Control method of an external cavity narrow linewidth semiconductor laser and related device

Abstract

This application discloses a control method and related apparatus for an external cavity narrow linewidth semiconductor laser. The control method includes sampling a first PD signal output by the laser to obtain a PD signal sequence; obtaining an initial periodic waveform based on the PD signal sequence; sending a bias current adjustment signal and / or a triangular wave amplitude adjustment signal to obtain a first periodic waveform; sending a center temperature adjustment signal to obtain a second periodic waveform; sending a silicon resistor adjustment signal to obtain a third periodic waveform; sending a bias current step adjustment signal and sampling it; and locking the laser based on the sampling results. The control method of this application achieves efficient, real-time dynamic control of the external cavity narrow linewidth semiconductor laser, ensuring that the external cavity narrow linewidth semiconductor laser is continuously in the optimal operating state. Compared with traditional control methods, it effectively reduces computational complexity, enhances adaptability, and has broad application prospects.

Description

Technical Field

[0001] This application belongs to the field of external cavity semiconductor laser technology, specifically relating to a control method and related apparatus for an external cavity narrow linewidth semiconductor laser. Background Technology

[0002] External cavity semiconductor lasers (ECDLs) have been widely used in sensing, lidar, quantum technology and other fields due to their narrow linewidth and tuning capabilities. The optimal performance of an ECDL depends on the selection of parameters such as laser current, temperature, phase and PZT voltage. To achieve the best performance of an ECDL, it is necessary to adjust and control these parameters.

[0003] Currently, most ECDL control methods employ fixed parameters or manual adjustment, which have significant shortcomings in real-time performance and accuracy. Environmental changes can alter the optimal settings of the ECDL, necessitating intelligent algorithms to monitor and adjust these parameters to maintain the laser's optimal operation. To address this issue, some researchers have begun exploring the use of intelligent algorithms for dynamic parameter adjustment to optimize ECDL performance. However, these methods typically require substantial computational resources, struggle to adapt to real-time environmental changes, and their practicality has not been fully validated. Summary of the Invention

[0004] The purpose of this application is to provide a control method and related device for an external cavity narrow linewidth semiconductor laser, in order to solve the technical problems that most of the existing ECDL control methods use fixed parameters or manual adjustment methods, which have obvious deficiencies in real-time performance and accuracy, while intelligent algorithms usually require a lot of computing resources and are difficult to adapt to environmental changes in real time, and their practicality has not been fully verified.

[0005] To achieve the above objectives, one technical solution adopted in this application is:

[0006] A method for controlling an external cavity narrow linewidth semiconductor laser is provided, comprising:

[0007] The first PD signal output by the laser is sampled to obtain a PD signal sequence. The first PD signal is the photoelectric signal output by the laser in response to the input signal to which a triangular wave signal is applied.

[0008] Based on the PD signal sequence, the initial periodic waveform of the first PD signal is obtained;

[0009] Based on the triangular wave signal and the initial periodic waveform, a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal are sent to adjust the position of the initial periodic waveform to obtain the first periodic waveform of the first PD signal. The sampling time corresponding to the first periodic waveform is located within a rising edge period or a falling edge period of the triangular wave signal.

[0010] Based on the triangular wave signal and the first periodic waveform, a center temperature adjustment signal is sent to adjust the position of the maximum signal value of the first periodic waveform, thereby obtaining the second periodic waveform of the first PD signal. The sampling time corresponding to the maximum signal value of the second periodic waveform is located at the center position of the rising edge period or the center position of the falling edge period of the triangular wave signal.

[0011] Based on the second period waveform and the expected waveform, a silicon resistor adjustment signal is sent to obtain a third period waveform, which conforms to the expected waveform.

[0012] A bias current step adjustment signal is sent, and the second PD signal output by the laser is sampled during the bias current adjustment process. Based on the sampling result, the laser is locked. The second PD signal is the photoelectric signal output by the laser in response to an input signal for which the triangular wave signal has not been applied.

[0013] In one or more embodiments, the step of sampling the first PD signal output by the laser to obtain a PD signal sequence includes:

[0014] Using the rising edge of the triangular wave signal as the sampling start point, n sampling times are uniformly set in each cycle of the triangular wave signal, and the first PD signal is sampled at each sampling time to obtain the PD signal sequence.

[0015] In one or more embodiments, the step of obtaining the initial periodic waveform of the first PD signal based on the PD signal sequence includes:

[0016] Traversing the signal points in the PD signal sequence The maximum value of the first PD signal is obtained. and minimum value In the formula, i = 1, 2, ..., n, Let be the amplitude of the signal sampled at time i;

[0017] The boundary threshold PD is calculated based on the following formula. threshold :

[0018] In the formula, n is a positive integer greater than 1, and i = 1, 2, ..., n;

[0019] Select a signal with a strength equal to the boundary threshold PD from the PD signal sequence. threshold signal points as boundary points

[0020] The boundary points are determined based on the following formula. Classify the points to obtain either the descent effective boundary point U or the ascent effective boundary point D:

[0021]

[0022] Based on the effective descent boundary point U and the effective rising boundary point D, the initial periodic waveform of the first PD signal is obtained.

[0023] In one or more embodiments, the step of sending a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal based on the triangular wave signal and the initial periodic waveform to adjust the position of the initial periodic waveform and obtain the first periodic waveform of the first PD signal includes:

[0024] Determine whether the initial periodic waveform is located between the preset left boundary and the preset right boundary of the sampling time;

[0025] If not, send a bias current adjustment signal until the initial period waveform is located between the preset left boundary of the sampling time and the right boundary of the sampling time;

[0026] Determine whether the width of the initial periodic waveform is greater than a first threshold or less than a second threshold, wherein the width of the initial periodic waveform is the sampling time D. k and the sampling time U corresponding to the effective descent boundary point U k The difference between them;

[0027] If the width of the initial periodic waveform is greater than the first threshold, a triangular wave signal amplitude reduction signal is sent until the width of the initial periodic waveform is less than the first threshold.

[0028] If the width of the initial periodic waveform is less than the second threshold, a triangular wave signal amplitude increase signal is sent until the width of the initial periodic waveform is greater than the second threshold.

[0029] In one or more embodiments, the step of sending a bias current adjustment signal until the initial periodic waveform is located between the preset left boundary and the right boundary of the sampling time includes:

[0030] Determine the sampling time D corresponding to the rising valid boundary point D. k Is it less than the left boundary of the sampling time?

[0031] If so, send a bias current reduction signal until the sampling time D.k Less than the left boundary of the sampling time;

[0032] If not, send a bias current increase signal until the sampling time U corresponding to the effective descent boundary point U is reached. k It is less than the right boundary of the sampling time.

[0033] In one or more embodiments, the step of sending a center temperature adjustment signal based on the triangular wave signal and the first periodic waveform to adjust the position of the maximum signal value of the first periodic waveform to obtain a second periodic waveform of the first PD signal includes:

[0034] Traverse the first period waveform to obtain the sampling time max corresponding to the maximum signal value. k ;

[0035] The sampling time max is determined based on the following formula. k The left boundary L and right boundary R of the maximum sampling time: L = (mU) k +D k ) / m+1, R=(U k +mD k ) / m+1, where m is a positive integer greater than 1;

[0036] Determine the sampling time max k Does the following relationship hold: L≤max? k ≤R;

[0037] If the sampling time max k When the sampling time is less than the left boundary L of the maximum value, a center temperature reduction signal is sent until the sampling time is max. k The left boundary L is greater than the maximum value at the sampling time.

