Laser temperature closed-loop control system and control and performance evaluation method thereof

Abstract

The invention relates to the technical field of lasers, and provides a laser temperature closed-loop control system and a control and performance evaluation method thereof.The system comprises a power module, an interaction module, a master control module, a current source module, a temperature acquisition module, a slave control module, a temperature control module and a laser, according to the invention, the high-digit ADC acquisition circuit is used for temperature signal acquisition, and the precise reference voltage source and the digital filtering technology are combined, so that the precise sensing of tiny temperature change is realized; the application of the integral separation type PID control algorithm not only ensures the quick responsiveness of the system when the temperature deviation is large, but also ensures the no-static-error accurate adjustment when the temperature is close to the target temperature.

Description

Technical Field

[0001] This invention relates to the field of laser technology, specifically to a laser temperature closed-loop control system and its control and performance evaluation method. Background Technology

[0002] High-precision lasers are the core light source of modern optoelectronic systems, and their performance stability directly determines the performance of the entire system. In fields such as industrial processing, fiber optic communication, medical equipment, and scientific research, key characteristics of lasers, such as center wavelength and output power, are extremely sensitive to operating temperature. The temperature drift coefficient of a typical semiconductor laser can reach over 0.1 nm / ℃, and its output power also fluctuates significantly with temperature changes.

[0003] The effects of temperature fluctuations are systemic: on the one hand, they can cause changes in the bandgap and refractive index of the active material, leading to wavelength drift. In dense wavelength division multiplexing systems with a channel spacing of only 0.4 nm, a drift of 0.1 nm is enough to cause serious channel crosstalk; on the other hand, they can change the optical length of the resonant cavity, which may induce multi-mode competition or even "mode hopping" phenomena, degrading the beam quality; in addition, they can accelerate device aging and shorten the service life.

[0004] Existing temperature control solutions have significant limitations: analog PID control systems are affected by component parameter temperature drift and nonlinearity, making it difficult to achieve long-term stability better than ±0.1℃; a single microcontroller architecture needs to handle human-machine interaction and real-time temperature control tasks simultaneously, which can easily lead to system response delays; and there is a lack of a synchronous quantitative evaluation mechanism for control effect and drive current stability.

[0005] To address the aforementioned problems, we propose a closed-loop temperature control system for lasers and its control and performance evaluation method. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a closed-loop temperature control system for lasers and its control and performance evaluation method, which overcomes the deficiencies of existing technologies, achieves ultra-high precision temperature control, improves system reliability, and establishes a comprehensive performance evaluation system.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A laser temperature closed-loop control system, comprising:

[0009] A power supply module is used to provide electrical energy to the various functional modules within the laser.

[0010] The interaction module is used to receive user commands and display system status;

[0011] The main control module, connected to the interaction module and the current source module, is used to process user commands and control the system's operating mode.

[0012] The current source module, controlled by the main control module, is used to provide driving current for the laser;

[0013] The temperature acquisition module is used to acquire the real-time temperature signal of the laser and convert it into a digital signal.

[0014] The slave control module is connected to the temperature acquisition module and the main control module, and is used to process temperature data and execute control algorithms.

[0015] A temperature control module, controlled by the slave module, is used to adjust the temperature of the laser;

[0016] The laser emits laser light under the control of the driving current and precise temperature.

[0017] Preferably, the interaction module includes:

[0018] The display unit uses an OLED display screen to intuitively display the laser's working mode, output power, set temperature, and real-time temperature;

[0019] The input unit uses a button array for users to set parameters and switch modes;

[0020] The communication interface uses a UART serial port to enable data communication between the laser and external devices.

[0021] Preferably, the temperature acquisition module includes:

[0022] The excitation circuit, consisting of a precision reference voltage source and a high-precision low-temperature drift resistor, is a constant voltage source used to provide stable electrical excitation for the temperature sensing element.

