A low-noise direct-current temperature control system for an SLD light source of an optical fiber gyroscope and a control method thereof

Abstract

The application relates to a low-noise direct-current temperature control system for an SLD light source of an optical fiber gyroscope and a control method thereof, and the system comprises a thermistor acquisition module, an ambient temperature sensor, a main control module, a digital-analog converter and a direct-current temperature control circuit; the thermistor acquisition module is used for acquiring the resistance value of a thermistor; the ambient temperature sensor is used for collecting ambient temperature; the main control module internally integrates a temperature compensation unit, can dynamically adjust a temperature control set point according to pre-stored full-temperature test data, and comprehensively processes data from the thermistor and the ambient temperature sensor to generate a digital control signal; the digital-analog converter is responsible for converting the digital signal into an analog voltage; the direct-current temperature control circuit is used for receiving the digital control signal and outputting a temperature control current, and the semiconductor refrigerator is used for temperature control of a light-emitting diode chip according to the temperature control current. Compared with the prior art, the application significantly improves the anti-interference ability and the optical fiber gyroscope precision.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensing and optoelectronic device temperature control technology, and in particular to a low-noise DC temperature control system and control method for fiber optic gyroscope SLD light sources. Background Technology

[0002] Superluminescent diodes (SLDs) are commonly used light sources in fiber optic gyroscopes. Due to their strong temperature dependence, stable operation of fiber optic gyroscopes requires a good match between the light source and the temperature control circuit. The SLD light source mainly consists of a light-emitting diode die, a thermoelectric cooler (TEC), a thermistor, a heat sink, and an optocoupler. Changes in the light emission from the diode or in the ambient temperature first alter the resistance of the thermistor. This thermistor, along with three resistors of the same resistance, forms an H-type resistor network. Changes in the thermistor's resistance change the voltage difference across this network. This voltage difference is then output to the temperature control chip's controller via a PID circuit. The controller then uses PWM (Pulse Width Modulation) and inductor filtering to control the magnitude and direction of the current applied to the TEC. Assuming the voltage difference caused by an increase in the thermistor's resistance is positive, the polarity of the temperature control current applied to the TEC by the PWM signal generated by the PID controller should be such that it reduces the thermistor's resistance, and the magnitude of this current should match the magnitude of the reduction in the thermistor's resistance caused by the TEC.

[0003] Commonly used temperature control chips include the MAX1978, which integrates an H-bridge circuit, and the ADN8830, which requires an external H-bridge circuit. The chip-based solution is mature and widely used in typical fiber optic gyroscope solutions. However, with the miniaturization and integration of fiber optic gyroscopes, the noise generated by the PWM method of the MAX1978 / ADN8830 is increasingly interfering with the gyroscope system signal. For example, patent application CN210128717U discloses a light-emitting diode (LED) temperature control device for fiber optic gyroscopes based on the ADN8835. This device uses a voltage divider circuit composed of a voltage divider resistor and a thermistor to collect the light source temperature and utilizes the PWM control module and H-bridge drive circuit inside the ADN8835 chip to control the magnitude and direction of the TEC current via PWM to achieve rapid and stable control of the light source temperature. This device still relies on PWM switching modulation to drive the TEC, failing to solve the problem of electromagnetic interference from high-frequency PWM signals and their harmonics to integrated fiber optic gyroscope systems. In particular, for three-in-one integrated devices (SLD light source, coupler, and detector) and four-in-one integrated devices (SLD light source, coupler, detector, and Y waveguide), the integrated devices mean that the spatial distance between the TEC temperature control pin and the detector output pin is very close. The PWM signal will inevitably interfere with the detector signal, which greatly reduces the accuracy of the fiber optic gyroscope in the current integrated solution. Therefore, there is an urgent need for a low-noise temperature control method to adapt to the current miniaturized / integrated fiber optic gyroscope solution.

