High-stability fiber pulse MOPA laser control method and fiber pulse laser

Abstract

The present application discloses a high-stability fiber pulse MOPA laser control method and a fiber pulse laser, which belongs to the field of drive circuit technology. The laser circuit is connected to a control board; the control board is used to output a pulse width modulation signal, a repetition frequency signal, a switching optical signal and a power signal; in the laser circuit, the frequency modulation circuit outputs a frequency modulation signal according to the repetition frequency signal; the seed pulse generating circuit outputs a seed pulse and an index signal according to the pulse width modulation signal and the frequency modulation signal when receiving a trigger signal; the light output adjustment circuit obtains and outputs a light output phase compensation signal according to the switching optical signal and the index signal; the power adjustment circuit outputs a power compensation signal according to the power signal and the index signal; the gain circuit compensates the seed pulse with the power compensation signal according to the light output phase compensation signal and the power compensation signal, and outputs a laser pulse. The power linearity of the laser pulses of different frequencies output by this method remains stable with respect to the energy of the single pulse, thereby improving the stability of the laser pulse.

Description

Technical Field

[0001] The present application belongs to the technical field of drive circuits, and in particular relates to a high-stability fiber pulse MOPA laser control method and a fiber pulse laser. Background Art

[0002] Pulsed fiber lasers have the advantages of small size, high single pulse energy and high conversion efficiency, so they can further replace traditional lasers and be widely used in many fields.

[0003] Currently, the most challenging nonlinear limiting factor for high-power fiber lasers with pulsed fiber structures is transverse mode instability (TMI), a new type of limiting factor. This can be achieved by increasing the TMI threshold through methods such as bending the main fiber. The control system can also be improved by controlling the pump width and seed phase. This can be achieved by adjusting the pulse width of the pump pulse and its temporal phase with the seed pulse.

[0004] Due to the differences in the extraction efficiency of the amplifier at different output frequencies, the single pulse energy corresponding to the pulse pump width at different frequencies is unstable, which affects the stability of the laser pulse. Summary of the Invention

[0005] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a high-stability fiber pulse MOPA laser control method and fiber pulse laser, which outputs laser pulses of different frequencies with stable power linearity and single pulse energy, thereby improving the stability of the laser pulses.

[0006] In a first aspect, the present application provides a high-stability fiber pulse MOPA laser control method, which is applied to a laser circuit, wherein the laser circuit is connected to a control board;

[0007] The laser circuit includes: a board controller and a laser generating circuit;

[0008] The control board is used to output pulse width modulation signals, repetition rate signals, switching optical signals and power signals;

[0009] The board controller includes a frequency modulation circuit, a light output regulation circuit and a power regulation circuit which are interconnected;

[0010] The laser generating circuit includes a seed pulse generating circuit and a gain circuit connected in sequence;

[0011] The method comprises:

[0012] Outputting a frequency modulation signal according to the re-frequency signal through the frequency modulation circuit;

[0013] When a trigger signal is received, the seed pulse generating circuit outputs a seed pulse and an index signal according to the pulse width modulation signal and the frequency modulation signal;

[0014] Obtaining a light output phase compensation signal according to the switching light signal and the index signal through the light output adjustment circuit and outputting the signal;

[0015] outputting a power compensation signal according to the power signal and the index signal through the power regulation circuit;

[0016] The seed pulse is compensated by the gain circuit according to the output light phase compensation signal and the power compensation signal, and a laser pulse is output.

[0017] According to one embodiment of the present application, the light output adjustment circuit includes a light output control module, a light output duration control module, and a light output phase control module connected in sequence; the light output adjustment circuit obtains and outputs a light output phase compensation signal according to the switching light signal and the index signal, including:

[0018] Obtaining a light output control signal according to the switch light signal through the light output control module;

[0019] Outputting a pumping duration signal through the light emission duration control module according to the light emission control signal, the input frequency, the index signal and the trigger pulse;

[0020] The light output phase control module outputs the light output phase compensation signal according to the pump duration signal and the input frequency.

[0021] According to one embodiment of the present application, the power regulation circuit includes a current intensity control module and a power control module connected in sequence; outputting a power compensation signal according to the power signal and the index signal through the power regulation circuit includes:

[0022] Outputting a current intensity signal and a current control signal according to the input frequency and the index signal through the current intensity control module;

[0023] performing gain control on the laser pulse according to the current control signal through the gain circuit;

[0024] The power control module outputs the power compensation signal according to the current intensity signal.