[0023] The temperature sensing element is a negative temperature coefficient thermistor integrated inside the laser. The thermistor is connected in series with a reference resistor to form a voltage divider network.

[0024] An ADC acquisition circuit, whose input terminal is connected to a node of the voltage divider network, is used to acquire the analog voltage signal of the node and convert it into a digital signal;

[0025] When the temperature changes, the resistance of the thermistor changes, causing a corresponding change in the voltage of the voltage divider network nodes. The slave control module reads the digital voltage value converted by the ADC acquisition circuit through the communication protocol and calculates the real-time temperature of the laser based on the resistance-temperature characteristic relationship of the thermistor. The resistance-temperature characteristic relationship is calculated using the B-value method formula, as shown below:

[0026]

[0027] In the formula, For temperature The resistance value at that time, Rated temperature The resistance value below, is the material constant of the thermistor.

[0028] Preferably, the slave control module reads the digital voltage signal from the ADC acquisition circuit via the SPI communication protocol;

[0029] The slave control module converts the voltage value into a temperature value according to the B-value formula, and uses an integral-separated PID control algorithm to compare the real-time temperature with the set target temperature to calculate the control quantity; the output of the integral-separated PID control algorithm can be expressed as:

[0030]

[0031] In the formula, where, This is the control output at the k-th sampling time. This is the current temperature deviation. , , These are the proportional, integral, and differential coefficients, respectively. The integral separation coefficient is denoted as .

[0032] Preferably, when the slave control module acquires the voltage signal through the ADC acquisition circuit, it executes a digital filtering program; the digital filtering program is specifically a median filtering algorithm, and its execution flow is as follows: within one sampling period, the ADC acquisition circuit performs N consecutive and rapid voltage samplings on the thermistor voltage divider circuit to form an original sampling sequence [V1, V2, ..., Vn], where N is an odd number greater than 1; all sampled values ​​in the original sampling sequence are sorted in ascending or descending order according to their numerical values; the value located in the middle of the sorted sequence is selected as the effective voltage value output for that sampling period.

[0033] Preferably, the core of the temperature control module is a semiconductor cooler driver chip, which is used to receive control signals from the slave control module and generate bidirectional current to drive the semiconductor cooler, thereby performing precise cooling or heating control on the laser; the control signal is used to set the magnitude and direction of the current.

[0034] When the semiconductor cooler driver chip is a dedicated temperature control driver, the slave module provides an analog voltage signal to the driver through a DAC module to set the current magnitude, and simultaneously provides a digital level signal to the driver through a GPIO pin to set the current direction; the output voltage expression of the DAC module is:

[0035]

[0036] In the formula, where, For reference voltage, Enter the 12-bit numeric code from MCU2; This refers to the resolution of the DAC module.

[0037] A method for closed-loop temperature control and performance evaluation of a laser, applied to the temperature closed-loop control system, includes the following steps:

[0038] Step S1: Initialize the system hardware and set the target operating temperature and target drive current of the laser;

[0039] Step S2: The temperature acquisition module obtains the voltage signal of the thermistor integrated inside the laser through a constant voltage source and a voltage divider circuit;

[0040] The ADC acquisition circuit converts the voltage signal into a digital signal and transmits it to the slave control module via the SPI interface;

[0041] The slave control module performs digital filtering on the collected voltage data;

[0042] The slave control module converts the filtered voltage value into the real-time operating temperature of the laser based on the formula for the B value of the thermistor.

[0043] Step S3: The slave control module calculates the deviation between the real-time temperature and the target temperature. =Tset−Tcurrent;

[0044] An integral-separation PID control algorithm is used to calculate the deviation and generate a corresponding control signal. When the temperature deviation is | When | is greater than the set threshold, the coefficient of the integral term β = 0; otherwise, β = 1.

