Pulse number self-correction control device, method and fiber laser

Abstract

The embodiment of the present invention discloses a pulse number self-correction control device, method and fiber laser, which includes a signal output circuit, a signal delay circuit, an acousto-optic modulation driver and a coupling pulse circuit. The acousto-optic modulation driver is used to select an optical pulse signal from the seed optical signal output by the signal output circuit; the coupling pulse circuit is used to convert the optical pulse signal into an electrical pulse signal; the signal delay circuit is used to identify the pulse number of the electrical pulse signal and adjust the delay time of the acousto-optic drive signal that drives the acousto-optic modulation driver according to the pulse number, so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number. The embodiment of the present invention uses the optical pulse signal selected by the acousto-optic modulation driver as the effect feedback for adjusting the acousto-optic drive signal, thereby adjusting the delay of the acousto-optic drive signal, realizing self-calibration of the frequency-selective pulse, and improving the reliability and accuracy of the frequency-selective pulse calibration.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber lasers, and in particular to a pulse number self-correction control device and method and an optical fiber laser. Background Art

[0002] Currently, pulse count control for low-repetition-rate ultrafast fiber lasers on the market is primarily achieved through circuit-controlled acousto-optic modulator (AOM) drivers. In the optical path, differences in fiber length and incomplete synchronization between the seed source signal and the repetition-rate signal result in discrepancies between the time the seed light signal reaches the AOM driver for each laser and the time the AOM driver switches on and off, using the repetition-rate signal as a switching time reference. Circuit-wise, hardware delays in processing the repetition-rate signal, along with transmission line length delays in the seed source repetition signal and the AOM driver's drive signal, further increase the time difference between the AOM driver's on / off switch and the time the seed light signal reaches the AOM driver. This discrepancy often causes the AOM driver to activate only after the seed light signal arrives, resulting in the selected optical pulse signal having a half-pulse at the first or last pulse train. While this phenomenon can be corrected by adjusting the time delay and pulse width before shipment using an oscilloscope or other means, it can recur with age due to changes in transmission delay caused by aging of the machine's optical path and circuitry.

[0003] Although adjusting the pulse delay before shipment using an oscilloscope or other observational methods temporarily achieves the goal of accurately controlling the number of pulses, due to the limitations of the circuit's main control chip's oscillation frequency, it can often only achieve a delay step of a few nanoseconds, making this method of manually adjusting the delay time-consuming and labor-intensive. Furthermore, the delay is only fixed on the circuit's main control chip after adjustment. However, this time difference, caused by many factors, often changes as the machine ages, making this method of fixed delay unreliable. Therefore, how to achieve self-correction control of the pulse number of the frequency-selective pulses of a fiber laser is an urgent problem that needs to be solved. Summary of the Invention

[0004] In a first aspect, the present invention provides a pulse number self-correction control device, comprising:

[0005] a signal output circuit for generating a seed optical signal of a low repetition rate femtosecond pulse and a repetition rate signal having the same frequency as the seed optical signal, and amplifying the seed optical signal;

[0006] a signal delay circuit, configured to receive the repetition frequency signal, select a rising edge of any pulse of the repetition frequency signal as a time starting point, and generate an acousto-optic driving signal according to the time starting point, a preset frequency selection frequency, and a preset number of pulses;

[0007] an acousto-optic modulation driver, configured to select a specific frequency and a specific number of pulses from the amplified seed light signal according to the acousto-optic drive signal, to obtain an optical pulse signal;

[0008] a coupled pulse circuit, configured to divide the optical pulse signal selected by the acousto-optic modulation driver according to a predetermined ratio to obtain a first low-power optical signal, and convert the first low-power optical signal into a first electrical pulse signal;

[0009] The signal delay circuit is also used to receive the first electrical pulse signal, identify the number of pulses of the first electrical pulse signal, and preliminarily adjust the delay time of the acousto-optic drive signal according to the number of pulses, so that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset number of pulses. After the preliminary adjustment, the delay time of the acousto-optic drive signal is adjusted again, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic drive signal.

[0010] In an optional embodiment, the signal delay circuit is used to:

[0011] intercepting the number of pulses corresponding to a preset period of time in the first electrical pulse signal;

[0012] Preliminarily adjusting the delay time of the acousto-optic driving signal according to the pulse number so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number;

[0013] After the initial adjustment, the delay time of the acousto-optic driving signal is adjusted again, and the number of pulses corresponding to the preset cycle time in the second electrical pulse signal is intercepted, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic driving signal, wherein the second electrical pulse signal is obtained by converting the optical pulse signal selected by the acousto-optic modulation driver through the coupling pulse circuit after the delay time is adjusted again.

