Active damping regulated tunable laser and damping regulation method

Abstract

This application proposes an actively damped tunable laser and a damping control method, relating to the field of precision optics. The laser includes: a laser output mechanism for generating zero-order diffracted light as the laser output light and generating first-order diffracted light as external cavity feedback light; a beam splitting mechanism for separating a predetermined proportion of sampled light from the laser output light; and a wavelength tuning mechanism including a rotatable mirror, a piezoelectric drive module, an optical detection module, an electromagnetic damping module, and a piezoelectric damping module. The servo detection surface of the rotatable mirror receives the sampled light and reflects it to form displacement detection light. The optical detection module determines the mirror's pose change information, wavelength, and power based on the displacement detection light. The electromagnetic damping module provides electromagnetic damping to the magnetic support. The piezoelectric damping module provides reverse piezoelectric damping to the mirror. A controller adjusts the electrical signal supplied to the wavelength tuning mechanism. This scheme ensures stable mirror operation.

Description

Technical Field

[0001] This application relates to the field of precision optics technology, and in particular to an actively damped tunable laser and a damping control method. Background Technology

[0002] Ultra-precise tunable lasers are core laser sources for semiconductor metrology equipment such as wafer pattern geometry measurement and Fizeau interferometers. In the field of semiconductor metrology, ultra-precise external cavity tunable lasers can provide precise wavelength selection through micro-displacement of actuators, making them ideal tools for fine spectral analysis. The core components of a Littman-type external cavity tunable laser are a gain chip, a diffraction grating, and a frequency selection element. The diffraction grating has different diffraction angles for different wavelengths. The wavelength scanning principle involves simultaneously rotating the frequency selection element (mirror) to achieve wavelength selection, and using an actuator to drive a rotating arm centered on a perfect pivot point, which carries the mirror, enabling mode-skipping-free wavelength scanning and tuning.

[0003] Traditional tunable lasers use piezoelectric-driven mirrors for tuning, which suffers from problems such as large start-up shock, high-speed vibration, and uncontrollable motion curves. This leads to uneven movement of the mirror mount during tuning, causing back-and-forth oscillations and jitters. Consequently, the output laser wavelength exhibits nonlinear changes over time, making it impossible to achieve linear wavelength output. This severely affects the measurement accuracy and stability of systems such as spectral detection, lidar, and optical communication. Summary of the Invention

[0004] In view of this, this application proposes a tunable laser with active damping control and a damping control method.

[0005] In a first aspect, this application provides an actively damped tunable laser, comprising: a laser output mechanism, a beam splitting mechanism, a wavelength tuning mechanism, and a controller; The laser output mechanism is used to generate zero-order diffracted light as laser output light and to generate first-order diffracted light as external cavity feedback light. The beam splitting mechanism is used to separate a predetermined proportion of sampled light from the laser output light and transmit the sampled light to the wavelength tuning mechanism. The wavelength tuning mechanism includes a rotatable mirror, a piezoelectric drive module, an optical detection module, an electromagnetic damping module, and a piezoelectric damping module. The rotatable mirror is provided with a frame arm, a follow-up detection surface, and a magnetic support. The magnetic support is connected to the frame arm. The follow-up detection surface of the rotatable mirror receives the sampled light and reflects it to form displacement detection light. The piezoelectric drive module is used to adjust the pose of the rotatable mirror under the drive of a first drive voltage. The optical detection module is used to determine the pose change information of the rotatable mirror, as well as the wavelength and power of the laser output light, based on the displacement detection light. The electromagnetic damping module is used to provide electromagnetic damping to the magnetic support under the excitation of an excitation current. The piezoelectric damping module is located on the frame arm away from the rotation axis and is used to provide reverse damping to suppress high-frequency vibrations of the rotatable mirror under the drive of a second drive voltage. The controller is used to adjust the first driving voltage, the excitation current, and the second driving voltage according to the pose change information, the wavelength and power of the laser output light.

[0006] In one embodiment, the controller is further configured to: The target pose of the rotatable mirror, the target output wavelength of the laser, and the target output power are obtained. The pose change information, the wavelength and power of the laser output light are compared with the corresponding target parameters to obtain the pose deviation, wavelength deviation, and power deviation. The first driving voltage is adjusted based on the pose deviation, the wavelength deviation, and the power deviation until the wavelength deviation and the power deviation converge within a preset error allowable range. The excitation current output to the electromagnetic damping module is adjusted according to the pose change information of the rotatable reflector, and the second driving voltage is adjusted according to the high-frequency vibration component in the pose change information of the rotatable reflector.

[0007] In one embodiment, the controller is further configured to: Based on the pose deviation, the first driving voltage is coarsely adjusted until the actual pose of the reflector converges to the target pose within the preset pose error range. The first driving voltage is dynamically fine-tuned according to the wavelength deviation and power deviation until the wavelength deviation and power deviation no longer increase and are stably maintained within the preset error allowable range.

[0008] In one embodiment, the controller is further configured to: For the pose change information of the rotatable reflector, the low-frequency motion component, motion velocity and pose deviation are extracted by low-pass filtering, and the high-frequency vibration component of the pose is separated by high-pass filtering. Using the low-frequency motion components of the pose obtained by filtering, the motion velocity, and the pose deviation as inputs, the excitation current is dynamically adjusted using a PID control algorithm. The high-frequency vibration components of the posture extracted are used as input, and the second driving voltage is dynamically adjusted by a PID control algorithm after signal noise reduction processing.

[0009] In one embodiment, the controller is further configured to: A discrete model of the rotational dynamics of a rotatable mirror is established based on low-frequency motion components of the pose, motion velocity, and pose deviation. Define the prediction time domain and control time domain of model predictive control, and construct an optimization function with the objectives of minimizing pose tracking error and suppressing low-frequency oscillations; Based on the maximum output limit of excitation current, the saturation constraint of electromagnetic damping torque and the optimization function, the discretized model of the rotational dynamics of the rotatable mirror is solved by rolling optimization in the control time domain to obtain the optimal excitation current sequence in the prediction time domain. Each control cycle corrects the model state based on real-time pose detection data, selects the optimal excitation current corresponding to the current moment in the prediction time domain, corrects and optimizes the excitation current after PID adjustment, and outputs the optimal excitation current for the current cycle.

[0010] In one embodiment, the wavelength tuning mechanism further includes a temperature sensor for detecting temperature information of the rotatable mirror; the controller is further configured to: Input features are constructed based on the high-frequency vibration components of the posture and the temperature information; The input features are input into a pre-trained lightweight LSTM model, which outputs an adaptive compensation voltage for the second driving voltage. The unfrozen parameters of the lightweight LSTM model are fine-tuned online at preset intervals using real-time collected pose high-frequency vibration components and temperature information. If the total voltage after superimposing the adaptive compensation voltage and the second drive voltage adjusted by the PID is within the preset voltage allowable range, then the adaptive compensation voltage and the second drive voltage adjusted by the PID will be superimposed and output. If the total voltage after superposition exceeds the preset allowable voltage range, the output voltage clamp will be adjusted to the preset allowable voltage extreme value.

[0011] In one embodiment, the laser output mechanism includes: a semiconductor laser diode, a collimating optical element, and a diffraction grating; The semiconductor laser diode is used to output the initial beam; The collimating optical element is located in the output optical path of the semiconductor laser diode and is used to collimate the initial beam and output collimated light. The diffraction grating is located in the transmission optical path of the collimated light and is used to disperse the collimated light, outputting the zero-order diffraction light and the first-order diffraction light. The first-order diffraction light is reflected by the rotatable mirror to the diffraction grating, and then reflected back into the cavity of the semiconductor laser diode through the diffraction grating and the collimating optical element to form an external cavity resonance.