[0045] Step S4: The slave control module transmits the control signal obtained in step S3 to the temperature control module;

[0046] When the semiconductor cooler driver chip is a dedicated temperature control driver, the slave module outputs an analog voltage signal to the dedicated temperature control driver through the DAC module to set the current magnitude, and at the same time outputs a digital level signal to the temperature control driver through a GPIO pin to set the current direction, thereby driving the semiconductor cooler to perform precise cooling or heating operations on the laser.

[0047] Step S5: Return to step S2 and repeat steps S2 to S4 to form a continuous closed-loop temperature control; after the laser reaches a stable state, perform a temperature and current stability assessment.

[0048] Temperature data is continuously recorded within a set time period. The temperature stability ST is calculated using the following formula: ST = ×100%, where Tmax and Tmin are the highest and lowest temperatures recorded during the test, respectively.

[0049] The output of the synchronously monitored current source module is used to calculate the current stability SI using the following formula: ST = ×100%, where Imax and Imin are the maximum and minimum currents recorded during the test, respectively.

[0050] This invention provides a closed-loop temperature control system for a laser and its control and performance evaluation method. It offers the following advantages: by employing a high-bit ADC acquisition circuit (such as an 18-bit AD4003) for temperature signal acquisition, combined with a precision reference voltage source and digital filtering technology, precise sensing of minute temperature changes is achieved; the application of an integral-separated PID control algorithm ensures both rapid response when the temperature deviation is large and precise, steady-state error-free adjustment when approaching the target temperature.

[0051] By physically separating the real-time, computationally intensive temperature control task (dedicated to MCU2) from general tasks such as human-machine interaction and system management (handled by MCU1), task blocking and resource contention are effectively avoided.

[0052] By defining and calculating two quantitative indicators, temperature stability and current stability, an objective and accurate evaluation standard for the output performance of lasers is provided.

[0053] Support for two mainstream TEC drive architectures (integrated H-bridge and dedicated temperature control driver) allows the system to be flexibly configured according to different laser power, cost budget and accuracy requirements. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the system framework of the present invention;

[0055] Figure 2 This is a flowchart of the temperature acquisition and signal processing of the present invention;

[0056] Figure 3 This is a flowchart illustrating the dual-mode temperature control execution process of the present invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] See attached document Figures 1-3 As shown, a laser temperature closed-loop control system includes:

[0059] A power supply module is used to provide electrical energy to the various functional modules within the laser.

[0060] The interaction module is used to receive user commands and display system status;

[0061] The main control module (MCU1), connected to the interaction module and the current source module, is used to process user commands and control the system's operating mode;

[0062] The current source module, controlled by the main control module, is used to provide driving current for the laser;

[0063] The temperature acquisition module is used to acquire the real-time temperature signal of the laser and convert it into a digital signal.

[0064] The slave control module (MCU2) is connected to the temperature acquisition module and the master control module, and is used to process temperature data and execute control algorithms.

[0065] A temperature control module, controlled by the slave module, is used to adjust the temperature of the laser;

[0066] The laser emits laser light under the control of the driving current and precise temperature.

[0067] The interaction module includes:

[0068] The display unit uses an OLED display screen to intuitively display the laser's working mode, output power, set temperature, and real-time temperature;

[0069] The input unit uses a button array for users to set parameters and switch modes;

[0070] The communication interface uses a UART serial port to enable data communication between the laser and external devices.

[0071] The temperature acquisition module includes:

[0072] The excitation circuit, consisting of a precision reference voltage source and a high-precision low-temperature drift resistor, is a constant voltage or constant current source used to provide stable electrical excitation for the temperature sensing element.

[0073] The temperature sensing element is a negative temperature coefficient (NTC) thermistor integrated inside the laser. The thermistor is connected in series with a reference resistor to form a voltage divider network.

