Fiber bragg grating temperature adjusting method and device of laser and medium

Abstract

The invention relates to the technical field of ultrafast laser, and discloses a fiber bragg grating temperature adjusting method and device of a laser and a medium. The method comprises the following steps: fixing a grid region of the chirp fiber grating in a V-shaped groove formed by a plurality of copper blocks driven by TECs; the temperatures of a plurality of TECs are independently controlled; the method comprises the following steps: calibrating the influence of temperature change on grating second-order dispersion in advance through an experiment, and establishing a mapping relation between temperature and second-order dispersion amount so as to determine chirp amount corresponding to different temperatures; in the operation process of the femtosecond laser, the width of the amplified spectrum is monitored in real time, the temperature parameters of the multiple TECs are dynamically adjusted according to the monitoring result, the second-order dispersion amount of the grating is adjusted through the mapping relation, and self-adaptive management of the input pulse chirp amount is achieved; wherein when it is monitored that the amplified spectrum width is broadened to be greater than the preset broadening, the multiple TEC temperatures are adjusted to linearly increase progressively in the preset range, so that after the pulse is amplified by the gain fiber, the spectrum is broadened and compressed to be narrower pulse width.

Description

Technical Field

[0001] This application relates to the field of ultrafast laser technology, and in particular to a method, device and medium for regulating the temperature of a fiber grating in a laser. Background Technology

[0002] In the field of ultrafast lasers, femtosecond fiber lasers are widely used in precision machining, biomedicine, and other fields due to their combination of high beam quality, high integration, and stable output characteristics. To obtain narrower pulse widths, pulse dispersion needs to be controlled through pre-chirp management techniques to enhance fiber nonlinearity and achieve spectral broadening. Traditional pre-chirp management schemes (such as grating pairs) rely on spatial optical path adjustment, which suffers from high system complexity, poor mechanical stability, and limited adjustment accuracy. On the other hand, grating dispersion adjustment methods based on mechanical stretching or phase masks have slow response speeds (typically requiring several seconds to minutes) and are prone to introducing stress that leads to non-uniform dispersion, making it difficult to meet the requirements of high-stability femtosecond laser systems. Therefore, a method is urgently needed to solve at least one of the above problems. Summary of the Invention

[0003] This application provides a method, device, and medium for regulating the temperature of fiber optic gratings in lasers, aiming to solve the problems in existing technologies where self-similar parabolic pulse amplification is limited by stimulated Raman scattering in optical fibers, pre-chirp management amplification relies on complex grating pair structures, and gain management nonlinear amplification requires optimization of numerous parameters, none of which propose a solution for achieving fully integrated chirp regulation through distributed temperature control.

[0004] In a first aspect, embodiments of this application provide a method for adjusting the temperature of a fiber Bragg grating in a laser, comprising: The grating region of the chirped fiber grating is fixed in a V-groove formed by copper blocks driven by multiple TECs, so that the grating region is in a uniform temperature action region composed of multiple copper blocks; by independently controlling the temperature of multiple TECs, a linearly increasing temperature is applied to the grating region, and the grating period is changed by utilizing the thermo-optic effect of the fiber material. The effect of temperature change on the second-order dispersion of the grating was calibrated in advance through experiments, and the mapping relationship between temperature and second-order dispersion was established to determine the chirp amount corresponding to different temperatures. During the operation of the femtosecond laser, the width of the amplified spectrum is monitored in real time. Based on the monitoring results, the temperature parameters of multiple TECs are dynamically adjusted. The second-order dispersion of the grating is adjusted through the mapping relationship to achieve adaptive management of the input pulse chirp. Specifically, when the amplified spectrum width is detected to be wider than the preset width, the temperature of multiple TECs is adjusted to increase linearly within the preset range, so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width.

[0005] In some embodiments, fixing the grating region of the chirped fiber grating within a V-groove formed by multiple TEC-driven copper blocks, so that the grating region is in a uniform temperature action area formed by multiple copper blocks, includes: uniformly placing the grating region of the chirped fiber grating on four TEC-driven copper blocks, each copper block being 10 mm long and having a V-groove etched in the middle of the copper block, fixing the grating region to the surface of the copper block through the V-groove, so that the four copper blocks form a continuous temperature action area, ensuring that the grating region is uniformly heated as a whole.

[0006] In some embodiments, the number of TECs is four; the step of applying a linearly increasing temperature to the grating region by independently controlling the temperature of multiple TECs and using the thermo-optical effect of the optical fiber material to change the grating period includes: controlling the temperature of the four TECs to increase linearly from the first end to the second end according to a preset gradient, so that a uniform temperature gradient is formed in the grating region along the length direction, and changing the grating period and the dispersion at the corresponding position based on the thermal expansion effect and thermo-optical effect of the optical fiber material.

[0007] In some embodiments, the step of pre-calibrating the effect of temperature change on the second-order dispersion of the grating through experiments and establishing a mapping relationship between temperature and second-order dispersion to determine the chirp corresponding to different temperatures includes: applying different temperature combinations to each TEC within a preset temperature range, measuring the corresponding second-order dispersion of the grating, recording the corresponding data of temperature parameters and second-order dispersion, and generating a temperature-dispersion mapping table or function by fitting to determine the chirp adjustment accuracy of the grating at different temperatures.

[0008] In some embodiments, the real-time monitoring of the width of the amplified spectrum during the operation of the femtosecond laser includes: acquiring the amplified spectral signal output by the femtosecond laser in real time using a spectrometer, extracting the wavelength range of the spectrum and calculating the spectral width, and transmitting the spectral width data to the control system in real time as a feedback signal for adjusting the TEC temperature.

[0009] In some embodiments, the step of dynamically adjusting the temperature parameters of multiple TECs based on monitoring results includes: when the amplified spectral width is not detected to reach a preset broadening threshold, the control system adjusts the temperature combination of the TECs according to the temperature-dispersion mapping relationship in a preset step size until the spectral width reaches or exceeds the preset broadening threshold; during the temperature adjustment process, the temperatures of the four TECs are kept to change synchronously in a linearly increasing gradient to avoid uneven grid temperature.

[0010] In some embodiments, adjusting the second-order dispersion of the grating through the mapping relationship to achieve adaptive management of the input pulse chirp includes: determining the required second-order dispersion based on the real-time monitored spectral width through the temperature-dispersion mapping relationship, and then calculating the corresponding TEC temperature parameters; changing the grating dispersion by adjusting the TEC temperature so that the chirp corresponding to the negative or positive chirp of the input pulse is adapted to the nonlinear amplification process of the gain fiber, ensuring that the pulse broadens the spectrum during amplification due to the combined effects of self-phase modulation, dispersion, and gain, and is ultimately compressed to the target pulse width.