[0014] In an optional embodiment, the signal delay circuit includes:

[0015] a repetition frequency detection circuit, configured to convert the repetition frequency signal into a repetition frequency electrical signal;

[0016] A timing logic circuit is used to receive the repetitive frequency electrical signal, select any rising edge of the pulse of the repetitive frequency electrical signal as a time starting point, and generate an acousto-optic driving signal according to the time starting point, a preset frequency selection frequency and a preset number of pulses; receive the optical pulse signal output by the acousto-optic modulation driver, identify the number of pulses of the optical pulse signal, and preliminarily adjust the delay time of the acousto-optic driving signal according to the number of pulses so that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset number of pulses; and after the preliminarily adjustment, adjust the delay time of the acousto-optic driving signal again, record the time mean corresponding to the extra pulses, and use the time mean as the optimal delay time of the acousto-optic driving signal.

[0017] In an optional embodiment, the signal output circuit includes:

[0018] A low repetition rate seed source, used to generate a seed optical signal of a low repetition rate femtosecond pulse and a repetition rate signal having the same frequency as the seed optical signal;

[0019] A pump laser is used to amplify and stabilize the seed light signal.

[0020] In an optional embodiment, the coupled pulse circuit includes:

[0021] a coupler for dividing the optical pulse signal selected by the acousto-optic modulation driver according to a predetermined ratio to obtain a low-power signal;

[0022] The photodetector circuit is used to convert the low-power signal into an electrical pulse signal.

[0023] In an optional embodiment, it further includes an acousto-optic modulation driver circuit;

[0024] The acousto-optic modulation driver circuit is used to receive the acousto-optic driving signal from the signal delay circuit and output a control signal that meets the working level of the acousto-optic modulation driver according to the acousto-optic driving signal;

[0025] The acousto-optic modulation driver is further configured to perform an operation of selecting a specific frequency and a specific number of pulses on the seed light signal according to the control signal.

[0026] In a second aspect, the present invention provides a pulse number self-correction control method, comprising:

[0027] receiving a repetition frequency signal from a signal output circuit, and selecting any rising edge of a pulse of the repetition frequency signal as a time starting point;

[0028] generating an acousto-optic driving signal according to the time starting point, the preset frequency selection frequency, and the preset number of pulses, so that the acousto-optic modulation driver selects a seed light signal output by the signal output circuit with a specific frequency and a specific number of pulses according to the acousto-optic driving signal to obtain an optical pulse signal;

[0029] Receive a first electrical pulse signal, identify the pulse number of the first electrical pulse signal, and preliminarily adjust the delay time of the acousto-optic drive signal according to the pulse number so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number. After the preliminary adjustment, adjust the delay time of the acousto-optic drive signal again, record the time mean corresponding to the extra pulses, and use the time mean as the optimal delay time of the acousto-optic drive signal; wherein the first electrical pulse signal is obtained by performing signal conversion on a first low-power signal obtained by dividing the optical pulse signal according to a predetermined ratio.

[0030] In an optional embodiment, the delay time of the acousto-optic drive signal is preliminarily adjusted according to the number of pulses so that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset number of pulses, and after the preliminary adjustment, the delay time of the acousto-optic drive signal is adjusted again, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic drive signal, including:

[0031] intercepting the number of pulses corresponding to a preset period of time in the first electrical pulse signal;

[0032] Preliminarily increasing or decreasing the delay time of the acousto-optic driving signal according to the pulse number, so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number;

[0033] After the preliminary adjustment, the delay time of the acousto-optic driving signal is increased and decreased again, and the number of pulses corresponding to the preset cycle time in the second electrical pulse signal is intercepted, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic driving signal, wherein the second electrical pulse signal is obtained by converting the optical pulse signal selected by the acousto-optic modulation driver through the coupling pulse circuit after adjusting the delay time again.

[0034] In a third aspect, the present invention provides a low repetition rate ultrafast fiber laser, comprising a memory and at least one processor, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the aforementioned pulse number self-correction control method.

[0035] In a fourth aspect, the present invention provides a computer storage medium storing a computer program, which, when executed, implements the aforementioned pulse number self-correction control method.

