Design method of gallium arsenide optical fiber temperature sensor

Abstract

The invention relates to a design method of a gallium arsenide optical fiber temperature sensor, and belongs to the technical field of optical fiber sensing. According to the sensor, a gallium arsenide wafer with the thickness of 125 microns is adopted as a temperature sensing element, and a dielectric transmission film and a high-reflection film are plated on the two faces of the wafer respectively. Vertical alignment of the optical fiber and the wafer is achieved through a three-dimensional adjusting platform, a 880 nm light source is adopted for irradiation, and a reflection spectrum is analyzed through a spectrograph. The sensor adopts a double-layer sleeve structure, an inner-layer teflon thin tube is provided with air holes, and an outer-layer spiral sleeve enhances the bending resistance. The packaging process is completed in a vacuum environment, and bubbles are prevented from being generated. The temperature measurement system takes STM32 as a main controller and outputs Modbus protocol data through an RS-485 bus. The sensor can realize measurement in a range of-40 to 180 DEG C in an oil immersion environment, the resolution ratio is 0.1 K, and the annual drift is less than 0.3%. The spiral sleeve structure enables the minimum bending radius to reach 15mm, and is suitable for slit installation of the transformer winding. The system resists 50Hz magnetic field interference, and the temperature measurement error is controlled within + / -0.5 DEG C.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber temperature sensors, and in particular to a design method for a gallium arsenide optical fiber temperature sensor. Background Art

[0002] During the operation of high-voltage power equipment, the winding temperature of oil-immersed transformers and generators directly affects the aging rate of insulation materials. Traditional temperature measurement methods, such as platinum resistance thermometers or infrared thermometers, have significant limitations: metal sensors are susceptible to electromagnetic interference, and infrared thermometers cannot directly measure the interior of the windings.

[0003] While existing fiber optic temperature sensors offer excellent resistance to electromagnetic interference, they suffer from issues such as insufficient packaging reliability and temperature response drift in long-term oil immersion. The voltage resistance and long-term stability of the temperature probe are particularly critical in high-voltage environments above 110 kV. Furthermore, existing sensors have poor installation adaptability within the confined space of transformers, and their large bending radius makes them difficult to deploy. These issues directly impact the accuracy of temperature monitoring data, which in turn affects the assessment of insulation aging. Summary of the Invention

[0004] The present invention aims to provide a method for designing a gallium arsenide optical fiber temperature sensor to solve the problems raised in the above background technology, which comprises the following steps: S1: Select the materials for the GaAs fiber optic temperature sensor, which mainly includes ST fiber optic connector, light guide fiber, GaAs temperature probe, inner Teflon tube and outer spiral sleeve; S2: Design the overall structure of the GaAs fiber optic temperature sensor; S3: Encapsulating the GaAs chip in the GaAs temperature probe; S4: Encapsulate the GaAs temperature probe; S5: Build a GaAs fiber optic temperature measurement system; S6: Build the hardware framework of the GaAs fiber optic temperature measurement system; S7: Design the hardware circuit and communication structure of the GaAs fiber optic temperature measurement system; S8: Design software for GaAs fiber optic temperature measurement system.

[0005] Furthermore, during the material selection phase, the components of the GaAs fiber optic temperature sensor are carefully selected. The main components include the ST fiber optic connector, light-guiding fiber, GaAs temperature probe, inner Teflon tubing, and outer spiral sheath. The inner Teflon tubing, serving as a protective sheath, requires special surface treatment, such as using one or more of the following methods: polytetrafluoroethylene plasma, radiation grafting, or laser treatment, to enhance its adhesive properties and ensure a secure bond with the optical fiber and other components. After treatment, the adhesive is measured using a rotational or titration viscometer (such as the Brookfield CP51) to ensure that it meets bonding requirements. The GaAs wafer used in the GaAs temperature probe adopts a reflective structure, is 125μm thick, and measures 200x200μm. This facilitates bonding between the optical fiber and the wafer and improves the reliability of the temperature probe packaging.