[0011] In some embodiments, the preset broadening is 23 nanometers, and the preset temperature range is 25°C to 25.6°C. When the amplified spectral width is detected to be broadened to above the preset broadening, the temperature of multiple TECs is adjusted to increase linearly within the preset range, so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width. This includes: when the spectral width reaches above 23 nanometers, maintaining the temperature of the four TECs in a linearly increasing gradient distribution of 25°C to 25.6°C, so that the pulse entering the multimode gain fiber is in a negative chirped state, and the spectrum is broadened due to self-phase modulation and dispersion effect during the amplification process, and a narrow pulse width of less than 113 femtoseconds is obtained through the grating compression device.

[0012] Secondly, embodiments of this application provide a computer device, the computer device including a memory and a processor, the memory being used to store a computer program, and the processor being used to execute the computer program and, when executing the computer program, implement the method provided in any embodiment of this application.

[0013] Thirdly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to implement the method provided in any embodiment of this application.

[0014] The fiber grating temperature control method, device, and medium for lasers provided in this application employ an all-fiber structure, seamlessly integrating the temperature control device with the chirped fiber grating. This avoids spatial optical path coupling loss, resulting in a smaller overall size compared to traditional gratings, and improving system integration and anti-interference capabilities. A uniform temperature gradient is applied by four TEC-driven copper blocks, utilizing the thermo-optical effect in conjunction with thermal expansion to regulate grating dispersion. Compared to traditional mechanical adjustment methods, dispersion control accuracy is improved, and the response time is shortened to less than 1 second, enabling rapid dynamic chirp management. The distributed temperature control structure avoids dispersion inhomogeneity caused by local stress, solving the drift problem of traditional mechanical adjustment and ensuring pulse parameter stability during long-term operation. This makes it suitable for high-reliability industrial processing and precision measurement scenarios. By real-time monitoring of the spectral width and feedback adjustment of the TEC temperature, the amplified spectrum can be effectively broadened from 12nm to above 23nm, ultimately achieving a narrow pulse width below 113 femtoseconds, significantly improving the output performance of the femtosecond laser.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart illustrating the steps of a fiber Bragg grating temperature control method for a laser, provided in one embodiment of this application. Figure 2 This is a schematic diagram of the structure of a fiber grating temperature control system for a laser according to an embodiment of this application; Figure 3 This is a schematic diagram of a temperature-controlled tuning grating provided in an embodiment of this application; Figure 4 This is a schematic block diagram of a fiber optic grating temperature control device for a laser, provided in one embodiment of this application. Figure 5 This is a schematic block diagram of the structure of a computer device provided in an embodiment of this application.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0021] It should be understood that, in order to clearly describe the technical solutions of the embodiments of the present invention, the terms "first" and "second" are used in the embodiments of the present invention to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0022] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0023] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] In the field of ultrafast lasers, femtosecond fiber lasers are widely used in precision machining, biomedicine, and other fields due to their combination of high beam quality, high integration, and stable output characteristics. To obtain narrower pulse widths, pulse dispersion needs to be controlled through pre-chirp management techniques to enhance fiber nonlinearity and achieve spectral broadening. Traditional pre-chirp management schemes (such as grating pairs) rely on spatial optical path adjustment, which suffers from high system complexity, poor mechanical stability, and limited adjustment accuracy. On the other hand, grating dispersion adjustment methods based on mechanical stretching or phase masks have slow response speeds (usually several seconds to minutes) and are prone to introducing stress, leading to non-uniform dispersion, which is difficult to meet the requirements of high-stability femtosecond laser systems. In addition, the self-similar parabolic pulse amplification used in existing technologies is limited by stimulated Raman scattering in the fiber, pre-chirp-managed amplification relies on complex grating pairs, and gain-managed nonlinear amplification requires optimization of numerous parameters. None of these solutions propose a fully integrated chirp adjustment solution through distributed temperature control.

[0026] This invention addresses the shortcomings of existing pre-chirped management devices, such as complex structure, inefficient adjustment, and insufficient stability. It provides a temperature-tuned all-fiber chirped management method. This method applies a uniform temperature gradient to the chirped fiber grating using a copper block array driven by multiple TECs, dynamically adjusting the dispersion by utilizing the thermo-optical effect of the fiber material. This avoids the mechanical drift and adjustment lag problems of traditional spatial optical paths. Please refer to... Figure 1 This application provides a method for adjusting the temperature of a fiber Bragg grating in a laser, applicable to applications such as... Figure 2 The fiber grating temperature control system of the laser shown.

[0027] like Figure 2 The mode-locked fiber oscillator has a center wavelength of 1030nm, a repetition rate of 36MHz, an output power of 5mW, and a pulse width of 2ps. The single-mode amplification gain fiber (6 / 125 YDF) is model PM-YSF-HI-HP, with a length of 0.5m. The single-mode LD has a maximum power of 400mW and a center wavelength of 976nm. The multimode LD is a multimode laser diode with a center wavelength of 915nm, a maximum power of 30W, and the 14 / 125 gain fiber is model PLMA-YDF-14 / 125-UF, with an absorption coefficient of 3.9±0.5 dB / m@915nm and a length of 1.5m. The chirped fiber gratings CFBG1 and CFBG2 have a center wavelength of 1030nm, a spectral bandwidth of 18nm, a second-order dispersion of 50ps / nm, and no higher-order dispersion. The two gratings are connected to the circulator in opposite directions. CFBG1 is encapsulated in a temperature-tuned device. The output collimator isolator functions as both a collimator and an isolator, outputting amplified light. The grating-compressor is a transmission grating with a line density of 1000 L / mm.

[0028] like Figure 3The temperature tuning device mainly consists of four TECs. A 10mm long copper block with a V-shaped groove engraved in the middle is fixed on each TEC, and the grating area is evenly placed on the four copper blocks. The dispersion of the fiber grating can be changed by adjusting the temperature of the four TECs. The mode-locked oscillator is amplified to 100 milliwatts through single-mode gain fiber, and then passed through two CFBGs. Since the two gratings have the same dispersion and are connected in opposite directions, the pulse width does not change significantly. When the temperature tuning device is not working, the amplification to 1W through 14 / 125 gain fiber results in a spectral width of approximately 12nm. Increasing the pump power to 5W does not significantly change the spectrum. Adjusting the grating pair distance at this point yields a minimum pulse width of 180fs. Adjusting the temperature of the four TECs and observing the amplified spectrum reveals that when the temperature of the four TECs increases linearly between 25-25.6℃, the amplified spectral width widens significantly, exceeding 23nm. Adjusting the grating pair distance yields a pulse width of 113fs.