[0074] An ADC acquisition circuit, whose input terminal is connected to a node of the voltage divider network, is used to acquire the analog voltage signal of the node and convert it into a digital signal;

[0075] When the temperature changes, the resistance of the thermistor changes, causing a corresponding change in the voltage of the voltage divider network nodes. The slave control module reads the digital voltage value converted by the ADC acquisition circuit through the communication protocol and calculates the real-time temperature of the laser based on the resistance-temperature characteristic relationship of the thermistor. The resistance-temperature characteristic relationship is calculated using the B-value method formula, as shown below:

[0076]

[0077] In the formula, For temperature The resistance value at (unit: Kelvin K) Rated temperature The resistance value (typically at 298.15K, or 25℃) is the material constant of the thermistor.

[0078] The slave control module reads digital voltage signals from the ADC acquisition circuit via the SPI communication protocol;

[0079] The slave control module converts the voltage value into a temperature value according to the B-value formula, and uses an integral-separated PID control algorithm to compare the real-time temperature with the set target temperature to calculate the control quantity; the output of the integral-separated PID control algorithm can be expressed as:

[0080]

[0081] In the formula, where, This is the control output at the k-th sampling time. This is the current temperature deviation. , , These are the proportional, integral, and differential coefficients, respectively. The integral separation coefficient is denoted as .

[0082] When the slave control module acquires the voltage signal through the ADC acquisition circuit, it executes a digital filtering program to improve the signal-to-noise ratio. Specifically, the digital filtering program is a median filtering algorithm, and its execution flow is as follows: Within one sampling period, the ADC acquisition circuit performs N consecutive and rapid voltage samplings on the thermistor voltage divider circuit, forming an original sampling sequence [V1, V2, ..., Vn], where N is an odd number greater than 1; all sampled values ​​in the original sampling sequence are sorted in ascending or descending order according to their numerical value; the value located in the middle of the sorted sequence is selected as the effective voltage value output for that sampling period. This algorithm effectively suppresses pulsed spike noise introduced by circuit noise or electromagnetic interference, thereby providing a more stable and reliable temperature data foundation for subsequent PID control algorithms.

[0083] The core of the temperature control module is a semiconductor cooler driver chip, which is used to receive control signals from the slave control module and generate bidirectional current to drive the semiconductor cooler, thereby enabling precise cooling or heating control of the laser.

[0084] The control signal is used to set the magnitude and direction of the current;

[0085] When the semiconductor cooler driver chip is an integrated H-bridge driver, the slave control module directly outputs two PWM signals to the input pin of the driver. By setting the logic relationship between the two PWM signals, the magnitude and direction of the current flowing through the semiconductor cooler can be controlled simultaneously.

[0086] When the semiconductor cooler driver chip is a dedicated temperature control driver, the slave module provides an analog voltage signal to the driver through a DAC module to set the current magnitude, and simultaneously provides a digital level signal to the driver through a GPIO pin to set the current direction; the output voltage expression of the DAC module is:

[0087]

[0088] In the formula, where, For reference voltage, Enter the 12-bit numeric code from MCU2; This refers to the resolution of the DAC module.

[0089] A method for closed-loop temperature control and performance evaluation of a laser, applied to the temperature closed-loop control system, includes the following steps:

[0090] Step S1: Initialize the system hardware and set the target operating temperature (Tset) and target drive current of the laser;

[0091] Step S2: The temperature acquisition module obtains the voltage signal of the thermistor integrated inside the laser through a constant voltage source and a voltage divider circuit;

[0092] The ADC acquisition circuit converts the voltage signal into a digital signal and transmits it to the slave control module via the SPI interface;

[0093] The slave control module performs digital filtering (such as median filtering) on ​​the acquired voltage data to eliminate random noise interference;

[0094] The slave module converts the filtered voltage value into the real-time operating temperature (Tcurrent) of the laser based on the formula for the B value of the thermistor.

[0095] Step S3: The slave control module calculates the deviation between the real-time temperature and the target temperature. =Tset−Tcurrent;

[0096] An integral-separation PID control algorithm is used to calculate the deviation and generate a corresponding control signal. When the temperature deviation is | When | is greater than the set threshold, the coefficient of the integral term β = 0; otherwise, β = 1.