[0025] According to one embodiment of the present application, the seed pulse generating circuit includes a pulse generating module and a seed module connected in sequence, and the seed pulse generating circuit outputs a seed pulse and an index signal according to the pulse width modulation signal and the frequency modulation signal when receiving a trigger signal, including:

[0026] The pulse generating module is triggered by the trigger signal and outputs a pulse signal and an index signal according to the pulse width modulation signal and the frequency modulation signal;

[0027] The seed module outputs the seed pulse according to the pulse signal.

[0028] According to one embodiment of the present application, the frequency modulation circuit includes a frequency measurement module, a frequency generation module, and a frequency phase control module connected in sequence, and outputting a frequency modulation signal according to the re-frequency signal through the frequency modulation circuit includes:

[0029] The frequency measurement module measures the repetition frequency signal to obtain an input frequency;

[0030] The frequency generating module outputs a trigger pulse according to the light-on signal and the input frequency, and the light-on signal is output by the light-out adjustment circuit according to the switching light signal;

[0031] The frequency phase control module outputs the frequency modulation signal according to the trigger pulse, the input frequency and the index signal.

[0032] According to one embodiment of the present application, the gain circuit includes a pre-amplifier module and a main amplifier module connected in sequence, and the gain circuit compensates the seed pulse according to the output light phase compensation signal and the power compensation signal to output a laser pulse, including:

[0033] The pre-amplifier module controls the light emission duration of the seed pulse according to the light emission phase compensation signal and the current intensity signal, and outputs an amplified signal;

[0034] The main amplifier module performs phase compensation on the amplified signal according to the output light phase compensation signal and the power compensation signal to obtain and output the laser pulse.

[0035] According to one embodiment of the present application, the laser circuit further includes a clock circuit, and the clock circuit is connected to the control board. The method further includes:

[0036] Generate an output clock signal according to the internal clock signal of the laser through the clock circuit;

[0037] Clock synchronization is performed through the control board according to the output clock signal.

[0038] According to one embodiment of the present application, the method further includes:

[0039] The clock circuit also receives an input clock signal from the control board, and performs clock synchronization on the pulse width modulation signal, the repetition frequency signal, the switching optical signal and the power signal through the input clock signal.

[0040] According to one embodiment of the present application, the laser circuit further includes: a central processing unit, and the method further includes:

[0041] The central processing unit is used to configure parameters of the frequency modulation circuit, the light output adjustment circuit and the power adjustment circuit in the board controller.

[0042] In a second aspect, the present application provides a fiber pulse laser for executing the high-stability fiber pulse MOPA laser control method as described in the first aspect.

[0043] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application.

[0044] The present application provides a high-stability fiber pulse MOPA laser control method and fiber pulse laser, which have the following beneficial effects compared with the prior art:

[0045] (1) By compensating with the output phase compensation signal and the power compensation signal, the power linearity of the output laser pulses of different frequencies and the energy of the single pulse remain stable, so that the energy of the single pulses of different frequencies can be consistent, thereby improving the stability and output consistency of the laser pulses.

[0046] (2) In the pre-amplifier module, the seed pulse is amplified by a smaller pump energy to increase the power of the seed pulse to a suitable level to achieve maximum gain while avoiding over-saturation or nonlinear effects; in the main amplifier module, the signal is further amplified to achieve the required output power, ensuring that the output laser pulse has higher power and stability. In a multi-stage high-power system, there are differences in the control circuit signals of each stage of the amplifier, which can easily cause timing problems. The amplifier synchronous light output phase adjustment logic ensures the safety of the light output timing of each stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0048] Figure 1This is one of the structural diagrams of the laser circuit provided in the embodiment of the present application;

[0049] Figure 2 This is a flow chart of a high-stability fiber pulsed MOPA laser control method provided in an embodiment of the present application;

[0050] Figure 3 This is the second structural diagram of the laser circuit provided in the embodiment of the present application;

[0051] Figure 4 This is one of the curve diagrams of power reduction frequency provided in the embodiment of the present application;