[0029] Specifically, such as Figure 1 As shown, the fiber grating temperature adjustment method for the provided laser includes steps S101 to S103. Details are as follows: Step S101. Fix the grating region of the chirped fiber grating in a V-groove formed by copper blocks driven by multiple TECs, so that the grating region is in a uniform temperature action area composed of multiple copper blocks; by independently controlling the temperature of multiple TECs, apply a linearly increasing temperature to the grating region, and use the thermo-optic effect of the fiber material to change the grating period.

[0030] Specifically, through hardware structure design, the grating region of the chirped fiber grating (CFBG) is fixed in a temperature-controlled, uniform temperature region. A thermoelectric cooler (TEC) is used to drive a copper block array to generate a linear temperature gradient. The grating period is changed through the thermo-optic effect of the fiber material, thereby adjusting its dispersion characteristics.

[0031] The temperature tuning device consists of an array of four TEC-driven copper blocks, each 10mm long with a V-shaped groove etched in the center to fix the CFBG's gate region. The gate region is evenly placed within the V-shaped grooves of the four copper blocks along the axial direction, ensuring close contact for efficient heat conduction. The TECs are distributed, with each TEC independently controlling the temperature of its corresponding copper block, forming a linearly increasing temperature gradient along the gate region's axial direction (e.g., a linear increase in temperature range of 25-25.6℃ in the embodiment).

[0032] The temperature regulation principle includes: the thermo-optic effect of the optical fiber material causes its refractive index to change with temperature, and the temperature gradient causes a small change in the grating period, thereby changing the dispersion characteristics of the CFBG (especially the second-order dispersion).

[0033] By independently adjusting the temperature of the four TECs, each segment of the gate area is placed in a different temperature environment, forming a uniform temperature gradient distribution and avoiding the problem of uneven dispersion caused by local stress or temperature unevenness (unlike the stress-introduced defects of the traditional mechanical stretching method).

[0034] Step S102. The effect of temperature change on the second-order dispersion of the grating is calibrated in advance through experiments, and the mapping relationship between temperature and second-order dispersion is established to determine the chirp amount corresponding to different temperatures.

[0035] Specifically, a quantitative mapping relationship between temperature change and CFBG second-order dispersion is established in advance through experiments, providing data basis for subsequent dynamic adjustment and ensuring the precise correspondence between temperature control and dispersion adjustment.

[0036] The experimental calibration method includes: Controlling variables: fixing the input optical parameters of the CFBG (e.g., center wavelength 1030 nm, spectral bandwidth 18 nm), and only changing the TEC temperature (single-variable adjustment or gradient adjustment). Measurement tools: using a spectrometer to monitor the output spectral characteristics, and accurately measuring the second-order dispersion of the CFBG at different temperatures (unit: ps / nm) using a dispersion measurement device (e.g., frequency-resolved optical switching method FROG, grating pair compression experiment). Data fitting: recording the relationship between temperature (e.g., 25℃, 25.2℃, 25.4℃, 25.6℃) and the corresponding second-order dispersion, and establishing a linear or nonlinear mapping model (in this example, the initial value of the second-order dispersion is 50 ps / nm, dynamically adjusted under temperature gradient through thermo-optical effects).

[0037] The purpose of calibration is to eliminate the hysteresis and nonlinear error of temperature regulation, so that in subsequent real-time regulation, the temperature parameter can be directly mapped to the target dispersion, thus achieving a precise correspondence between "temperature control and dispersion regulation".

[0038] Step S103. During the operation of the femtosecond laser, the width of the amplified spectrum is monitored in real time. The temperature parameters of multiple TECs are dynamically adjusted according to the monitoring results. The second-order dispersion of the grating is adjusted through the mapping relationship to achieve adaptive management of the input pulse chirp. When the amplified spectrum width is detected to be wider than the preset width, the temperature of multiple TECs is adjusted to increase linearly within the preset range so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width.

[0039] Specifically, during laser operation, the TEC temperature is dynamically adjusted to adjust the CFBG dispersion based on the pre-calibrated temperature-dispersion mapping relationship by real-time monitoring of the amplified spectral width, thereby achieving adaptive optimization of pulse chirp and ultimately obtaining a narrower pulse width through spectral broadening and compression.

[0040] The real-time monitoring mechanism connects a spectrometer (or an integrated spectral monitoring module) to the amplification link to acquire the spectral width amplified by a gain fiber (e.g., 14 / 125 YDF, 1.5m in length) in real time (in this example, the initial spectral width is approximately 12nm, which is broadened to >23nm after adjustment). A preset spectral broadening threshold (e.g., 20nm) is set, and when the spectral width is detected to reach or exceed this threshold, the temperature adjustment module is triggered.

[0041] The dynamic adjustment logic includes: Forward adjustment: When it is necessary to enhance the nonlinear effect to broaden the spectrum, the temperature of the four TECs is linearly increased within a preset range (e.g., 25-25.6℃) to generate a temperature gradient in the CFBG grating region, increasing its second-order dispersion and introducing pre-chirp to optimize the nonlinear broadening efficiency of the pulse in the gain fiber. Feedback control: Based on the spectral broadening effect (e.g., in this embodiment, the spectral width increases from 12nm to >23nm), the required temperature gradient parameters are calculated in reverse through a mapping relationship, and the TEC power is adjusted in a closed loop until the spectrum is broadened to the optimal state.

[0042] Pulse width optimization is achieved by using a larger dispersion-nonlinear effect coupling effect to broaden the spectrum when the pulse, after being pre-chirped by CFBG, enters the gain fiber for amplification. Subsequently, the dispersion is compensated by a grating to the compressor (1000L / mm line density), and finally a narrower pulse width is obtained (compressed from 180fs to 113fs in the example).

[0043] In some embodiments, fixing the grating region of the chirped fiber grating within a V-groove formed by multiple TEC-driven copper blocks, so that the grating region is in a uniform temperature action area formed by multiple copper blocks, includes: uniformly placing the grating region of the chirped fiber grating on four TEC-driven copper blocks, each copper block being 10 mm long and having a V-groove etched in the middle of the copper block, fixing the grating region to the surface of the copper block through the V-groove, so that the four copper blocks form a continuous temperature action area, ensuring that the grating region is uniformly heated as a whole.

[0044] The hardware structure design achieves uniform fixation of the chirped fiber grating (CFBG) grating area and coverage of the temperature-affected area, ensuring uniform heating of the grating area as a whole and avoiding local stress or temperature deviation.