[0012] In one embodiment, the optical detection module includes a narrowband filter unit, a spot collimation and convergence unit, and a detection unit; The narrowband filter unit is used to filter the displacement detection light and output filtered light in the target laser band. The light spot collimation and focusing unit is used to collimate and focus the filtered light, and output the focused light spot to the photosensitive surface of the detection unit; The detection unit is used to detect the position of the focused light spot, determine the pose change information of the rotatable reflector based on the position change information of the focused light spot, perform photoelectric conversion on the focused light spot, and determine the wavelength and power of the laser output light based on the converted electrical signal.

[0013] In one embodiment, the wavelength tuning mechanism further includes a support cavity; the electromagnetic damping module includes a magnetically shielded cylinder and an excitation coil; The magnetic shielding cylinder is disposed in the supporting cavity; The excitation coil is disposed inside the magnetic shielding cylinder. The excitation coil is coaxially arranged with the magnetic support. The magnetic support moves synchronously with the rotatable reflector, cutting the magnetic field lines generated by the excitation coil to form electromagnetic damping.

[0014] Secondly, this application also provides a damping control method for a tunable laser, the damping control method being applied to the tunable laser as described in the first aspect; the damping control method includes: The target pose of the rotatable mirror, the target output wavelength of the laser, and the target output power are obtained. The pose change information, the wavelength and power of the laser output light are compared with the corresponding target parameters to obtain the pose deviation, wavelength deviation, and power deviation. The first driving voltage is adjusted based on the pose deviation, the wavelength deviation, and the power deviation until the wavelength deviation and the power deviation converge within a preset error allowable range. The excitation current output to the electromagnetic damping module is adjusted according to the pose change information of the rotatable reflector, and the second driving voltage is adjusted according to the high-frequency vibration component in the pose change information of the rotatable reflector.

[0015] The actively damped tunable laser disclosed in this application has the following advantages over related technologies: 1. The tunable laser of this application generates zero-order diffraction light as laser output light and first-order diffraction light as external cavity feedback light through the laser output mechanism, thereby realizing laser tuning and output. The beam splitting mechanism separates sample light from the laser output light and sends it to the wavelength tuning mechanism. At the same time, the rotatable mirror converts the sample light into displacement detection light by means of its own follow-up detection surface. The optical detection module can synchronously calculate the position change information of the rotatable mirror and the laser output wavelength and power based on the displacement detection light, thereby realizing optical path multiplexing, simplifying the overall optical layout, reducing the layout of redundant optical components, and providing reliable data feedback for subsequent precise closed-loop control.

[0016] 2. The wavelength tuning mechanism includes a piezoelectric drive module, an electromagnetic damping module, and a piezoelectric damping module. The piezoelectric drive module can precisely adjust the position of the rotatable reflector through the first drive voltage to achieve tunable laser wavelength output. The electromagnetic damping module applies electromagnetic damping to the magnetic support to suppress low-frequency vibration. The piezoelectric damping module is located at a key position on the support arm of the mirror frame away from the rotation axis, and is specially designed to provide reverse damping to suppress high-frequency vibration. By adopting a high- and low-frequency zone damping coordinated control method, the vibration disturbance of the rotatable reflector can be weakened across the entire frequency band, ensuring the stability of the reflector's working posture. This solves the problems of large start-up impact, easy vibration during high-speed movement, and uncontrollable motion curve of traditional piezoelectric driven reflectors, making the tuning motion of the rotatable reflector smooth and controllable.

[0017] 3. Based on the real-time acquired pose change information, laser wavelength and power, the controller adjusts the first driving voltage, excitation current and second driving voltage in a closed-loop linkage, deeply integrating wavelength tuning with full-band active damping control. This can precisely constrain the motion trajectory of the reflector, avoid nonlinear fluctuations in the output laser wavelength over time, achieve linear and stable wavelength output, significantly improve the working stability and tuning accuracy of the tunable laser, and effectively meet the requirements of measurement accuracy and system stability for applications such as spectral detection, lidar, and optical communication. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the optical path structure of an actively damped tunable laser in one embodiment of this application; Figure 2 This is a schematic diagram illustrating the principle of battery damping control in one embodiment of this application; Figure 3This is a schematic diagram showing the connection relationship between the controller and the wavelength tuning mechanism in one embodiment of this application; Figure 4 This is a schematic diagram of the optical path structure of the optical detection module in one embodiment of this application; Figure 5 This is a schematic diagram of the battery damping module in one embodiment of this application; Figure 6 This is a flowchart illustrating a damping control method for a tunable laser in one embodiment of this application.

[0020] Explanation of reference numerals in the attached figures: 1-Laser output mechanism, 11-Semiconductor laser diode, 12-Collimating optical element, 13-Diffraction grating, 2-Wavelength tuning mechanism, 21-Rotable mirror, 211-Mirror mount arm, 212-Magnetic support, 213-Rotating shaft, 22-Piezoelectric drive module, 23-Optical detection module, 231-Narrowband filter unit, 232-Bright spot collimation and focusing unit, 233-Detection unit, 24-Piezoelectric damping module, 25-Electromagnetic damping module, 251-Magnetic shielding cylinder, 252-Excitation coil, 26-Support cavity, 3-Beam splitting mechanism, 31-Beam splitting element, 32-Mirror element, 33-Collimating element, 4-Controller. Detailed Implementation

[0021] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] In some embodiments, such as Figures 1 to 3 As shown, this application provides an actively damped tunable laser, including: a laser output mechanism 1, a beam splitting mechanism 3, a wavelength tuning mechanism 2, and a controller 4.

[0023] The laser output mechanism 1 is used to generate zero-order diffracted light as the laser output light and first-order diffracted light as the external cavity feedback light. The laser output mechanism 1 can output collimated light, which is then dispersed by a diffraction grating 13. The grating decomposes the collimated light into diffracted light of different orders according to the principle of light diffraction. The zero-order diffracted light, due to its concentrated energy and stable propagation direction, is directly selected as the laser output light to meet the core requirements of high-resolution spectroscopy, precision measurement, and other applications. The first-order diffracted light, as the external cavity feedback light, is designed with a corresponding optical path structure to reflect back along the original optical path into the active cavity of the laser output mechanism 1, forming a stable external cavity resonant structure.

[0024] Beam splitting mechanism 3 is used to separate a predetermined proportion of sample light from the laser output light and transmit the sample light to wavelength tuning mechanism 2. Beam splitting mechanism 3 separates a small portion of the beam as sample light from the zero-order diffracted laser output light generated by laser output mechanism 1 according to a fixed intensity ratio (e.g., 5%), retaining the majority of the laser beam as the effective output of the entire machine, ensuring the integrity of the external cavity resonant optical path energy without loss. Beam splitting mechanism 3 may include beam splitting element 31, mirror element 32, and collimating element 33. Beam splitting element 31 is used to separate the sample light from the laser output light, mirror element 32 is used to reflect the sample light to change the beam transmission direction, and collimating element 33 is used to collimate the reflected sample light and transmit the collimated sample light to wavelength tuning mechanism 2.