[0052] Figure 5 This is the second schematic diagram of the power reduction frequency curve provided in the embodiment of the present application;

[0053] Figure 6 This is a schematic diagram of the structure of the FIFO delay module provided in an embodiment of the present application;

[0054] Figure 7 The pump width provided in the embodiment of the present application is 1 / f o Schematic diagram of single pulse energy curve at (40μs);

[0055] Figure 8 Schematic diagram of a single pulse energy curve when the pump width is 1 / fo+fl provided in an embodiment of the present application;

[0056] Figure 9 Schematic diagram of the single-pulse pump pulse width when the pump width is 1 / fo+fl provided in an embodiment of the present application;

[0057] Figure 10 200kHz power reduction point deviation curve diagram provided in an embodiment of the present application;

[0058] Figure 11 This is a schematic diagram of the attenuation curve of the 200kHz power reduction point provided in an embodiment of the present application.

[0059] Reference numerals:

[0060] Laser circuit 100 ; board controller 110 ; frequency modulation circuit 111 ; light output regulation circuit 112 ; power regulation circuit 113 ; laser generating circuit 120 ; seed pulse generating circuit 121 ; gain circuit 122 ; control board 200 . DETAILED DESCRIPTION

[0061] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0062] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0063] The highly stable fiber pulse MOPA laser control method and the fiber pulse laser provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0064] The high-stability fiber pulse MOPA laser control method is applied to laser circuits;

[0065] like Figure 1 As shown, the laser circuit 100 is connected to the control board 200;

[0066] The laser circuit includes: a board controller 110 and a laser generating circuit 120;

[0067] The control board 200 is used to output pulse width modulation signals, repetition rate signals, switching optical signals and power signals;

[0068] The board controller 110 includes a frequency modulation circuit 111, a light output adjustment circuit 112 and a power adjustment circuit 113 which are connected to each other;

[0069] The laser generating circuit 120 includes a seed pulse generating circuit 121 and a gain circuit 122 connected in sequence;

[0070] like Figure 2 As shown, the method includes:

[0071] S1, outputting a frequency modulation signal according to the re-frequency signal through the frequency modulation circuit 111;

[0072] S2, when receiving a trigger signal, the seed pulse generating circuit 121 outputs a seed pulse and an index signal according to the pulse width modulation signal and the frequency modulation signal;

[0073] S3, obtaining and outputting a light output phase compensation signal according to the switching light signal and the index signal through the light output adjustment circuit 112;

[0074] S4, outputting a power compensation signal according to the power signal and the index signal through the power regulation circuit 113;

[0075] S5 , using the gain circuit 122 , the seed pulse is compensated according to the output light phase compensation signal and the power compensation signal, and a laser pulse is output.

[0076] Among them, the master oscillator power amplifier (MOPA) can provide high-quality and high-power laser output.

[0077] The control board may include a control chip, such as a Field-Programmable Gate Array (FPGA).

[0078] The pulse width modulation signal is used to control the pulse width of the seed pulse. The repetition rate signal is used as a reference signal of the frequency to limit the number of laser pulses output per unit time. The switching light signal is used to control whether the laser emits a laser beam. The power signal is used to limit the power of the laser beam emitted by the laser.

[0079] It can be understood that the pulse width modulation signal, the repetition rate signal, the switching optical signal and the power signal have clock synchronization.

[0080] The output light phase compensation signal is used to adjust the frequency of the seed pulse, and the output light phase of the pump is affected by the frequency.

[0081] In actual execution, the control board 200 outputs the pulse width modulation signal to the seed pulse generating circuit 121 , outputs the repetition frequency signal to the frequency modulation circuit 111 , outputs the switching light signal to the light output adjustment circuit 112 , and outputs the power signal to the power adjustment circuit 113 .

[0082] The frequency modulation circuit 111 outputs a frequency modulation signal according to the re-frequency signal, and outputs the frequency modulation signal to the seed pulse generating circuit 121;

[0083] In the laser generating circuit 120, the seed pulse generating circuit 121, upon receiving the trigger signal, outputs a seed pulse and an index signal according to the pulse width modulation signal and the frequency modulation signal. The frequency modulation signal is used to adjust the phases of the pulse signal and the index signal. The seed pulse is output to the gain circuit 122, and the index signal is output to the frequency modulation circuit 111, the light output adjustment circuit 112, and the power adjustment circuit 113 respectively.