[0045] The hardware structure parameters adopt four copper blocks driven by TECs. Each copper block has a length of 10 mm, and a V-shaped groove is machined in the middle (the depth and width of the groove are adapted to the outer diameter of the optical fiber, such as a 125-μm single-mode optical fiber). The fixing method is to place the grating area of the CFBG (i.e., the effective action area of the Bragg grating) axially and uniformly in the V-shaped grooves of the four copper blocks, and make the optical fiber closely fit with the copper blocks through a small amount of thermal conductive glue or mechanical clamping, forming a continuous temperature action area (the total action length is 40 mm, and the four copper blocks are connected end to end). The uniform heating design ensures the maximum heat conduction area between the optical fiber and the copper blocks through the arc-shaped contact surface of the V-shaped groove. At the same time, the four copper blocks are arranged continuously, so that the grating area is in a temperature-controlled area throughout the whole process, avoiding sudden changes in the temperature gradient in the edge area.

[0046] In some embodiments, the number of the TECs is four; by independently controlling the temperatures of the multiple TECs, applying a linearly increasing temperature in the grating area, and using the thermo-optic effect of the optical fiber material to change the grating period, it includes: linearly increasing the temperatures of the four TECs from the first end to the second end according to a preset gradient, so as to form a uniform temperature gradient along the length direction of the grating area, and based on the thermal expansion effect and thermo-optic effect of the optical fiber material, changing the grating period and the dispersion amount at the corresponding position.

[0047] By controlling the temperature gradient distribution of the four TECs, a uniform temperature increase is formed axially in the grating area, and the dispersion amount is dynamically adjusted by using the thermo-optic effect (the refractive index changes with temperature) and thermal expansion effect (the grating period changes with temperature) of the optical fiber material.

[0048] TEC control strategy: Define the two ends of the CFBG as the "first end" and the "second end". The temperatures of the four TECs are set as T1, T2, T3, and T4 in sequence from the first end to the second end, and T1 < T2 < T3 < T4 is satisfied (such as 25°C, 25.2°C, 25.4°C, 25.6°C in the embodiment), forming a linear temperature gradient of 0.6°C / 40 mm.

[0049] The physical effect mechanism includes: Thermo-optic effect: When the temperature rises, the refractive index n of the optical fiber increases. According to the grating period formula λB = 2nΛ (Λ is the grating period), the change in the refractive index directly affects the Bragg wavelength, and then changes the dispersion characteristics. Thermal expansion effect: The temperature gradient causes micro-expansion of each section in the grating area, and the grating period Λ changes slightly along the axis, forming a gradually changing dispersion distribution, equivalently adjusting the second-order dispersion amount. The gradient uniformity is ensured by the high-precision temperature control of the TEC (precision ±0.1°C), ensuring that the temperature difference between adjacent copper blocks is consistent and avoiding uneven dispersion introduced by non-linear gradients.

[0050] In some embodiments, the step of pre-calibrating the effect of temperature change on the second-order dispersion of the grating through experiments and establishing a mapping relationship between temperature and second-order dispersion to determine the chirp corresponding to different temperatures includes: applying different temperature combinations to each TEC within a preset temperature range, measuring the corresponding second-order dispersion of the grating, recording the corresponding data of temperature parameters and second-order dispersion, and generating a temperature-dispersion mapping table or function by fitting to determine the chirp adjustment accuracy of the grating at different temperatures.

[0051] By experimentally measuring the second-order dispersion under different TEC temperature combinations, a precise mathematical mapping relationship was established, providing a quantitative basis for subsequent adjustment.

[0052] Experimental conditions included: fixed input light parameters: center wavelength 1030 nm, spectral bandwidth 18 nm, and initial second-order dispersion of 50 ps / nm (without temperature control). Temperature scan range: individual TEC temperatures from 20℃ to 30℃, with four TECs combined in a gradient (e.g., T1=25+x, T2=25+2x, T3=25+3x, T4=25+4x, where x is a step size of 0.1℃).

[0053] The measurement method uses the frequency-resolved optical switching method (FROG) or a grating to broaden the time domain of the compressed experimental measurement pulse after passing through CFBG, and then inversely calculates the second-order dispersion (formula: Δt=|D2|*Δλ, where D2 is the second-order dispersion and Δλ is the spectral bandwidth).

[0054] Record the second-order dispersion corresponding to each set of temperature parameters (T1-T4), and generate a linear mapping function by fitting using the least squares method (e.g., D2=k*ΔT+D20, where k is the temperature coefficient and D20 is the initial dispersion). Accuracy is ensured by measuring each temperature after it has stabilized for 30 seconds (to avoid TEC dynamic response errors), repeating the measurement three times and taking the average value to ensure the mapping table error is <5%.

[0055] In some embodiments, the real-time monitoring of the width of the amplified spectrum during the operation of the femtosecond laser includes: acquiring the amplified spectral signal output by the femtosecond laser in real time using a spectrometer, extracting the wavelength range of the spectrum and calculating the spectral width, and transmitting the spectral width data to the control system in real time as a feedback signal for adjusting the TEC temperature.

[0056] The spectrometer acquires and amplifies spectral signals in real time, extracts the spectral width as a feedback signal, and provides real-time data support for temperature regulation.

[0057] The monitoring hardware acquires the spectrum (center wavelength 1030nm, initial bandwidth 12nm) amplified by a high-resolution spectrometer (resolution ≤0.1nm), such as OceanOptics HR4000, in real time by connecting it to the amplification link.

[0058] The spectrometer transmits raw spectral data to the control system (such as an FPGA or microcontroller) via USB or fiber optic interface. The control system calculates the spectral width, defined as the 3dB bandwidth (the wavelength range at which peak power drops by 3dB) or full width at half maximum (FWHM). For example, in this embodiment, the spectral width is broadened from 12nm to >23nm. The monitoring period is set to 10ms to ensure rapid response to spectral changes (superior to the second-level response of traditional mechanical adjustment).

[0059] In some embodiments, the step of dynamically adjusting the temperature parameters of multiple TECs based on monitoring results includes: when the amplified spectral width is not detected to reach a preset broadening threshold, the control system adjusts the temperature combination of the TECs according to the temperature-dispersion mapping relationship in a preset step size until the spectral width reaches or exceeds the preset broadening threshold; during the temperature adjustment process, the temperatures of the four TECs are kept to change synchronously in a linearly increasing gradient to avoid uneven grid temperature.

[0060] Based on real-time spectral width feedback, the TEC temperature combination is dynamically adjusted through preset thresholds and gradient adjustment strategies to ensure uniform temperature change in the gate region.

[0061] Threshold trigger: The preset spectral broadening threshold is 20nm (the actual target in the example is 23nm). When the measured bandwidth is <20nm, temperature adjustment is triggered.

[0062] The adjustment strategy involves synchronously increasing the temperatures of the four TECs in 0.1℃ increments (e.g., from 25℃, 25.2℃, 25.4℃, 25.6℃ to 25.1℃, 25.3℃, 25.5℃, 25.7℃), maintaining a constant temperature gradient difference of 0.2℃. After each adjustment, a 500ms wait (TEC thermal equilibrium time) is allowed before acquiring spectral data to avoid temperature overshoot or hysteresis. Uniformity assurance: Individual adjustment of a single TEC temperature is prohibited; the four TECs are forced to change synchronously with a fixed gradient (e.g., T2 = T1 + 0.2℃, T3 = T2 + 0.2℃, T4 = T3 + 0.2℃) to ensure the linearity of the gate temperature gradient.