[0097] Step S4: The slave control module transmits the control signal obtained in step S3 to the temperature control module;

[0098] When the semiconductor cooler driver chip is an integrated H-bridge driver, the slave control module directly generates two PWM signals and outputs them to the corresponding pins of the integrated H-bridge driver (such as DRV8838). By setting the phase relationship of the two PWM signals, the driver is controlled to generate bidirectional current of the required magnitude and direction to drive the semiconductor cooler (TEC).

[0099] When the semiconductor cooler driver chip is a dedicated temperature control driver, the slave module outputs an analog voltage signal to the dedicated temperature control driver (such as MAX1978) through a DAC module (such as MCP4725) to set the current magnitude, and at the same time outputs a digital level signal to the temperature control driver through a GPIO pin to set the current direction, thereby driving the semiconductor cooler (TEC) to perform precise cooling or heating operations on the laser.

[0100] Step S5: Return to step S2 and repeat steps S2 to S4 to form a continuous closed-loop temperature control; after the laser reaches a stable state, perform a temperature and current stability assessment.

[0101] Temperature data is continuously recorded within a set duration (e.g., short-term 2 hours, long-term 24 hours). The temperature stability ST is calculated using the following formula: ST = ×100%, where Tmax and Tmin are the highest and lowest temperatures recorded during the test, respectively;

[0102] The output of the synchronously monitored current source module is used to calculate the current stability SI using the following formula: ST = ×100%, where Imax and Imin are the maximum and minimum currents recorded during the test, respectively.

[0103] Example: First, the power supply module provides stable +5V and +3.3V voltages to the entire system; the main control module MCU1 (model STM32F407) is connected to the interaction module via the UART interface and controls the current source module via the I2C interface; the slave control module MCU2 (model STM32H743) is connected to the temperature acquisition module via the SPI interface and to the temperature control module via the GPIO and I2C interfaces.

[0104] Thermistor: Murata NCP03XH103F05RL, resistance 10kΩ±1%, B value 3435K±1%;

[0105] Reference resistor: VISHAY PLT series, resistance 10kΩ, accuracy ±0.1%, temperature drift ±25ppm / ℃;

[0106] Reference voltage source: ADI ADR445, output 4.096V, initial accuracy ±0.02%, noise 1.2μVpp;

[0107] ADC acquisition circuit: ADI AD4003, 18-bit resolution, sampling rate 2MSPS

[0108] The temperature control module adopts a dedicated temperature control driver architecture:

[0109] TEC driver chip: MAX1978, maximum output current ±2.5A;

[0110] DAC module: MCP4725, 12-bit resolution, I2C interface;

[0111] GPIO direction control: PC15 pin of STM32H743;

[0112] Control algorithm parameters:

[0113] Sampling period: 10ms;

[0114] PID parameters: =2.5, =0.8, =0.5,

[0115] Integration separation threshold: ±0.5℃;

[0116] Median filter sampling points: N=5;

[0117] Working process: After the system is powered on, the system is first initialized (step S1); MCU1 and MCU2 complete the peripheral configuration, set the target temperature Tset=25.00℃, and the target drive current Iset=80mA;

[0118] Entering the temperature acquisition stage (step S2); the excitation circuit provides a stable voltage of 4.096V, and the thermistor and the 10kΩ reference resistor divide the voltage; at 25℃, the thermistor resistance is 10kΩ, and the voltage at the voltage divider node is 2.048V;

[0119] When the temperature changes, the resistance of the thermistor changes according to the formula for the B value: Where 298.15K is the thermodynamic temperature of standard room temperature 25℃;