[0084] The light output adjustment circuit 112 outputs a light output phase compensation signal for controlling the pumping duration according to the switching optical signal and the index signal;

[0085] The power regulation circuit 113 outputs the power compensation signal according to the power signal and the index signal;

[0086] The gain circuit 122 performs phase compensation and power compensation according to the output light phase compensation signal and the power compensation signal, and outputs a laser pulse.

[0087] According to the high-stability fiber pulse MOPA laser control method provided in the embodiment of the present application, compensation is performed by outputting a light phase compensation signal and a power compensation signal, so that the power linearity of the output laser pulses of different frequencies and the energy of the single pulse remain stable, so that the energy of the single pulses of different frequencies can be consistent, thereby improving the stability and output consistency of the laser pulses.

[0088] In some embodiments, as Figure 3 As shown, the frequency modulation circuit 111 includes a frequency measurement module, a frequency generation module and a frequency phase control module connected in sequence. The frequency modulation circuit outputs a frequency modulation signal according to the re-frequency signal, including:

[0089] The frequency measurement module measures the repetition frequency signal to obtain an input frequency;

[0090] The frequency generating module outputs a trigger pulse according to the light-on signal and the input frequency, and the light-on signal is output by the light-out adjustment circuit according to the switching light signal;

[0091] The frequency phase control module outputs the frequency modulation signal according to the trigger pulse, the input frequency and the index signal.

[0092] Among them, the trigger pulse is used for frequency phase control, and the index signal is used to control the pulse phase in the frequency phase control module.

[0093] In actual execution, the frequency measurement module measures the repetition frequency signal input by the control board 200 to obtain the real-time input frequency;

[0094] The current intensity control module determines the current intensity of the pre-amplifier module and the main amplifier module according to the input frequency and the index signal, and generates a current intensity signal;

[0095] The light output duration control module determines the pumping duration of the pre-amplifier module and the main amplifier module according to the input frequency to compensate for the frequency single pulse energy stability;

[0096] The optical phase control module mainly generates a phase compensation signal based on the input frequency and pump duration, and outputs it to the preamplifier module and the main amplifier module. It compensates the frequency-phase characteristics of the seed pulse and the preamplifier module and the main amplifier module at different frequencies, so that the pulse phase of the seed pulse and the pump phase remain unchanged, thereby ensuring the amplifier efficiency and reducing the amplifier's ASE (Amplified Spontaneous Emission), especially when operating at low repetition rates.

[0097] Under the control of the switching signal, the frequency generation module generates a trigger pulse consistent with the input frequency and gives it to the frequency phase control module; at the same time, the output trigger pulse also serves as the synchronization signal of the light emission duration control module.

[0098] The frequency phase control module generates a frequency modulation signal according to the input frequency, index signal and trigger pulse. The frequency modulation signal is used to adjust the phase of the seed pulse under different seed widths and compensate for the frequency and phase characteristics of the preamplifier module.

[0099] In some embodiments, the gain circuit 122 includes a pre-amplifier module and a main amplifier module connected in sequence. The gain circuit compensates the seed pulse according to the output phase compensation signal and the power compensation signal to output a laser pulse, including:

[0100] The pre-amplifier module controls the light emission duration of the seed pulse according to the light emission phase compensation signal and the current intensity signal, and outputs an amplified signal;

[0101] The main amplifier module performs phase compensation on the amplified signal according to the output light phase compensation signal and the power compensation signal to obtain and output the laser pulse.

[0102] It is understandable that both the pre-amplifier module and the main amplifier module in the gain circuit 122 can adjust the gain of the seed pulse through pump power regulation and timing control.

[0103] For pump power regulation, the output power of the pump light source (such as a laser diode, xenon lamp, etc.) can be adjusted to precisely control the particle excitation level in the gain medium.

[0104] For timing control, the pump light's on and off times can be adjusted so that the pump energy is transferred to the seed pulse at the appropriate moment.

[0105] In the pre-amplifier module, the pump duration and amplitude are adjusted according to the current intensity signal to control the light output intensity. The excitation level of the laser gain medium can be controlled, thereby adjusting the gain of the seed pulse. The seed pulse is phase compensated according to the light output phase compensation signal, and the phase of the seed pulse is corrected to restore its phase to the ideal state, ensuring that the seed pulse maintains optimal coherence after amplification.