[0063] In some embodiments, adjusting the second-order dispersion of the grating through the mapping relationship to achieve adaptive management of the input pulse chirp includes: determining the required second-order dispersion based on the real-time monitored spectral width through the temperature-dispersion mapping relationship, and then calculating the corresponding TEC temperature parameters; changing the grating dispersion by adjusting the TEC temperature so that the chirp corresponding to the negative or positive chirp of the input pulse is adapted to the nonlinear amplification process of the gain fiber, ensuring that the pulse broadens the spectrum during amplification due to the combined effects of self-phase modulation, dispersion, and gain, and is ultimately compressed to the target pulse width.

[0064] The required second-order dispersion is calculated in real time based on the spectral width, and the TEC parameters are inversely derived through the temperature-dispersion mapping relationship to achieve the matching of chirp and nonlinear amplification process.

[0065] Chirp type control introduces negative chirp (low pulse leading frequency and high trailing frequency) into the CFBG by heating when enhanced spectral broadening is needed (e.g., before a pulse enters the gain fiber). This chirp works synergistically with the self-phase modulation (SPM) effect of the gain fiber to achieve more efficient spectral broadening. Conversely, if the spectrum is too broad, positive chirp is introduced by lowering the temperature to suppress excessive broadening.

[0066] The mathematical model, based on the nonlinear Schrödinger equation (NLSE), establishes a pulse propagation model in the gain fiber, determining the relationship between the optimal second-order dispersion and the spectral width W (e.g., optimal second-order dispersion = a). W+b).

[0067] The target temperatures for the four TECs are calculated using the mapping relationship Ti = 1 / f (optimal second-order dispersion) (where f is the calibration positive function provided in the above embodiment). This forms a closed loop of "spectral monitoring → dispersion calculation → temperature adjustment → effect feedback," with control parameters updated every 200ms.

[0068] In some embodiments, the preset broadening is 23 nanometers, and the preset temperature range is 25°C to 25.6°C. When the amplified spectral width is detected to be broadened to above the preset broadening, the temperature of multiple TECs is adjusted to increase linearly within the preset range, so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width. This includes: when the spectral width reaches above 23 nanometers, maintaining the temperature of the four TECs in a linearly increasing gradient distribution of 25°C to 25.6°C, so that the pulse entering the multimode gain fiber is in a negative chirped state, and the spectrum is broadened due to self-phase modulation and dispersion effect during the amplification process, and a narrow pulse width of less than 113 femtoseconds is obtained through the grating compression device.

[0069] Based on specific implementation parameters (preset spectral width 23nm, temperature range 25-25.6℃), efficient pulse width compression is achieved by fixing the temperature gradient distribution.

[0070] The target parameters are set as follows: Spectral broadening target: ≥23nm (25nm was measured in the example), corresponding to the best nonlinear broadening effect. TEC temperature distribution: The temperatures of the first to fourth ends are 25℃, 25.2℃, 25.4℃, and 25.6℃ respectively, forming a total temperature difference of 0.6℃ and a gradient of 0.2℃ / 10mm.

[0071] The negatively chirped pulse (with approximately 10% increased dispersion) after CFBG modulation during pulse evolution is fed into a 14 / 125 gain fiber. Under 30W multimode pumping, due to self-phase modulation (SPM) and dispersion broadening effects, the spectrum broadens from 12nm to over 23nm. The broadened pulse is then compensated for dispersion by a grating compressor (1000L / mm scribe line density), ultimately reducing the pulse width from 180fs to 113fs (superior to 180fs using traditional methods). Stability assurance: Once the spectral width exceeds 23nm, the TEC temperature gradient is locked to avoid dispersion fluctuations caused by over-adjustment, ensuring long-term stable output.

[0072] In some embodiments, transfer learning technology is used to quickly transfer the temperature-dispersion model of a calibrated device to a new device, solving the problem of time-consuming traditional experimental calibration (several hours for a single device) and enabling rapid deployment in mass production.

[0073] The source and target domain design includes: Source domain data: calibration data from the first 10 CFBG devices (200 sets of temperature-dispersion data for each device) to build the basic neural network model. Target domain fine-tuning: only 20 sets of data were collected for the new device (10% of the traditional workload), the first 3 layers of the model were frozen (sharing common thermo-optical effects), and only the parameters of the last 2 layers were fine-tuned to adapt the model to the manufacturing differences of the new device (such as grating writing errors).

[0074] The domain adaptation technique uses the maximum mean difference (MMD) algorithm to reduce the distribution difference between the source domain and the target domain, ensuring that the prediction error of the model after migration is less than 2%, and reducing the calibration time from 2 hours to 15 minutes.

[0075] After the new device is connected to the system, the online calibration automatically collects 5 sets of data every 10 hours to update the migration model, compensates for fiber aging (such as refractive index drift) during long-term use, and achieves "plug and play" rapid calibration.

[0076] In some embodiments, a fuzzy logic controller (FLC) is designed to handle the nonlinearity and uncertainty in temperature regulation. By dynamically adjusting the TEC temperature gradient through fuzzy rules, the oscillation problem of traditional PID control in strongly coupled systems is solved.

[0077] The fuzzy system construction includes: Input variables: spectral width deviation (measured value - preset value, universe of discourse [-5nm, +5nm]), deviation change rate (universe of discourse [-2nm / s, +2nm / s]). Output variable: TEC temperature adjustment (ΔT, universe of discourse [-0.3℃, +0.3℃]), ensuring that the four TECs are adjusted synchronously by the same ΔT, maintaining a constant gradient difference. Fuzzy rules: 25 IF-THEN rules are designed (e.g., "IF deviation is positive and the change rate is positive, THEN increase ΔT"), using triangular membership functions, and the centroid method is used for fuzzy resolution.

[0078] The real-time control process outputs width data from the spectrometer in real time, calculates the deviation e and the rate of change ec, and inputs them to the controller after fuzzification. The controller outputs ΔT to the TEC drive module. For example, when the spectral width is insufficient (e=-2nm) and shrinks (ec=-1nm / s), the "medium-amplitude heating" rule (ΔT=+0.2℃) is triggered.

[0079] By combining historical adjustment data, the membership function parameters of fuzzy rules are periodically optimized to adapt to the influence of different ambient temperatures (such as the difference between winter and summer room temperature) on the thermo-optical effect, thereby improving robustness.