[0036] The embodiments of the present invention have the following beneficial effects:

[0037] An embodiment of the present invention provides a pulse number self-correction control device. The device uses the optical pulse signal selected by the acousto-optic modulation driver as feedback for adjusting the acousto-optic drive signal. By adjusting the delay of the acousto-optic drive signal, the device avoids the acousto-optic modulation driver switching upon the arrival of the optical pulse signal, which would otherwise cause pulse shedding. This device achieves self-calibration of the frequency-selective pulse, thereby greatly reducing the complexity of manually adjusting the frequency-selective pulse delay and improving the reliability and accuracy of the frequency-selective pulse calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope of protection of the present invention. In each of the drawings, similar components are numbered similarly.

[0039] Figure 1 A schematic diagram of an implementation of a pulse number self-correction control method according to an embodiment of the present invention is shown;

[0040] Figure 2 A schematic structural diagram of a pulse number self-correction control device according to an embodiment of the present invention is shown;

[0041] Figure 3 Another structural diagram of the pulse number self-correction control device according to an embodiment of the present invention is shown;

[0042] Figure 4 A pulse schematic diagram of the acousto-optic driving signal under two time delays in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0044] The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the figures is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort are intended to be within the scope of protection of the present invention.

[0045] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present invention, are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0046] In addition, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0047] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present invention pertain. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present invention.

[0048] Example 1

[0049] Please refer to Figure 1 An embodiment of the present invention provides a pulse number self-correction control method, which is described in detail below.

[0050] S110, receiving a repetition frequency signal from a low repetition frequency seed source, and selecting any rising edge of a pulse of the repetition frequency signal as a time starting point.

[0051] S120, generating an acousto-optic driving signal according to the time starting point, the preset frequency selection frequency, and the preset number of pulses, so that the acousto-optic modulation driver selects a seed optical signal with a specific frequency and a specific number of pulses output by the signal output circuit according to the acousto-optic driving signal to obtain an optical pulse signal.

[0052] S130, receiving a first electrical pulse signal, identifying the number of pulses of the first electrical pulse signal, and preliminarily adjusting the delay time of the acousto-optic drive signal based on the number of pulses so that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver is consistent with a preset number of pulses. After the preliminarily adjustment, the delay time of the acousto-optic drive signal is adjusted again, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic drive signal; wherein the first electrical pulse signal is obtained by performing signal conversion on a first low-power signal obtained by dividing the optical pulse signal according to a predetermined ratio.

[0053] The low repetition rate seed source generates a seed light signal of a low repetition rate femtosecond pulse and a repetition rate signal with a frequency consistent with the seed light signal.

[0054] Receive a repetition frequency signal from a low repetition frequency seed source, and select any rising edge pulse of the repetition frequency signal as the time starting point, and then generate an acousto-optic driving signal based on the time starting point, the preset frequency selection frequency and the preset number of pulses, and transmit the acousto-optic driving signal to the acousto-optic modulation driver to drive the acousto-optic modulation driver to select a specific frequency and a specific number of pulses of the seed light signal from the low repetition frequency seed source to obtain an optical pulse signal. This process can be implemented based on a timing logic circuit, such as an FPGA circuit. After the acousto-optic modulation driver selects the optical pulse signal, it can divide the optical pulse signal according to a predetermined ratio through a coupling pulse circuit to obtain a first low-power signal, and convert the first low-power signal into a first electrical pulse signal, and transmit the first electrical pulse signal to the timing logic circuit. Among them, the preset frequency selection frequency and the preset number of pulses are the frequency selection frequency and the number of pulses preset by the user, so their specific values ​​are not limited here.

[0055] The number of pulses of the first electrical pulse is identified by a sequential logic circuit, and the delay time of the output acousto-optic drive signal is dynamically adjusted based on the number of pulses of the first electrical pulse signal. Specifically, when it is identified that the number of pulses of the first electrical pulse signal is inconsistent with a preset number of pulses, the delay time of the acousto-optic drive signal is adjusted to increase or decrease the time delay of the acousto-optic drive signal accordingly, so that the number of pulses of the selected optical pulse signal is consistent with the preset number of pulses. The delay time is then increased or decreased based on the current delay, and the delay time intermediate between the increase and decrease in delay that results in an extra pulse is selected as the optimal delay.