[0006] Furthermore, during the overall structural design phase, special attention was paid to the coating of the GaAs wafer and the selection of fiber optic connectors. The GaAs wafer is coated with a dielectric transmission film and a dielectric high-reflection film on both sides. During packaging, the optical fiber must ensure contact with the transmission-coated side. The ST fiber optic connector features an insertion loss of <0.3 dB and a keyed bayonet-type locking structure that complies with the IEC 874-10 standard for quick installation. Heat shrink tubing is also installed on one end of the ST connector to prevent breakage of the internal optical fiber due to collisions or excessive bending. The entire optical cable is protected by a double layer of tubing. The outermost layer is a Teflon spiral tubing, which enhances the sensor's flexibility and prevents tangling. The innermost layer is a Teflon tube with small holes, which is both air- and water-permeable, preventing the sensor from floating when measuring water or oil temperatures.

[0007] Furthermore, during the GaAs temperature probe packaging stage, the bare fiber end face must be processed, flattened, and cleaned using end-face grinding. The packaging platform includes a reflectance spectrum test optical path, an optical adjustment platform, a heating platform, a fiber microscope system, and an LCD display. The optical adjustment platform allows three-dimensional adjustment to ensure the accurate positioning of the optical fiber and the GaAs wafer. The heating platform is a SET high-precision digital display constant temperature heating table used for curing and heating high-temperature adhesives. The monitoring lens is a high-magnification microscope connected to an LCD display for clear observation of the packaging image. The light source is the AvaLight-DH-S deep ultraviolet deuterium-halogen tungsten lamp, and the spectrometer is the AvaSpec-ULS2048XL spectrum analyzer to ensure accurate spectral data collection and analysis.

[0008] Furthermore, the GaAs fiber optic temperature measurement system was constructed. The system primarily consists of a main control unit, a light source driver module, a fiber optic optical path system, a spectral detection device, and an external output module. The main control unit, using an STM32 microcontroller with an ARM architecture core, is responsible for light source control, spectral information demodulation, and temperature information output. The light source driver module is responsible for sequentially illuminating the light sources and performing adaptive adjustments. The fiber optic optical path system is responsible for light transmission. The spectral detection device performs photoelectric conversion on the temperature probe's reflected spectrum and transmits the information to the main control unit for analysis.

[0009] Furthermore, during the hardware framework construction phase, the light source driver circuit was designed. A light source with a central wavelength of 880 nm was selected. The voltage was adjusted using an LM2596 voltage regulator chip in conjunction with the microcontroller's built-in DAC function. This allowed for adjustment of the light intensity and control of the light source's on / off function. Spectral information was collected via a serial port, using a baud rate of 384,000, which was higher than the conventional rate, to improve data transmission efficiency. An RS-485 bus protection circuit was also incorporated to ensure data transmission stability.

[0010] Furthermore, during the hardware circuit and communication structure design phase, we focused on the stability of the light source driver circuit and the efficiency of spectral information acquisition. By rationally designing the circuit and communication structure, we ensured stable system operation and accurate data transmission.

[0011] Furthermore, in the software design phase, the system main process manages the UART communication module, USB communication module, and LCD display module. The main control board communicates with the light source driver board via the UART serial port to control the light source on the light source driver board. After the spectrometer receives the reflected light signal from the sensor, the main control board sends a command through the USB interface to control the spectrometer to demodulate the spectral data, and calls the temperature-wavelength algorithm relationship to demodulate the temperature value, which is displayed on the LCD screen. This process is cyclical after the system starts running to realize the function of real-time demodulation of temperature signals. At the same time, the system supports multiple temperature measurement channels. After the main control unit selects a channel, it collects and analyzes the gallium arsenide reflection spectrum data to realize the system temperature measurement function. By adopting the above technical solution, the GaAs fiber optic temperature sensor can be fully compatible with the internal working environment of oil-immersed transformers and generator windings, meeting the requirements of safe, reliable and stable operation.

[0012] Compared with the existing technology, the beneficial effects of the present invention are: the designed gallium arsenide optical fiber temperature sensor can work stably for a long time, has excellent insulation performance and high-voltage resistance, and is highly reliable, robust, and interchangeable. The temperature probe is small in size and compatible with transformer and generator installation environments, and has moderate cost.

