Temperature control method and system for narrow linewidth laser

Abstract

The present invention discloses a temperature control method and system for a narrow linewidth laser, which belongs to the technical field of narrow linewidth laser device design, and comprises the following steps: obtaining a TEC temperature control target value; according to a control variable method, based on the real-time power supply current power consumption peak value corresponding to the laser chip under different adjustment steps; P i , obtain the maximum step value; adjust the TEC temperature control target value according to the maximum step value, and obtain the maximum control period based on the measured estimated value corresponding to the sampling of the voltage analog signal at both ends of the thermistor; measure the voltage at both ends of the thermistor, and make a difference comparison between the actual measured voltage value and the target voltage value to obtain the error direction and error magnitude; step-adjust the TEC current control analog signal to the TEC temperature control target value; re-measure the voltage at both ends of the thermistor after a delay, and continuously and dynamically control the temperature of the narrow linewidth laser. The system is used to implement the method. The present invention solves the problem of large temperature control error of narrow linewidth lasers.

Description

Technical Field

[0001] The invention belongs to the technical field of narrow linewidth laser device design, and in particular relates to a temperature control method and system for a narrow linewidth laser. Background Art

[0002] Narrow linewidth laser is a laser light source module with an extremely narrow spectral linewidth. In order to ensure the normal operation of the laser chip in the narrow linewidth laser, thermistors and semiconductor coolers (TEC) are usually used as feedback and control elements respectively to form a hardware circuit to ensure that the laser chip works in the correct temperature environment. Although the hardware circuit generally has a temperature control function, the control accuracy cannot meet the requirements of narrow linewidth lasers, which can easily lead to unqualified spectral linewidth indicators. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a temperature control method and system for a narrow linewidth laser, which solves the problem of large temperature control error of a narrow linewidth laser.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0005] In one aspect, the present invention provides a method for controlling the temperature of a narrow linewidth laser, comprising the following steps:

[0006] S1, obtain TEC temperature control target value;

[0007] S2. According to the control variable method, the real-time power supply current power consumption peak value P corresponding to the laser chip under different adjustment steps i , get the maximum step value;

[0008] S3, adjusting the TEC temperature control target value according to the maximum step value, and obtaining the maximum control period based on the measured estimated value corresponding to the sampling of the voltage analog signal across the thermistor;

[0009] S4, measuring the voltage across the thermistor, and performing a difference comparison between the actual measured voltage value and the target voltage value to obtain the error direction and error magnitude;

[0010] S5, according to the error direction and error magnitude, based on the maximum step value and the maximum control cycle, step-by-step adjust the TEC current control analog signal to the TEC temperature control target value;

[0011] S6. Repeat S4 and S5 to continuously and dynamically control the temperature of the narrow linewidth laser.

[0012] The beneficial effects of the present invention are as follows: a temperature control method for a narrow linewidth laser provided by the present invention analyzes the real-time power supply current power consumption peak value of a laser chip under different adjustment steps by a control variable method, and obtains a maximum step value while ensuring stability; the present invention adjusts the target value of TEC temperature control according to the maximum step value, and calculates the maximum control period according to the sampling value of the voltage analog signal at both ends of the thermistor; after obtaining the maximum step value and the maximum control period, the present invention measures the voltage at both ends of the thermistor, and compares the actually measured voltage value with the target voltage value, obtains the direction and size of the error, and realizes step-by-step adjustment of the TEC current control analog signal to the TEC temperature control target value, thus repeatedly measuring the voltage at both ends of the thermistor and step-by-step adjusting the TEC current control analog signal, and realizes high-precision continuous dynamic control of the temperature of the narrow linewidth laser; the present invention realizes the temperature control of the narrow linewidth laser, ensures that the optical signal emitted by the narrow linewidth laser has an extremely narrow spectral linewidth, and improves the control accuracy and stability of the TEC.

[0013] Furthermore, the initial value of the TEC temperature control target value is the voltage value across the thermistor next to the laser chip.

[0014] The beneficial effect of adopting the above further scheme is that in the present invention, the voltage value across the thermistor next to the laser chip is used as the initial value of the TEC temperature control target value, which can effectively avoid excessive instantaneous power consumption when setting the TEC temperature control target value for the first time.