[0120] The ADC acquisition circuit samples the voltage of the voltage divider node at a frequency of 100kHz and transmits the digital voltage value to MCU2 through the SPI interface; MCU2 executes the median filtering algorithm: continuously samples 5 voltage values ​​[V1, V2, V3, V4, V5], sorts them, and takes the median value V3 as the valid sample value;

[0121] Next, control calculations are performed (step S3); MCU2 converts the filtered voltage value into a temperature value and calculates the temperature deviation. =25.00−Tcurrent; When |ek|>0.5℃, set β=0; otherwise, β=1; Execute the integral separation PID algorithm to calculate the control quantity. :

[0122] Then temperature adjustment is performed (step S4); MCU2 will send the control quantity... Convert to DAC input code CODE: CODE= Where 4096 is the total number of quantization levels (2¹²) of the 12-bit DAC (MCP4725); the output voltage of the MCP4725 is set via the I2C interface, and simultaneously according to... The symbol sets the GPIO level, controlling the MAX1978 to output the corresponding bidirectional TEC drive current;

[0123] The system executes steps S2 to S4 (step S5) in a loop to form closed-loop control; once the laser temperature stabilizes (temperature fluctuation is less than ±0.01℃ within 30 minutes), performance evaluation is initiated.

[0124] Performance test results: Long-term stability test conducted at 25℃ for 24 hours:

[0125] Temperature data: Tmax = 25.008℃, Tmin = 24.992℃;

[0126] Temperature stability: ST = (25.008 - 24.992) / (25.008 + 24.992) × 100% = 0.016%;

[0127] Current data: Imax = 80.05mA, Imin = 79.96mA;

[0128] Current stability: SI = (80.05 - 79.96) / (80.05 + 79.96) × 100% = 0.056%;

[0129] The test results show that the temperature control accuracy reaches ±0.008℃, the temperature stability is better than 0.02%, and the current stability is better than 0.06%, which meets the requirements of distributed fiber optic sensing systems for the stability of laser source wavelength.

[0130] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A closed-loop temperature control system for a laser, characterized in that, include: A power supply module is used to provide electrical energy to the various functional modules within the laser. The interaction module is used to receive user commands and display system status; The main control module, connected to the interaction module and the current source module, is used to process user commands and control the system's operating mode. The current source module, controlled by the main control module, is used to provide driving current for the laser; The temperature acquisition module is used to acquire the real-time temperature signal of the laser and convert it into a digital signal. The slave control module is connected to the temperature acquisition module and the main control module, and is used to process temperature data and execute control algorithms. A temperature control module, controlled by the slave module, is used to adjust the temperature of the laser; The laser emits laser light under the control of the driving current and precise temperature.

2. The laser temperature closed-loop control system according to claim 1, characterized in that, The interaction module includes: The display unit uses an OLED display screen to intuitively display the laser's working mode, output power, set temperature, and real-time temperature; The input unit uses a button array for users to set parameters and switch modes; The communication interface uses a UART serial port to enable data communication between the laser and external devices.

3. The laser temperature closed-loop control system according to claim 1, characterized in that, The temperature acquisition module includes: The excitation circuit, consisting of a precision reference voltage source and a high-precision low-temperature drift resistor, is a constant voltage source used to provide stable electrical excitation for the temperature sensing element. The temperature sensing element is a negative temperature coefficient thermistor integrated inside the laser. The thermistor is connected in series with a reference resistor to form a voltage divider network. An ADC acquisition circuit, whose input terminal is connected to a node of the voltage divider network, is used to acquire the analog voltage signal of the node and convert it into a digital signal; When the temperature changes, the resistance of the thermistor changes, causing a corresponding change in the voltage of the voltage divider network nodes. The slave control module reads the digital voltage value converted by the ADC acquisition circuit through the communication protocol and calculates the real-time temperature of the laser based on the resistance-temperature characteristic relationship of the thermistor. The resistance-temperature characteristic relationship is calculated using the B-value method formula, as shown below: In the formula, For temperature The resistance value at that time, Rated temperature The resistance value below, is the material constant of the thermistor.