[0038] If the sampling time max k When the sampling time exceeds the right boundary R of the maximum value, a center temperature increase signal is sent until the sampling time max. k The sampling time is less than the right boundary R of the maximum value.

[0039] In one or more embodiments, the step of sending a silicon resistor adjustment signal to obtain a third periodic waveform based on the second periodic waveform and the expected waveform includes:

[0040] Determine whether the second period waveform conforms to the following formula:

[0041]

[0042] In the formula, The signal strength at the left boundary L of the maximum sampling time. The signal strength at the right boundary R of the maximum value sampling time is T1, which is a preset third threshold, and T2 is a preset fourth threshold.

[0043] If not, send a silicon resistor adjustment signal until the second cycle waveform conforms to the above formula.

[0044] In one or more embodiments, the step of sending a bias current step adjustment signal and sampling the second PD signal output by the laser during the bias current adjustment process, and locking the laser based on the sampling result, includes:

[0045] Multiple target current values ​​Ci are determined based on the following formula:

[0046] Ci = pz + dac_val max_k / i,

[0047] In the formula, i is a positive integer, and dac_val max_k pz is the output value of the digital-to-analog converter at the sampling time corresponding to the maximum value of the signal in the second period waveform, and pz is the magnitude of the bias current corresponding to the third period waveform;

[0048] Send a bias current step adjustment signal to adjust the bias current to a target current value;

[0049] When the bias current adjustment is completed, a triangular wave amplitude zeroing signal is sent and the second PD signal output by the laser is sampled to obtain the PD scan value;

[0050] The PD scan value and the boundary threshold PD threshold Compare;

[0051] If the PD scan value is greater than the boundary threshold PD threshold The laser was initially located;

[0052] If the PD scan value is less than the boundary threshold PD threshold Send a triangular wave amplitude recovery signal and a bias current step adjustment signal to adjust the bias current to the next target current value;

[0053] Repeat the above steps until the PD scan value is greater than the boundary threshold PD. threshold The laser was initially located.

[0054] In one or more embodiments, it further includes:

[0055] The second PD signal output by the laser after initial locking is polled and sampled, and the PD values ​​P1, P2 and P3 obtained from three samplings are collected into the first queue;

[0056] Compare the magnitudes of P1, P2, and P3 in the first queue;

[0057] If P1 < P2 < P3, send a bias current increasing signal to increase the bias current by a preset value, and repeat the above steps until P2 > P1 and P2 > P3, then lock the laser;

[0058] If P1 > P2 > P3, send a bias current decreasing signal to decrease the bias current by a preset value, and repeat the above steps until P2 > P1 and P2 > P3, then lock the laser.

[0059] In one or more embodiments, it further includes:

[0060] Poll and sample the second PD signal output by the locked laser;

[0061] Compare the PD value of each polling sample with the PD value when the laser is locked. If the difference between the PD value of the polling sample and the PD value when the laser is locked is greater than the fifth threshold, repeat the step of sending the bias current step adjustment signal, and sample the second PD signal output by the laser during the bias current adjustment process. Based on the sampling results, lock the laser.

[0062] In one or more embodiments, synchronized with the step of comparing the PD value of each polling sample with the PD value when the laser is locked, it further includes:

[0063] Compare the PD value of each polling sample with the boundary threshold PD threshold If the PD value of the polling sample is less than the boundary threshold PD threshold , then reset the laser and repeat the step of sampling the first PD signal output by the laser to obtain the PD signal sequence.

[0064] To achieve the above object, another technical solution adopted by this application is:

[0065] Provide a control device for an external cavity narrow linewidth semiconductor laser, including:

[0066] A sampling module for sampling the first PD signal output by the laser to obtain a PD signal sequence, where the first PD signal is the optoelectronic signal output by the laser for an input signal applied with a triangular wave signal;

[0067] An initial positioning module for obtaining the initial periodic waveform of the first PD signal based on the PD signal sequence;

[0068] The first position adjustment module sends a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal based on the triangular wave signal and the initial periodic waveform to adjust the position of the initial periodic waveform and obtain the first periodic waveform of the first PD signal. The sampling time corresponding to the first periodic waveform is located within a rising edge period or a falling edge period of the triangular wave signal.

[0069] The second position adjustment module is used to send a center temperature adjustment signal based on the triangular wave signal and the first periodic waveform to adjust the position of the signal maximum value of the first periodic waveform, thereby obtaining the second periodic waveform of the first PD signal. The sampling time corresponding to the signal maximum value of the second periodic waveform is located at the center position of the rising edge period or the center position of the falling edge period of the triangular wave signal.

[0070] A waveform adjustment module is used to send a silicon resistor adjustment signal based on the second period waveform and the expected waveform to obtain a third period waveform, wherein the third period waveform conforms to the expected waveform;

[0071] The locking module is used to send a bias current step adjustment signal and sample the second PD signal output by the laser during the bias current adjustment process. Based on the sampling result, the laser is locked. The second PD signal is the photoelectric signal output by the laser in response to an input signal for which the triangular wave signal is not applied.

[0072] In one or more embodiments, it further includes:

[0073] A lock-up status monitoring module is used to poll and sample the second PD signal output by the locked laser.

[0074] The adjustment module is used to compare the PD value sampled in each poll with the PD value when the laser is locked. If the difference between the PD value sampled in each poll and the PD value when the laser is locked is greater than a fifth threshold, the locking module is controlled to relock the laser.

[0075] In one or more embodiments, the adjustment module is further configured to combine the PD value sampled in each polling with the boundary threshold PD. threshold If the PD value of the polled sample is less than the boundary threshold PD, then... threshold If so, the laser is reset, and the sampling module is controlled to resample in order to relock the laser.

[0076] To achieve the above objectives, another technical solution adopted in this application is:

[0077] An electronic device is provided, comprising:

[0078] At least one processor; and

[0079] A memory storing instructions that, when executed by the at least one processor, cause the at least one processor to perform the control method for an external cavity narrow linewidth semiconductor laser as described in any of the above embodiments.

[0080] To achieve the above objectives, another technical solution adopted in this application is:

[0081] A machine-readable storage medium is provided, storing executable instructions that, when executed, cause the machine to perform a control method for an external cavity narrow linewidth semiconductor laser as described in any of the above embodiments.

