VCSEL active area temperature measurement system and measurement method based on Raman spectrum

Abstract

The invention provides a VCSEL active area temperature measurement system and method based on Raman spectrum, and the system comprises a Raman spectrum temperature measurement module which is used for achieving the non-contact measurement of the temperature of a VCSEL active area; and the data processing and control system is used for processing the Raman spectrum data and controlling the working state of the VCSEL. Real-time and non-contact monitoring of the working temperature of the VCSEL is achieved, the system can monitor possible temperature changes of the VCSEL working for a long time in real time, the working state of the VCSEL is automatically adjusted, performance reduction or damage caused by too high or too low temperature is prevented, the reliability of the VCSEL is improved, and the service life of the VCSEL is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor technology, and particularly to a vertical cavity surface emitting laser (VCSEL) active region temperature measurement system and method based on Raman spectrum, which is particularly suitable for monitoring and researching optical catastrophic damage (COD) in VCSEL. BACKGROUND

[0002] VCSEL is a kind of high-efficiency semiconductor laser, which has a wide range of applications in optical communication, sensor, laser printing and other fields. The transmission performance of VCSEL is affected by many factors, among which the thermal effect is one of the most important factors. In order to obtain larger modulation bandwidth and transmission rate, the active region volume of high-speed VCSEL is usually set to be small, which is not conducive to heat dissipation, resulting in internal temperature rise, which in turn causes a series of problems such as carrier leakage and non-radiative recombination, internal quantum efficiency drop, active region gain reduction, etc., leading to power rollover and modulation bandwidth saturation in advance, reducing the performance and stability of the device and shortening the service life.

[0003] The internal heat source of VCSEL can be mainly divided into two parts: one part is the heat generated by DBR after power-on, and the other part is the heat generated by melting and recrystallization in the cavity area. When the temperature of the active region of VCSEL is too high, the modulation bandwidth of VCSEL will be affected, and the heat accumulated inside will cause thermal limitation if it cannot be dissipated in time, which will reduce the performance and stability of the device. The output wavelength of VCSEL is affected by temperature and operating current. Keeping the temperature constant and changing the laser current, the laser wavelength increases with the increase of current. Keeping the laser current constant, the laser wavelength increases with the increase of temperature. Therefore, the control of temperature is crucial to the performance of VCSEL.

[0004] Optical catastrophic damage (COD) is a failure mode of high-power laser, which is usually caused by overloading of semiconductor PN junction due to excessive power density and absorption of too much gain generated optical energy, resulting in melting and recrystallization in the cavity area, and a large number of lattice defects in the affected area, which destroys the performance of the device. The generation of COD is usually in nanoseconds, with a positive feedback cycle, so it is necessary to monitor the whole process of defect formation. The existing chip defect detection methods usually use photodiodes to monitor the light power of the device, but they can only roughly monitor the start time of COD, and cannot accurately reflect the damage and termination of COD. SUMMARY

[0005] The present application aims to provide a VCSEL active region temperature measurement system based on Raman spectroscopy, which realizes real-time and non-contact monitoring of the working temperature of VCSEL, especially in the application of optical catastrophic damage (COD) research, to improve the reliability and service life of VCSEL.

[0006] The VCSEL active region temperature measurement system based on Raman spectroscopy proposed by the present application includes two main parts: the first part is a Raman spectrum temperature measurement module, which is used to realize non-contact measurement of the temperature of the VCSEL active region; the second part is a data processing and control system, which is used to process Raman spectrum data and control the working state of the VCSEL.

[0007] Among them, the Raman spectrum temperature measurement module includes the following components: Laser: provides test laser to excite VCSEL active region, wavelength and power are selected according to the characteristics of VCSEL material; Micro-positioning system: used to accurately align the test laser to the light emitting hole of the VCSEL.

[0008] Optical system: mainly includes lenses, used to focus the test laser to the light emitting hole of the VCSEL, and collect the reflected Raman scattered light; Raman spectrometer: used to collect the Raman scattered light of the VCSEL active region and convert it into an electrical signal; Narrowband filter: filters out the working laser emitted by the VCSEL, and only allows the Raman scattered light to reach the detector; The data processing and control system includes the following components: Data acquisition unit: used to receive the electrical signal output by the Raman spectrometer and convert it into a digital signal; Control system: calculates the temperature of the VCSEL active region according to the Raman spectrum data, and adjusts the working state of the VCSEL as needed; Computer: used to store and analyze temperature data, and control the entire measurement process.