4. The laser temperature closed-loop control system according to claim 3, characterized in that, The slave control module reads digital voltage signals from the ADC acquisition circuit via the SPI communication protocol; The slave control module converts the voltage value into a temperature value according to the B-value formula, and uses an integral-separated PID control algorithm to compare the real-time temperature with the set target temperature to calculate the control quantity; the output of the integral-separated PID control algorithm can be expressed as: In the formula, where, This is the control output at the k-th sampling time. This is the current temperature deviation. , , These are the proportional, integral, and differential coefficients, respectively. The integral separation coefficient is denoted as .

5. A laser temperature closed-loop control system according to claim 4, characterized in that, When the slave control module acquires the voltage signal through the ADC acquisition circuit, it executes a digital filtering program. The digital filtering program is specifically a median filtering algorithm, and its execution process is as follows: within one sampling period, the ADC acquisition circuit performs N consecutive and rapid voltage samplings on the thermistor voltage divider circuit to form an original sampling sequence [V1, V2, ..., Vn], where N is an odd number greater than 1; all sampled values ​​in the original sampling sequence are sorted in ascending or descending order according to their numerical values; the value located in the middle of the sorted sequence is selected as the effective voltage value output for that sampling period.

6. The laser temperature closed-loop control system according to claim 1, characterized in that, The core of the temperature control module is a semiconductor cooler driver chip, which receives control signals from the slave control module and generates bidirectional current to drive the semiconductor cooler, thereby precisely controlling the cooling or heating of the laser; the control signal is used to set the magnitude and direction of the current. When the semiconductor cooler driver chip is a dedicated temperature control driver, the slave module provides an analog voltage signal to the driver through a DAC module to set the current magnitude, and simultaneously provides a digital level signal to the driver through a GPIO pin to set the current direction; the output voltage expression of the DAC module is: In the formula, where, For reference voltage, Enter the 12-bit numeric code from MCU2; This refers to the resolution of the DAC module.

7. A method for closed-loop temperature control and performance evaluation of a laser, applied to the temperature closed-loop control system described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1: Initialize the system hardware and set the target operating temperature and target drive current of the laser; Step S2: The temperature acquisition module obtains the voltage signal of the thermistor integrated inside the laser through a constant voltage source and a voltage divider circuit; The ADC acquisition circuit converts the voltage signal into a digital signal and transmits it to the slave control module via the SPI interface; The slave control module performs digital filtering on the collected voltage data; The slave control module converts the filtered voltage value into the real-time operating temperature of the laser based on the formula for the B value of the thermistor. Step S3: The slave control module calculates the deviation between the real-time temperature and the target temperature. =Tset−Tcurrent; An integral-separation PID control algorithm is used to calculate the deviation and generate a corresponding control signal. When the temperature deviation is | When | is greater than the set threshold, the coefficient of the integral term β = 0; otherwise, β = 1. Step S4: The slave control module transmits the control signal obtained in step S3 to the temperature control module; When the semiconductor cooler driver chip is a dedicated temperature control driver, the slave module outputs an analog voltage signal to the dedicated temperature control driver through the DAC module to set the current magnitude, and at the same time outputs a digital level signal to the temperature control driver through a GPIO pin to set the current direction, thereby driving the semiconductor cooler to perform precise cooling or heating operations on the laser. Step S5: Return to step S2 and repeat steps S2 to S4 to form a continuous closed-loop temperature control; after the laser reaches a stable state, perform a temperature and current stability assessment. Temperature data is continuously recorded within a set time period. The temperature stability ST is calculated using the following formula: ST = ×100%, where Tmax and Tmin are the highest and lowest temperatures recorded during the test, respectively. The output of the synchronously monitored current source module is used to calculate the current stability SI using the following formula: ST = ×100%, where Imax and Imin are the maximum and minimum currents recorded during the test, respectively.

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