[0082] The advantages of this application, which differ from existing technologies, are:

[0083] The control method of this application achieves efficient, real-time dynamic control of external cavity narrow linewidth semiconductor lasers, ensuring that the external cavity narrow linewidth semiconductor lasers are always in the best working state; compared with traditional control methods, it effectively reduces computational complexity, enhances adaptability, and has broad application prospects. Attached Figure Description

[0084] Figure 1 This is a schematic flowchart of one embodiment of the control method for an external cavity narrow linewidth semiconductor laser of this application;

[0085] Figure 2 This is a schematic diagram of one embodiment of the external cavity narrow linewidth semiconductor laser of this application;

[0086] Figure 3 This is a diagram of the PD signal output by the laser in response to the first PD signal;

[0087] Figure 4 yes Figure 1 A flowchart of one embodiment corresponding to step S200;

[0088] Figure 5 yes Figure 1 A flowchart of one embodiment corresponding to step S300;

[0089] Figure 6 yes Figure 1 A flowchart of one embodiment corresponding to step S400;

[0090] Figure 7 yes Figure 1 A flowchart of one embodiment corresponding to step S600;

[0091] Figure 8 This is a linewidth diagram of the laser after locking the laser according to one embodiment of this application;

[0092] Figure 9 This is a graph showing the relationship between the PD value and time of the laser after locking the laser according to one embodiment of the laser in this application;

[0093] Figure 10 This is a schematic diagram of one embodiment of the control device for the external cavity narrow linewidth semiconductor laser of this application;

[0094] Figure 11 This is a schematic diagram of one embodiment of the electronic device of this application. Detailed Implementation

[0095] The present application will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present application.

[0096] This application is mainly used to achieve adaptive adjustment of parameters of external cavity semiconductor lasers (ECDL) based on intelligent control algorithms. Specifically, it is used to analyze the PD signal output by the laser in operation, and adjust the laser parameters based on the analysis results to achieve efficient and real-time dynamic control of the ECDL, so that the ECDL can continuously work in the optimal working state.

[0097] Please see Figure 1 , Figure 1 This is a flowchart illustrating one embodiment of the control method for an external cavity narrow linewidth semiconductor laser of this application.

[0098] The control method includes:

[0099] S100. Sample the first PD signal output by the laser to obtain the PD signal sequence.

[0100] The first PD signal is the photoelectric signal output by the laser in response to the input signal to which a triangular wave signal has been applied.

[0101] Specifically, please refer to Figure 2 , Figure 2 This is a schematic diagram of one embodiment of the external cavity narrow linewidth semiconductor laser of this application.

[0102] like Figure 2 As shown, the external cavity narrow linewidth semiconductor laser includes a fiber laser (DFB), a lens, an external cavity feedback structure, and a PD photoelectric sensor.

[0103] The optical fiber emitted by the DFB excitation passes through the lens and cavity in sequence before exiting. The PD receives the optical signal and converts it into an electrical signal.

[0104] The output of the PD controller is a linear combination of proportional and derivative terms, which correspond to the difference between the system output and the desired output, and the rate of change of the output, respectively. In the absence of other modulation signals, the PD controller output will be calculated linearly directly based on the weights of these two terms; therefore, the PD signal will be a straight line.

[0105] To make the PD signal have visible periodic changes, a triangular wave signal is added to the input of the laser, and the laser is sampled in response to the modulation signal with the added triangular wave signal to obtain a PD signal sequence. The PD signal sequence includes multiple sampling points, and each sampling point includes the sampling time and its corresponding signal strength.

[0106] Specifically, the sampling method can be to start the sampling from the rising edge of the triangular wave signal, uniformly set n sampling times in each cycle of the triangular wave signal, sample the first PD signal at each sampling time, and thus obtain n sampling points. Collect these n sampling points into a queue to obtain the PD signal sequence.

[0107] Please see Figure 3 , Figure 3 This is a diagram of the PD signal output by the laser in response to the first PD signal. As shown in the figure, the PD signal exhibits periodicity under the influence of the triangular wave signal.

[0108] In one implementation, the initial amplitude of the triangular wave signal can be 500mV, the signal frequency can be 100Hz, and 200 sampling times can be uniformly set in each triangular signal cycle. The ADC function is used for sampling to obtain a PD signal sequence including 200 sampling points.

[0109] S200. Based on the PD signal sequence, the initial periodic waveform of the first PD signal is obtained.

[0110] Based on the acquired PD signal sequence, the boundary threshold of the PD signal can be determined by the signal intensity corresponding to the sampling point in the sequence, and the initial periodic waveform of the first PD signal can be obtained based on the boundary threshold.

[0111] Specifically, please refer to Figure 4 , Figure 4 yes Figure 1 A flowchart of one embodiment corresponding to step S200.

[0112] Methods for obtaining the initial periodic waveform include:

[0113] S201. Traverse the signal points in the PD signal sequence to obtain the maximum and minimum values ​​of the first PD signal.

[0114] Specifically, the signal point can be represented as The maximum value of the first PD signal can be expressed as: The minimum value of the first PD signal can be expressed as:

[0115] In the formula, i = 1, 2, ..., n, Let be the amplitude of the signal sampled at time i.

[0116] S202. The boundary threshold is calculated based on the formula.

[0117] Specifically, the formula is as follows:

[0118]

[0119] In the formula, PD threshold The threshold value is defined as n, where n is a positive integer greater than 1, i = 1, 2, ..., n; based on the maximum value of the first PD signal. and minimum value The boundary threshold is calculated.

[0120] Among them, the boundary threshold PD threshold The value of n represents the minimum strength of the PD signal. The value of n can be preset based on the actual working conditions. In one implementation, n can be taken from 2, 3, 4, and 5. When a higher boundary threshold is required, n can be preset to 2; when a lower boundary threshold is required, n can be preset to 5.

[0121] S203. Select signal points whose signal strength is equal to the boundary threshold from the PD signal sequence as boundary points.

[0122] After obtaining the boundary threshold PD threshold Then, the PD signal sequence can be used to select PD signals with an intensity equal to the boundary threshold. threshold The sampling points are used as boundary points

[0123] S204. Based on the formula, classify the boundary points to obtain the descent valid boundary point U or the ascending valid boundary point D.

[0124] The formula is as follows:

[0125]

[0126] After obtaining the boundary points In order to obtain the initial periodic waveform by segmenting the PD signal sequence based on the boundary points, it is also necessary to confirm whether the boundary points are the left or right boundaries of the waveform.

[0127] Based on the above formula, for boundary points In a PD signal sequence, if the PD value at time k-1 is greater than the PD value at time k, then time k is the descent effective boundary U; if the PD value at time k is less than the PD value at time k+1, then time k is the rise effective boundary D.

[0128] S205. Based on the effective descent boundary point U and the effective rising boundary point D, the initial periodic waveform of the first PD signal is obtained.

[0129] Once the effective descent boundary point U and the effective rise boundary point D are obtained, a segment between the effective descent boundary point U and the effective rise boundary point D can be extracted from the PD signal sequence as the initial periodic waveform.

[0130] It should be noted that the method described above for obtaining the initial periodic waveform involves extracting the initial periodic waveform from the PD signal sequence within one rising or falling edge period of the triangular wave signal. For example, in step S201, the maximum value of the first PD signal... and minimum value Both are located within the same rising or falling edge; within one cycle of a triangular wave signal, there should be two initial periodic waveforms, which are located at the rising and falling edges respectively.

[0131] S300: Based on the triangular wave signal and the initial periodic waveform, send a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal to adjust the position of the initial periodic waveform and obtain the first periodic waveform of the first PD signal.