[0025] The wavelength tuning mechanism 2 includes a rotatable mirror 21, a piezoelectric drive module 22, an optical detection module 23, an electromagnetic damping module 25, and a piezoelectric damping module 24. The rotatable mirror 21 is provided with a mirror frame arm 211, a follow-up detection surface, and a magnetic support 212. The magnetic support 212 is connected to the mirror frame arm 211. The follow-up detection surface of the rotatable mirror 21 receives sampled light and reflects the sampled light to form displacement detection light. The piezoelectric drive module 22 is used to adjust the position and orientation of the rotatable mirror 21 under the drive of a first drive voltage. The optical detection module 23 is used to determine the position and orientation change information of the rotatable mirror 21, as well as the wavelength and power of the laser output light, based on the displacement detection light. The electromagnetic damping module 25 is used to provide electromagnetic damping to the magnetic support 212 under the excitation of the excitation current. The piezoelectric damping module 24 is located on the mirror frame arm 211 away from the rotating shaft 213 and is used to provide reverse damping to suppress high-frequency vibrations to the rotatable mirror 21 under the drive of a second drive voltage.

[0026] The rotatable reflector 21 integrates a frame arm 211, a follow-up detection surface, and a magnetic support 212. The magnetic support 212 and the frame arm 211 are connected to form an integrated linkage structure. The rotatable reflector 21 accurately receives the sampled light transmitted by the beam splitter 3 through its own follow-up detection surface and reflects the sampled light to generate displacement detection light, providing a dedicated optical path carrier for subsequent state detection. Based on the inverse piezoelectric effect, the piezoelectric drive module 22 can accurately drive and adjust the deflection posture of the rotatable reflector 21 under the action of the first drive voltage output by the controller 4, thereby realizing the tuning control of the laser output wavelength. The optical detection module 23 can detect the incident position of the displacement detection light, calculate the real-time posture change information of the rotatable reflector 21 based on the change of the incident position, and then perform photoelectric conversion on the displacement detection light. Based on the converted electrical signal, the wavelength and power parameters of the laser output light are determined, providing accurate and reliable feedback data for the closed-loop control of the whole machine. The electromagnetic damping module 25 generates a magnetic field under excitation current, applying controllable electromagnetic damping to the magnetic support 212, effectively suppressing low-frequency oscillations and starting shocks during the tuning process of the rotatable reflector 21. The piezoelectric damping module 24 is located at a critical stress position on the mirror frame arm 211 away from the rotating shaft 213. Driven by the second driving voltage, it outputs a reverse damping force to counteract the high-frequency vibrations generated during the high-speed movement of the rotatable reflector 21. Through precise piezoelectric tuning combined with the high- and low-frequency synergistic vibration suppression of the electromagnetic and piezoelectric dual modules, the defects of unsmooth tuning movement and easy shaking and oscillation of traditional reflectors are fundamentally improved.

[0027] The controller 4 is used to adjust the first driving voltage, the excitation current and the second driving voltage according to the pose change information, the wavelength and power of the laser output light.

[0028] It is understandable that the controller 4 uses the real-time feedback information on the pose change of the rotatable reflector 21, the wavelength parameters of the laser output light, and the power parameters from the optical detection module 23 as the basis for closed-loop control. It senses the laser's operating status and reflector pose disturbances in real time, and dynamically and adaptively adjusts the first driving voltage of the piezoelectric drive module 22, the excitation current of the electromagnetic damping module 25, and the second driving voltage of the piezoelectric damping module 24 based on the detection data. On the one hand, it achieves fine-tuned control of the rotatable reflector 21's pose by precisely adjusting the first driving voltage, thus completing the continuous tunable output of the laser wavelength. On the other hand, it synchronously matches and adjusts the excitation current and the second driving voltage, outputting corresponding low-frequency electromagnetic damping and high-frequency reverse damping as needed. This counteracts the start-up shock, high and low frequency vibrations, and attitude oscillations during the reflector tuning process in real time, constructing a closed-loop control system integrating wavelength tuning and full-band active damping, ensuring that the laser always maintains stable operation and high-precision stable light output.

[0029] The aforementioned tunable laser generates zero-order diffraction light as the laser output light and first-order diffraction light as the external cavity feedback light through the laser output mechanism 1, thereby achieving laser tuning and output. The beam splitting mechanism 3 separates the sample light from the laser output light and sends it to the wavelength tuning mechanism 2. At the same time, the rotatable mirror 21 converts the sample light into displacement detection light by means of its own follow-up detection surface. The optical detection module 23 can synchronously calculate the position change information of the rotatable mirror 21 and the laser output wavelength and power based on the displacement detection light, thereby realizing optical path multiplexing, simplifying the overall optical layout, reducing the layout of redundant optical components, and providing reliable data feedback for subsequent precise closed-loop control. The wavelength tuning mechanism 2 includes a piezoelectric drive module 22, an electromagnetic damping module 25, and a piezoelectric damping module 24. The piezoelectric drive module 22 can precisely adjust the position of the rotatable reflector 21 through the first drive voltage to achieve tunable laser wavelength output. The electromagnetic damping module 25 applies electromagnetic damping to the magnetic support 212 to suppress low-frequency vibration. The piezoelectric damping module 24 is located at a key position on the mirror support arm 211 away from the rotating shaft 213, and is specially designed to provide reverse damping to suppress high-frequency vibration. By adopting a high- and low-frequency zone damping coordinated control method, it can reduce the vibration disturbance of the rotatable reflector 21 across the entire frequency band, ensuring the stability of the reflector's working posture. This solves the problems of large start-up impact, easy vibration during high-speed movement, and uncontrollable motion curve of traditional piezoelectric driven reflectors, making the tuning motion of the rotatable reflector 21 smooth and controllable. Based on the real-time acquired pose change information, laser wavelength and power, controller 4 adjusts the first driving voltage, excitation current and second driving voltage in a closed-loop linkage, deeply integrating wavelength tuning with full-band active damping control. This can precisely constrain the motion trajectory of the reflector, avoid nonlinear fluctuations in the output laser wavelength over time, achieve linear and stable wavelength output, significantly improve the working stability and tuning accuracy of the tunable laser, and effectively meet the requirements of measurement accuracy and system stability for applications such as spectral detection, lidar, and optical communication.

[0030] In some embodiments, the controller 4 is further configured to: acquire the target pose of the rotatable reflector 21, the target output wavelength of the laser, and the target output power; compare the pose change information, the wavelength and power of the laser output light with the corresponding target parameters to obtain the pose deviation, wavelength deviation, and power deviation; adjust the first driving voltage based on the pose deviation, wavelength deviation, and power deviation until the wavelength deviation and power deviation converge within a preset error allowable range; adjust the excitation current output to the electromagnetic damping module 25 according to the pose change information of the rotatable reflector 21; and adjust the second driving voltage according to the high-frequency vibration component in the pose change information of the rotatable reflector 21.

[0031] It can be understood that the actual pose change information collected in real time is compared with the preset target pose one by one and the difference is calculated to obtain the pose deviation. The actual output wavelength of the laser is compared with the preset target output wavelength to obtain the wavelength deviation. The actual output power of the laser is compared with the preset target output power to obtain the power deviation. Then, based on the positive and negative directions and magnitudes of various deviations, the amplitude and offset of the first driving voltage output to the piezoelectric drive module 22 can be dynamically and adaptively corrected. By adjusting the first driving voltage in real time, the driving stroke and output force of the piezoelectric drive module 22 are changed, thereby finely adjusting the deflection angle and spatial pose of the rotatable reflector 21. At the same time, the actual wavelength and power parameters of the laser are continuously collected in real time and the deviation comparison and voltage correction process is repeated to perform closed-loop iterative control until the wavelength deviation and power deviation are stably close to the target output wavelength and target output power, thereby achieving precise locking and steady-state control of the laser output wavelength and optical power.