[0080] In some embodiments, a closed-loop control strategy is constructed using a deep reinforcement learning (DRL) algorithm (such as DQN), with the pulse width compression result as the reward signal, and the optimal temperature regulation strategy is automatically learned to solve the experience dependence problem of traditional threshold-triggered regulation.

[0081] The State-Action-Reward definition includes: State: Contains 8 dimensions of data, including current spectral width, second-order dispersion prediction, TEC temperature combination, and pump power. Action: Discretizes the temperature adjustment step size (±0.05℃, ±0.1℃, ±0.15℃), with a total of 7 actions (including hold), ensuring that the temperature gradient difference after each action is ≤0.2℃. Reward: Defined as R = 1 / Δt current - 1 / Δt initial (Δt is the pulse width). When the pulse width is <120fs, an additional reward of +10 is added; when the spectrum is too wide (>25nm), a penalty of -5 is applied.

[0082] By simulating pulse propagation in a simulation environment (based on the NLSE equation), 100,000 training episodes are generated, enabling the agent to learn to adjust the temperature under different pump powers to maximize pulse width compression efficiency. The state is collected every 50ms, and the optimal action is output through a DQN network to adjust the TEC temperature and update the experience replay pool, achieving adaptability under dynamic environments (such as temperature drift and pump fluctuations). A soft upper limit (35℃) and a lower limit (15℃) for temperature adjustment are set to prevent fiber overheating damage; a "regression to preset gradient" strategy is triggered when the reward decreases for 10 consecutive steps to avoid the algorithm getting trapped in local optima.

[0083] In some embodiments, a deep neural network (DNN) is constructed to replace traditional experimental calibration. The model is trained using historical temperature-dispersion data to predict the second-order dispersion under any temperature combination in real time, thus solving the problem of the complexity of the mapping relationship caused by nonlinear thermo-optic effects.

[0084] Data acquisition and modeling included: Training dataset: 2000 sets of data (temperature combinations + measured dispersion) were collected through orthogonal experiments, including scenarios such as linear / nonlinear gradients and independent adjustment of a single TEC, covering a temperature range of 20-35℃. Network structure: A fully connected network with 4 inputs (T1-T4) and 1 output (D2) was designed. The hidden layers used ReLU activation function, the output layer had linear activation, and the loss function was mean squared error (MSE). The Adam optimizer was used to train until MSE < 0.5 (ps / nm). 2 .

[0085] The online predictive application uses the control system to input the current four TEC temperature values ​​in real time, and then uses a neural network to predict the second-order dispersion, replacing the traditional lookup table method and supporting sub-second response. An online learning mechanism is incorporated: each measured dispersion data point (e.g., measured via FROG) serves as a new sample to update the model, adapting to device aging during long-term operation (e.g., TEC efficiency degradation).

[0086] Error compensation combined with fiber optic temperature distribution simulation (COMSOL modeling) uses the axial temperature field distribution of the grating region as an auxiliary input to the neural network to improve prediction accuracy.

[0087] Please see Figure 4 As shown, Figure 4 This is a schematic diagram of the structure of a fiber Bragg grating temperature regulation device 200 for a laser provided in this application embodiment. The fiber Bragg grating temperature regulation device 200 is used to execute the steps of the fiber Bragg grating temperature regulation method for lasers shown in the above embodiments. The fiber Bragg grating temperature regulation device 200 can be a single server or a server cluster, or it can be a terminal, such as a handheld terminal, a laptop computer, a wearable device, or a robot.

[0088] like Figure 4 As shown, the fiber grating temperature control device 200 for the laser includes: The period changing unit 201 is used to fix the grating region of the chirped fiber grating in a V-shaped groove formed by copper blocks driven by multiple TECs, so that the grating region is in a uniform temperature action area composed of multiple copper blocks; by independently controlling the temperature of multiple TECs, a linearly increasing temperature is applied to the grating region, and the grating period is changed by utilizing the thermo-optic effect of the fiber material.

[0089] The chirp determination unit 202 is used to pre-calibrate the effect of temperature change on the second-order dispersion of the grating through experiments, establish the mapping relationship between temperature and second-order dispersion, and thus determine the chirp amount corresponding to different temperatures.

[0090] The chirp management unit 203 is used to monitor the width of the amplified spectrum in real time during the operation of the femtosecond laser, dynamically adjust the temperature parameters of multiple TECs according to the monitoring results, and adjust the second-order dispersion of the grating through the mapping relationship to achieve adaptive management of the chirp of the input pulse; wherein, when the amplified spectrum width is detected to be wider than the preset width, the temperature of multiple TECs is adjusted to increase linearly within the preset range, so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width.

[0091] In some embodiments, fixing the grating region of the chirped fiber grating within a V-groove formed by multiple TEC-driven copper blocks, so that the grating region is in a uniform temperature action area formed by multiple copper blocks, includes: uniformly placing the grating region of the chirped fiber grating on four TEC-driven copper blocks, each copper block being 10 mm long and having a V-groove etched in the middle of the copper block, fixing the grating region to the surface of the copper block through the V-groove, so that the four copper blocks form a continuous temperature action area, ensuring that the grating region is uniformly heated as a whole.

[0092] In some embodiments, the number of TECs is four; the step of applying a linearly increasing temperature to the grating region by independently controlling the temperature of multiple TECs and using the thermo-optical effect of the optical fiber material to change the grating period includes: controlling the temperature of the four TECs to increase linearly from the first end to the second end according to a preset gradient, so that a uniform temperature gradient is formed in the grating region along the length direction, and changing the grating period and the dispersion at the corresponding position based on the thermal expansion effect and thermo-optical effect of the optical fiber material.

[0093] In some embodiments, the step of pre-calibrating the effect of temperature change on the second-order dispersion of the grating through experiments and establishing a mapping relationship between temperature and second-order dispersion to determine the chirp corresponding to different temperatures includes: applying different temperature combinations to each TEC within a preset temperature range, measuring the corresponding second-order dispersion of the grating, recording the corresponding data of temperature parameters and second-order dispersion, and generating a temperature-dispersion mapping table or function by fitting to determine the chirp adjustment accuracy of the grating at different temperatures.

[0094] In some embodiments, the real-time monitoring of the width of the amplified spectrum during the operation of the femtosecond laser includes: acquiring the amplified spectral signal output by the femtosecond laser in real time using a spectrometer, extracting the wavelength range of the spectrum and calculating the spectral width, and transmitting the spectral width data to the control system in real time as a feedback signal for adjusting the TEC temperature.

[0095] In some embodiments, the step of dynamically adjusting the temperature parameters of multiple TECs based on monitoring results includes: when the amplified spectral width is not detected to reach a preset broadening threshold, the control system adjusts the temperature combination of the TECs according to the temperature-dispersion mapping relationship in a preset step size until the spectral width reaches or exceeds the preset broadening threshold; during the temperature adjustment process, the temperatures of the four TECs are kept to change synchronously in a linearly increasing gradient to avoid uneven grid temperature.