[0132] After obtaining the initial periodic waveform, the position of the initial periodic waveform needs to be adjusted so that it is completely within the preset sampling period of one rising or falling edge of the triangular wave signal.

[0133] The method for adjusting the position of the initial periodic waveform involves adjusting the bias current or the amplitude of the triangular wave signal. The specific method for adjusting the position of the initial periodic waveform is detailed below; please refer to [link / reference]. Figure 5 , Figure 5 yes Figure 1 A flowchart of one embodiment corresponding to step S300.

[0134] S301. Determine whether the initial periodic waveform is located between the preset left boundary of the sampling time and the right boundary of the sampling time.

[0135] The left and right boundaries of the sampling time are preset boundaries within one rising or falling edge period of the triangular wave signal. Their purpose is to limit the initial periodic waveform to be located between the left and right boundaries of the sampling time.

[0136] In one implementation, when there are 200 sampling times with uniform intervals in one period of the triangular wave signal, for one rising edge period of the triangular wave signal, the left boundary of the sampling time can be the 5th sampling time, and the right boundary of the sampling time can be the 95th sampling time.

[0137] If not, i.e., the initial periodic waveform is not located between the left and right boundaries of the sampling time, then proceed to step S302:

[0138] S302. Send a bias current adjustment signal until the initial period waveform is located between the preset left boundary of the sampling time and the right boundary of the sampling time.

[0139] Specifically, the initial periodic waveform is shifted to the left or right by sending a bias current adjustment signal to ensure that the initial periodic waveform is located between the preset left boundary of the sampling time and the right boundary of the sampling time.

[0140] In one implementation, the sampling time D corresponding to the rising valid boundary point D is first determined. k Is it less than the left boundary at the sampling time?

[0141] If so, that is, the sampling time D corresponding to the rising valid boundary point D. k If the current is less than the left boundary of the sampling time, a bias current reduction signal is sent until the sampling time D. k Less than the left boundary at the sampling time.

[0142] By sending a bias current reduction signal, the bias current of the laser is controlled to decrease, thereby shifting the waveform to the right until the sampling time D corresponding to the effective rising boundary point D is reached. k Less than the left boundary at the sampling time.

[0143] If not, that is, the sampling time D corresponding to the rising valid boundary point D. k If the current exceeds the left boundary of the sampling time, a bias current increase signal is sent until the sampling time U corresponding to the effective descent boundary point U is reached. k Less than the right boundary at the sampling time.

[0144] Understandably, the initial periodic waveform is not located between the left and right boundaries of the sampling time, and the sampling time corresponding to the effective rising boundary point D is D. k When the sampling time is greater than the left boundary of the sampling time, the sampling time U corresponding to the effective boundary point U of the descent is... k It must be greater than the right boundary of the sampling time.

[0145] Therefore, a bias current increase signal can be sent to control the increase of the laser's bias current, thereby shifting the waveform to the left until the sampling time U corresponding to the effective descent boundary point U is reached. k Less than the right boundary at the sampling time.

[0146] In one implementation, the aforementioned bias current decrease signal and bias current increase signal can be signals that control the step change of the bias current of the laser. The step can be 5mA. At the end of each step, a re-evaluation can be performed to ultimately ensure that the initial periodic waveform is located between the left boundary and the right boundary of the sampling time.

[0147] After confirming that the initial periodic waveform is located at the left and right boundaries of the sampling time, proceed to step S303:

[0148] S303. Determine whether the width of the initial periodic waveform is greater than the first threshold or less than the second threshold.

[0149] Specifically, the width of the initial periodic waveform, which is the difference between the effective rising boundary and the effective falling boundary, needs to be adjusted and optimized when the width is too large (i.e., greater than the preset first threshold) or too small (i.e., less than the preset second threshold).

[0150] The first and second thresholds can be preset based on actual working conditions.

[0151] S304. If the width of the initial periodic waveform is greater than the first threshold, send a triangular wave signal with a reduced amplitude until the width of the initial periodic waveform is less than the first threshold.

[0152] When the width of the initial periodic waveform is greater than the first threshold, a triangular wave signal amplitude reduction signal can be sent to reduce the amplitude of the triangular wave signal, thereby making the width of the initial periodic waveform less than the first threshold.

[0153] S305. If the width of the initial periodic waveform is less than the second threshold, send a triangular wave signal with increased amplitude until the width of the initial periodic waveform is greater than the second threshold.

[0154] When the width of the initial waveform is less than the second threshold, a triangular wave signal amplitude increase signal can be sent to increase the amplitude of the triangular wave signal, thereby making the width of the initial periodic waveform greater than the second threshold.

[0155] In one embodiment, the above-mentioned triangular wave amplitude reduction signal and triangular wave amplitude increase signal can be signals that control the amplitude step change of the triangular wave signal. The step can be 50mV. At the end of each step, a re-judgment can be made to ultimately ensure that the width of the initial periodic waveform is between the first threshold and the second threshold.

[0156] Based on the above position adjustment of the initial periodic waveform, a first periodic waveform can be obtained that is located between the left boundary of the sampling time and the right boundary of the sampling time, and whose width is between the first threshold and the second threshold.

[0157] S400: Based on the triangular wave signal and the first period waveform, a center temperature adjustment signal is sent to adjust the position of the maximum value of the first period waveform, thereby obtaining the second period waveform of the first PD signal.

[0158] The sampling time corresponding to the maximum value of the second period waveform is located at the center of the rising edge period or the falling edge period of the triangular wave signal.

[0159] After adjusting the waveform's position, its shape also needs to be adjusted. This can be done by controlling the laser's center temperature parameter to adjust the position of the waveform's maximum signal value, ensuring that the sampling time corresponding to the maximum value is located at the center of the rising or falling edge of the triangular wave.

[0160] Specifically, please refer to Figure 6 , Figure 6 yes Figure 1 A flowchart of one embodiment corresponding to step S400.

[0161] Methods for adjusting the position of the maximum signal value in the first cycle waveform include:

[0162] S401. Traverse the waveform of the first cycle to obtain the sampling time max corresponding to the maximum signal value. k .

[0163] S402. Determine the sampling time max based on the formula. k The left boundary L and the right boundary R of the maximum sampling time.

[0164] The formula is as follows: L=(mU k +D k ) / m+1, R=(U k +mD k ) / m+1, where m is a positive integer greater than 1;

[0165] Based on the sampling time D corresponding to the rising effective boundary point D k and the sampling time U corresponding to the effective boundary point U of descent k Determine the sampling time max corresponding to the maximum value of the signal. k The left boundary L and right boundary R of the maximum sampling time are defined. Here, m can be selected based on actual operating conditions; for example, when it is necessary to maximize the sampling time, the left boundary L and right boundary R are defined. k When limiting to a larger range, m can be set to 2, requiring the sampling time max to be increased. k When the range is limited to a smaller area, m can be set to 10.

[0166] S403, Determine the sampling time max k Is it greater than or equal to L and less than or equal to R?

[0167] S404, If the sampling time max k When the sampling time is less than the left boundary L of the maximum value, a center temperature reduction signal is sent until the sampling time is max. k The left boundary L is greater than the maximum value sampling time.