[0032] The controller 4 analyzes the pose change information of the rotatable reflector 21 in real time, identifies the movement speed and attitude fluctuation of the reflector, and dynamically adjusts the excitation current supplied to the electromagnetic damping module 25 according to the adaptive adjustment characteristics of high speed with large damping and low speed with small damping. When the rotatable reflector 21 moves at a high speed and the attitude deviation fluctuates violently, the excitation current is actively increased, so that the electromagnetic damping module 25 outputs a larger damping torque to quickly suppress the starting impact and low-frequency large-amplitude oscillation. When the reflector is in a low-speed fine-tuning state and the attitude tends to be stable, the excitation current is reduced in time to match a smaller output damping torque to avoid excessive damping interfering with the precision pose tuning action. At the same time, the controller 4 accurately extracts the high-frequency vibration component from the pose change information of the rotatable reflector 21 through signal filtering and component analysis, and dynamically adjusts the second driving voltage of the piezoresistive damping module 24 according to the amplitude and frequency characteristics of the high-frequency vibration component, accurately outputting the appropriate reverse damping force to specifically suppress the high-frequency micro-jitter and resonance interference generated by the mirror frame arm 211.

[0033] In some embodiments, the controller 4 is further configured to: coarsely adjust the first driving voltage based on the pose deviation until the actual pose of the reflector converges to the target pose within a preset pose error range; and dynamically finely adjust the first driving voltage according to the wavelength deviation and power deviation until the wavelength deviation and power deviation no longer increase and are stably maintained within a preset error allowable range.

[0034] In the application, controller 4 first uses the pose deviation of the rotatable reflector 21 as the main control variable to perform a wide-range coarse adjustment of the first driving voltage of the piezoelectric drive module 22. Based on the positive and negative directions and magnitude of the pose deviation, the output value of the first driving voltage is proportionally corrected to quickly compensate for large offsets between the actual pose of the reflector and the target pose. Coarse adjustment is continuously performed through closed-loop iteration until the actual pose of the reflector converges relative to the target pose and stabilizes within the preset pose error range, thus completing rapid coarse pose alignment. The pose deviation coarse adjustment formula is as follows:

[0035] The pose convergence constraint is as follows: ; This is the first driving voltage after coarse pose adjustment. This is the initial reference value for the first driving voltage. In order to adjust the proportional coefficient, For the orientation deviation of the rotatable reflector 21, This is the preset pose error range threshold.

[0036] After the coarse pose adjustment is achieved, the process transitions to fine-tuning. Controller 4 uses wavelength and power deviations as correction criteria to dynamically adjust the first driving voltage in small increments. This compensates for fluctuations in laser wavelength and output power caused by minor pose drifts. The controller monitors the trends of wavelength and power deviations in real time throughout the process, continuously iteratively adjusting the first driving voltage until the wavelength and power deviations no longer show a continuously increasing trend and can be stably maintained within their respective preset error tolerance ranges. This achieves step-by-step convergence and high-precision steady-state control of pose, wavelength, and power. The dynamic fine-tuning formulas for wavelength and power deviations are as follows:

[0037] The convergence constraints for wavelength and power are as follows: ; For laser wavelength deviation, For laser power deviation; This is the real-time output value of the first driving voltage. and These are the wavelength and power modulation ratios, respectively. and The preset error range thresholds are for wavelength and power, respectively.

[0038] In some embodiments, the controller 4 is further configured to: extract low-frequency motion components, motion speed, and pose deviation of the rotatable reflector 21 through low-pass filtering for pose change information, and separate high-frequency vibration components of the pose through high-pass filtering; dynamically adjust the excitation current using a PID control algorithm with the filtered low-frequency motion components, motion speed, and pose deviation as input; and dynamically adjust the second driving voltage using a PID control algorithm after signal noise reduction processing with the separated high-frequency vibration components of the pose as input.

[0039] Understandably, controller 4 first performs layered filtering and analysis on the real-time acquired original pose change information of the rotatable reflector 21. On the one hand, it filters out high-frequency jitter and resonance clutter interference through low-pass filtering, accurately extracting the low-frequency motion component, real-time motion speed, and pose deviation that characterize the overall operating state of the reflector from the original pose signal. On the other hand, it removes the low-frequency basic motion component through high-pass filtering, and separates the high-frequency vibration component of the pose caused by mechanical resonance, structural micro-jitter, and high-speed tuning, thus achieving effective decoupling of the low-frequency motion signal and the high-frequency vibration signal.

[0040] The formula for a first-order low-pass filter is: The formula for a first-order high-pass filter is: in, Sampling time, This is the original pose change signal of the rotatable mirror 21. The low-pass filter outputs the low-frequency motion components of the pose. The high-pass filter outputs the high-frequency vibration components of the pose. This is the filtering smoothing coefficient.

[0041] After decoupling the low-frequency motion signal and the high-frequency vibration signal, the low-frequency motion component of the pose, motion velocity, and pose deviation extracted by the low-pass filter are used as inputs. A PID control algorithm is introduced for closed-loop calculation. The excitation current is adaptively tuned and adjusted based on the real-time dynamic changes of the three components. This adapts to the high-speed, high-damping and low-speed, low-damping control characteristics of the reflector, accurately suppressing starting shocks and low-frequency reciprocating oscillations. Simultaneously, the high-frequency vibration component of the pose separated by the high-pass filter is first subjected to signal denoising processing to remove invalid noise such as detection noise and environmental electromagnetic interference. The denoised clean high-frequency vibration component is then used as another input, introduced into the PID control algorithm for closed-loop calculation. After algorithm calculation, the second driving voltage is dynamically adjusted to output a targeted reverse damping force, achieving precise suppression of the high-frequency micro-vibrations of the reflector.

[0042] The PID control formula for excitation current (low-frequency input) is as follows: in, The real-time motion velocity of the reflector's pose. For real-time pose deviation, For excitation current, These are the proportional, integral, and derivative coefficients for the PID control of the excitation current.

[0043] The PID control formula for the second drive voltage (high-frequency input) is: in, This is the second driving voltage. The proportional, integral, and derivative coefficients for the second driving voltage PID control.

[0044] In some embodiments, the controller 4 is further configured to: establish a discrete model of the rotational dynamics of the rotatable reflector 21 based on the low-frequency motion components of the pose, motion speed, and pose deviation; set the prediction time domain and control time domain of the model predictive control, and construct an optimization function aimed at minimizing the pose tracking error and suppressing low-frequency oscillations; perform rolling optimization on the discrete model of the rotational dynamics of the rotatable reflector 21 in the control time domain based on the maximum output limit of the excitation current, the saturation constraint condition of the electromagnetic damping torque, and the optimization function, to obtain the optimal excitation current sequence in the prediction time domain; and correct the model state according to the real-time pose detection data in each control cycle, select the optimal excitation current corresponding to the current moment in the prediction time domain, correct and optimize the excitation current after PID adjustment, and output the optimal excitation current of the current cycle.