[0009] The VCSEL active region temperature measurement system based on Raman spectroscopy proposed by the present application can monitor the working temperature of the VCSEL in real time, which is of great significance to improve the reliability and prolong the service life of the VCSEL.

[0010] The present application also proposes a VCSEL active region temperature measurement method based on Raman spectroscopy, which uses the above measurement system to measure the temperature of the VCSEL, including the following steps: First, the test laser is accurately aligned to the light emitting hole of the VCSEL through the micro-positioning system; then, the laser emits test laser to excite the VCSEL active region to generate Raman scattered light; The optical system collects the Raman scattered light and transmits it to the Raman spectrometer; The Raman spectrometer converts the Raman scattered light into electrical signals, which are received and digitized by the data acquisition unit. The control system calculates the temperature of the VCSEL active region based on the Raman spectral data and displays the temperature reading through the computer interface.

[0011] If the real-time calculated temperature of the VCSEL active region exceeds the preset range, the control system will adjust the working parameters of the VCSEL to maintain the optimal working temperature.

[0012] Optionally, the micro-positioning system includes a host computer, a single-chip microcomputer, a driving circuit, a precision motor, a scanning mirror, a feedback system, and a fine adjustment stage. The host computer issues instructions, the single-chip microcomputer receives and processes the instructions, and then controls the driving circuit to drive the precision motor, thereby controlling the movement of the scanning mirror. At the same time, the feedback system constantly monitors the state of the scanning mirror and the fine adjustment stage components, and feeds back signals to the single-chip microcomputer. The single-chip microcomputer performs closed-loop control based on these feedback signals to ensure the accuracy and stability of the system.

[0013] Optionally, the optical system includes a collection lens, a focusing lens, and a collimating lens. The collection lens is arranged between the laser chip to be tested and the narrowband filter, and is used to collect the light emitted from the laser chip to be tested. The focusing lens and the collimating lens are arranged in parallel between the laser chip to be tested and the laser. The combination of the focusing lens and the collimating lens collimates and focuses the light beam emitted by the laser 10.

[0014] Optionally, the control system is configured to calculate the temperature using the intensity ratio of the Stokes line and the anti-Stokes line.

[0015] Optionally, the process of analyzing the temperature data by the computer includes: Obtaining the temperature data obtained by the data acquisition unit; Data preprocessing, using Kalman filtering to remove system noise; data cleaning, removing missing data and outliers and correcting by interpolation; The computer performs trend analysis on the temperature data; Setting the upper and lower limits of the temperature according to safety requirements or specific work needs; Visualizing the temperature data through a graphical interface.

[0016] The above and other objects, advantages, and features of the present application will become more apparent from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0017] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting in Figure 1 A schematic diagram of a Raman spectrum-based VCSEL active region temperature measurement system according to an embodiment of the present application is shown. Figure 2 A schematic diagram of a micro-positioning system according to an embodiment of the present application is shown. Figure 3 A schematic diagram of an optical system according to an embodiment of the present application is shown. Wherein, 10-laser, 20-micro-positioning system, 30-optical system, 40-Raman spectrometer, 50-narrowband filter, 60-laser chip to be measured, 70-power supply. DETAILED DESCRIPTION

[0018] Embodiments of the present application will be described below with reference to the accompanying drawings, which should be understood as merely illustrative and not limiting.

[0019] In combination Figure 1 , the embodiment of the present application provides a Raman spectrum-based VCSEL active region temperature measurement system, which includes a Raman spectrum temperature measurement module and a data processing and control system, wherein the Raman spectrum temperature measurement module is used to realize non-contact measurement of the VCSEL active region temperature, and the data processing and control system is used to process Raman spectrum data and control the working state of the VCSEL.

[0020] The Raman spectrum temperature measurement module includes a laser 10, a micro-positioning system 20, an optical system 30, a Raman spectrometer 40, and a narrowband filter 50.

[0021] The laser 10 provides test laser for exciting the VCSEL active region, and the wavelength and power are selected according to the characteristics of the VCSEL material; the laser 10 is located at the front end of the system and is used to emit test laser.