[0015] Furthermore, S2 comprises the following steps:

[0016] S21, using a current detection chip to measure the total current power consumption P when the laser chip is working stably;

[0017] S22, according to the control variable method, select different step S i As the adjustment step of the TEC temperature control target value, and record the corresponding real-time current total power consumption peak value P under different adjustment steps i , where i is a positive integer;

[0018] S23, from all the real-time current total power consumption peak values ​​P that are less than 1.5 times the total current power consumption P i Select the maximum real-time current total power consumption peak value P imax The real-time current total power consumption peak value P imax The corresponding step is taken as the maximum step value.

[0019] The beneficial effect of adopting the above further scheme is: the present invention detects the total power consumption peak value of the system power supply current during the asynchronous step regulation through the control variable method, thereby ensuring that the maximum step value is obtained when the system is stable, thereby providing a basis for stably controlling the TEC temperature when the system is stable.

[0020] Furthermore, S3 comprises the following steps:

[0021] S31, setting the TEC temperature control target value, and adjusting the TEC temperature control target value according to the maximum step value;

[0022] S32, according to the preset sampling interval, use the analog-to-digital conversion chip to sample the voltage analog signal at both ends of the thermistor, obtain the measurement estimation values ​​corresponding to several samplings, and record the time interval between completing the setting of the temperature control target value and obtaining the corresponding measurement estimation value for each sampling;

[0023] S33, if the deviations between the measurement estimation values ​​corresponding to the five consecutive samplings and the average values ​​of the measurement estimation values ​​corresponding to the five samplings are all less than the estimated deviations, the time between the completion of setting the temperature control target value and the last sampling of the five samplings to obtain the corresponding measurement estimation value is taken as the interval period;

[0024] S34, repeat S31-S33 several times, and average the interval period of each time to obtain the maximum control period.

[0025] The beneficial effect of adopting the above further scheme is that the interval period obtained based on the method of the present invention effectively ensures the stability of the system, and the average of the repeatedly obtained interval periods effectively improves the accuracy and effectiveness of the maximum control period, providing a basis for achieving high-precision control of TEC.

[0026] Furthermore, the S4 comprises the following steps:

[0027] S41, measuring the voltage across the thermistor to obtain a voltage analog signal;

[0028] S42, continuously sampling the voltage analog signal at both ends of the thermistor using an analog-to-digital conversion chip to obtain a voltage digital sampling signal;

[0029] S43, processing the voltage digital sampling signal through Kalman filtering to obtain the Kalman filtering gain corresponding to each sampling;

[0030] S44, determine in turn whether the Kalman filter gain corresponding to each sampling is less than the preset Kalman filter gain threshold, if so, take the measurement estimate value corresponding to the sampling as the true measurement voltage value, stop judging, and enter S45, otherwise return to S41;

[0031] S45, performing a difference comparison between the actual measured voltage value and the target voltage value, and calculating the error direction and error magnitude.

[0032] The beneficial effect of adopting the above further scheme is: the present invention obtains the true measurement value corresponding to the sampling by comparing the Kalman filter gain corresponding to each sampling with the preset Kalman filter gain threshold, and then makes a difference comparison between the true measurement value and the target voltage value to obtain the error direction and error magnitude, which effectively ensures the accuracy of the error direction and error magnitude and provides a basis for improving the accuracy and stability of TEC control.

[0033] Further, the S43 comprises the following steps:

[0034] S431, setting the first sampling value of the voltage digital sampling signal to be the sampling value corresponding to the first sampling;

[0035] S432, setting an initial estimation value according to the sampling value corresponding to the first sampling;

[0036] S433, square the estimated deviation used for the initial estimated value to obtain the variance corresponding to the first sampling;

[0037] S434, calculating the Kalman gain corresponding to the first sampling based on the variance and uncertainty value corresponding to the first sampling;

[0038] The calculation expression of the Kalman gain corresponding to the first sampling is as follows:

[0039] ,

[0040] Among them, K1 represents the Kalman gain corresponding to the first sampling, P1 represents the variance corresponding to the first sampling, and R1 represents the uncertainty value;

[0041] S435, calculating the measurement estimate corresponding to the first sampling according to the Kalman gain and the initial estimate corresponding to the first sampling;

[0042] The calculation expression of the measurement estimation value corresponding to the first sampling is as follows:

[0043] ,

[0044] in, represents the measurement estimate corresponding to the first sampling, represents the initial estimated value, and Z1 represents the sampling value corresponding to the first sampling;

[0045] S436, setting the second sampling value of the voltage digital sampling signal to be the sampling value corresponding to the second sampling;