[0013] The temperature measurement system accurately and in real time measures the ambient temperature of the GaAs fiber optic temperature sensor and displays the data simultaneously on an LCD screen. The GaAs fiber optic temperature sensor is fully compatible with the internal operating environment of oil-immersed transformers and generator windings, meeting the requirements for safe, reliable, and stable operation. The temperature measurement system boasts an accuracy of ±1°C, a resolution of 0.1°C, and a measurement range of -40°C to 200°C. Furthermore, the fiber optic temperature sensor and system have passed national standard certification testing and received user certification, demonstrating the feasibility of the designed temperature measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Graphs showing the reflection spectra of gallium arsenide wafers of different sizes according to the present invention; Figure 2 This is a schematic diagram of the gallium arsenide wafer structure of the present invention; Figure 3 This is a schematic diagram of the light reflection of the gallium arsenide wafer of the present invention; Figure 4 This is a schematic structural diagram of the gallium arsenide optical fiber temperature sensor of the present invention; Figure 5 This is a schematic structural diagram of the gallium arsenide temperature probe of the present invention; Figure 6 This is a flow chart of the optical fiber end face polishing process of the present invention; Figure 7 This is a schematic diagram of the packaging platform for the gallium arsenide temperature probe of the present invention; Figure 8 This is a process flow chart of the gallium arsenide temperature probe packaging process of the present invention; Figure 9 This is a physical picture of the gallium arsenide temperature probe of the present invention; Figure 10 This is an overall block diagram of the gallium arsenide optical fiber temperature measurement system of the present invention; Figure 11 This is the minimum system diagram of the main control unit of the present invention; Figure 12 The RS-485 bus circuit of the present invention; Figure 13 This is a functional structure diagram of the gallium arsenide optical fiber temperature measurement software of the present invention; Figure 14 This is the main loop logic diagram of the system of the present invention; Figure 15 This is a flow chart of data collection and processing of the present invention. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] See also Figure 1-15 The present invention provides a technical solution: a design method of a gallium arsenide optical fiber temperature sensor. Material selection and pretreatment A 125μm-thick, 200×200μm gallium arsenide wafer was used, coated on both sides with a dielectric transmission film and a high-reflection film. The inner Teflon tubing was plasma-treated to improve adhesion. Adhesion was measured using a Brookfield CP51 viscometer, ensuring that the steel ball test met the 5-second adhesion standard. The outer spiral sleeve was made of Teflon for enhanced flexibility and tangle resistance.

[0017] Fiber end face processing The cut fiber end face is polished to ensure flatness. After cleaning, the end face quality is checked under a high-power microscope to avoid tiny particles affecting the optical coupling efficiency. The specific polishing and cleaning process is as follows: Use a precision fiber cleaver to cut the optical fiber to ensure a smooth cut and reduce the subsequent grinding workload. Inspect the end face after cutting to avoid chipping or tilting. Fix the optical fiber on the grinding fixture with the end face facing down against the grinding pad; use a 15μm diamond grinding wheel for preliminary grinding to remove burrs and unevenness caused by cutting; apply uniform pressure during grinding and move in an 8-shaped trajectory for about 30 seconds; switch to a 5μm alumina grinding wheel and continue grinding for 20 seconds; maintain the same motion trajectory to further reduce surface roughness; inspect the end face with a microscope during this period to ensure there are no obvious scratches; switch to a 1μm silica polishing film, add water for lubrication, and gently grind for 15 seconds; the end face should now have a mirror effect, and the reflected light spot should be uniform and without distortion; wipe the end face in one direction with a dust-free cotton swab soaked in anhydrous ethanol to remove residual abrasive particles; then blow dry with a nitrogen gun to avoid fiber or water stains; place the gallium arsenide wafer on the SET heating table with the transmission film coated side facing up. Illuminate with an AvaLight-DH-S light source and monitor the reflectance spectrum with an AvaSpec-ULS2048XL spectrometer. Adjust the three-dimensional optical platform to align the fiber perpendicularly to the wafer until the reflected light intensity at 880 nm reaches its peak. Apply high-temperature adhesive to secure the wafer and heat to 120°C to accelerate curing. In addition to gluing the wafer and the fiber end face, in another embodiment, micro-electromechanical system technology can be used to batch process the fiber end face grooves and grow quartz films by plasma deposition. The crystal sheet is thinned to about 50 microns using chemical mechanical polishing and accurately placed in the groove using vacuum adsorption. Experimental data shows that this structure has a temperature resolution of up to 0.1K in the range of -50℃ to 300℃, an annual drift of less than 0.5%, and vibration resistance improved by more than 3 times. Compared with traditional gluing methods, the suspended structure shows better repeatability in temperature cycling tests.