[0022] The micro-positioning system 20 is connected with the laser 10 and accurately aligns the laser position, and is specifically used to accurately align the test laser to the light-emitting hole of the VCSEL.

[0023] Figure 2 A schematic diagram of the micro-positioning system 20 according to an embodiment of the present application is shown. As Figure 2 shown, the micro-positioning system 20 according to an embodiment of the present application can include a host computer 21, a single-chip microcomputer 22, a driving circuit 23, a precision motor 24, a scanning mirror 25, a feedback system 26, and a fine adjustment table 27, etc.

[0024] The host computer 21 is the highest control unit of the system, which is responsible for issuing instructions. These instructions can be about the motion trajectory of the scanning mirror, position adjustment, and other operation requirements. The host computer 21 can set the path of laser scanning or the range of microscopic observation.

[0025] The single-chip microcomputer 22 is connected with the host computer 21, used for receiving the control instructions of the host computer 21 and processing them. The single-chip microcomputer 22 controls the subsequent precision motor drive circuit 23 according to the control instructions, and also receives the signals of the feedback system to perform accurate closed-loop control on the whole system.

[0026] The single-chip microcomputer 22 is connected with the precision motor 24 via the precision motor drive circuit 23. The control signals output by the single-chip microcomputer 22 are amplified and processed by the drive circuit 23, and then drive the precision motor 24 to act. The precision motor 24 can accurately rotate according to the signals of the drive circuit 23, drive the scanning mirror 25 to move accordingly, and then adjust the angle and position of the scanning mirror 25, so as to change the optical path or other paths that need to be scanned.

[0027] The feedback system 26 includes a CCD camera 261, a photodiode 262, and a position encoder 263. The CCD camera 261 can be used to obtain image information of the fine adjustment table 27 or the scanning area. The photodiode 262 is mainly used for detecting optical signals, which can convert optical signals into electrical signals. The position encoder 263 is used to determine the accurate position of the scanning mirror 25 or the fine adjustment table 27, so as to convert the mechanical position into an electrical signal and feed it back to the single-chip microcomputer 22, ensuring the motion accuracy of the system. For example, the position encoder can accurately feed back the angle of the scanning mirror, so that the system can adjust the position of the scanning mirror in real time to meet the requirements.

[0028] The working principle of the microscopic positioning system 20 in this embodiment is that the host computer 21 issues instructions, the single-chip microcomputer 22 receives and processes the instructions, and then controls the drive circuit 23 to drive the precision motor 24, and further controls the motion of the scanning mirror 25. At the same time, the feedback system 26 constantly monitors the state of components such as the scanning mirror 25 and the fine adjustment table 27, and feeds back the signals to the single-chip microcomputer 22. The single-chip microcomputer 22 performs closed-loop control according to these feedback signals to ensure the accuracy and stability of the system.

[0029] The optical system 30 is connected with the laser 10 and the Raman spectrometer 40, focuses the laser, and collects the Raman scattered light. The optical system 30 in this embodiment mainly includes a lens, which is used to focus the test laser to the light-emitting hole of the VCSEL, and collect the reflected Raman scattered light. Figure 3 The optical system schematic diagram of the embodiment of the present application is shown as Figure 3As shown, the optical system 30 of the present embodiment can include a collection lens 31, a focusing lens 32, and a collimating lens 33. The collection lens 31 is disposed between the laser chip 60 to be measured and the narrowband filter 50, and is mainly used to collect light emitted from the laser chip 60 to be measured. The focusing lens 32 and the collimating lens 33 are disposed in parallel between the laser chip 60 to be measured and the laser 10, and the combination of the focusing lens 32 and the collimating lens 33 can collimate and focus the light beam. The collimating lens 33 can make the divergent light beam emitted from the laser 10 into a parallel light beam, and the focusing lens 32 can focus the parallel light beam to a focal point, which can be set near the laser chip 60 to be measured or at other suitable positions as needed.

[0030] Raman spectrometer 40: immediately after the optical system, used to collect the Raman scattered light of the VCSEL active region and convert it into an electrical signal.

[0031] Narrowband filter 50: located in front of the Raman spectrometer 40, blocking non-Raman scattered light, filtering out the working laser emitted by the VCSEL, and allowing only Raman scattered light to reach the detector.