[0106] Among them, the appropriate current intensity ensures that the gain of the laser medium is within an ideal range, avoiding over-saturation or insufficient gain.

[0107] When a signal passes through a gain medium, it may be affected by medium nonlinear effects, dispersion effects, or other environmental factors, causing the signal phase to shift.

[0108] In the main amplifier module, the output phase compensation signal can adjust the phase error of the amplified signal and correct the phase of the seed pulse; the power compensation signal can fine-tune the power of the amplified signal to ensure that the power of the output laser pulse is always stable at the target value.

[0109] The output phase compensation signal and the power compensation signal work together to ensure that the gain process of the output laser pulse can provide sufficient output power while ensuring the coherence and stability of the signal.

[0110] In this embodiment, in the pre-amplifier module, the seed pulse is amplified by a relatively small pump energy, raising the power of the seed pulse to a suitable level to achieve maximum gain while avoiding over-saturation or nonlinear effects. In the main amplifier module, the signal is further amplified to achieve the required output power, ensuring that the output laser pulse has higher power and stability. In a multi-stage high-power system, there are differences in the control circuit signals of each stage of the amplifier, which can easily cause timing problems. The amplifier synchronous light output phase adjustment logic ensures the safety of the light output timing of each stage.

[0111] In some embodiments, the power regulation circuit 113 includes a current intensity control module and a power control module connected in sequence; the power regulation circuit outputs a power compensation signal according to the power signal and the index signal, including:

[0112] Outputting a current intensity signal and a current control signal according to the input frequency and the index signal through the current intensity control module;

[0113] Performing gain control on the laser pulse according to the current control signal through the gain circuit 122;

[0114] The power control module outputs the power compensation signal according to the current intensity signal.

[0115] The index signal is used in the current intensity control module to control the current intensity.

[0116] Since different seed pulses require different pump widths, real-time seed phase adjustment is required.

[0117] The pulse width of the seed pulse is 0.5 to 500 ns, and the corresponding pump width may vary from 5 ns to 100 μs. Therefore, the phase control of the seed requires high delay accuracy and a wide range. The frequency phase control module is equipped with FIFO (First In, First Out) delay logic.

[0118] like Figure 4 As shown, the horizontal axis is frequency, the unit is kHz, and the vertical axis is average power, the unit is W, such as Figure 5 As shown, the horizontal axis is frequency in kHz, and the vertical axis is energy in mJ. When the working clock is 200MHz, the laser power reduction frequency is 40kHz, and the frequency works at 20kHz, the frequency phase control module needs to achieve a lag of 180° (delay of 25μs).

[0119] The phase control module mainly includes phase conversion delay logic and FIFO delay logic.

[0120] like Figure 6 As shown in the figure, in the FIFO delay logic implementation principle, the input is CLK, IN, the setting logic (delay value), and the output is OUT.

[0121] At the delay value T d After confirmation, calculate the number of delay clocks D required n :

[0122] D n =T d / T c

[0123] Among them, T c is the clock period of the FIFO.

[0124] Assume that the maximum storage depth of FIFO is D epth , single bit, then the RAM occupied is D epth *bit resources, from storage unit 0 to D epth –D n All the storage units are set to 0, then the D n After CLK, the IN state is output, that is, T d After the delay time, the output is in IN state.

[0125] In the pre-amplifier module, frequency-phase characteristic compensation is performed. The pump drive generally adopts a linear constant current source. Its frequency-amplitude characteristic is similar to that of a low-pass filter, and its bandwidth is approximately 1MHz. Therefore, at different frequencies, the actual current phase is offset (maximum lag of 90°). To ensure the stability of the pre-amplifier current and seed pulse phase, compensation is required at different frequency seed phases.

[0126] The pulse generating module receives the trigger pulse and outputs a seed pulse with the pulse width required by the control board 200, which is loaded into the radio frequency amplifier to drive the seed pump to output a laser pulse with the corresponding pulse width.

[0127] The pulse signal can be generated by delay multiplication, phase-locked loop or DDS.