[0168] When sampling time max k When the sampling time is less than the left boundary L of the maximum value, a center temperature reduction signal can be sent to lower the center temperature of the laser, making the sampling time max... k Shift to the right until the left boundary L of the sampling time is greater than the maximum value.

[0169] S405, If the sampling time max k When the sampling time exceeds the right boundary R of the maximum value, a center temperature increase signal is sent until the sampling time max. k The right boundary R is less than the maximum value sampling time.

[0170] When sampling time max k When the sampling time exceeds the right boundary R of the maximum value, a center temperature increase signal can be sent to increase the center temperature of the laser, making the sampling time max... k Shift left until it is less than the right boundary R of the maximum sampling time.

[0171] Based on the above control, the sampling time max corresponding to the maximum signal value can be obtained. k The second-cycle waveform is located at the center. The center temperature increase signal and center temperature decrease signal can be signals controlling the step-by-step change of the center temperature; for example, the center temperature can increase or decrease by 0.15 degrees each time until the target is reached.

[0172] S500, based on the second-cycle waveform and the expected waveform, sends a silicon resistor adjustment signal to obtain the third-cycle waveform.

[0173] At the sampling time max corresponding to the maximum value of the adjusted signal k After determining the position, the shape of the second-cycle waveform is adjusted based on the expected waveform to conform to the expected waveform.

[0174] Specifically, the formula for the expected waveform can be as follows:

[0175]

[0176] T1 is the preset third threshold, and T2 is the preset fourth threshold, which can be selected based on the actual working conditions.

[0177] The signal strength at the left boundary L of the maximum sampling time. The signal strength at the right boundary R at the maximum sampling time is denoted as R.

[0178] As the formula shows, the expected waveform further limits the sampling time max corresponding to the maximum signal value. k The location, and the sampling time max corresponding to the maximum signal value. k The signal strength difference between the left boundary L and the right boundary R is used to ensure that the waveform achieves the expected shape.

[0179] Determine whether the second-cycle waveform conforms to the formula for the expected waveform. If not, send a signal to increase or decrease the silicon resistance until the silicon resistance reaches its maximum or minimum value. Control the continuous change of the silicon resistance until the waveform conforms to the formula for the expected waveform, thus obtaining the third-cycle waveform.

[0180] In one embodiment, if the waveform still cannot conform to the formula of the expected waveform when the silicon resistance continues to increase to the maximum value or the silicon resistance continues to decrease to the minimum value, the waveform of that period can be abandoned, and the PD signal sequence in the next triangular wave signal period can be selected to sequentially perform the above steps S200 to S500 to obtain the PD signal waveform that conforms to the expected waveform.

[0181] When abandoning the waveform of a certain cycle, the silicon resistor can be directly adjusted to the extreme value of the other end. For example, if the silicon resistor is continuously increased to the maximum value and still cannot meet the formula of the expected waveform, the silicon resistor can be directly adjusted to the minimum value, and then the waveform of that cycle can be abandoned and the waveform of the next cycle can be selected. At this time, the silicon resistor can be adjusted from the minimum value to improve efficiency.

[0182] To address the issue of uneven distribution, a strategy based on a maximum threshold constraint is adopted, and a timeout mechanism is designed. After the above process is cycled for 100 cycles, if the maximum signal position of the waveform still cannot reach the expected position or the waveform still cannot be adjusted to the expected shape, it will automatically exit to prevent the system from looping indefinitely due to errors or abnormal conditions.

[0183] S600 sends a bias current step adjustment signal and samples the second PD signal output by the laser during the bias current adjustment process. Based on the sampling result, the laser is locked.

[0184] The second PD signal is the photoelectric signal output by the laser in response to the input signal for which no triangular wave signal has been applied.

[0185] After obtaining the third-cycle waveform that is located at the predetermined position and conforms to the expected waveform, the bias current of the laser can be further optimized to lock the laser in the optimal mode.

[0186] The optimized strategy is to adjust the bias current of the laser by sending a bias current step adjustment signal, and to sample the second PD signal of the laser during the adjustment process.

[0187] Specifically, please refer to Figure 7 , Figure 7 yes Figure 1 A flowchart of one embodiment corresponding to step S600.

[0188] Optimization methods may include:

[0189] S601. Determine multiple target current values ​​Ci based on the formula.

[0190] The formula is as follows: Ci = pz + dac_val max_k / i,

[0191] In the formula, i is a positive integer, and dac_val max_k pz is the output value of the digital-to-analog converter at the sampling moment corresponding to the maximum value of the signal in the second period waveform, and pz is the magnitude of the bias current corresponding to the third period waveform.

[0192] First, the target current value can be determined based on the magnitude of the bias current corresponding to the third cycle waveform (i.e., the current bias current magnitude pz) and the output value of the digital-to-analog converter.

[0193] Due to the different properties of various lasers, the target current value will vary. Therefore, multiple target current values ​​are set, and the optimal solution is selected by iterating through them.

[0194] S602, Send a bias current step adjustment signal to adjust the bias current to a target current value.

[0195] First, a bias current step adjustment signal can be sent to adjust the bias current to one of the target current values.

[0196] To improve the adjustment rate of the bias current, the bias current step adjustment signal can be a signal that enables differential adjustment of the bias current. Specifically, when the difference between the current bias current and the target current value to be adjusted is within a set range, the adjustment step of the bias motor can be lower, and the adjustment speed can be slower; when the difference between the current bias current and the target current value to be adjusted is outside a set range, the adjustment step of the bias motor can be higher, and the adjustment speed can be faster.

[0197] For example, when the difference between the current bias current and the target current value to be adjusted is less than or equal to 20, the adjustment step of the bias current can be 1; when the difference between the current bias current and the target current value to be adjusted is greater than 20, the adjustment step of the bias current can be 5.

[0198] S603. When the bias current adjustment is completed, a triangular wave amplitude zeroing signal is sent and the second PD signal output by the laser is sampled to obtain the PD scan value.

[0199] When the bias current is adjusted to a target current value, a triangular wave amplitude zeroing signal can be sent to make the amplitude of the triangular wave signal 0, and the second PD signal of the laser can be sampled to obtain the PD scan value.

[0200] In one implementation, the second PD signal of the laser can be sampled multiple times, and the average value of the multiple samples can be taken as the PD scan value, thereby improving the control accuracy.

[0201] S604. Compare the PD scan value with the boundary threshold.

[0202] S605. If the PD scan value is greater than the boundary threshold, the laser is initially locked.

[0203] S606. If the PD scan value is less than the boundary threshold, send a triangular wave amplitude recovery signal and a bias current step adjustment signal to adjust the bias current to the next target current value.

[0204] S607. Repeat the above steps until the PD scan value is greater than the boundary threshold, and initially lock the laser.

[0205] Understandably, the PD scan value and the boundary threshold PD are compared. threshold Compare the values; if the PD scan value is greater than the boundary threshold PD... threshold This allows for initial laser locking by locking the laser's bias current; however, if the PD scan value is less than the boundary threshold PD... threshold This resets the triangular wave amplitude and resends the bias current step adjustment signal to adjust the bias current to the next target current value. This process is repeated until the PD scan value exceeds the boundary threshold PD at a target current value. threshold The bias current of the laser is locked, thus initially locking the laser.