[0046] S437, based on the Kalman gain corresponding to the first sampling and the variance corresponding to the first sampling, updating the variance and Kalman gain corresponding to the second sampling;

[0047] The calculation expressions of the variance and Kalman gain corresponding to the second sampling are as follows:

[0048] ,

[0049] ,

[0050] Among them, K2 represents the Kalman gain corresponding to the second sampling, and P2 represents the variance corresponding to the second sampling;

[0051] S438, calculating the measurement estimate corresponding to the second sampling according to the Kalman gain corresponding to the second sampling and the measurement estimate corresponding to the first sampling;

[0052] The calculation expression of the measurement estimation value corresponding to the second sampling is as follows:

[0053] ,

[0054] in, represents the measurement estimate corresponding to the second sampling, and Z2 represents the sampling value corresponding to the second sampling;

[0055] S439, according to S431-S438, derive the Kalman filter gain corresponding to each sampling in sequence;

[0056] The calculation expression of the Kalman filter gain corresponding to each sampling is as follows:

[0057] ,

[0058] ,

[0059] Among them, P n represents the variance corresponding to the nth sampling, K n-1 represents the Kalman filter gain corresponding to the n-1th sampling, P n-1 represents the variance corresponding to the n-1th sampling, K n represents the Kalman filter gain corresponding to the nth sampling, represents the estimated value corresponding to the nth sampling, Represents the estimated value corresponding to the n-1th sampling, Z n Represents the sampling value corresponding to the nth sampling, where n is greater than or equal to 2.

[0060] The beneficial effect of adopting the above further scheme is: the present invention provides a method for processing the voltage digital sampling signal through Kalman filtering to obtain the Kalman filter gain corresponding to each sampling, and based on the Kalman filter gain corresponding to each sampling, the measurement estimate value suitable for the actual measured voltage value can be accurately obtained, thereby effectively ensuring the accuracy of the error direction and error size, and further providing a basis for high-precision control of TEC.

[0061] Furthermore, the S5 comprises the following steps:

[0062] S51, determine whether the error is greater than the maximum step value, if so, proceed to S52, otherwise proceed to S53;

[0063] S52, determining whether the error direction is the first error direction, if so, increasing the maximum step value of the TEC current control analog signal, and delaying the maximum control cycle before entering S6, otherwise, decreasing the maximum step value of the TEC current control analog signal, and delaying the maximum control cycle before entering S6;

[0064] S53, setting the minimum adjustment deviation and the minimum control period;

[0065] S54, judging whether the error is smaller than the minimum adjustment deviation, if so, the TEC current control analog signal is not adjusted, and the process goes to S6 after the minimum control period is delayed, otherwise, the process goes to S55;

[0066] S55, if the error is smaller than the maximum step value and larger than the minimum adjustment deviation, the TEC current control change amount and the TEC current control change period are calculated according to the error;

[0067] S56, correspondingly taking the TEC current control variation amount and the TEC current control variation cycle as the adjustment step value and the adjustment cycle;

[0068] S57, determine whether the error direction is the first error direction, if so, increase the adjustment step value of the TEC current control analog signal, and enter S6 after a delay adjustment period, otherwise reduce the adjustment step value of the TEC current control analog signal, and enter S6 after a delay adjustment period.

[0069] The beneficial effect of adopting the above further scheme is: the present invention provides a comparison result between the error size and the maximum step value and the minimum adjustment deviation, respectively, and performs corresponding step adjustments or directly does not adjust, and determines whether to increase or decrease the adjustment amount according to the error direction, thereby ensuring the control accuracy and stability of TEC.

[0070] Furthermore, the calculation expressions of the TEC current control change amount and the TEC current control change period in S55 are respectively as follows:

[0071] ,

[0072] ,

[0073] ,

[0074] in, Indicates the change in TEC current control, E indicates the error size, Indicates the minimum adjustment deviation, S max Indicates the maximum step value, Indicates the TEC current control change cycle, T max Indicates the maximum control period, V tm Indicates the actual measured voltage value, V goal represents the target voltage value, and || represents the absolute value operation.

[0075] The beneficial effect of adopting the above further scheme is: the present invention provides a method for calculating the TEC current control change amount and the TEC current control change period, and obtains the TEC current control change amount and the TEC current control change period by the ratio of the difference between the error size and the minimum adjustment deviation to the maximum step value, thereby achieving high-precision control of TEC under smaller control adjustment amounts and smaller control adjustment periods.