[0128] In some embodiments, the seed pulse generating circuit 121 includes a pulse generating module and a seed module connected in sequence. When the seed pulse generating circuit receives a trigger signal, the seed pulse and index signal are output according to the pulse width modulation signal and the frequency modulation signal, including:

[0129] The pulse generating module is triggered by the trigger signal and outputs a pulse signal and an index signal according to the pulse width modulation signal and the frequency modulation signal;

[0130] The seed module outputs the seed pulse according to the pulse signal.

[0131] In some embodiments, the light output adjustment circuit 112 includes a light output control module, a light output duration control module, and a light output phase control module connected in sequence; the light output adjustment circuit obtains and outputs a light output phase compensation signal according to the switching optical signal and the index signal, including:

[0132] Obtaining a light output control signal according to the switch light signal through the light output control module;

[0133] Outputting a pumping duration signal through the light emission duration control module according to the light emission control signal, the input frequency, the index signal and the trigger pulse;

[0134] The light output phase control module outputs the light output phase compensation signal according to the pump duration signal and the input frequency.

[0135] The optical control module primarily synchronizes the optical switching control signals from the control board, resolving cross-clock domain issues. One channel outputs the optical switching signal to the frequency generator module, forcing synchronization with the switching signal. Another channel outputs the optical control signal to the optical duration control module.

[0136] After receiving the light emission control signal, the light emission duration control module generates a pump duration signal by synchronizing the seed pulse width (index signal) and the current frequency (input frequency) through the trigger pulse to control the pump light emission time to ensure the stability of the light pulse energy.

[0137] When working at low frequency, the amplifier pump extraction efficiency in the gain circuit 122 is low, so the light emission time is prolonged; the functional relationship is: The functional relationship is obtained by o Below the frequency of / 2, the pump width is adjusted without changing the energy.

[0138] Formula 2: y = ax b +c; coefficients a = 105.37, b = -0.348, c = -40. The above coefficients will be adjusted according to different machines. x represents the input frequency f, and y represents the adjustment amount of the pump width under low frequency operation f l , we can get the functional relationship:

[0139] f l =af b +c

[0140] like Figure 7-Figure 9 As shown in Figure 2, the single pulse energy is significantly improved after compensation using Formula 2. Figure 7 is the uncompensated energy curve, after compensation Figure 8 , the pulse energy stability is significantly improved.

[0141] When working at high frequency, due to the low-pass characteristics of the constant current source, the pump output power will become higher in the frequency transition band, and the light output time will be reduced in this frequency band. h , the functional relationship is f h =ψ(f); the functional relationship is obtained by o / 2 to f o The pump width is adjusted while the frequency and energy remain unchanged. The fitting formula is as follows:

[0142] like Figure 10 As shown in 11, for formula 3: f h =af + b; coefficients a = 0.5454, b = -84.136; where the independent variable x is the operating frequency divided by the power reduction frequency. The above deviations are mainly caused by the circuit bandwidth and the pump's own characteristics.

[0143] The power reduction frequency point is f o , then the pump light emission time T on for:

[0144] T on =1 / f o +f l –fh ;

[0145] Where 1 / f o is the reference width of the pulse pump, used as the reference time.

[0146] The output light phase control module receives the pump duration signal from the output light duration control module, combines it with the input frequency, and outputs the output light phase compensation signal through the output light phase control module to control the pump light output of the pre-amplifier module and the main amplifier module. The output light intensity is controlled by the output light intensity control logic.

[0147] Due to the current value, wire length, constant current source loop parameters, and frequency-phase characteristics of the pump constant current source in the pre-amplifier module and the main amplifier module, there are differences in the phase of the gain control of the seed pulse by the pre-amplifier module and the main amplifier module. The output phase control signal can compensate for this difference, achieve synchronization, and further improve the stability of the laser pulse energy.

[0148] In the light intensity control logic, the current intensity control module caches the peak current corresponding to each seed pulse width in the preamplifier module and the main amplifier module in its memory. After the pulse width is confirmed according to the input frequency, the peak current of the preamplifier module and the main amplifier module is indexed according to the index signal. The actual current of the preamplifier module and the main amplifier module is calculated based on the functional relationship between the peak current of the preamplifier module and the main amplifier module and the frequency, and the current control signal and current intensity signal are obtained. They are directly loaded onto the pump of the preamplifier module, and the current intensity signal is output to the power control module.