[0045] To achieve high-precision damping control of the low-frequency motion of the rotatable reflector 21, model predictive control (MPC) can be implemented in addition to the aforementioned PID regulation. The controller 4 first constructs a continuous dynamic model reflecting the rotation law of the reflector based on its mechanical characteristics and low-frequency motion features, using the low-frequency motion components of the pose extracted by low-pass filtering, real-time motion velocity, and pose deviation as core state variables. This model is then transformed into a discrete dynamic model of the rotatable reflector 21's rotation adapted to digital control through discretization (first-order forward difference method). Based on the rigid body rotation law, the continuous dynamic model is as follows:

[0046] For the sampling time, the first-order forward difference method is used for discretization (sampling period). The discrete model is obtained as follows: Definition of associated state variables: ( (Moment pose deviation) ( (Movement speed at all times) in, The moment of inertia of the rotatable mirror 21; for Low-frequency motion components of position and posture at any given moment; for Target pose angle at any given time; for Temporal pose deviation; for Constant speed of movement; This is the mechanical damping coefficient; The electromagnetic damping torque satisfies the following condition with the excitation current: ; For constant disturbance torque; This is the current-to-torque conversion factor; for Constant excitation current; To control the sampling period; To predict the time domain, It is a positive integer, representing the number of sampling periods for future predictions; To control the time domain, It is a positive integer representing the number of currently adjustable sampling periods.

[0047] Subsequently, considering the system's dynamic response speed and hardware computing power, the prediction time domain of Model Predictive Control (MPC) was rationally set. (The total number of sampling periods to be predicted in the future determines the prediction accuracy) and the control time domain (The total number of sampling periods for which control can be applied, balancing real-time performance and control degrees of freedom, to satisfy...) ), and with pose tracking error ( With minimization as the core objective, a multi-objective optimization function is constructed by superimposing a motion velocity penalty term (to suppress low-frequency oscillations) and an excitation current change rate penalty term (to avoid damping shocks caused by sudden current changes), and adjusting the priority of each objective through weighting coefficients. The multi-objective optimization function is as follows: in, for Time prediction The rotatable reflector has a 21-position orientation deviation. for Time prediction Excitation current at all times for Time prediction Constant speed of movement; These are the weighting coefficients for pose deviation, motion speed, and current change rate, respectively. The excitation current change rate, , .

[0048] In the optimization solution stage, the hardware physical constraints (maximum output limit of excitation current to prevent overload of the drive circuit) and electromagnetic characteristic constraints (saturation constraint of electromagnetic damping torque to avoid damping failure due to magnetic circuit saturation) are transformed into mathematical inequality constraints. Combined with the constructed optimization function and the discrete model of rotational dynamics, the optimal excitation current sequence corresponding to each sampling moment in the prediction time domain is obtained through iterative solution using a rolling optimization algorithm (such as quadratic programming) within the control time domain. The corresponding constraint conditions are:

[0049] in, These are the upper and lower limits of the excitation current, respectively; These are the saturation limits of electromagnetic damping torque.

[0050] To address model parameter drift and external disturbances, each control cycle utilizes real-time pose data acquired by the optical detection module 23 to correct the model's current state and compensate for prediction errors. Subsequently, the current value corresponding to the current cycle is extracted from the optimal excitation current sequence to correct the excitation current output by the previous PID control, thus offsetting the static error and dynamic lag of the PID. Finally, the optimal excitation current for the current cycle is output, achieving dual-closed-loop coordinated control. This ensures both the accuracy of low-frequency oscillation suppression and the real-time performance and stability of damping adjustment. The formula for the optimal excitation current output for the current cycle is:

[0051] in, for The excitation current after PID regulation at any given time; This is the amount by which the MPC corrects the PID current. ; for The optimal excitation current that is ultimately output at any given time.

[0052] In some embodiments, the wavelength tuning mechanism 2 further includes a temperature sensor for detecting the temperature information of the rotatable reflector 21; the controller 4 is also used to: construct input features based on the pose high-frequency vibration components and temperature information; input the input features into a pre-trained lightweight LSTM (Long Short-Term Memory) model, and output an adaptive compensation voltage for the second driving voltage; if the total voltage after superimposing the adaptive compensation voltage and the PID-adjusted second driving voltage is within a preset voltage allowable range, then the adaptive compensation voltage and the PID-adjusted second driving voltage are superimposed and output; if the superimposed total voltage exceeds the preset voltage allowable range, then the output voltage is clamped and adjusted to the preset allowable voltage extreme value. Specifically, at preset intervals, the unfrozen parameters of the lightweight LSTM model are fine-tuned online using real-time acquired pose high-frequency vibration components and temperature information.

[0053] Among them, the lightweight LSTM model simplifies the LSTM network layers and reduces the number of hidden layer neurons compared to the ordinary LSTM model. Combined with weight pruning, sparsification and quantization compression, it greatly reduces the number of model parameters and computational overhead, meeting the requirements of real-time inference and low-latency operation of embedded controller 4.

[0054] For offline training of lightweight LSTM models, the first step is to construct a dataset. Temperature time-series data and high-frequency vibration components of different ambient temperatures, vibration frequencies and amplitudes are collected under various working conditions. The corresponding ideal second driving voltage compensation values ​​are matched to construct a labeled time-series training dataset, which is then divided into training set, validation set and test set according to proportions.

[0055] It should be noted that the process for determining the ideal second driving voltage compensation value can be as follows: First, a laser calibration experimental platform is built, covering the entire operating temperature range of the entire machine, different tuning conditions, and external disturbance conditions. The rotatable reflector 21 is artificially excited to generate typical high-frequency vibrations of different frequencies and amplitudes. The pose high-frequency vibration components and real-time temperature information under each condition are collected with high precision through the optical detection module 23 and the temperature sensor. At the same time, the basic second driving voltage after the current PID adjustment and the residual amplitude of the high-frequency vibration of the reflector are recorded. Under each steady-state condition, a closed-loop test is performed by gradually fine-tuning the superimposed compensation voltage. The high-frequency vibration suppression effect of the reflector is continuously observed. When the pose high-frequency vibration amplitude decays to the minimum, there is no obvious residual jitter, and the driving voltage does not exceed the hardware allowable range, the superimposed compensation voltage corresponding to that condition is determined as the ideal second driving voltage compensation value under the current vibration component and temperature matching. Simultaneously, structural dynamics simulation and piezoelectric coupling model simulation can be combined to solve the compensation voltage required to completely offset high-frequency vibration in theory, and cross-calibrate and correct it with the experimental calibration value; after traversing all temperature and high-frequency vibration characteristic working conditions, a standard label dataset is formed as the basis for supervision labels for offline training of lightweight LSTM models.

[0056] Then, the model input is composed of high-frequency vibration components of pose and temperature information, the supervision label is the ideal adaptive compensation voltage, the mean square error is selected as the loss function, and iterative training is carried out in conjunction with the gradient descent optimization algorithm. The model convergence status is monitored in real time using the validation set, and the hyperparameters are repeatedly tuned until the loss function converges and the prediction accuracy of the test set reaches the target. The weights of the pre-trained lightweight LSTM model are saved.

[0057] To update the network periodically (e.g., every 100ms) while maintaining the core network structure, a layered parameter freezing setting is adopted: the lightweight LSTM is designed in layers, and the network parameters responsible for basic temporal feature extraction and vibration pattern recognition in the bottom layer are set as frozen parameters, which remain unchanged during training and subsequent online fine-tuning; the weights and biases related to feature mapping and compensation voltage fitting output in the upper layer are set as unfrozen, fine-tunable parameters, preserving space for online adaptive updates.