[0076] On the other hand, the present invention also provides a system for a temperature control method based on a narrow linewidth laser, comprising:

[0077] TEC, used to provide stable operating temperature for narrow linewidth lasers;

[0078] The laser chip installed on the TEC is used to control the current size and direction at both ends of the TEC and adjust the cooling or heating capacity of the TEC;

[0079] The thermistor is set next to the laser chip to monitor the operating temperature of the laser chip;

[0080] The analog-to-digital conversion chip is used to sample the voltage analog signal at both ends of the thermistor to obtain a voltage digital sampling signal;

[0081] The single-chip microcomputer is used to cooperate with the current detection chip to monitor the total current power consumption, obtain the maximum step value, receive the voltage digital sampling signal, analyze and obtain the maximum control cycle, output the current control digital signal for controlling the size and direction of the TEC current based on the maximum step value, and control the delay according to the maximum control cycle;

[0082] A digital-to-analog conversion chip is used to convert the current control digital signal into a TEC current control analog signal to adjust the current magnitude and direction at both ends of the TEC;

[0083] Current detection chip, used to monitor the total current power consumption in conjunction with the analog-to-digital converter of the microcontroller.

[0084] The beneficial effects of the present invention are as follows: a system based on a temperature control method for a narrow linewidth laser provided by the present invention is a system corresponding to the temperature control method for the narrow linewidth laser, and is used to implement the above method to achieve high-precision temperature control of the narrow linewidth laser, thereby ensuring that the optical signal emitted by the narrow linewidth laser has an extremely narrow spectral linewidth, thereby improving the control accuracy and stability of TEC.

[0085] Other advantages of the present invention will be analyzed in more detail in subsequent embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0087] Figure 1 This is a flow chart of the steps of a temperature control method for a narrow linewidth laser in Example 1 of the present invention.

[0088] Figure 2 This is a block diagram of a system for a temperature control method based on a narrow linewidth laser in Example 2 of the present invention. DETAILED DESCRIPTION

[0089] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0090] Example 1: Figure 1 As shown, in one embodiment of the present invention, the present invention provides a temperature control method for a narrow linewidth laser, comprising the following steps:

[0091] S1, obtain TEC temperature control target value;

[0092] The initial value of the TEC temperature control target value is the voltage value across the thermistor next to the laser chip.

[0093] Using the voltage value across the thermistor next to the laser chip as the initial value of the TEC temperature control target value can effectively avoid excessive instantaneous power consumption when setting the TEC temperature control target value for the first time.

[0094] S2. According to the control variable method, the real-time power supply current power consumption peak value P corresponding to the laser chip under different adjustment steps i , get the maximum step value;

[0095] The S2 comprises the following steps:

[0096] S21. Use the current detection chip to measure the total current power consumption P of the laser chip when it is working stably. In this embodiment, the power supply current power consumption during stable operation is the power supply current power consumption when the current fluctuation is within ±10mA.

[0097] S22, according to the control variable method, select different step S i As the adjustment step of the TEC temperature control target value, and record the corresponding real-time current total power consumption peak value P under different adjustment steps i , where i is a positive integer;

[0098] S23, from all the real-time current total power consumption peak values ​​P that are less than 1.5 times the total current power consumption P i Select the maximum real-time current total power consumption peak value P imax The real-time current total power consumption peak value P imax The corresponding step is taken as the maximum step value.

[0099] S3, adjusting the TEC temperature control target value according to the maximum step value, and obtaining the maximum control period based on the measured estimated value corresponding to the sampling of the voltage analog signal across the thermistor;

[0100] The S3 comprises the following steps:

[0101] S31. Set the TEC temperature control target value, and adjust the TEC temperature control target value according to the maximum step value. In this embodiment, in the process of obtaining the maximum step cycle, when the TEC temperature control target value is adjusted with the maximum step value, the adjustment can be set to start from the initial value of the TEC temperature control target value, or it can be set to start from any other suitable TEC temperature control target value according to the actual situation.