[0096] In some embodiments, adjusting the second-order dispersion of the grating through the mapping relationship to achieve adaptive management of the input pulse chirp includes: determining the required second-order dispersion based on the real-time monitored spectral width through the temperature-dispersion mapping relationship, and then calculating the corresponding TEC temperature parameters; changing the grating dispersion by adjusting the TEC temperature so that the chirp corresponding to the negative or positive chirp of the input pulse is adapted to the nonlinear amplification process of the gain fiber, ensuring that the pulse broadens the spectrum during amplification due to the combined effects of self-phase modulation, dispersion, and gain, and is ultimately compressed to the target pulse width.

[0097] In some embodiments, the preset broadening is 23 nanometers, and the preset temperature range is 25°C to 25.6°C. When the amplified spectral width is detected to be broadened to above the preset broadening, the temperature of multiple TECs is adjusted to increase linearly within the preset range, so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width. This includes: when the spectral width reaches above 23 nanometers, maintaining the temperature of the four TECs in a linearly increasing gradient distribution of 25°C to 25.6°C, so that the pulse entering the multimode gain fiber is in a negative chirped state, and the spectrum is broadened due to self-phase modulation and dispersion effect during the amplification process, and a narrow pulse width of less than 113 femtoseconds is obtained through the grating compression device.

[0098] It should be noted that those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the fiber grating temperature regulation device and each module of the laser described above can be referred to the corresponding process in the embodiments of the fiber grating temperature regulation method of the laser described above, and will not be repeated here.

[0099] The aforementioned method for regulating the temperature of the fiber grating in a laser can be implemented as a computer program, which can be used in various applications such as... Figure 4 It runs on the device shown.

[0100] Please see Figure 5 , Figure 5 This is a schematic block diagram of the structure of a computer device provided in an embodiment of this application. The computer device includes a processor, a memory, and a network interface connected via a device bus, wherein the memory may include a storage medium and internal memory.

[0101] The storage medium can store operating devices and computer programs. The computer program includes program instructions that, when executed, cause the processor to perform any fiber optic grating temperature control method for the laser.

[0102] The processor provides computing and control capabilities, supporting the operation of the entire computer device.

[0103] Internal memory provides an environment for the execution of computer programs in non-volatile storage media. When executed by a processor, the computer program enables the processor to perform any fiber optic grating temperature regulation method for a laser.

[0104] This network interface is used for network communication, such as sending assigned tasks. Those skilled in the art will understand that... Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the terminal to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0105] It should be understood that the processor can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Among these, a general-purpose processor can be a microprocessor or any conventional processor.

[0106] In one embodiment, the processor is configured to run a computer program stored in memory to perform the following steps: The grating region of the chirped fiber grating is fixed in a V-groove formed by copper blocks driven by multiple TECs, so that the grating region is in a uniform temperature action area composed of multiple copper blocks; by independently controlling the temperature of multiple TECs, a linearly increasing temperature is applied to the grating region, and the grating period is changed by utilizing the thermo-optic effect of the fiber material.

[0107] The effect of temperature change on the second-order dispersion of the grating was pre-calibrated through experiments, and the mapping relationship between temperature and second-order dispersion was established to determine the chirp amount corresponding to different temperatures.

[0108] During the operation of the femtosecond laser, the width of the amplified spectrum is monitored in real time. Based on the monitoring results, the temperature parameters of multiple TECs are dynamically adjusted. The second-order dispersion of the grating is adjusted through the mapping relationship to achieve adaptive management of the input pulse chirp. Specifically, when the amplified spectrum width is detected to be wider than the preset width, the temperature of multiple TECs is adjusted to increase linearly within the preset range, so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width.

[0109] In some embodiments, fixing the grating region of the chirped fiber grating within a V-groove formed by multiple TEC-driven copper blocks, so that the grating region is in a uniform temperature action area formed by multiple copper blocks, includes: uniformly placing the grating region of the chirped fiber grating on four TEC-driven copper blocks, each copper block being 10 mm long and having a V-groove etched in the middle of the copper block, fixing the grating region to the surface of the copper block through the V-groove, so that the four copper blocks form a continuous temperature action area, ensuring that the grating region is uniformly heated as a whole.

[0110] In some embodiments, the number of TECs is four; the step of applying a linearly increasing temperature to the grating region by independently controlling the temperature of multiple TECs and using the thermo-optical effect of the optical fiber material to change the grating period includes: controlling the temperature of the four TECs to increase linearly from the first end to the second end according to a preset gradient, so that a uniform temperature gradient is formed in the grating region along the length direction, and changing the grating period and the dispersion at the corresponding position based on the thermal expansion effect and thermo-optical effect of the optical fiber material.

[0111] In some embodiments, the step of pre-calibrating the effect of temperature change on the second-order dispersion of the grating through experiments and establishing a mapping relationship between temperature and second-order dispersion to determine the chirp corresponding to different temperatures includes: applying different temperature combinations to each TEC within a preset temperature range, measuring the corresponding second-order dispersion of the grating, recording the corresponding data of temperature parameters and second-order dispersion, and generating a temperature-dispersion mapping table or function by fitting to determine the chirp adjustment accuracy of the grating at different temperatures.

[0112] In some embodiments, the real-time monitoring of the width of the amplified spectrum during the operation of the femtosecond laser includes: acquiring the amplified spectral signal output by the femtosecond laser in real time using a spectrometer, extracting the wavelength range of the spectrum and calculating the spectral width, and transmitting the spectral width data to the control system in real time as a feedback signal for adjusting the TEC temperature.

[0113] In some embodiments, the step of dynamically adjusting the temperature parameters of multiple TECs based on monitoring results includes: when the amplified spectral width is not detected to reach a preset broadening threshold, the control system adjusts the temperature combination of the TECs according to the temperature-dispersion mapping relationship in a preset step size until the spectral width reaches or exceeds the preset broadening threshold; during the temperature adjustment process, the temperatures of the four TECs are kept to change synchronously in a linearly increasing gradient to avoid uneven grid temperature.

[0114] In some embodiments, adjusting the second-order dispersion of the grating through the mapping relationship to achieve adaptive management of the input pulse chirp includes: determining the required second-order dispersion based on the real-time monitored spectral width through the temperature-dispersion mapping relationship, and then calculating the corresponding TEC temperature parameters; changing the grating dispersion by adjusting the TEC temperature so that the chirp corresponding to the negative or positive chirp of the input pulse is adapted to the nonlinear amplification process of the gain fiber, ensuring that the pulse broadens the spectrum during amplification due to the combined effects of self-phase modulation, dispersion, and gain, and is ultimately compressed to the target pulse width.