[0058] At preset fixed intervals, the system automatically initiates an online fine-tuning process: First, it collects high-frequency vibration components at the 21 poses of the rotatable reflector and overall machine temperature information in real time. After denoising, normalization, and temporal reconstruction, online temporal feature samples are generated. The frozen parameters at the bottom layer of the lightweight LSTM are kept fixed and not updated; only the unfrozen learnable parameters at the top layer are made available. The real-time constructed input feature samples are input into the model for forward inference, and the loss error between the model's predicted adaptive compensation voltage and the actual optimal compensation voltage is calculated. A small learning rate backpropagation gradient algorithm is used, and only the unfrozen network weights, biases, and other parameters are iteratively corrected and updated to avoid large weight fluctuations that could damage the original model's generalization ability. After fine-tuning, the model's inference weights are updated immediately, enabling the lightweight LSTM to continuously adapt to changes in field conditions such as temperature drift, changes in mechanical vibration characteristics, and aging of piezoelectric components, and to correct the second driving voltage compensation amount in real time, ensuring long-term stable and reliable high-frequency vibration suppression.

[0059] It is understandable that the system synchronously collects the high-frequency vibration components of the rotatable reflector 21 and the laser's operating temperature information, performs data normalization, timing alignment, and feature standardization on the two types of time-series signals, and fuses them to construct multi-dimensional time-series input features adapted to the model input. The constructed input features are fed into a lightweight LSTM model that has completed offline pre-training. Leveraging the advantages of lightweight LSTM in mining timing correlations and fitting nonlinear coupling relationships, it accurately learns the correlation between high-frequency vibration amplitude, frequency, and temperature drift, and intelligently calculates and outputs a second driving voltage adaptive compensation voltage to counteract high-frequency vibration disturbances. Subsequently, the controller 4 performs output voltage limiting logic judgment, superimposing the adaptive compensation voltage output by the lightweight LSTM with the second driving voltage tuned by the PID algorithm. If the superimposed total driving voltage is within the preset safe voltage allowable range of the piezoresistive damping module 24 and the driving circuit, the superimposed voltage is directly used as the final control voltage output, realizing the synergistic vibration suppression of PID basic regulation plus LSTM intelligent compensation. If the total voltage after superposition exceeds the preset upper and lower voltage limits, in order to avoid overvoltage damage to piezoelectric devices and drive hardware and to prevent abnormal saturation of damping torque, voltage clamping adjustment is automatically performed to forcibly limit the output voltage to the preset maximum or minimum voltage value.

[0060] Meanwhile, the system sets a fixed preset time interval to periodically trigger the model adaptive update mechanism. It uses the high-frequency vibration components and temperature information of the pose collected in real time on site to fine-tune the network parameters of the unfrozen part in the lightweight LSTM model online. It maintains the accuracy of high-frequency vibration compensation and damping control in the long term by mitigating the characteristic shift caused by adapter aging, environmental temperature drift and micro deformation of mechanical structure.

[0061] In some embodiments, such as Figure 1As shown, the laser output mechanism 1 includes: a semiconductor laser diode 11, a collimating optical element 12, and a diffraction grating 13.

[0062] The semiconductor laser diode 11 is used to output the initial beam.

[0063] The collimating optical element 12 is located in the output optical path of the semiconductor laser diode 11 and is used to collimate the initial beam and output collimated light.

[0064] The diffraction grating 13 is located in the transmission optical path of the collimated light and is used to disperse the collimated light, outputting zero-order diffraction light and first-order diffraction light. The first-order diffraction light is reflected by the rotatable mirror 21 to the diffraction grating 13, and then reflected back into the cavity of the semiconductor laser diode 11 through the diffraction grating 13 and the collimating optical element 12, forming an external cavity resonance.

[0065] The semiconductor laser diode 11 is the core device for laser generation in the external cavity semiconductor laser. Based on the photoelectric conversion principle of stimulated emission, it generates and emits an initial beam with a certain spatial divergence angle and irregular beam propagation direction under electrical excitation. The collimating optical element 12 can be a special optical shaping element such as an aspherical collimating lens or lens group. It is precisely coaxially set in the output optical path of the semiconductor laser diode 11, matching the propagation path of the initial beam. It can focus and collimate the initial beam with divergent characteristics, cancel the spatial divergence trend of the beam, and output collimated light with consistent propagation direction, regular beam cross-section, and meeting the subsequent dispersion requirements. This provides an incident beam that meets the optical conditions for the precise dispersion of the subsequent diffraction grating 13.

[0066] The diffraction grating 13 is a dispersive optical element with a periodic grating scribe structure. It is arranged in the subsequent transmission optical path of the collimated light. After the collimated light is incident on the grating working surface of the diffraction grating 13 at a preset incident angle, it is dispersed based on the grating diffraction effect. The incident collimated light is separated according to its wavelength characteristics and emitted at different diffraction angles. The diffracted light propagating along the original incident light direction is the zero-order diffracted light, which serves as the final output light of the external cavity semiconductor laser. The first-order diffracted light emitted at a specific diffraction angle serves as the external cavity feedback light. It is transmitted in reverse along the original optical path to the active region of the semiconductor laser diode 11 to form optical feedback, providing key feedback light conditions for the resonant oscillation of the external cavity semiconductor laser.

[0067] The rotatable mirror 21 is located in the transmission optical path of the first-order diffracted light. It is used to reflect the first-order diffracted light to the diffraction grating 13, and then back to the cavity of the semiconductor laser diode 11 through the diffraction grating 13 and the collimating optical element 12 to form an external cavity resonance.

[0068] It is understood that the rotatable mirror 21 is a high-precision optical reflective element with a high-reflectivity coating. It is precisely positioned on the dedicated transmission optical path of the first-order diffracted light emitted from the diffraction grating 13, and the reflective surface forms a matching angle with the incident path of the first-order diffracted light, ensuring that the first-order diffracted light can be efficiently incident on the surface of the mirror. This mirror can directionally reflect the incident first-order diffracted light, using its high reflectivity to reduce light energy loss, and reflect the first-order diffracted light back to the working surface of the original diffraction grating 13 along a preset optical path. Furthermore, its rotatable characteristic allows for the indirect alteration of the geometric parameters of the feedback optical path by adjusting the reflection angle. The first-order diffracted light, reflected by the rotatable mirror 21, is re-injected into the diffraction grating 13. Based on the grating's reverse diffraction effect, it is re-integrated into a beam propagating along a specific path. This beam then propagates along the reverse optical path of the collimating optical element 12. At this point, the collimating optical element 12 plays a reverse propagation adaptation role, guiding the feedback beam precisely through its own optical channel to avoid optical path deviation. Finally, the feedback beam is reflected back into the cavity of the semiconductor laser diode 11. The feedback light oscillates back and forth in this external cavity and is continuously amplified, satisfying the phase matching and gain conditions of laser oscillation, ultimately enabling the laser to achieve stable external cavity resonant output.

[0069] In some embodiments, such as Figure 4 As shown, the optical detection module 23 includes a narrowband filter unit 231, a spot collimation and convergence unit 232, and a detection unit 233.

[0070] The narrowband filter unit 231 is used to filter the displacement detection light and output filtered light in the target laser band.

[0071] The light spot collimation and focusing unit 232 is used to collimate and focus the filtered light, and output the focused light spot to the photosensitive surface of the detector unit 233.

[0072] The detection unit 233 is used to detect the position of the focused spot, determine the pose change information of the rotatable mirror 21 based on the position change information of the focused spot, and perform photoelectric conversion on the focused spot. Based on the converted electrical signal, the wavelength and power of the laser output light are determined.