[0056] It should be noted that determining whether an optical pulse signal has been collected is done by setting a comparison value and comparing the optical pulse signal with the comparison value. If the comparison value is greater than or equal to the comparison value, it is determined that the optical pulse signal has been collected; if the comparison value is less than the comparison value, it is determined that the optical pulse signal has not been collected. Therefore, the collected optical pulse signal cannot accurately reflect the actual optical signal. The set comparison value can be set according to actual conditions and is not limited here. When the delay time of the acousto-optic drive signal is initially adjusted so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number, some small pulse signals in the actual optical pulse signal may be ignored. Therefore, it is necessary to adjust the time delay of the acousto-optic drive signal again to accurately select the optical pulse signal and achieve self-correction of the pulse number of the optical pulse signal.

[0057] In this embodiment, a cycle time of a desired number of pulses is pre-set, the pulses corresponding to the first electrical pulse signal within the cycle time are intercepted, the pulse number of the first electrical pulse signal is identified, and the delay time of the acousto-optic drive signal is preliminarily adjusted based on the pulse number, that is, the selection time of the optical pulse signal is controlled by increasing or decreasing the delay time so that the pulse number of the optical signal selected by the acousto-optic modulation driver is consistent with the preset pulse number. The delay time of the acousto-optic drive signal is then adjusted again, that is, the delay time is increased or decreased again, so that the acousto-optic modulation driver selects another optical pulse signal, and a second electrical pulse signal is obtained after processing by the coupled pulse circuit. Since, regardless of whether the delay time is increased or decreased, the second electrical pulse signal will be intercepted within the preset cycle time due to the extra pulses compared to the first electrical pulse signal. If the preset cycle time is located midway between the pulses of the first and second electrical pulse signals, that is, when the first and second electrical pulse signals are simultaneously intercepted during the cycle time with the increased and decreased delays, half a pulse of the first electrical pulse signal and half a pulse of the second electrical pulse signal can be intercepted under the increased and decreased delays. The average of the times corresponding to increasing and decreasing the delay is calculated and used as the optimal delay time for the acousto-optic drive signal. This optimal delay time is then used to indirectly control the number of pulses in the optical pulse signal selected by the acousto-optic modulation driver, achieving pulse number correction of the optical pulse signal.

[0058] At the software display implementation level, a selected optical pulse signal (electrical pulse signal) can be displayed through an interface, and a cycle time of a desired number of pulses is pre-set. When the optical pulse signal is intercepted within this cycle time, the interface displays a rectangular frame that selects a portion of the optical pulse signal. When the delay time of the acousto-optic driving signal is initially adjusted so that the number of pulses of the selected optical pulse signal is consistent with the preset number of pulses, the delay time of the acousto-optic driving signal is adjusted again. If half a pulse of the first optical pulse signal and the second optical pulse signal is selected in the rectangular frame when increasing or decreasing the delay, the average of the times corresponding to the increase and decrease of the delay is used as the optimal delay time.

[0059] Exemplarily, the time delay when the number of pulses of the first electric pulse signal is adjusted to be consistent with the preset number of pulses is t, the delay is increased, and the increased delay Δt1 resulting in the appearance of extra pulses is recorded, and then the delay is restored to t, the delay is reduced, and the reduced delay Δt2 resulting in the appearance of extra pulses is recorded. The optimal delay time T = t-(Δt1-Δt2) / 2 (if the sign of T is +, it indicates a corresponding increase in delay, and if the sign is -, it indicates a corresponding decrease in delay).

[0060] In this embodiment, the delay time of the acousto-optic drive signal that drives the acousto-optic modulation driver is dynamically adjusted by comparing the pulse number of the optical pulse signal selected by the acousto-optic modulation driver with a preset pulse number, so that the pulse number of the selected optical pulse signal is consistent with the preset pulse number, thereby achieving self-calibration of the frequency-selective pulse number, thereby greatly reducing the complexity of manually adjusting the frequency-selective pulse delay and improving the reliability and accuracy of the frequency-selective pulse calibration.

[0061] Example 2

[0062] Please refer to Figure 2 , an embodiment of the present invention provides a pulse number self-correction control device, comprising:

[0063] The signal output circuit 10 is used to generate a seed optical signal of a low repetition rate femtosecond pulse and a repetition rate signal having the same frequency as the seed optical signal, and to amplify the seed optical signal.

[0064] The signal delay circuit 20 is used to receive the repetition frequency signal, select any pulse rising edge of the repetition frequency signal as the time starting point, and generate the sound and light driving signal according to the time starting point, the preset frequency selection frequency and the preset number of pulses.

[0065] The acousto-optic modulation driver 30 is used to select a specific frequency and a specific number of pulses from the amplified seed optical signal according to the acousto-optic driving signal to obtain an optical pulse signal.