[0102] S32, according to the preset sampling interval, use the analog-to-digital conversion chip to sample the voltage analog signal at both ends of the thermistor, obtain the measurement estimate values ​​corresponding to several samplings, and record the time interval between the completion of setting the temperature control target value and each sampling to obtain the corresponding measurement estimate value; in this embodiment, the preset sampling interval is 10ms;

[0103] S33, if the deviations between the measurement estimation values ​​corresponding to the five consecutive samplings and the average values ​​of the measurement estimation values ​​corresponding to the five samplings are all less than the estimated deviation, the time between the completion of setting the temperature control target value and the last sampling of the five samplings to obtain the corresponding measurement estimation value is taken as the interval period; in this embodiment, the estimated deviation is 10 LSB;

[0104] S34, repeat S31-S33 several times, and average the interval period of each time to obtain the maximum control period.

[0105] S4, measuring the voltage across the thermistor, and performing a difference comparison between the actual measured voltage value and the target voltage value to obtain the error direction and error magnitude;

[0106] The S4 comprises the following steps:

[0107] S41, measuring the voltage across the thermistor to obtain a voltage analog signal;

[0108] S42, using an analog-to-digital conversion chip to continuously sample the voltage analog signal at both ends of the thermistor to obtain a voltage digital sampling signal; in this embodiment, the analog-to-digital conversion chip is a 16-bit ADC chip, and its measurement error is 6 least significant bits (LSB). Resolution is the minimum analog increment corresponding to the change in the least significant bit. Therefore, in this embodiment, the measurement variance of the analog-to-digital conversion chip is 6*6=36, that is, the uncertainty value R1=36.

[0109] S43, processing the voltage digital sampling signal through Kalman filtering to obtain the Kalman filtering gain corresponding to each sampling;

[0110] The S43 comprises the following steps:

[0111] S431, setting the first sampling value of the voltage digital sampling signal to be the sampling value corresponding to the first sampling;

[0112] S432, set the initial estimated value according to the sampling value corresponding to the first sampling; in this embodiment, the estimated value adopts an estimated deviation of 10 LSB, then the variance P1=10 2 =100;

[0113] S433, square the estimated deviation used for the initial estimated value to obtain the variance corresponding to the first sampling;

[0114] S434, calculating the Kalman gain corresponding to the first sampling based on the variance and uncertainty value corresponding to the first sampling;

[0115] The calculation expression of the Kalman gain corresponding to the first sampling is as follows:

[0116] ,

[0117] Among them, K1 represents the Kalman gain corresponding to the first sampling, P1 represents the variance corresponding to the first sampling, and R1 represents the uncertainty value;

[0118] S435, calculating the measurement estimate corresponding to the first sampling according to the Kalman gain and the initial estimate corresponding to the first sampling;

[0119] The calculation expression of the measurement estimation value corresponding to the first sampling is as follows:

[0120] ,

[0121] in, represents the measurement estimate corresponding to the first sampling, represents the initial estimated value, and Z1 represents the sampling value corresponding to the first sampling;

[0122] S436, setting the second sampling value of the voltage digital sampling signal to be the sampling value corresponding to the second sampling;

[0123] S437, based on the Kalman gain corresponding to the first sampling and the variance corresponding to the first sampling, updating the variance and Kalman gain corresponding to the second sampling;

[0124] The calculation expressions of the variance and Kalman gain corresponding to the second sampling are as follows:

[0125] ,

[0126] ,

[0127] Among them, K2 represents the Kalman gain corresponding to the second sampling, and P2 represents the variance corresponding to the second sampling;

[0128] S438, calculating the measurement estimate corresponding to the second sampling according to the Kalman gain corresponding to the second sampling and the measurement estimate corresponding to the first sampling;

[0129] The calculation expression of the measurement estimation value corresponding to the second sampling is as follows:

[0130] ,

[0131] in, represents the measurement estimate corresponding to the second sampling, and Z2 represents the sampling value corresponding to the second sampling;

[0132] S439, according to S431-S438, derive the Kalman filter gain corresponding to each sampling in sequence;

[0133] The calculation expression of the Kalman filter gain corresponding to each sampling is as follows:

[0134] ,

[0135] ,

[0136] Among them, P n represents the variance corresponding to the nth sampling, K n-1 represents the Kalman filter gain corresponding to the n-1th sampling, P n-1 represents the variance corresponding to the n-1th sampling, K n represents the Kalman filter gain corresponding to the nth sampling, represents the estimated value corresponding to the nth sampling, Represents the estimated value corresponding to the n-1th sampling, Z n Represents the sampling value corresponding to the nth sampling, where n is greater than or equal to 2.