[0073] The detection unit 233 can employ a position-sensitive detector (PSD) or a high-precision area array photodetector to acquire the center coordinates of the focused spot on the photosensitive plane in real time. By comparing these coordinates with the reference center coordinates of the spot, the lateral and longitudinal position offsets are obtained. Based on the optical focal length and optical path geometry of the spot collimation and convergence unit 232, the two-dimensional deflection angle of the rotatable mirror 21 is calculated from the spot position offset. This deflection angle and its change over time represent the pose change information of the rotatable mirror 21. Geometric optical path relationship formula:

[0074] in, The equivalent focal length of the collimation and convergence unit 232; The coordinates of the light spot reference center; To focus the coordinates of the light spot center in real time; , representing the horizontal and vertical offset of the light spot, respectively.

[0075] The small-angle approximation simplifies to: The pose change information can be represented by a two-dimensional pose angle vector: , These represent the X-axis and Y-axis deflection attitude angles of the reflector, respectively.

[0076] To calculate the laser output wavelength, the detector unit 233 needs to be spectrally calibrated beforehand to establish calibration curves for different incident laser wavelengths and the detector's photoelectric response voltage. The narrowband filter unit 231 fixes the transmission range of the target wavelength band. The detector unit 233 converts the filtered light into a photoelectric response voltage. The measured voltage is substituted into the calibration fitting function, and the real-time wavelength of the laser output light is obtained through inversion. The formula for calculating the real-time wavelength of the laser output light is:

[0077] Under linear calibration conditions: in, The real-time wavelength of the laser output light; A pre-calibrated wavelength-voltage fitting function; The measured voltage of the photoelectric response corresponding to the wavelength; This is the wavelength-voltage proportionality coefficient. The bias constant is used to calibrate the wavelength.

[0078] Based on the photoelectric linear response characteristics of the photodetector, the optical power and the photoelectric conversion output voltage are linearly related. Power-voltage calibration is performed beforehand using a standard light source to obtain calibration coefficients. After the detector unit 233 outputs its photoelectric voltage, the laser output optical power is directly calculated by substituting it into the calibration formula. The corresponding calculation formula is:

[0079] in, The output voltage of the photoelectric conversion corresponding to the optical power; To increase the output optical power of the laser; This refers to the photoelectric power conversion calibration coefficient; This is the power for dark current substrate compensation.

[0080] It is understandable that the narrowband filter unit 231 receives the displacement detection light output from the rotatable mirror 21 and filters out ambient stray light, system stray reflected light, and non-target band interference light through its narrowband spectral filtering characteristics, retaining the pure filtered light of the target laser band required for laser operation, thus suppressing the interference of stray light noise on detection accuracy from the source. After receiving the filtered light, the spot collimation and focusing unit 232 first collimates and corrects the diverging beam, and then completes the beam focusing and spot shaping through the optical lens group, shaping the scattered beam into a focused spot with uniform energy distribution and regular contour, and accurately projecting it onto the photosensitive detection surface of the detection unit 233. The detection unit 233 has dual functions of spot position detection and photoelectric signal conversion. On the one hand, it collects the coordinate position of the focused spot on the photosensitive surface in real time, and calculates the deflection angle and attitude offset of the rotatable mirror 21 based on the offset change law of the spot position, thereby obtaining complete pose change information. On the other hand, the optical signal of the focused spot is linearly converted into an electrical signal. Combined with preset calibration parameters and photoelectric response characteristics, the real-time wavelength and output power of the laser output light are calculated based on the converted electrical signal, so as to realize the integrated high-precision detection of three core parameters, namely pose, wavelength and power, in a single displacement detection light.

[0081] In some embodiments, such as Figure 2 and Figure 5 As shown, the wavelength tuning mechanism 2 also includes a support cavity 26; the electromagnetic damping module 25 includes a magnetic shielding cylinder 251 and an excitation coil 252.

[0082] The magnetic shielding cylinder 251 is disposed in the support cavity 26.

[0083] The excitation coil 252 is set inside the magnetic shielding cylinder 251. The excitation coil 252 and the magnetic support 212 are arranged coaxially. The magnetic support 212 moves synchronously with the rotatable reflector 21, cutting the magnetic field lines generated by the excitation coil 252 to form electromagnetic damping.

[0084] The wavelength tuning mechanism 2 can also be mounted on the support cavity 26.

[0085] It is understood that the support cavity 26 provides a stable installation support and structural limit protection for the electromagnetic damping module 25. The electromagnetic damping module 25 includes a magnetic shielding cylinder 251 and an excitation coil 252. The magnetic shielding cylinder 251 is fixedly assembled in a preset position inside the support cavity 26, which can effectively shield stray magnetic field interference from the external environment and avoid the external magnetic field distortion affecting the distribution of internal magnetic field lines and thus the damping performance. The excitation coil 252 is embedded in the internal cavity of the magnetic shielding cylinder 251, and the magnetic support 212 connected to the rotatable reflector 21 is coaxially arranged with high precision to ensure that the magnetic field distribution is uniform and symmetrical. When the rotatable reflector 21 performs attitude deflection and tuning movements, it will drive the magnetic support 212 to perform synchronous linkage movements. During the movement, the magnetic support 212 continuously cuts the magnetic field lines generated when the excitation coil 252 is energized, and generates induced electromotive force and induced current based on the electromagnetic induction effect, thereby forming a reverse electromagnetic damping force to buffer the starting impact, low frequency oscillation and attitude jitter of the rotatable reflector 21 during the tuning process.

[0086] Based on the same inventive concept, this application also provides a damping control method for a tunable laser, which is applied to any of the above-described tunable laser schemes; such as Figure 6 As shown, the damping control method includes the following steps S601 to S603.

[0087] S601: Obtain the target pose of the rotatable mirror, the target output wavelength of the laser, and the target output power. Compare the pose change information, the wavelength and power of the laser output light with the corresponding target parameters to obtain the pose deviation, wavelength deviation, and power deviation.

[0088] S602: Adjust the first driving voltage based on the pose deviation, wavelength deviation and power deviation until the wavelength deviation and power deviation converge within the preset error allowable range.

[0089] S603: Adjust the excitation current output to the electromagnetic damping module according to the position change information of the rotatable reflector, and adjust the second driving voltage according to the high-frequency vibration component in the position change information of the rotatable reflector.

[0090] It should be noted that the damping control method provided in this application embodiment and the tunable laser provided in this application embodiment are based on the same inventive concept. Therefore, the specific implementation of this embodiment can refer to the aforementioned implementation of the tunable laser, and the repeated parts will not be described again.

[0091] In some embodiments, an electronic device provided in this application includes a processor and a memory; the memory stores a computer program, wherein the computer program, when executed by the processor, implements the damping control method of the tunable laser described above.

[0092] Specifically, the processor may include, for example, a general-purpose microprocessor, an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor may also include onboard memory for caching purposes. The processor may be a single processing unit or multiple processing units for performing different actions of the method flow according to embodiments of this application.

[0093] Memory can be any medium capable of containing, storing, transmitting, propagating, or transmitting instructions. For example, memory can include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, instruments, or propagation media. Specific examples of memory include: magnetic storage devices such as magnetic tape or hard disk drives (HDDs); optical storage devices such as optical discs (CD-ROMs); and also random access memory (RAM) or flash memory; and / or wired / wireless communication links.

[0094] This application also provides a non-transitory computer storage medium storing a computer program thereon, which, when executed by a processor, implements the damping control method for the tunable laser described above. This computer-readable medium may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into that device / apparatus / system. The aforementioned computer-readable medium carries one or more programs, which, when executed, implement the method as described in the embodiments of this application.

[0095] According to embodiments of this application, a computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wired, optical fiber, radio frequency signals, etc., or any suitable combination thereof.