[0066] The coupling pulse circuit 40 is used to divide the optical pulse signal selected by the acousto-optic modulation driver 30 according to a predetermined ratio to obtain a first low-power signal, and convert the first low-power signal into a first electrical pulse signal.

[0067] The signal delay circuit 20 is also used to receive the first electrical pulse signal, identify the pulse number of the first electrical pulse signal, and preliminarily adjust the delay time of the acousto-optic driving signal according to the pulse number so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number. After the preliminary adjustment, the delay time of the acousto-optic driving signal is adjusted again, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic driving signal.

[0068] Refer to Figure 3 The signal output circuit 10 includes a low-repetition-rate seed source 11 and a pump laser 12. The low-repetition-rate seed source 11 is used to generate a low-repetition-rate femtosecond pulse seed optical signal and a repetition-rate signal with the same frequency as the seed optical signal. The pump laser 12 is used to amplify and stabilize the seed optical signal. The pump laser 12 amplifies and stabilizes the seed optical signal, allowing the acousto-optic modulation driver 30 to select a specific frequency and number of pulses from the amplified seed optical signal.

[0069] The signal delay circuit 20 includes a repetition frequency detection circuit 21 and a sequential logic circuit 22. The repetition frequency detection circuit 21 is used to convert the repetition frequency signal into a repetition frequency electrical signal that can be recognized by the sequential logic circuit. The sequential logic circuit 22 is used to receive the repetition frequency electrical signal, select any rising edge of the repetition frequency electrical signal as the time starting point, and generate an acousto-optic drive signal based on the time starting point, a preset frequency selection frequency, and a preset number of pulses. The sequential logic circuit 22 also receives the optical pulse signal output by the acousto-optic modulation driver 30, identifies the number of pulses in the optical pulse signal, and adjusts the delay time of the acousto-optic drive signal based on the pulse number to achieve self-correction of the optical pulse signal.

[0070] The coupled pulse circuit 40 includes a coupler 41 and a photodetector circuit 42. The coupler 41 is used to divide the optical pulse signal selected by the acousto-optic modulation driver into a predetermined ratio to obtain a low-power signal. The photodetector circuit 42 is used to convert the low-power signal into an electrical pulse signal that can be recognized by the sequential logic circuit 22.

[0071] Optionally, this embodiment further includes an acousto-optic modulation driver circuit 50, which is used to receive the acousto-optic drive signal from the timing logic circuit 22 and output a control signal that meets the working level of the acousto-optic modulation driver 30 based on the acousto-optic drive signal; the acousto-optic modulation driver 30 is also used to select a specific frequency and a specific number of pulses of the seed light signal based on the control signal.

[0072] In this embodiment, the sequential logic circuit 22 generates an acousto-optic drive signal (PWM / PFM signal) to drive the acousto-optic modulation driver 30 based on the frequency selection and pulse count preset by the user, combined with the starting time. Thus, in this embodiment, the seed light signal or repetition rate signal generated by the low repetition rate seed source 11 serves as the time reference for generating the acousto-optic drive signal.

[0073] The sequential logic circuit 22 receives the optical pulse signal output by the AOM driver 30, identifies the pulse number of the optical pulse signal, and dynamically adjusts the delay time of the AOM drive signal based on the pulse number to avoid switching when the optical pulse arrives, which would result in the effect of cutting out half a pulse. This process continues until the optical pulse selected by the AOM driver 30 matches the preset pulse number (preset pulse number). For example, the sequential logic circuit 22 employs an FPGA circuit.

[0074] It's worth noting that the AOM driver 30 uses the AOM drive signal as a switching timing reference. When it receives the AOM drive signal, it turns on to receive the seed light signal and select the optical pulse signal from it. However, due to differences in fiber length and incomplete synchronization between the seed light signal and the repetition signal in the optical path, the time it takes for the seed light signal from each laser to reach the AOM driver 30 is inconsistent with its switching timing. Furthermore, circuitry-wise, hardware delays in processing the repetition signal, along with transmission delays in the repetition signal and the AOM drive signal caused by the length of the transmission line, further increase the discrepancy between the switching timing of the AOM driver 30 and the time it takes for the seed light signal to reach the AOM driver 30. This discrepancy often causes the AOM driver 30 to turn on only after the seed light signal arrives, resulting in the selected optical pulse signal exhibiting half a pulse at the first or last pulse train (pulse cutting). In other words, the significant difference between the switching time of the AOM driver 30 and the time the seed light signal arrives at the AOM driver 30 causes pulse cutting in the optical pulse signal selected by the AOM driver 30. Therefore, the sequential logic circuit 22 preliminarily adjusts the delay time of the AOM driver signal to intercept the number of pulses corresponding to a preset cycle time in the first electrical pulse signal. The delay time of the AOM driver signal is preliminarily adjusted based on the number of pulses to adjust the switching time of the AOM driver 30 accordingly. This ensures that each pulse of the optical pulse signal selected by the AOM driver 30 is a complete pulse and the number of pulses in the optical pulse signal is consistent with the preset number of pulses, thus avoiding pulse cutting.