[0206] In one implementation, for a laser that has been initially locked, the bias current after locking can be further adjusted and optimized. The optimization method implements a peak search method based on "three-point judgment" in the core of the control logic to determine the optimal bias current value.

[0207] Specifically, the methods for further adjusting and optimizing the bias current are as follows:

[0208] S608. The second PD signal output by the laser after initial locking is polled and sampled, and the PD values ​​P1, P2 and P3 obtained from the three samplings are collected into the first queue.

[0209] In one embodiment, multiple PD values can be sampled each time a sample is taken, and the average value is collected in the first queue, thereby improving the control accuracy.

[0210] S609. Compare the magnitudes of P1, P2, and P3 in the first queue.

[0211] S610. If P1 < P2 < P3, send a bias current increasing signal to increase the bias current by a preset value, and repeat the above steps until P2 > P1 and P2 > P3, then lock the laser.

[0212] If P1 < P2 < P3, send a bias current increasing signal to increase the bias current of the laser by a preset value. It can be understood that each time the preset value is increased, polling and sampling can be performed three times again to judge the relationship of the three values until P2 > P1 and P2 > P3. At this time, the bias current is used as the optimal bias current, and the laser can be locked.

[0213] S611. If P1 > P2 > P3, send a bias current decreasing signal to decrease the bias current by a preset value, and repeat the above steps until P2 > P1 and P2 > P3, then lock the laser.

[0214] If P1 > P2 > P3, send a bias current decreasing signal to decrease the bias current of the laser by a preset value. It can be understood that each time the preset value is decreased, polling and sampling can be performed three times again to judge the relationship of the three values until P2 > P1 and P2 > P3. At this time, the bias current is used as the optimal bias current, and the laser can be locked.

[0215] In one embodiment, if the initially locked laser obtains P1, P2, and P3 that meet P2 > P1 and P2 > P3 after polling and sampling three times, the laser can be directly locked without further adjusting the increase or decrease of the bias current.

[0216] Based on the above steps, the adjustment and optimization of the bias current are achieved, and finally the laser is locked in the optimal working state. Please refer to Figure 8 , Figure 8 is the linewidth diagram of the laser after the laser is locked in an embodiment of the present application. As Figure 8 shown, the locked laser has excellent monochromaticity and frequency stability.

[0217] In one embodiment, to ensure the stable operation of the laser, it further includes a process of continuously monitoring and adjusting the key parameters of the locked laser. Specifically:

[0218] S700. Poll and sample the second PD signal output by the locked laser.

[0219] S800. Compare the PD value sampled in each poll with the PD value when the laser is locked. If the difference between the PD value sampled in each poll and the PD value when the laser is locked is greater than the fifth threshold, repeat step S600.

[0220] Please see Figure 9 , Figure 9 This is a graph showing the relationship between the PD value and time of the laser after locking the laser according to one embodiment of the laser in this application. Figure 9 As shown, ideally, the relationship between the laser's PD value and time should remain a straight line. However, due to changes in the laser's environment, the laser's optimal settings may change, leading to variations in the PD value. Therefore, it is necessary to poll and sample the laser after locking and compare it with the PD value at the time of locking. If the difference is greater than the fifth threshold, step S600 needs to be repeated to relock the laser, ensuring that the laser is in its optimal operating state in real time.

[0221] The fifth threshold can be preset based on actual working conditions. In one embodiment, the fifth threshold can be 30.

[0222] In one implementation, the following steps are also performed synchronously with step S800:

[0223] S900, the PD value and boundary threshold PD sampled in each polling session are... theshold Compare the results; if the PD value of the polled samples is less than the boundary threshold PD... threshold If the laser is reset, steps S100 to S600 are repeated.

[0224] Specifically, if the PD value of the polled samples is lower than the boundary threshold PD threshold If the value is low, the laser needs to be reset, the parameters readjusted, and the sensor relocked.

[0225] Through the above steps, adaptive, efficient, and real-time dynamic control of the laser can be achieved, enabling the narrow-linewidth external cavity semiconductor laser to continuously operate in its optimal working state. Compared with traditional control methods, this approach improves adaptability and reduces computational complexity.

[0226] This application also provides a control device for an external cavity narrow linewidth semiconductor laser. Please refer to [link to relevant documentation]. Figure 10 , Figure 10 This is a schematic diagram of one embodiment of the control device for the external cavity narrow linewidth semiconductor laser of this application.

[0227] The control device includes a sampling module 21, an initial positioning module 22, a first position adjustment module 23, a second position adjustment module 24, a waveform adjustment module 25, and a locking module 26.

[0228] The sampling module 21 is used to sample the first PD signal output by the laser to obtain a PD signal sequence. The first PD signal is the photoelectric signal output by the laser in response to the input signal to which a triangular wave signal has been applied.

[0229] The initial positioning module 22 is used to obtain the initial periodic waveform of the first PD signal based on the PD signal sequence;

[0230] The first position adjustment module 23 sends a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal based on the triangular wave signal and the initial period waveform to adjust the position of the initial period waveform and obtain the first period waveform of the first PD signal. The sampling time corresponding to the first period waveform is located within a rising edge period or a falling edge period of the triangular wave signal.

[0231] The second position adjustment module 24 is used to send a center temperature adjustment signal based on the triangular wave signal and the first period waveform to adjust the position of the maximum value of the first period waveform, so as to obtain the second period waveform of the first PD signal. The sampling time corresponding to the maximum value of the second period waveform is located at the center position of the rising edge period or the falling edge period of the triangular wave signal.

[0232] The waveform adjustment module 25 is used to send a silicon resistor adjustment signal based on the second-cycle waveform and the expected waveform to obtain the third-cycle waveform, which conforms to the expected waveform.

[0233] The locking module 26 is used to send a bias current step adjustment signal and sample the second PD signal output by the laser during the bias current adjustment process. Based on the sampling result, the laser is locked. The second PD signal is the photoelectric signal output by the laser in response to the input signal for which no triangular wave signal has been applied.

[0234] In one embodiment, the system further includes a lock status monitoring module 27 and an adjustment module 28.

[0235] The lockout state monitoring module 27 is used to poll and sample the second PD signal output by the locked laser.

[0236] The adjustment module 28 is used to compare the PD value sampled in each poll with the PD value when the laser is locked. If the difference between the PD value sampled in each poll and the PD value when the laser is locked is greater than the fifth threshold, the locking module is controlled to relock the laser.

[0237] In one implementation, the adjustment module 28 is further configured to adjust the PD value sampled in each polling and the boundary threshold PD. threshold Compare the results; if the PD value of the polled samples is less than the boundary threshold PD... threshold If the laser is reset, the sampling module will be controlled to resample in order to relock the laser.

[0238] As per the above reference Figures 1 to 9 This specification describes a control method for an external-cavity narrow-linewidth semiconductor laser according to embodiments thereof. The details mentioned in the above description of the method embodiments also apply to the control device for the external-cavity narrow-linewidth semiconductor laser according to embodiments thereof. The control device for the external-cavity narrow-linewidth semiconductor laser described above can be implemented in hardware, software, or a combination of hardware and software.