[0096] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0097] Those skilled in the art will understand that the features described in the various embodiments of this application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this application. In particular, the features described in the various embodiments of this application can be combined and / or combined in various ways without departing from the spirit and teachings of this application. All such combinations and / or combinations fall within the scope of this application. Therefore, the scope of this application should not be limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A tunable laser with active damping control, characterized in that, include: Laser output mechanism, beam splitting mechanism, wavelength tuning mechanism, and controller; The laser output mechanism is used to generate zero-order diffracted light as laser output light and to generate first-order diffracted light as external cavity feedback light. The beam splitting mechanism is used to separate a predetermined proportion of sampled light from the laser output light and transmit the sampled light to the wavelength tuning mechanism. The wavelength tuning mechanism includes a rotatable mirror, a piezoelectric drive module, an optical detection module, an electromagnetic damping module, and a piezoelectric damping module. The rotatable mirror is provided with a frame arm, a follow-up detection surface, and a magnetic support. The magnetic support is connected to the frame arm. The follow-up detection surface of the rotatable mirror receives the sampled light and reflects it to form displacement detection light. The piezoelectric drive module is used to adjust the pose of the rotatable mirror under the drive of a first drive voltage. The optical detection module is used to determine the pose change information of the rotatable mirror, as well as the wavelength and power of the laser output light, based on the displacement detection light. The electromagnetic damping module is used to provide electromagnetic damping to the magnetic support under the excitation of an excitation current. The piezoelectric damping module is located on the frame arm away from the rotation axis and is used to provide reverse damping to suppress high-frequency vibrations of the rotatable mirror under the drive of a second drive voltage. The controller is used to adjust the first driving voltage, the excitation current, and the second driving voltage according to the pose change information, the wavelength and power of the laser output light.

2. The tunable laser with active damping control as described in claim 1, characterized in that, The controller is also used for: The target pose of the rotatable mirror, the target output wavelength of the laser, and the target output power are obtained. The pose change information, the wavelength and power of the laser output light are compared with the corresponding target parameters to obtain the pose deviation, wavelength deviation, and power deviation. The first driving voltage is adjusted based on the pose deviation, the wavelength deviation, and the power deviation until the wavelength deviation and the power deviation converge within a preset error allowable range. The excitation current output to the electromagnetic damping module is adjusted according to the pose change information of the rotatable reflector, and the second driving voltage is adjusted according to the high-frequency vibration component in the pose change information of the rotatable reflector.

3. The tunable laser with active damping control as described in claim 2, characterized in that, The controller is also used for: Based on the pose deviation, the first driving voltage is coarsely adjusted until the actual pose of the reflector converges to the target pose within the preset pose error range. The first driving voltage is dynamically fine-tuned according to the wavelength deviation and power deviation until the wavelength deviation and power deviation no longer increase and are stably maintained within the preset error allowable range.

4. The tunable laser with active damping control as described in claim 2, characterized in that, The controller is also used for: For the pose change information of the rotatable reflector, the low-frequency motion component, motion velocity and pose deviation are extracted by low-pass filtering, and the high-frequency vibration component of the pose is separated by high-pass filtering. Using the low-frequency motion components of the pose obtained by filtering, the motion velocity, and the pose deviation as inputs, the excitation current is dynamically adjusted using a PID control algorithm. The high-frequency vibration components of the posture extracted are used as input, and the second driving voltage is dynamically adjusted by a PID control algorithm after signal noise reduction processing.

5. The tunable laser with active damping control as described in claim 4, characterized in that, The controller is also used for: A discrete model of the rotational dynamics of a rotatable mirror is established based on low-frequency motion components of the pose, motion velocity, and pose deviation. Define the prediction time domain and control time domain of model predictive control, and construct an optimization function with the objectives of minimizing pose tracking error and suppressing low-frequency oscillations; Based on the maximum output limit of excitation current, the saturation constraint of electromagnetic damping torque and the optimization function, the discretized model of the rotational dynamics of the rotatable mirror is solved by rolling optimization in the control time domain to obtain the optimal excitation current sequence in the prediction time domain. Each control cycle corrects the model state based on real-time pose detection data, selects the optimal excitation current corresponding to the current moment in the prediction time domain, corrects and optimizes the excitation current after PID adjustment, and outputs the optimal excitation current for the current cycle.

6. The tunable laser with active damping control as described in claim 4, characterized in that, The wavelength tuning mechanism further includes a temperature sensor for detecting the temperature information of the rotatable reflector; the controller is also used for: Input features are constructed based on the high-frequency vibration components of the posture and the temperature information; The input features are input into a pre-trained lightweight LSTM model, which outputs an adaptive compensation voltage for the second driving voltage. The unfrozen parameters of the lightweight LSTM model are fine-tuned online at preset intervals using real-time collected pose high-frequency vibration components and temperature information. If the total voltage after superimposing the adaptive compensation voltage and the second drive voltage adjusted by the PID is within the preset voltage allowable range, then the adaptive compensation voltage and the second drive voltage adjusted by the PID will be superimposed and output. If the total voltage after superposition exceeds the preset allowable voltage range, the output voltage clamp will be adjusted to the preset allowable voltage extreme value.

7. The tunable laser with active damping control as described in claim 1, characterized in that, The laser output mechanism includes: a semiconductor laser diode, a collimating optical element, and a diffraction grating; The semiconductor laser diode is used to output the initial beam; The collimating optical element is located in the output optical path of the semiconductor laser diode and is used to collimate the initial beam and output collimated light. The diffraction grating is located in the transmission optical path of the collimated light and is used to disperse the collimated light, outputting the zero-order diffraction light and the first-order diffraction light. The first-order diffraction light is reflected by the rotatable mirror to the diffraction grating, and then reflected back into the cavity of the semiconductor laser diode through the diffraction grating and the collimating optical element to form an external cavity resonance.

8. The tunable laser with active damping control as described in claim 1, characterized in that, The optical detection module includes a narrowband filter unit, a spot collimation and convergence unit, and a detection unit; The narrowband filter unit is used to filter the displacement detection light and output filtered light in the target laser band. The light spot collimation and focusing unit is used to collimate and focus the filtered light, and output the focused light spot to the photosensitive surface of the detection unit; The detection unit is used to detect the position of the focused light spot, determine the pose change information of the rotatable reflector based on the position change information of the focused light spot, perform photoelectric conversion on the focused light spot, and determine the wavelength and power of the laser output light based on the converted electrical signal.

9. The tunable laser with active damping control as described in claim 1, characterized in that, The wavelength tuning mechanism also includes a support cavity; the electromagnetic damping module includes a magnetic shielding cylinder and an excitation coil. The magnetic shielding cylinder is disposed in the supporting cavity; The excitation coil is disposed inside the magnetic shielding cylinder. The excitation coil is coaxially arranged with the magnetic support. The magnetic support moves synchronously with the rotatable reflector, cutting the magnetic field lines generated by the excitation coil to form electromagnetic damping.

10. A damping control method for a tunable laser, characterized in that, The damping control method is applied to the tunable laser as described in any one of claims 1 to 9; The damping control method includes: The target pose of the rotatable mirror, the target output wavelength of the laser, and the target output power are obtained. The pose change information, the wavelength and power of the laser output light are compared with the corresponding target parameters to obtain the pose deviation, wavelength deviation, and power deviation. The first driving voltage is adjusted based on the pose deviation, the wavelength deviation, and the power deviation until the wavelength deviation and the power deviation converge within a preset error allowable range. The excitation current output to the electromagnetic damping module is adjusted according to the pose change information of the rotatable reflector, and the second driving voltage is adjusted according to the high-frequency vibration component in the pose change information of the rotatable reflector.

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