[0137] S44, determine in sequence whether the Kalman filter gain corresponding to each sampling is less than the preset Kalman filter gain threshold, if so, take the measured estimated value corresponding to the sampling as the true measured voltage value, stop judging, and enter S45, otherwise return to S41; in this embodiment, the preset Kalman filter gain threshold is 0.05;

[0138] S45, compare the actual measured voltage value with the target voltage value, and calculate the error direction and error magnitude. In this embodiment, when the difference between the actual measured voltage value and the target voltage value is greater than zero, it corresponds to an error direction, i.e., the first error direction; when the difference between the actual measured voltage value and the target voltage value is less than zero, it corresponds to another error direction, i.e., the second error direction; according to the error direction and magnitude, it is convenient to determine whether to increase the maximum step value or decrease the maximum step value when stepping the TEC temperature control target value.

[0139] S5, according to the error direction and error magnitude, based on the maximum step value and the maximum control cycle, step-by-step adjust the TEC current control analog signal to the TEC temperature control target value;

[0140] The S5 comprises the following steps:

[0141] S51, determine whether the error is greater than the maximum step value, if so, proceed to S52, otherwise proceed to S53;

[0142] S52, determining whether the error direction is the first error direction, if so, increasing the maximum step value of the TEC current control analog signal, and delaying the maximum control cycle before entering S6, otherwise, decreasing the maximum step value of the TEC current control analog signal, and delaying the maximum control cycle before entering S6;

[0143] S53, setting the minimum adjustment deviation and the minimum control period; in this embodiment, the minimum adjustment deviation is 3 LSB, and the minimum control period is 1 second;

[0144] S54, judging whether the error is smaller than the minimum adjustment deviation, if so, the TEC current control analog signal is not adjusted, and the process goes to S6 after the minimum control period is delayed, otherwise, the process goes to S55;

[0145] S55, if the error is smaller than the maximum step value and larger than the minimum adjustment deviation, the TEC current control change amount and the TEC current control change period are calculated according to the error;

[0146] The calculation expressions of the TEC current control variation and the TEC current control variation period in S55 are as follows:

[0147] ,

[0148] ,

[0149] ,

[0150] in, Indicates the change in TEC current control, E indicates the error size, Indicates the minimum adjustment deviation, S max Indicates the maximum step value, Indicates the TEC current control change cycle, T max Indicates the maximum control period, V tm Indicates the actual measured voltage value, V goal represents the target voltage value, and || represents the absolute value operation.

[0151] S56, correspondingly taking the TEC current control variation amount and the TEC current control variation cycle as the adjustment step value and the adjustment cycle;

[0152] S57, determine whether the error direction is the first error direction, if so, increase the adjustment step value of the TEC current control analog signal, and enter S6 after a delay adjustment period, otherwise reduce the adjustment step value of the TEC current control analog signal, and enter S6 after a delay adjustment period.

[0153] S6. Repeat S4 and S5 to continuously and dynamically control the temperature of the narrow linewidth laser.

[0154] Example 2: Figure 2 As shown, based on Example 1, the present invention provides a system for a temperature control method based on a narrow linewidth laser, comprising:

[0155] TEC, used to provide stable operating temperature for narrow linewidth lasers;

[0156] The laser chip installed on the TEC is used to control the current size and direction at both ends of the TEC and adjust the cooling or heating capacity of the TEC;

[0157] The thermistor is set next to the laser chip to monitor the operating temperature of the laser chip;

[0158] The analog-to-digital conversion chip is used to sample the voltage analog signal at both ends of the thermistor to obtain a voltage digital sampling signal;

[0159] The single-chip microcomputer is used to cooperate with the current detection chip to monitor the total current power consumption, obtain the maximum step value, receive the voltage digital sampling signal, analyze and obtain the maximum control cycle, output the current control digital signal for controlling the size and direction of the TEC current based on the maximum step value, and control the delay according to the maximum control cycle;

[0160] A digital-to-analog conversion chip is used to convert the current control digital signal into a TEC current control analog signal to adjust the current magnitude and direction at both ends of the TEC;

[0161] Current detection chip, used to monitor the total current power consumption in conjunction with the analog-to-digital converter of the microcontroller.

[0162] In this embodiment, the laser chip is placed on the TEC as a heat source, and the cooling or heating amount of the TEC is adjusted by controlling the current size and direction at both ends of the TEC, thereby ensuring that the laser chip works at a fixed temperature.

[0163] This solution sets a thermistor next to the laser chip and uses a 16-bit analog-to-digital conversion chip to collect the voltage value across the thermistor. By monitoring the voltage value across the thermistor, the operating temperature of the laser chip can be effectively fed back.