[0075] Furthermore, the acousto-optic modulation driver 30 is further configured to select a specific frequency and number of pulses from the seed optical signal based on the delayed acousto-optic drive signal to obtain an adjusted optical pulse signal. The coupled pulse circuit is further configured to divide the adjusted optical pulse signal according to a predetermined ratio to obtain a second low-power signal, and to convert the second low-power signal into a second electrical pulse signal. The signal delay circuit 20 is further configured to, after initially adjusting the delay time of the acousto-optic drive signal, further adjust the delay time of the acousto-optic drive signal, intercept the number of pulses in the second electrical pulse signal corresponding to a preset cycle time, record the time average corresponding to the extra pulses, and use the time average as the optimal delay time of the acousto-optic drive signal.

[0076] Specifically, the sequential logic circuit 22 is further configured to adjust the time delay of the acousto-optic drive signal to increase or decrease the time delay of the acousto-optic drive signal accordingly when it is determined that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver 30 is inconsistent with a preset number of pulses. The acousto-optic modulation driver 30 is driven by the delayed acousto-optic drive signal to select a specific frequency and number of pulses from the seed optical signal to obtain an adjusted optical pulse signal.

[0077] The sequential logic circuit 22 is also used to pre-set a cycle time for a desired number of pulses, intercept the pulses corresponding to the first electrical pulse signal within the cycle time, identify the number of pulses of the first electrical pulse signal, and preliminarily adjust the delay time of the acousto-optic drive signal based on the number of pulses. That is, by increasing or decreasing the delay time, the selection time of the optical pulse signal is controlled so that the number of pulses of the optical signal selected by the acousto-optic modulation driver is consistent with the preset number of pulses. The delay time of the acousto-optic drive signal is then adjusted again, that is, the delay time is increased or decreased again, so that the acousto-optic modulation driver selects another optical pulse signal, and a second electrical pulse signal is obtained after processing by the coupled pulse circuit. Since, regardless of whether the delay time is increased or decreased, the second electrical pulse signal will be intercepted within the preset cycle time due to the extra pulses compared to the first electrical pulse signal. If the preset cycle time is located midway between the pulses of the first and second electrical pulse signals, that is, when the first and second electrical pulse signals are intercepted simultaneously during the cycle time with the increased and decreased delays, half a pulse of the first electrical pulse signal and half a pulse of the second electrical pulse signal can be intercepted under the increased and decreased delays. The average of the times corresponding to increasing and decreasing the delay is calculated and used as the optimal delay time for the acousto-optic drive signal. The pulse count self-correction control device then uses this optimal delay time to indirectly control the pulse count of the optical pulse signal selected by the acousto-optic modulation driver, achieving pulse count correction for the optical pulse signal.

[0078] like Figure 4As shown, the solid line and the dotted line corresponding to the acousto-optic driving signal respectively represent two selected acousto-optic driving signals, and the time difference corresponding to the extra pulse between the two acousto-optic driving signals is (t2-t1).

