthesizer, the arbitrary waveform generator, or the function generator with a source power amplifier.

7. The pulse cluster laser generating device according to claim 4, characterized in that, The main frequency is continuously adjustable, and the adjustment range of the main frequency is determined by the bandwidth of the high-frequency signal generator and the high-speed electro-optic modulator.

8. The pulse cluster laser generating device according to claim 5, characterized in that, The envelope I of the trigger pre-compensation signal output Satisfy the equation: ， The real-time output gain G(t) of the waveform generator satisfies the following relationship: ， G0 is the small-signal gain, E sat For optical fiber saturation absorption of energy, I input E is the envelope of the input signal of the waveform generator. out (t) represents the output energy of the waveform generator.

9. The pulse cluster laser generating device according to claim 2, characterized in that, The multi-stage optical power amplifier module includes at least one stage of optical power amplifier, which is the fiber optic power amplifier, or a solid-state laser amplifier, or a cascade of the fiber optic power amplifier and the solid-state laser amplifier.

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