[0032] The placement position of the VCSEL laser chip 60 to be measured should be after the focusing lens, at the focal point of the laser beam. Specifically, the VCSEL laser chip 60 to be measured should be in the focusing area, ensuring that the focused laser can excite Raman scattered light. The VCSEL laser chip 60 to be measured needs a power supply 70 to drive it to emit laser, is fixed by a stable support structure, and is connected to an external power supply module through a micro connector or a soldered port.

[0033] The data processing and control system 80 can include a data acquisition unit, a control system, and a computer.

[0034] Data acquisition unit: used to receive the electrical signal output by the Raman spectrometer and convert it into a digital signal. That is, the data acquisition unit receives analog signals from the spectrometer and sensors, converts them into digital signals, and transmits them to the control system. In the present embodiment, the data acquisition unit can specifically include an analog-to-digital converter (ADC), a filter circuit, and a temporary data storage. The analog signal (from the Raman spectrometer + temperature sensor + displacement sensor) enters the data acquisition unit through an analog input channel, is processed by a signal conditioner, is converted into a digital signal, is stored in a temporary data storage area, and is finally transmitted to the control system through a data interface.

[0035] Control system: Calculate the temperature of the active region of the VCSEL according to the Raman spectrum data, and adjust the working state of the VCSEL as needed. In this embodiment, the control system analyzes the received data, calculates the adjustment parameters of the laser or temperature control system according to the control algorithm, and transmits the results to the corresponding power execution module (such as the power module of the VCSEL, the control unit of the temperature control system, or the precision motor drive circuit) to execute.

[0036] It should be noted that the control system is the real-time core and bridge of the data processing and control system, and its function is: (a) Real-time calculation of the temperature of the active region of the VCSEL, and transmission of the data to the computer (host computer) together with other sensor data (such as stage temperature); (b) Receive high-level instructions sent by the computer downward, and transmit them to the corresponding module for execution.

[0037] Optionally, the control system can use the intensity ratio of Stokes and Anti-Stokes lines to calculate the temperature.

[0038] By measuring the intensity of Stokes and Anti-Stokes peaks with a Raman spectrometer, we get , .

[0039] From , we get

[0040] Where is the reduced Planck constant, ; is the Raman frequency shift, which is the difference between the frequency of scattered light and the frequency of incident light; k is the Boltzmann constant.

[0041] Adjusting the working state of the VCSEL as needed can include the following aspects: 1. If the calculated temperature is too high, manually reduce the laser current; (2) Temperature sensor (stage) warning, enable the thermoelectric cooler (or air cooling system), and automatically reduce the current; (3) Use a feedback control system to automatically adjust the working current of the VCSEL or the cooling system according to real-time temperature measurement data. And use the PID control algorithm to optimize temperature adjustment, so that the VCSEL operates at the best working temperature.

[0042] Computer: used for storing and analyzing temperature data, and controlling the entire measurement process. The computer receives and stores the data transmitted by the control system, and can also analyze the data in real time and display the experimental results through the user interface.

[0043] In an optional embodiment of the present application, the process of analyzing temperature data by the computer can include: S1, acquire temperature data obtained through the data acquisition unit. Temperature data is typically stored in time-series format, for example, temperature is recorded once per second or per minute; S2, Data preprocessing, using Kalman filtering to remove system noise; Data cleaning, removing missing data and outliers and correcting them through interpolation; S3, the computer performs trend analysis on temperature data, such as the rate of temperature change. An excessively large rate of change may indicate a problem with system stability and requires timely adjustment. S4 allows setting upper and lower temperature limits according to safety requirements or specific work needs, and this setting will intervene in the control system. S5 allows the computer to visualize temperature data through a graphical user interface (GUI).

[0044] This invention also provides a method for measuring the temperature of a VCSEL based on the aforementioned measurement system. First, a test laser is precisely aligned with the output aperture of the VCSEL using a microscopic positioning system. Then, the laser emits the test laser, exciting the active region of the VCSEL to generate Raman scattered light. An optical system collects the Raman scattered light and transmits it to a Raman spectrometer. The Raman spectrometer converts the Raman scattered light into electrical signals, which are received and digitized by a data acquisition unit. The control system calculates the temperature of the VCSEL's active region based on the Raman spectral data and displays the temperature reading on a computer interface. If the real-time calculated temperature of the VCSEL's active region exceeds a preset range, the control system adjusts the VCSEL's operating parameters to maintain the optimal operating temperature.