[0079] Furthermore, the low-repetition-rate seed source 11 generates a seed optical signal of low-repetition-rate femtosecond pulses, which is transmitted as the laser's signal light to the subsequent pump laser 12 for amplification. The pump laser 12 then outputs a repetition-rate signal with the same frequency as the seed optical signal to the repetition-rate detection circuit 70. After receiving the seed optical signal, the pump laser 12 amplifies and stabilizes the seed optical signal and transmits it to the acousto-optic modulation driver 30. The repetition-rate detection circuit 70 receives the repetition-rate signal from the low-repetition-rate seed source 11, converts it into a repetition-rate electrical signal that can be recognized by the sequential logic circuit 22, and then transmits the repetition-rate electrical signal to the sequential logic circuit 22 for recognition. The sequential logic circuit 22 uses any rising edge pulse of the received repetition-rate signal as the starting point and generates an acousto-optic drive signal for the acousto-optic modulation driver 30 based on the frequency selection and pulse number set by the user. The acousto-optic modulation driver circuit 50 receives the acousto-optic drive signal output by the sequential logic circuit 22 and converts it into a control signal that controls the acousto-optic modulation driver 30, thereby driving the acousto-optic modulation driver 30. The acousto-optic modulation driver 30 receives the control signal from the acousto-optic drive circuit and selects a specific frequency and specific number of pulses for the amplified optical signal. The coupler 41 separates a portion of the optical pulse signal selected by the acousto-optic modulation driver 30 into a low-power signal at a specific ratio and transmits it to the photodetector circuit 42. The photodetector circuit 42 converts the received optical signal separated by the coupler 41 into an electrical pulse signal that can be recognized by the timing logic circuit 22 and transmits it to the timing logic circuit 22. The timing logic circuit 22 detects the number of pulses in the electrical pulse signal output by the photodetector circuit 42 and adjusts the delay time of the acousto-optic drive signal based on the pulse number until the optical pulse signal selected by the acousto-optic modulation driver 30 is consistent with the preset pulse number, thereby obtaining the optimal delay time of the acousto-optic drive signal.

[0080] In this embodiment, the repetition rate signal or seed light signal from the low repetition rate seed source 11 is used as the time reference for generating the acousto-optic driving signal, and the light pulse signal selected by the acousto-optic modulation driver 30 is used as the effect feedback for adjusting the acousto-optic driving signal. Thus, by adjusting the delay of the acousto-optic driving signal, the acousto-optic modulation driver 30 is prevented from switching when the light pulse signal arrives, resulting in a pulse cutting phenomenon, thereby realizing self-calibration of the frequency-selective pulse, thereby greatly reducing the complexity of manually adjusting the frequency-selective pulse delay and improving the reliability and accuracy of the frequency-selective pulse calibration; furthermore, the pulse number control of the low repetition rate ultrafast fiber laser is realized, and the reliability of the fiber laser is improved.

[0081] An embodiment of the present invention further provides a low repetition rate ultrafast fiber laser, which includes a memory and at least one processor. The memory stores a computer program, and the processor is used to execute the computer program to implement the pulse number self-correction control method of the above embodiment.

[0082] The memory may include a program storage area and a data storage area. The program storage area may store an operating system and at least one application program required for a function; the data storage area may store data generated based on the use of the computer device (such as optical pulse signals, pulse counts, etc.). In addition, the memory may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0083] An embodiment of the present invention also provides a computer-readable storage medium, which stores machine-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to execute the steps of the pulse number self-correction control method of the above embodiment.

[0084] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or flowchart, and the combination of boxes in the structure diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0085] In addition, the functional modules or units in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0086] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0087] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A pulse number self-correction control device, characterized in that: include: a signal output circuit for generating a seed optical signal of a low repetition rate femtosecond pulse and a repetition rate signal having the same frequency as the seed optical signal, and amplifying the seed optical signal; a signal delay circuit, configured to receive the repetition frequency signal, select a rising edge of any pulse of the repetition frequency signal as a time starting point, and generate an acousto-optic driving signal according to the time starting point, a preset frequency selection frequency, and a preset number of pulses; an acousto-optic modulation driver, configured to select a specific frequency and a specific number of pulses from the amplified seed light signal according to the acousto-optic drive signal, to obtain an optical pulse signal; a coupled pulse circuit, configured to divide the optical pulse signal selected by the acousto-optic modulation driver according to a predetermined ratio to obtain a first low-power optical signal, and convert the first low-power optical signal into a first electrical pulse signal; The signal delay circuit is also used to receive the first electrical pulse signal, identify the number of pulses of the first electrical pulse signal, and preliminarily adjust the delay time of the acousto-optic drive signal according to the number of pulses so that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset number of pulses. After the preliminary adjustment, the delay time of the acousto-optic drive signal is adjusted again, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic drive signal.

2. The pulse number self-correction control device according to claim 1, characterized in that: The signal delay circuit is used for: intercepting the number of pulses corresponding to a preset period of time in the first electrical pulse signal; Preliminarily adjusting the delay time of the acousto-optic driving signal according to the pulse number so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number; After the initial adjustment, the delay time of the acousto-optic driving signal is adjusted again, and the number of pulses corresponding to the preset cycle time in the second electrical pulse signal is intercepted, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic driving signal, wherein the second electrical pulse signal is obtained by converting the optical pulse signal selected by the acousto-optic modulation driver through the coupling pulse circuit after the delay time is adjusted again.