[0239] Figure 11 This is a schematic diagram of one embodiment of the electronic device of this application. For example... Figure 11 As shown, the electronic device 30 may include at least one processor 31, a memory 32 (e.g., non-volatile memory), a RAM 33, and a communication interface 34, and the at least one processor 31, memory 32, RAM 33, and communication interface 34 are connected together via a bus 35. The at least one processor 31 executes at least one computer-readable instruction stored or encoded in the memory 32.

[0240] It should be understood that the computer-executable instructions stored in memory 32, when executed, cause at least one processor 31 to perform the above-described combinations in the various embodiments of this specification. Figures 1-5 The description includes various operations and functions.

[0241] In the embodiments of this specification, electronic device 30 may include, but is not limited to: personal computer, server computer, workstation, desktop computer, laptop computer, notebook computer, mobile electronic device, smartphone, tablet computer, cellular phone, personal digital assistant (PDA), handheld device, messaging device, wearable electronic device, consumer electronic device, etc.

[0242] According to one embodiment, a program product, such as a machine-readable medium, is provided. The machine-readable medium may have instructions (i.e., the elements implemented in software as described above), which, when executed by a machine, cause the machine to perform the above-described combinations of the various embodiments of this specification. Figures 1-5 The various operations and functions described. Specifically, a system or apparatus equipped with a readable storage medium storing software program code that implements the functions of any of the embodiments described above, and enabling the computer or processor of the system or apparatus to read and execute the instructions stored in the readable storage medium.

[0243] In this case, the program code read from the readable medium itself can perform the functions of any of the above embodiments, and therefore the machine-readable code and the readable storage medium storing the machine-readable code constitute a part of this specification.

[0244] Examples of readable storage media include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD-RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer or the cloud via a communication network.

[0245] Those skilled in the art will understand that the various embodiments disclosed above can be modified and varied without departing from the spirit of the invention. Therefore, the scope of protection of this specification should be defined by the appended claims.

[0246] It should be noted that not all steps and units in the above process and system structure diagrams are mandatory; some steps or units can be omitted according to actual needs. The execution order of each step is not fixed and can be determined as needed. The device structure described in the above embodiments can be a physical structure or a logical structure. That is, some units may be implemented by the same physical client, or some units may be implemented by multiple physical clients, or they may be jointly implemented by certain components in multiple independent devices.

[0247] In the above embodiments, the hardware units or modules can be implemented mechanically or electrically. For example, a hardware unit, module, or processor may include permanent dedicated circuitry or logic (such as a dedicated processor, FPGA, or ASIC) to perform the corresponding operation. The hardware unit or processor may also include programmable logic or circuitry (such as a general-purpose processor or other programmable processor), which can be temporarily configured by software to perform the corresponding operation. The specific implementation method (mechanical, dedicated permanent circuitry, or temporarily configured circuitry) can be determined based on cost and time considerations.

[0248] The specific embodiments described above with reference to the accompanying drawings are exemplary embodiments, but do not represent all embodiments that can be implemented or fall within the scope of the claims. The term "exemplary" as used throughout this specification means "serving as an example, instance, or illustration" and does not imply that it is "preferred" or "advantageous" compared to other embodiments. Specific details are included to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, well-known structures and apparatuses are shown in block diagram form to avoid obscuring the concepts of the described embodiments.

[0249] The foregoing description of this disclosure is provided to enable any person skilled in the art to implement or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles applicable herein can be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but is consistent with the widest scope of the principles and novel features disclosed herein.

Claims

1. A control method for an external cavity narrow linewidth semiconductor laser, characterized in that, include: The first PD signal output by the laser is sampled to obtain a PD signal sequence. The first PD signal is the photoelectric signal output by the laser in response to the input signal to which a triangular wave signal is applied. Based on the PD signal sequence, the initial periodic waveform of the first PD signal is obtained; Based on the triangular wave signal and the initial periodic waveform, a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal are sent to adjust the position of the initial periodic waveform to obtain the first periodic waveform of the first PD signal. The sampling time corresponding to the first periodic waveform is located within a rising edge period or a falling edge period of the triangular wave signal. Based on the triangular wave signal and the first periodic waveform, a center temperature adjustment signal is sent to adjust the position of the maximum signal value of the first periodic waveform, thereby obtaining the second periodic waveform of the first PD signal. The sampling time corresponding to the maximum signal value of the second periodic waveform is located at the center position of the rising edge period or the center position of the falling edge period of the triangular wave signal. Based on the second period waveform and the expected waveform, a silicon resistor adjustment signal is sent to obtain a third period waveform, which conforms to the expected waveform. A bias current step adjustment signal is sent, and the second PD signal output by the laser is sampled during the bias current adjustment process. Based on the sampling result, the laser is locked. The second PD signal is the photoelectric signal output by the laser in response to an input signal for which the triangular wave signal has not been applied.

2. The control method according to claim 1, characterized in that, The step of sampling the first PD signal output by the laser to obtain the PD signal sequence includes: Using the rising edge of the triangular wave signal as the sampling start point, n sampling times are uniformly set in each cycle of the triangular wave signal, and the first PD signal is sampled at each sampling time to obtain the PD signal sequence.

3. The control method according to claim 2, characterized in that, The step of obtaining the initial periodic waveform of the first PD signal based on the PD signal sequence includes: Traversing the signal points in the PD signal sequence The maximum value of the first PD signal is obtained. and minimum value In the formula, i = 1, 2, ..., n, Let be the amplitude of the signal sampled at time i; The boundary threshold PD is calculated based on the following equation threshold : In the formula, n is a positive integer greater than 1, and i = 1, 2, ..., n; Select a signal with a strength equal to the boundary threshold PD from the PD signal sequence. threshold signal points as boundary points The boundary points are determined based on the following formula. Classify the points to obtain either the descent effective boundary point U or the ascent effective boundary point D: Based on the effective descent boundary point U and the effective rising boundary point D, the initial periodic waveform of the first PD signal is obtained.

4. The control method according to claim 3, characterized in that, The step of sending a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal based on the triangular wave signal and the initial periodic waveform to adjust the position of the initial periodic waveform and obtain the first periodic waveform of the first PD signal includes: Determine whether the initial periodic waveform is located between the preset left boundary and the preset right boundary of the sampling time; If not, send a bias current adjustment signal until the initial period waveform is located between the preset left boundary of the sampling time and the right boundary of the sampling time; determining whether a width of the initial periodic waveform is greater than a first threshold or less than a second threshold, the width of the initial periodic waveform being a difference between the sampling instant D k and the sampling instant U corresponding to the falling active edge U k ​ If the width of the initial periodic waveform is greater than the first threshold, a triangular wave signal amplitude reduction signal is sent until the width of the initial periodic waveform is less than the first threshold. If the width of the initial periodic waveform is less than the second threshold, a triangular wave signal amplitude increase signal is sent until the width of the initial periodic waveform is greater than the second threshold.