[0164] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A temperature control method for a narrow linewidth laser, characterized in that: The steps include: S1, obtain TEC temperature control target value; S2. According to the control variable method, the real-time power supply current power consumption peak value P corresponding to the laser chip under different adjustment steps i , get the maximum step value; S3, adjusting the TEC temperature control target value according to the maximum step value, and obtaining the maximum control period based on the measured estimated value corresponding to the sampling of the voltage analog signal across the thermistor; S4, measuring the voltage across the thermistor, and performing a difference comparison between the actual measured voltage value and the target voltage value to obtain the error direction and error magnitude; S5, according to the error direction and error magnitude, based on the maximum step value and the maximum control cycle, step-by-step adjust the TEC current control analog signal to the TEC temperature control target value; S6. Repeat S4 and S5 to continuously and dynamically control the temperature of the narrow linewidth laser.

2. The temperature control method of a narrow linewidth laser according to claim 1, characterized in that: The initial value of the TEC temperature control target value is the voltage value across the thermistor next to the laser chip.

3. The temperature control method of a narrow linewidth laser according to claim 2, characterized in that: The S2 comprises the following steps: S21, using a current detection chip to measure the total current power consumption P when the laser chip is working stably; S22, according to the control variable method, select different step S i As the adjustment step of the TEC temperature control target value, and record the corresponding real-time current total power consumption peak value P under different adjustment steps i , where i is a positive integer; S23, from all the real-time current total power consumption peak values ​​P that are less than 1.5 times the total current power consumption P i Select the maximum real-time current total power consumption peak value P imax The real-time current total power consumption peak value P imax The corresponding step is taken as the maximum step value.

4. The temperature control method of a narrow linewidth laser according to claim 3, characterized in that: The S3 comprises the following steps: S31, setting the TEC temperature control target value, and adjusting the TEC temperature control target value according to the maximum step value; S32, according to the preset sampling interval, use the analog-to-digital conversion chip to sample the voltage analog signal at both ends of the thermistor, obtain the measurement estimation values ​​corresponding to several samplings, and record the time interval between completing the setting of the temperature control target value and obtaining the corresponding measurement estimation value for each sampling; S33, if the deviations between the measurement estimation values ​​corresponding to the five consecutive samplings and the average values ​​of the measurement estimation values ​​corresponding to the five samplings are all less than the estimated deviations, the time between the completion of setting the temperature control target value and the last sampling of the five samplings to obtain the corresponding measurement estimation value is taken as the interval period; S34, repeat S31-S33 several times, and average the interval period of each time to obtain the maximum control period.

5. The temperature control method of a narrow linewidth laser according to claim 4, characterized in that: The S4 comprises the following steps: S41, measuring the voltage across the thermistor to obtain a voltage analog signal; S42, continuously sampling the voltage analog signal at both ends of the thermistor using an analog-to-digital conversion chip to obtain a voltage digital sampling signal; S43, processing the voltage digital sampling signal through Kalman filtering to obtain the Kalman filtering gain corresponding to each sampling; S44, determine in turn whether the Kalman filter gain corresponding to each sampling is less than the preset Kalman filter gain threshold, if so, take the measurement estimate value corresponding to the sampling as the true measurement voltage value, stop judging, and enter S45, otherwise return to S41; S45, performing a difference comparison between the actual measured voltage value and the target voltage value, and calculating the error direction and error magnitude.