[0045] The operating temperature range of most VCSELs is typically given by the manufacturer in the datasheet, generally between 20°C and 80°C. An optimal operating temperature range is determined by experimentally measuring the VCSEL's performance (such as output power and spectral characteristics) at different temperatures, and this range can be used as a preset range. This embodiment does not limit the specific value of this range. When adjusting the VCSEL's operating parameters, the control system can adjust the laser current, use a cooling / heating system, adjust the bias voltage (manually set), or utilize a real-time temperature control feedback system.

[0046] Assuming that the maximum safe threshold for the temperature sensor in the experimental system is set to 80°C, the control system will trigger a high-temperature alarm and take corresponding adjustment measures when the stage temperature exceeds 80°C.

[0047] For example, the selected VCSEL operating temperature range is 25°C to 65°C, and through experimental tests, it is found that when the temperature exceeds 65°C, the light output of the VCSEL decreases significantly, and when the temperature exceeds 70°C, it may cause thermal damage. Therefore, the maximum temperature limit is set to 70°C, and the minimum temperature limit is set to 20°C, and the active region temperature is calculated in real time, and an alarm is given when it exceeds or is too low, at which time it can be manually modified or connected to a feedback control system.

[0048] After a long time of work, the temperature of the VCSEL may change. The system of the embodiment of the present application can monitor this change in real time and automatically adjust the working state of the VCSEL (such as combining the temperature sensor, calculating the value in real time to limit the temperature; if the temperature fluctuates greatly, the system will adjust itself according to the real-time feedback, not only through PID control to gradually optimize, but also can set up a machine learning model to adjust the working parameters, in order to prevent performance degradation or damage due to too high or too low temperature, especially in monitoring and preventing COD).

[0049] For example, the machine learning model is only an extension software module, and its working process can be as follows: 1. Feature data acquisition and processing: the control system (80) collects and integrates a multi-dimensional feature vector in real time for model input. The feature vector at least includes: (a) the real-time temperature of the VCSEL active region calculated from the Raman spectrometer (40) data; (b) the time rate of change of the real-time temperature (ΔT / Δt), which is used to represent the fluctuation trend of the temperature; (c) the current working current and output optical power of the VCSEL to be tested laser chip (60) (which can be monitored by the photodiode 262 in the feedback system 26); (d) the reference temperature of the stage or environment (which is provided by the following

reference temperature control and early warning module

[0050] 2. Machine learning model construction and training (offline stage): Model selection: select a machine learning model suitable for processing time series data, such as recurrent neural network (RNN), long short-term memory network (LSTM), or gradient boosting decision tree (GBDT).

[0051] Training data generation: run the VCSEL under various operating conditions (including normal, edge and limit conditions) through experimental operation, continuously collect the above-mentioned feature vectors, and label their "results" - such as "stable operation", "performance degradation" or "COD occurs".

[0052] Training objective: Train the model to be able to predict the probability (i.e. "risk score") of the VCSEL entering "performance degradation" or "COD" in a very short time (e.g. hundreds of milliseconds or seconds) in the future, according to the current input feature vector.

[0053] 3. Real-time inference and adaptive control (online phase): During system operation, the control system (80) will input the real-time collected feature vector into the trained machine learning model for "real-time inference".

[0054] The model outputs a "risk score" for the future state of the VCSEL in real time.

[0055] Control logic: When the "risk score" predicted by the model exceeds the preset safety threshold (i.e. the model "foresees" a large temperature fluctuation or COD risk about to occur), the model will take precedence over the PID control and immediately trigger a higher-level "preventive adjustment" instruction.

[0056] This "preventive adjustment" instruction (i.e. "adjust working parameters") is only for the laser chip (60) under test, for example: immediately reduce the VCSEL working current by a large margin, thereby cutting off the conditions for COD positive feedback before it occurs in nanoseconds, achieving effective prevention of COD.

[0057] In summary, the present application provides a VCSEL active region temperature measurement system based on Raman spectroscopy, which can realize real-time and non-contact monitoring of the working temperature of the VCSEL, and is of great significance for improving the performance and reliability of the VCSEL, especially in the study of optical catastrophic damage (COD).