5. The control method according to claim 4, characterized in that, The step of sending a bias current adjustment signal until the initial periodic waveform is between the left boundary and the right boundary of a preset sampling time includes: determining whether the sampling time point D corresponding to the rising effective boundary point D is less than the sampling time left boundary k whether the sampling time point D corresponding to the rising effective boundary point D is less than the sampling time left boundary If so, send a bias current reduction signal until the sampling time D. k Less than the left boundary of the sampling time; If not, send a bias current increase signal until the sampling time U corresponding to the effective descent boundary point U is reached. k It is less than the right boundary of the sampling time.

6. The control method according to claim 3, characterized in that, The step of sending a center temperature adjustment signal based on the triangular wave signal and the first periodic waveform to adjust the position of the signal maximum value of the first periodic waveform to obtain a second periodic waveform of the first PD signal includes: Traverse the first period waveform to obtain the sampling time max corresponding to the maximum signal value. k ; The sampling time max is determined based on the following formula. k The left boundary L and right boundary R of the maximum sampling time: L = (mU) k +D k ) / m+1, R=(U k +mD k ) / m+1, where m is a positive integer greater than 1; Determine the sampling time max k Does the following relationship hold: L≤max? k ≤R; If the sampling time max k When the sampling time is less than the left boundary L of the maximum value, a center temperature reduction signal is sent until the sampling time is max. k The left boundary L is greater than the maximum value at the sampling time. If the sampling time max k When the sampling time exceeds the right boundary R of the maximum value, a center temperature increase signal is sent until the sampling time max. k The sampling time is less than the right boundary R of the maximum value.

7. The control method according to claim 6, characterized in that, The step of sending a silicon resistance adjustment signal based on the second periodic waveform and an expected waveform to obtain a third periodic waveform includes: Determine whether the second periodic waveform conforms to the following formula: In the formula, The signal strength at the left boundary L of the maximum sampling time. The signal strength at the right boundary R of the maximum value sampling time is T1, which is a preset third threshold, and T2 is a preset fourth threshold. If not, send a silicon resistance adjustment signal until the second periodic waveform conforms to the above formula.

8. The control method according to claim 3, characterized in that, The step of sending a bias current step adjustment signal, sampling the second PD signal output by the laser during the bias current adjustment, and locking the laser based on the sampling result includes: Determine multiple target current values Ci based on the following formula: Ci=pz+dac_val max_k / and, In the formula, i is a positive integer, and dac_val max_k pz is the output value of the digital-to-analog converter at the sampling time corresponding to the maximum value of the signal in the second period waveform, and pz is the magnitude of the bias current corresponding to the third period waveform; Send a bias current step adjustment signal to adjust the bias current to one of the target current values; When the bias current adjustment is completed, send a triangular wave amplitude zeroing signal and sample the second PD signal output by the laser to obtain a PD scan value; The PD scan value and the boundary threshold PD threshold Compare; If the PD scan value is greater than the boundary threshold PD threshold The laser was initially located; If the PD scan value is less than the boundary threshold PD threshold Send a triangular wave amplitude recovery signal and a bias current step adjustment signal to adjust the bias current to the next target current value; Repeat the above steps until the PD scan value is greater than the boundary threshold PD. threshold The laser was initially located.

9. The control method according to claim 8, characterized in that, Further includes: Poll and sample the second PD signal output by the laser after preliminary locking, and collect the PD values P1, P2, and P3 obtained by sampling three times into a first queue; Compare the magnitudes of P1, P2, and P3 in the first queue; If P1 < P2 < P3, send a bias current increasing signal to increase the bias current by a preset value, and repeat the above steps until P2 > P1 and P2 > P3, then lock the laser; If P1 > P2 > P3, send a bias current decreasing signal to decrease the bias current by a preset value, and repeat the above steps until P2 > P1 and P2 > P3, then lock the laser.

10. The control method according to claim 3, characterized in that, Further includes: Poll and sample the second PD signal output by the locked laser; Compare the PD value of each poll sampling with the PD value when the laser is locked. If the difference between the PD value of the poll sampling and the PD value when the laser is locked is greater than a fifth threshold, then repeat the step of sending a bias current step adjustment signal, sampling the second PD signal output by the laser during the bias current adjustment, and locking the laser based on the sampling result.

11. The control method according to claim 10, characterized in that, Synchronized with the step of comparing the PD value of each poll sampling with the PD value when the laser is locked, further includes: The PD value sampled in each polling round and the boundary threshold PD threshold If the PD value of the polled sample is less than the boundary threshold PD, then... threshold If the laser is reset, the process of sampling the first PD signal output by the laser to obtain the PD signal sequence is repeated.

12. A control device for an external cavity narrow linewidth semiconductor laser, characterized in that, Includes: A sampling module, configured to sample the first PD signal output by the laser to obtain a PD signal sequence, where the first PD signal is an optoelectronic signal output by the laser for an input signal applied with a triangular wave signal; An initial positioning module, configured to obtain an initial periodic waveform of the first PD signal based on the PD signal sequence; The first position adjustment module sends a bias current adjustment signal and / or a triangular wave signal amplitude adjustment signal based on the triangular wave signal and the initial periodic waveform to adjust the position of the initial periodic waveform and obtain the first periodic waveform of the first PD signal. The sampling time corresponding to the first periodic waveform is located within a rising edge period or a falling edge period of the triangular wave signal. The second position adjustment module is used to send a center temperature adjustment signal based on the triangular wave signal and the first periodic waveform to adjust the position of the signal maximum value of the first periodic waveform, thereby obtaining the second periodic waveform of the first PD signal. The sampling time corresponding to the signal maximum value of the second periodic waveform is located at the center position of the rising edge period or the center position of the falling edge period of the triangular wave signal. A waveform adjustment module is used to send a silicon resistor adjustment signal based on the second period waveform and the expected waveform to obtain a third period waveform, wherein the third period waveform conforms to the expected waveform; The locking module is used to send a bias current step adjustment signal and sample the second PD signal output by the laser during the bias current adjustment process. Based on the sampling result, the laser is locked. The second PD signal is the photoelectric signal output by the laser in response to an input signal for which the triangular wave signal is not applied.

13. The control device according to claim 12, characterized in that, Also includes: A lock-up status monitoring module is used to poll and sample the second PD signal output by the locked laser. The adjustment module is used to compare the PD value sampled in each poll with the PD value when the laser is locked. If the difference between the PD value sampled in each poll and the PD value when the laser is locked is greater than a fifth threshold, the locking module is controlled to relock the laser.

14. The control device according to claim 13, characterized in that, The adjustment module is also used to adjust the PD value and the boundary threshold PD sampled in each polling cycle. threshold If the PD value of the polled sample is less than the boundary threshold PD, then... threshold If so, the laser is reset, and the sampling module is controlled to resample in order to relock the laser.

15. An electronic device, characterized in that, include: At least one processor; as well as A memory storing instructions that, when executed by the at least one processor, cause the at least one processor to perform the control method for an external cavity narrow linewidth semiconductor laser as described in any one of claims 1 to 11.

16. A machine-readable storage medium, characterized in that, The machine stores executable instructions that, when executed, cause the machine to perform a control method for an external cavity narrow linewidth semiconductor laser as described in any one of claims 1 to 11.

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