[0018] Double-layer tube packaging The inner Teflon tube is provided with a 0.5mm air hole, and high-temperature glue is used to fix the optical fiber and the chip. The outer spiral sleeve is wrapped for protection and enhanced resistance to bending. The packaging process is completed in a vacuum drying oven to avoid the generation of bubbles. The ST optical fiber connector is equipped with a heat shrink tubing to prevent bending damage. During the packaging process, the position of the optical fiber and the gallium arsenide chip is adjusted to be vertically aligned. The light from the light source enters the optical fiber coupler and is coupled into the gallium arsenide chip by the optical fiber. After being absorbed by the gallium arsenide chip, the unabsorbed light is reflected back to the optical fiber. The reflected light is demodulated and analyzed by the spectrometer and the reflection spectrum is displayed on the test software of the spectrometer on the computer. In this process, the position of the optical fiber is adjusted to maximize the peak light intensity of the gallium arsenide reflection spectrum. At this time, the gallium arsenide chip and the optical fiber can be fixed with high-temperature glue. High-temperature glue is added to bond the optical fiber and the gallium arsenide chip for coupling, and the addition is turned on at the same time. The hot stage allows the high-temperature glue to solidify quickly. A Teflon (PTFE) sleeve is used to protect the internal optical fiber. The Teflon tube, optical fiber, and probe temperature sensing point are encapsulated and protected inside with high-temperature glue. The entire encapsulation process is completed in a vacuum drying oven to avoid bubbles inside the temperature probe. The temperature probe has high-pressure resistance. After the internal Teflon tube is encapsulated, a spiral sleeve is added to the outside to strengthen the protection of the internal optical fiber. At the same time, the sensor has good flexibility, which is safe and reliable during installation and use. Finally, a high-temperature resistant heat shrink tube is used to fix the spiral sleeve to the ST optical fiber connector. The internal optical fiber and Teflon tube are completely encapsulated and protected.

[0019] Hardware system construction The main control unit uses an STM32F407, driven by an 880nm light source via an LM2596. Spectral data is transmitted via a 384,000 bps serial port and output via Modbus-RTU protocol on an RS-485 bus. A TVS diode protection circuit prevents surges. During operation, I / O controls the switching of each light source, while an internal DAC (digital-to-analog converter) adjusts the light source output amplitude for adaptive light source control. Internally, the system communicates with the spectrometer via a serial port to obtain spectral data for analysis. Simultaneously, a 485 interface chip is used to communicate with the external system via the RS-485 bus and standard Modbus-RTU protocol to transmit temperature data. Wired transmission options include CAN bus and 4-20 mA analog transmission, which are commonly used in industrial production. Wireless data transmission primarily involves cloud-based data acquisition and display. Locally, the temperature of each channel is displayed on a TFT screen via an SPI interface. In addition to temperature data, it has internal memory that can modify and store device and channel information, such as channel name, product model specifications, channel temperature alarm value, etc.

[0020] Software Process After the system starts, it loads a wavelength-temperature lookup table. The main loop sequentially switches temperature measurement channels, adjusts light source intensity, and collects spectral data. Temperature is calculated based on the reflection peak position, displayed on the TFT screen, and output via the 485 bus. Each channel has a 200ms measurement cycle, with adaptive integration time. After the system hardware is initialized, it first reads the configuration file burned into the ROM. The configuration file mainly calibrates the wavelength-temperature data comparison table. The spectrometer integration time is set according to the demodulated light intensity of the light source signal of the current temperature measurement channel. The spectrometer collects the light signal and demodulates the spectrum data. The data processing program is called to obtain the wavelength signal from the spectrum data, and the temperature signal corresponding to the current wavelength is found according to the wavelength lookup table. The temperature signal is displayed on the LCD screen, and then the system switches to the next channel. The temperature value of each channel is measured in this cycle.

[0021] Performance Verification Tests show that the sensor has a temperature measurement range of -40°C to 180°C in an oil-immersion environment with a resolution of 0.1K. Its annual drift is less than 0.3%, and its tolerance to 50Hz magnetic field interference is within ±0.5°C. The spiral sleeve structure allows for a minimum bending radius of 15mm, meeting transformer winding installation requirements.

[0022] Application deployment Sensors are connected to the temperature measurement system via ST connectors and placed along the gaps between transformer windings. A 485 bus connects to a host computer for real-time monitoring of hotspot temperatures. Long-term operating data can be stored and analyzed on a cloud platform, providing a basis for insulation aging assessment.