[0058] The above is only a preferred embodiment of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical solutions falling within the scope of the present application should be considered within the protection scope of the present application. It should be noted that for ordinary skilled persons in the art, some improvements and refinements without departing from the principles of the present application should also be considered within the protection scope of the present application.

Claims

1. A VCSEL active region temperature measurement system based on Raman spectroscopy, characterized in that, It includes a Raman spectroscopy temperature measurement module and a data processing and control system. The Raman spectroscopy temperature measurement module is used to achieve non-contact measurement of the temperature of the VCSEL active region, including: Laser: Provides test laser for exciting the active region of VCSEL; wavelength and power are selected according to the VCSEL material properties. Microscopic positioning system: used to precisely align the test laser to the output aperture of the VCSEL; Optical system: mainly includes lenses, used to focus the test laser onto the output aperture of the VCSEL and collect the reflected Raman scattered light; Raman spectrometer: used to collect Raman scattered light from the active region of VCSEL and convert it into an electrical signal; Narrowband filter: filters out the working laser emitted by the VCSEL, allowing only Raman scattered light to reach the detector; A data processing and control system is used to process Raman spectroscopy data and control the working state of the VCSEL; the data processing and control system includes a data acquisition unit, a control system, and a computer; Data acquisition unit: used to receive the electrical signals output by the Raman spectrometer and convert them into digital signals; Control system: Calculates the temperature of the active region of the VCSEL based on Raman spectroscopy data, and adjusts the operating status of the VCSEL as needed; Computer: Used to store and analyze temperature data, as well as control the entire measurement process.

2. The VCSEL active region temperature measurement system based on Raman spectroscopy according to claim 1, characterized in that, The microscopic positioning system includes a host computer, a microcontroller, a drive circuit, a precision motor, a scanning mirror, a feedback system, and a fine-tuning stage; The host computer issues commands, and the microcontroller receives and processes the commands to control the drive circuit to drive the precision motor, thereby controlling the movement of the scanning mirror. At the same time, the feedback system continuously monitors the status of the scanning mirror and the fine-tuning stage components and feeds the signals back to the microcontroller. The microcontroller performs closed-loop control based on these feedback signals to ensure the accuracy and stability of the system.

3. The VCSEL active region temperature measurement system based on Raman spectroscopy according to claim 1, characterized in that, The optical system includes a collecting lens, a focusing lens, and a collimating lens. The collecting lens is disposed between the laser chip under test and the narrowband filter to collect the light emitted from the laser chip under test. The focusing lens and the collimating lens are disposed in parallel between the laser chip under test and the laser. The combination of the focusing lens and the collimating lens collimates and focuses the light beam emitted by the laser 10.

4. The VCSEL active region temperature measurement system based on Raman spectroscopy according to any one of claims 1-3, characterized in that, The control system is used to calculate temperature using the intensity ratio of Stokes lines and anti-Stokes lines.

5. The VCSEL active region temperature measurement system based on Raman spectroscopy according to any one of claims 1-3, characterized in that, The process of computer analysis of temperature data includes: Acquire temperature data obtained through the data acquisition unit; Data preprocessing involves using Kalman filtering to remove system noise; data cleaning removes missing data and outliers and corrects them using interpolation. The computer performs trend analysis on the temperature data; Set upper and lower temperature limits according to safety requirements or specific work needs; Temperature data is visualized through a graphical interface.

6. A method for measuring the active region temperature of a VCSEL based on Raman spectroscopy, characterized in that, Temperature measurement of VCSEL using the measurement system according to any one of claims 1-5 includes the following steps: The test laser is precisely aligned with the output aperture of the VCSEL using a microscopic positioning system; the laser emits the test laser to excite the active region of the VCSEL to generate Raman scattered light; The optical system collects Raman scattered light and transmits it to the Raman spectrometer; The Raman spectrometer converts Raman scattered light into electrical signals, which are received and digitized by the data acquisition unit. The control system calculates the temperature of the active region of the VCSEL based on Raman spectroscopy data and displays the temperature readings through a computer interface.

7. The method for measuring the active region temperature of a VCSEL based on Raman spectroscopy according to claim 6, characterized in that, If the temperature calculated in real time in the active area of ​​the VCSEL exceeds the preset range, the control system will adjust the operating parameters of the VCSEL to maintain the optimal operating temperature.

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