[0149]

[0150] Where, f is the laser frequency, f o is the pulse pump frequency (reference), f h To reduce the power frequency.

[0151] When the laser frequency f is less than the pulse pump frequency boundary point f o When the pulse pump is working, the duty cycle will also decrease as the frequency decreases, and the pulse pump output peak current I max ; When the laser frequency f is greater than the pulse pump frequency cutoff point f o , and is less than the power reduction frequency f h When the laser frequency f is greater than the power reduction frequency f, the continuous pump calculates the current according to the frequency; when the laser frequency f is greater than the power reduction frequency f h , continuous pump output peak current I max ; Added f o The linear constant current source has a maximum frequency. When the frequency is greater than this, the linear constant current source will not respond.

[0152] The power control module determines the output power compensation signal according to the process application requirements based on the current intensity signal and the power signal, controls the output power of the main amplifier module, and loads the power percentage multiplied by the current of the main amplifier module onto the pump of the main amplifier module.

[0153] The power compensation signal is mainly used for attenuation. The current intensity is used to calculate the maximum current under the corresponding frequency and pulse. The pre-amplifier module directly outputs it, and the main amplifier module attenuates the power percentage and outputs the laser pulse.

[0154] In this embodiment, after the pulse width is determined, the pump width is different at each frequency. The laser circuit can ensure the stability of the power linearity and single pulse energy of the final output laser pulse, and can solve the problem of efficiency differences at different frequencies. Since the pump width of each frequency is different, the seed pulse phase is adjusted to ensure the maximum pump extraction efficiency of the amplifier and the safety of the laser when the parameters are changed. In order to ensure the alignment of the starting end of the marking process and the adjustment of the seed phase, the seed pulse is forced to be synchronized after the opening signal is valid. The seed phase adjustment range of different laser types is 5ns to 200μs, which is the synchronization of the timing system and a wide range of delay. The FIFO method is used to achieve delay, which has the characteristics of high precision, wide range, and complete synchronization. This is also an innovation of the present invention.

[0155] The high-stability fiber pulse MOPA laser control method provided in the embodiment of the present application can realize pump control to improve the TMI threshold, while correcting the frequency power nonlinear distortion and performing synchronization processing on the starting position control in the processing system.

[0156] In some embodiments, the laser circuit further includes a clock circuit, wherein the clock circuit is connected to the control board, and the method further includes:

[0157] Generate an output clock signal according to the internal clock signal of the laser through the clock circuit;

[0158] Clock synchronization is performed through the control board according to the output clock signal.

[0159] In some embodiments, the method further comprises:

[0160] The clock circuit receives the input clock signal of the control board, and performs clock synchronization on the pulse width modulation signal, the repetition frequency signal, the switching optical signal and the power signal through the input clock signal.

[0161] Among them, the clock circuit has a built-in phase-locked loop (PLL).

[0162] In this embodiment, by outputting a clock signal or inputting a clock signal, the laser circuit and the control board are completely synchronized, thereby achieving high-precision pulse control.

[0163] In some embodiments, the laser circuit further comprises: a central processing unit, and the method further comprises:

[0164] The central processing unit is used to configure parameters of the frequency modulation circuit, the light output adjustment circuit and the power adjustment circuit in the board controller.

[0165] The board controller can be implemented through FPGA logic, and the communication interface of the central processing unit (CPU) includes an Ethernet port and a serial port.

[0166] The present application also provides a fiber pulse laser for executing the high-stability fiber pulse MOPA laser control method as described in the above embodiment.

[0167] In the description of this application, "first feature" and "second feature" may include one or more such features.

[0168] In the description of this application, “plurality” means two or more.

[0169] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

[0170] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0171] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A high-stability fiber pulse MOPA laser control method, characterized in that: Applied to a laser circuit, the laser circuit is connected to a control board; The laser circuit includes: a board controller and a laser generating circuit; The control board is used to output pulse width modulation signals, repetition rate signals, switching optical signals and power signals; The board controller includes a frequency modulation circuit, a light output regulation circuit and a power regulation circuit which are interconnected; The laser generating circuit includes a seed pulse generating circuit and a gain circuit connected in sequence; The method comprises: Outputting a frequency modulation signal according to the re-frequency signal through the frequency modulation circuit; When a trigger signal is received, the seed pulse generating circuit outputs a seed pulse and an index signal according to the pulse width modulation signal and the frequency modulation signal; Obtaining a light output phase compensation signal according to the switching light signal and the index signal through the light output adjustment circuit and outputting the signal; outputting a power compensation signal according to the power signal and the index signal through the power regulation circuit; The seed pulse is compensated for by the gain circuit according to the output light phase compensation signal and the power compensation signal, and a laser pulse is output.