Claims

1. A design method for a gallium arsenide optical fiber temperature sensor, characterized in that: The following steps are involved: S1: Select the materials for the GaAs fiber optic temperature sensor, which mainly includes ST fiber optic connector, light guide fiber, GaAs temperature probe, inner Teflon tube and outer spiral sleeve; S2: Design the overall structure of the GaAs fiber optic temperature sensor; S3: Encapsulating the GaAs chip in the GaAs temperature probe; S4: Encapsulate the GaAs temperature probe; S5: Build a GaAs fiber optic temperature measurement system; S6: Build the hardware framework of the GaAs fiber optic temperature measurement system; S7: Design the hardware circuit and communication structure of the GaAs fiber optic temperature measurement system; S8: Design software for GaAs fiber optic temperature measurement system.

2. The design method of a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In S1, the inner Teflon tube is a protective sleeve, and its surface is treated so that it can be bonded with glue. The treatment method of the inner Teflon tube is one or more of polytetrafluoroethylene plasma method, radiation grafting method, laser treatment method, ion beam implantation method, high-temperature melting method, electrolytic reduction method and mechanochemical treatment method. After the inner Teflon tube is surface treated, its adhesiveness is measured to ensure that it meets the treatment requirements and achieves the purpose of stable and firm bonding. The adhesiveness is measured using a rotational or titration viscometer (such as Brookfield CP51). The appropriate model is selected according to the type of glue and viscosity range. The instrument needs to be calibrated before measurement, and the sample temperature is adjusted to the standard value (such as 25°C) to ensure the accuracy of the viscosity change with temperature. When measuring the adhesiveness, a part is cut with a tool and vertically pasted on a test plate inclined at 30°. Steel balls of different sizes are used to roll down freely, and the maximum steel ball number that the sample can adhere to for more than 5 seconds is recorded as the initial adhesiveness value. This method is simple and complies with national standards.

3. The design method of a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In S1, the GaAs chip used in the GaAs temperature probe adopts a reflective probe structure. Incident light passes through the GaAs chip twice and is absorbed twice. Therefore, the thickness of the GaAs chip is halved. A GaAs chip with a thickness of 125 μm can achieve the best performance in this design. The GaAs chip is slightly larger than 200*200 μm. The large chip area makes it easier to bond and couple the optical fiber to the chip, and the packaging of the temperature probe is more reliable.

4. The design method of a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In the S2, the gallium arsenide wafer is coated with a dielectric transmission film and a dielectric high-reflection film on both sides, respectively. When packaging the probe, care should be taken to ensure that the optical fiber contacts the side coated with the transmission film. The ST optical fiber connector has an insertion loss of <0.3 dB and complies with the IEC 874-10 standard. The connection method is a keyed bayonet-type locking structure, which facilitates quick installation. To ensure that the sensor is not damaged during transportation, use, and installation, a heat shrink tubing is added to one end of the ST connector to prevent collisions or excessive bending that may cause internal optical fiber breakage. The entire optical cable is protected by a double-layer tubing. The outermost layer is a Teflon spiral tubing, which is wrapped around the outside of the first layer of protective tubing. It can further protect the internal optical fiber, enhance the flexibility of the entire sensor, and effectively prevent the sensor from entanglement and knotting. The innermost layer is a Teflon tube, which is soft in texture and has small holes on it, making it breathable and water-permeable. When measuring some water or oil temperatures, the sensor will not float up. High-temperature glue is used to directly vertically couple the gallium arsenide temperature sensor chip with the optical fiber and bond them together. Then, the gallium arsenide chip and the end of the Teflon sleeve are also fixed with high-temperature glue to prevent the gallium arsenide chip from falling off during use; at the same time, the internal optical fiber is also bonded and fixed to the Teflon tube to avoid the sensor breaking during pulling.