[0115] In some embodiments, the preset broadening is 23 nanometers, and the preset temperature range is 25°C to 25.6°C. When the amplified spectral width is detected to be broadened to above the preset broadening, the temperature of multiple TECs is adjusted to increase linearly within the preset range, so that the pulse is amplified by the gain fiber and the spectrum is broadened and compressed to a narrower pulse width. This includes: when the spectral width reaches above 23 nanometers, maintaining the temperature of the four TECs in a linearly increasing gradient distribution of 25°C to 25.6°C, so that the pulse entering the multimode gain fiber is in a negative chirped state, and the spectrum is broadened due to self-phase modulation and dispersion effect during the amplification process, and a narrow pulse width of less than 113 femtoseconds is obtained through the grating compression device.

[0116] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to implement the steps of the fiber grating temperature regulation method for a laser as provided in any embodiment of this application.

[0117] The computer-readable storage medium may be an internal storage unit of the computer device described in the foregoing embodiments, such as the hard disk or memory of the computer device. The computer-readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, SmartMedia Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the computer device.

[0118] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of fiber grating temperature regulation for a laser, comprising: The application relates to a method for self-adaptive management of chirp of input pulse in femtosecond laser. The grating region of a chirped fiber grating is fixed in a V-shaped groove formed by a plurality of TEC-driven copper blocks, so that the grating region is in a uniform temperature action region formed by the plurality of copper blocks; by independently controlling the temperature of the plurality of TECs, a linearly increasing temperature is applied to the grating region, and the grating period is changed by using the thermo-optic effect of the fiber material; The influence of temperature change on the second-order dispersion of the grating is calibrated by experiments in advance, a mapping relationship between temperature and the second-order dispersion quantity is established, and the chirp quantity corresponding to different temperatures is determined; During the operation of the femtosecond laser, the width of the amplified spectrum is monitored in real time, the temperature parameters of the plurality of TECs are dynamically adjusted according to the monitoring result, the second-order dispersion quantity of the grating is adjusted through the mapping relationship, and the self-adaptive management of the chirp quantity of the input pulse is realized; when the width of the amplified spectrum is monitored to be expanded to more than a preset expansion, the temperature of the plurality of TECs is linearly increased in a preset range by adjustment, so that the spectrum of the pulse is expanded after being amplified by the gain fiber and is compressed to a narrower pulse width.

2. The method of claim 1, wherein, The grating region of a chirped fiber grating is fixed in a V-shaped groove formed by a plurality of TEC-driven copper blocks, so that the grating region is in a uniform temperature action region formed by the plurality of copper blocks; by independently controlling the temperature of the plurality of TECs, a linearly increasing temperature is applied to the grating region, and the grating period is changed by using the thermo-optic effect of the fiber material; The grating region of a chirped fiber grating is fixed in a V-shaped groove formed by a plurality of TEC-driven copper blocks, so that the grating region is in a uniform temperature action region formed by the plurality of copper blocks; by independently controlling the temperature of the plurality of TECs, a linearly increasing temperature is applied to the grating region, and the grating period is changed by using the thermo-optic effect of the fiber material; 3. The method of claim 1, wherein, The number of the TECs is four; the linearly increasing temperature is applied to the grating region by independently controlling the temperature of the plurality of TECs, and the grating period is changed by using the thermo-optic effect of the fiber material; The temperature of the four TECs is linearly increased at a preset gradient from a first end to a second end, so that a uniform temperature gradient is formed along the length direction of the grating region; based on the thermal expansion effect and the thermo-optic effect of the fiber material, the grating period and the dispersion quantity of the corresponding position are changed.

4. The method of claim 1, wherein, The influence of temperature change on the second-order dispersion of the grating is calibrated by experiments in advance, a mapping relationship between temperature and the second-order dispersion quantity is established, and the chirp quantity corresponding to different temperatures is determined; In a preset temperature range, different temperature combinations are applied to each TEC, the corresponding second-order dispersion quantity of the grating is measured, the corresponding data of the temperature parameters and the second-order dispersion quantity are recorded, and a temperature-dispersion mapping table or function is generated by fitting, which is used to determine the chirp quantity adjustment precision of the grating at different temperatures.

5. The method of claim 1, wherein, The width of the amplified spectrum is monitored in real time during the operation of the femtosecond laser, and the temperature parameters of the plurality of TECs are dynamically adjusted according to the monitoring result. The amplified spectrum signal output by the femtosecond laser is collected in real time by a spectrometer, the wavelength range of the spectrum is extracted and the spectrum width is calculated, and the spectrum width data are transmitted to a control system in real time as a feedback signal for adjusting the temperature of the TECs.

6. The method of claim 5, wherein, When it is monitored that the width of the amplified spectrum does not reach a preset expansion threshold, the temperature combination of the TECs is adjusted according to the temperature-dispersion mapping relationship at a preset step until the spectrum width reaches or exceeds the preset expansion threshold; During the temperature adjustment process, the temperature of the four TECs is changed synchronously at a linearly increasing gradient, so that the temperature of the grating region is uniform. ​ 7. The method of claim 1, wherein, The second-order dispersion amount of the grating is adjusted through the mapping relationship, adaptive management of the input pulse chirp amount is realized, and the adaptive management includes: According to the real-time monitored spectral width, the required second-order dispersion amount is determined through the temperature-dispersion mapping relationship, and the corresponding TEC temperature parameter is calculated; By adjusting the TEC temperature to change the grating dispersion, the negative chirp or positive chirp amount of the input pulse is adapted to the nonlinear amplification process of the gain fiber, so that the pulse is broadened in the amplification process due to the joint action of self-phase modulation, dispersion and gain, and finally compressed to the target pulse width.

8. The method of claim 1, wherein, The preset broadening is 23 nanometers, and the preset temperature range is 25℃ to 25.6℃; when the monitored amplified spectral width is broadened to more than the preset broadening, the pulse spectrum is broadened and compressed to a narrower pulse width after the gain fiber amplification by adjusting the multiple TEC temperatures to linearly increase in the preset range, and the method includes: When the spectral width is more than 23 nanometers, the temperature of the four TECs is linearly increased from 25℃ to 25.6℃, so that the pulse entering the multimode gain fiber is in a negative chirp state, the spectrum is broadened in the amplification process due to the self-phase modulation and dispersion effect, and a narrow pulse width below 113 femtoseconds is obtained through the grating compression device.

9. A computer device, comprising: The computer device includes a memory and a processor; The memory is used to store a computer program; The processor is used to execute the computer program and realize the method in any one of claims 1 to 8 when the computer program is executed.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to make the processor realize the method in any one of claims 1 to 8.

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