3. The pulse number self-correction control device according to claim 1, characterized in that: The signal delay circuit comprises: a repetition frequency detection circuit, configured to convert the repetition frequency signal into a repetition frequency electrical signal; A timing logic circuit is used to receive the repetitive frequency electrical signal, select any rising edge of the pulse of the repetitive frequency electrical signal as a time starting point, and generate an acousto-optic driving signal according to the time starting point, a preset frequency selection frequency and a preset number of pulses; receive the optical pulse signal output by the acousto-optic modulation driver, identify the number of pulses of the optical pulse signal, and preliminarily adjust the delay time of the acousto-optic driving signal according to the number of pulses so that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset number of pulses; and after the preliminarily adjustment, adjust the delay time of the acousto-optic driving signal again, record the time mean corresponding to the extra pulses, and use the time mean as the optimal delay time of the acousto-optic driving signal.

4. The pulse number self-correction control device according to claim 1, characterized in that: The signal output circuit includes: A low repetition rate seed source, used to generate a seed optical signal of a low repetition rate femtosecond pulse and a repetition rate signal having the same frequency as the seed optical signal; A pump laser is used to amplify and stabilize the seed light signal.

5. The pulse number self-correction control device according to claim 1, characterized in that: The coupled pulse circuit includes: a coupler for dividing the optical pulse signal selected by the acousto-optic modulation driver according to a predetermined ratio to obtain a low-power signal; The photodetector circuit is used to convert the low-power signal into an electrical pulse signal.

6. The pulse number self-correction control device according to claim 1, characterized in that: Also included is an acousto-optic modulation driver circuit; The acousto-optic modulation driver circuit is used to receive the acousto-optic driving signal from the signal delay circuit and output a control signal that meets the working level of the acousto-optic modulation driver according to the acousto-optic driving signal; The acousto-optic modulation driver is further configured to select a specific frequency and a specific number of pulses of the seed light signal according to the control signal.

7. A pulse number self-correction control method, characterized in that: include: receiving a repetition frequency signal from a signal output circuit, and selecting any rising edge of a pulse of the repetition frequency signal as a time starting point; generating an acousto-optic driving signal according to the time starting point, the preset frequency selection frequency, and the preset number of pulses, so that the acousto-optic modulation driver selects a seed light signal output by the signal output circuit with a specific frequency and a specific number of pulses according to the acousto-optic driving signal to obtain an optical pulse signal; A first electrical pulse signal is received, the number of pulses of the first electrical pulse signal is identified, and the delay time of the acousto-optic drive signal is preliminarily adjusted according to the number of pulses, so that the number of pulses of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset number of pulses. After the preliminarily adjustment, the delay time of the acousto-optic drive signal is adjusted again, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic drive signal; wherein, the first electrical pulse signal is obtained by converting the optical pulse signal into a first low-power signal obtained by dividing the optical pulse signal according to a predetermined ratio via a coupling pulse circuit.

8. The pulse number self-correction control method according to claim 7, characterized in that: The method comprises: preliminarily adjusting the delay time of the acousto-optic driving signal according to the pulse number so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number; and adjusting the delay time of the acousto-optic driving signal again after the preliminary adjustment, recording the time mean corresponding to the extra pulses, and using the time mean as the optimal delay time of the acousto-optic driving signal. intercepting the number of pulses corresponding to a preset period of time in the first electrical pulse signal; Preliminarily increasing or decreasing the delay time of the acousto-optic driving signal according to the pulse number, so that the pulse number of the optical pulse signal selected by the acousto-optic modulation driver is consistent with the preset pulse number; After the preliminary adjustment, the delay time of the acousto-optic driving signal is increased and decreased again, and the number of pulses corresponding to the preset cycle time in the second electrical pulse signal is intercepted, and the time mean corresponding to the extra pulses is recorded, and the time mean is used as the optimal delay time of the acousto-optic driving signal, wherein the second electrical pulse signal is obtained by converting the optical pulse signal selected by the acousto-optic modulation driver through the coupling pulse circuit after adjusting the delay time again.

9. A low repetition rate ultrafast fiber laser, characterized in that: The fiber laser includes a memory and at least one processor, the memory stores a computer program, and the processor is configured to execute the computer program to implement the pulse number self-correction control method according to any one of claims 7 to 8.

10. A computer storage medium, characterized in that The device stores a computer program, which, when executed, implements the pulse number self-correction control method according to any one of claims 7 to 8.

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