5. The method for designing a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In S4, the bare fiber end face needs to be processed before packaging the gallium arsenide wafer. For the newly cut optical fiber, the end face is often uneven. The end face grinding method grinds the end face of the cut optical fiber. After grinding, there will still be tiny particles on the optical fiber end face, so it needs to be cleaned. The packaging platform of GaAs wafer mainly includes reflection spectrum test optical path, optical adjustment platform, heating platform, fiber microscope system and LCD display. The optical adjustment platform is mainly used to adjust the relative position of optical fiber and GaAs wafer. The optical platform can be adjusted in three dimensions and can accurately adjust the position of optical fiber and wafer in the x, y and z directions, so that the incident light can be coupled into the GaAs wafer as much as possible. At the same time, the reflected light absorbed by the GaAs wafer can be vertically coupled into the optical fiber. The heating platform is a SET high-precision digital display constant temperature heating table with a heating range of 30℃~350℃, which is used for curing and heating of high-temperature glue. Since the glue takes a long time to cure at room temperature, heating to an appropriate temperature can shorten the curing time and improve the packaging efficiency. The monitoring lens is a high-power microscope. The lens is connected to the LCD display to monitor the packaging. The screen is clearly observed, and the relative position of the gallium arsenide chip and the optical fiber is fine-tuned by observing the monitoring screen to align the optical fiber vertically with the chip. The light source is a deep ultraviolet deuterium-halogen tungsten lamp light source of model AvaLight-DH-S. The halogen tungsten lamp light source can provide a continuous band from 360nm to 2500nm. It is known that the absorption band of gallium arsenide is near-infrared, which can meet the coverage range of the absorption band. The working life of the halogen tungsten lamp light source is up to 1000 hours, which is suitable for long-term packaging experiments. The spectrometer model is AvaSpec-ULS2048XL. This spectrum analyzer uses a CCD detector, a 2048-pixel linear array, and a pixel height of 500μm. The spectrometer is equipped with USB2.0 and RS-232 interfaces on the peripherals, which are convenient for connection to a computer and combined with the host computer software to collect and analyze spectral data.

6. The method for designing a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In S4, a temperature probe packaging experimental platform is constructed, power switches of various experimental devices are turned on, optical path parts are connected, and a gallium arsenide wafer is placed on the heating platform with the side coated with the anti-reflection film facing upward.

7. The method for designing a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In the S5, the gallium arsenide fiber optic temperature measurement system mainly includes: a main control unit, a light source driving module, an optical fiber optical path system, a spectrum detection device, and an external output module; the main control unit is the control core of the entire system, responsible for the control of the light source and the demodulation of the spectrum information and the output of the temperature information; the light source driving module is used to light the light source in sequence and the adaptive adjustment of each light source; the optical fiber optical path system is mainly used for the transmission of the light path, the incident light of the light source and the reflected light of the gallium arsenide crystal; the spectrum detection device mainly performs photoelectric conversion on the reflected spectrum of the temperature probe, and transmits the converted information to the main control unit for analysis.

8. The method for designing a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In the S6, the main control unit is the core part of the entire system. The temperature measurement system uses an STM32 microcontroller with an ARM architecture as the core as the main control.

9. The method for designing a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In S7, a light source driving circuit is designed. The light source of this design selects a light source with a central wavelength of 880 nm and a spectral range of 320 nm to 1440 nm. The light source can be directly driven by DC power and uses an LM2596 voltage regulator chip. The voltage is adjusted in conjunction with the DAC function of the microcontroller. The light intensity amplitude of each light source can be adjusted. At the same time, the switch of each light source is controlled by switching the I / O, achieving the requirement of adaptive adjustment of the light source. For the collection of internal spectral information, the serial port is used directly for collection, and a baud rate of 384000, which is higher than the conventional baud rate, is used to improve data transmission efficiency and speed up the collection and processing speed of the system. RS-485 is selected, and the transmission end of the RS-485 bus must be protected. While using an isolation chip, a TVS diode is added to the circuit design. When the two ends of the diode are subjected to a reverse transient high-energy impact, the diode can change the high impedance between the two poles to low impedance at a speed of 10-12 seconds, absorb up to several kilowatts of surge power, stabilize the voltage between the two poles at a fixed value, and effectively protect the devices in the subsequent circuit.

10. The method for designing a gallium arsenide optical fiber temperature sensor according to claim 1, characterized in that: In the S8, the system main process mainly manages three modules, namely the UART communication module, the USB communication module, and the LCD display module; the main process enters the main loop program after startup, the main control board and the light source driver board communicate through the UART serial port, control the light source on the light source driver board, and light up the light source channel through the GPIO on the main control board; the spectrometer receives the reflected light signal of the sensor, the main control board sends a command through the USB interface, controls the spectrometer to demodulate the spectral data, and calls the temperature-wavelength algorithm relationship, demodulates the temperature value according to the read spectral data, and displays the temperature value through the LCD screen. This process is cyclically performed after the system starts running, and the temperature signal is demodulated in real time; During the acquisition process, the temperature measurement system has multiple temperature measurement channels. After the main control unit selects a channel, it needs to collect and analyze the gallium arsenide reflectance spectrum data to realize the system temperature measurement function.

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