6. The temperature control method of a narrow linewidth laser according to claim 5, characterized in that: The S43 comprises the following steps: S431, setting the first sampling value of the voltage digital sampling signal to be the sampling value corresponding to the first sampling; S432, setting an initial estimation value according to the sampling value corresponding to the first sampling; S433, square the estimated deviation used for the initial estimated value to obtain the variance corresponding to the first sampling; S434, calculating the Kalman gain corresponding to the first sampling based on the variance and uncertainty value corresponding to the first sampling; The calculation expression of the Kalman gain corresponding to the first sampling is as follows: ， Among them, K1 represents the Kalman gain corresponding to the first sampling, P1 represents the variance corresponding to the first sampling, and R1 represents the uncertainty value; S435, calculating the measurement estimate corresponding to the first sampling according to the Kalman gain and the initial estimate corresponding to the first sampling; The calculation expression of the measurement estimation value corresponding to the first sampling is as follows: ， in, represents the measurement estimate corresponding to the first sampling, represents the initial estimated value, and Z1 represents the sampling value corresponding to the first sampling; S436, setting the second sampling value of the voltage digital sampling signal to be the sampling value corresponding to the second sampling; S437, based on the Kalman gain corresponding to the first sampling and the variance corresponding to the first sampling, updating the variance and Kalman gain corresponding to the second sampling; The calculation expressions of the variance and Kalman gain corresponding to the second sampling are as follows: ， ， Among them, K2 represents the Kalman gain corresponding to the second sampling, and P2 represents the variance corresponding to the second sampling; S438, calculating the measurement estimate corresponding to the second sampling according to the Kalman gain corresponding to the second sampling and the measurement estimate corresponding to the first sampling; The calculation expression of the measurement estimation value corresponding to the second sampling is as follows: ， in, represents the measurement estimate corresponding to the second sampling, and Z2 represents the sampling value corresponding to the second sampling; S439, according to S431-S438, derive the Kalman filter gain corresponding to each sampling in sequence; The calculation expression of the Kalman filter gain corresponding to each sampling is as follows: ， ， Among them, P n represents the variance corresponding to the nth sampling, K n-1 represents the Kalman filter gain corresponding to the n-1th sampling, P n-1 represents the variance corresponding to the n-1th sampling, K n represents the Kalman filter gain corresponding to the nth sampling, represents the estimated value corresponding to the nth sampling, Represents the estimated value corresponding to the n-1th sampling, Z n Represents the sampling value corresponding to the nth sampling, where n is greater than or equal to 2.

7. The temperature control method of a narrow linewidth laser according to claim 6, characterized in that: The S5 comprises the following steps: S51, determine whether the error is greater than the maximum step value, if so, proceed to S52, otherwise proceed to S53; S52, determining whether the error direction is the first error direction, if so, increasing the maximum step value of the TEC current control analog signal, and delaying the maximum control cycle before entering S6, otherwise, decreasing the maximum step value of the TEC current control analog signal, and delaying the maximum control cycle before entering S6; S53, setting the minimum adjustment deviation and the minimum control period; S54, judging whether the error is smaller than the minimum adjustment deviation, if so, the TEC current control analog signal is not adjusted, and the process goes to S6 after the minimum control period is delayed, otherwise, the process goes to S55; S55, if the error is smaller than the maximum step value and larger than the minimum adjustment deviation, the TEC current control change amount and the TEC current control change period are calculated according to the error; S56, correspondingly taking the TEC current control variation amount and the TEC current control variation cycle as the adjustment step value and the adjustment cycle; S57, determine whether the error direction is the first error direction, if so, increase the adjustment step value of the TEC current control analog signal, and enter S6 after a delay adjustment period, otherwise reduce the adjustment step value of the TEC current control analog signal, and enter S6 after a delay adjustment period.

8. The temperature control method of a narrow linewidth laser according to claim 7, characterized in that: The calculation expressions of the TEC current control variation and the TEC current control variation period in S55 are as follows: ， ， ， in, Indicates the change in TEC current control, E indicates the error size, Indicates the minimum adjustment deviation, S max Indicates the maximum step value, Indicates the TEC current control change cycle, T max Indicates the maximum control period, V tm Indicates the actual measured voltage value, V goal represents the target voltage value, and || represents the absolute value operation.

9. A system based on the temperature control method of a narrow linewidth laser according to any one of claims 1 to 8, characterized in that: include: TEC, used to provide stable operating temperature for narrow linewidth lasers; The laser chip installed on the TEC is used to control the current size and direction at both ends of the TEC and adjust the cooling or heating capacity of the TEC; The thermistor is set next to the laser chip to monitor the operating temperature of the laser chip; The analog-to-digital conversion chip is used to sample the voltage analog signal at both ends of the thermistor to obtain a voltage digital sampling signal; The single-chip microcomputer is used to cooperate with the current detection chip to monitor the total current power consumption, obtain the maximum step value, receive the voltage digital sampling signal, analyze and obtain the maximum control cycle, output the current control digital signal for controlling the size and direction of the TEC current based on the maximum step value, and control the delay according to the maximum control cycle; A digital-to-analog conversion chip is used to convert the current control digital signal into a TEC current control analog signal to adjust the current magnitude and direction at both ends of the TEC; Current detection chip, used to monitor the total current power consumption in conjunction with the analog-to-digital converter of the microcontroller.

Images