2. The high-stability fiber pulse MOPA laser control method according to claim 1, characterized in that: The light output adjustment circuit includes a light output control module, a light output duration control module, and a light output phase control module connected in sequence; the light output adjustment circuit obtains and outputs a light output phase compensation signal according to the switching optical signal and the index signal, including: Obtaining a light output control signal according to the switch light signal through the light output control module; Outputting a pumping duration signal through the light emission duration control module according to the light emission control signal, the input frequency, the index signal and the trigger pulse; The light output phase control module outputs the light output phase compensation signal according to the pump duration signal and the input frequency.

3. The high-stability fiber pulse MOPA laser control method according to claim 2, characterized in that: The power regulation circuit includes a current intensity control module and a power control module connected in sequence; the power regulation circuit outputs a power compensation signal according to the power signal and the index signal, including: Outputting a current intensity signal and a current control signal according to the input frequency and the index signal through the current intensity control module; performing gain control on the laser pulse according to the current control signal through the gain circuit; The power control module outputs the power compensation signal according to the current intensity signal.

4. The high-stability fiber pulse MOPA laser control method according to claim 1, characterized in that: The seed pulse generating circuit includes a pulse generating module and a seed module connected in sequence. When the seed pulse generating circuit receives a trigger signal, it outputs a seed pulse and an index signal according to the pulse width modulation signal and the frequency modulation signal, including: The pulse generating module is triggered by the trigger signal and outputs a pulse signal and an index signal according to the pulse width modulation signal and the frequency modulation signal; The seed module outputs the seed pulse according to the pulse signal.

5. The high-stability fiber pulse MOPA laser control method according to claim 1, characterized in that: The frequency modulation circuit includes a frequency measurement module, a frequency generation module, and a frequency phase control module connected in sequence. The frequency modulation circuit outputs a frequency modulation signal according to the re-frequency signal, including: The frequency measurement module measures the repetition frequency signal to obtain an input frequency; The frequency generating module outputs a trigger pulse according to the light-on signal and the input frequency, and the light-on signal is output by the light-out adjustment circuit according to the switching light signal; The frequency phase control module outputs the frequency modulation signal according to the trigger pulse, the input frequency and the index signal.

6. The high-stability fiber pulse MOPA laser control method according to claim 1, characterized in that: The gain circuit includes a pre-amplifier module and a main amplifier module connected in sequence. The gain circuit compensates the seed pulse according to the output light phase compensation signal and the power compensation signal to output a laser pulse, including: The pre-amplifier module controls the light emission duration of the seed pulse according to the light emission phase compensation signal and the current intensity signal, and outputs an amplified signal; The main amplifier module performs phase compensation on the amplified signal according to the output light phase compensation signal and the power compensation signal to obtain and output the laser pulse.

7. The high-stability fiber pulse MOPA laser control method according to claim 1, characterized in that: The laser circuit further includes a clock circuit, and the clock circuit is connected to the control board. The method further includes: Generate an output clock signal according to the internal clock signal of the laser by the clock circuit; Clock synchronization is performed through the control board according to the output clock signal.

8. The high-stability fiber pulse MOPA laser control method according to claim 7, characterized in that: The method further comprises: The clock circuit receives the input clock signal of the control board, and performs clock synchronization on the pulse width modulation signal, the repetition frequency signal, the switching optical signal and the power signal through the input clock signal.

9. The high-stability fiber pulse MOPA laser control method according to claim 1, characterized in that: The laser circuit further includes: a central processing unit, and the method further includes: The central processing unit is used to configure parameters of the frequency modulation circuit, the light output adjustment circuit and the power adjustment circuit in the board controller.

10. A fiber pulse laser, characterized in that: Used to execute the high-stable fiber pulse MOPA laser control method according to any one of claims 1 to 9.

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