[0004] Furthermore, since the thermistor forms an H-type resistor network with a resistor of fixed resistance, and although the thermistor is placed close to the light source chip, its temperature still deviates from the chip temperature. This is especially noticeable during full-temperature testing, where the difference in output wavelength between high and low temperatures is greatest. The relationship between the light source output wavelength and temperature change during constant temperature control is as follows: Figure 1 As shown, the output wavelength is 1309.37 nm at a low temperature of -40℃, and 1308.94 nm at a high temperature of +70℃, a wavelength change of 0.43 nm. For semiconductor lasers, the wavelength temperature drift coefficient is generally 0.1 nm / ℃, thus it can be deduced that the temperature of the light source die changes by about 4.3℃. Furthermore, the output wavelength is longer at low temperatures (due to increased die temperature) and shorter at high temperatures (due to decreased die temperature). This indicates a discrepancy between the temperature represented by the thermistor and the die temperature. Overheating at low temperatures leads to a higher die temperature and a longer wavelength, while overcooling at high temperatures leads to a lower die temperature and a shorter wavelength. Important indicators of fiber optic gyroscopes, such as zero-bias stability and scaling factor, are closely related to wavelength. Therefore, a solution is needed that can adjust the temperature control point according to the actual temperature based on the light source characteristics. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a low-noise DC temperature control system and its control method for fiber optic gyroscope SLD light sources, which significantly improves anti-interference capability and fiber optic gyroscope accuracy.

[0006] The objective of this invention can be achieved through the following technical solutions: A low-noise DC temperature control system for a fiber optic gyroscope SLD light source, wherein the fiber optic gyroscope SLD light source includes a light-emitting diode die, a semiconductor cooler, a thermistor, a heat sink, and an optical coupling component; the low-noise DC temperature control system includes a thermistor acquisition module, an ambient temperature sensor, a main control module, a digital-to-analog converter, and a DC temperature control circuit. The thermistor acquisition module is used to acquire the resistance value of the thermistor, and its output terminal is connected to the main control module through an SPI digital interface; The ambient temperature sensor is used to collect ambient temperature, and its output is connected to the main control module through a general-purpose I / O interface; The main control module is used to receive the resistance value of the thermistor and the ambient temperature. It integrates a temperature compensation unit, which dynamically adjusts the temperature control setpoint based on the pre-stored full-temperature test data and generates corresponding digital control signals according to the data from the thermistor acquisition module and the ambient temperature sensor. The digital-to-analog converter is connected to the main control module and is used to receive the digital control signal and convert it into a corresponding analog voltage. The DC temperature control circuit is used to receive the digital control signal output by the main control module and output a temperature control current, and to control the temperature of the light-emitting diode die through the semiconductor cooler according to the temperature control current.

[0007] Furthermore, the DC temperature control circuit includes a full-bridge circuit and a constant current source circuit. The full-bridge circuit is connected to the semiconductor cooler, with PMOS transistors Q1 and Q2 as its upper half-bridge and NMOS transistors Q3 and Q4 as its lower half-bridge. The NMOS transistor Q3 is connected to a first constant current source circuit, which includes an operational amplifier U1 and a resistor R1. The NMOS transistor Q4 is connected to a second constant current source circuit, which includes an operational amplifier U2 and a resistor R2.

[0008] Furthermore, the DC temperature control circuit is equipped with logic control switches for controlling the conduction and cutoff of each transistor, including logic control switch S1 and logic control switch S2.

[0009] According to another aspect of the present invention, a control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source is provided. The fiber optic gyroscope SLD light source includes a light-emitting diode chip, a semiconductor cooler, a thermistor, a heat sink, and an optical coupling component. The method for temperature control of the fiber optic gyroscope SLD light source using the low-noise DC temperature control system described above includes the following steps: The resistance value of the thermistor is acquired in real time by the thermistor acquisition module; Ambient temperature is collected in real time using an ambient temperature sensor; The main control module receives the resistance value of the thermistor and the ambient temperature, and the temperature compensation unit dynamically adjusts the temperature control setpoint based on the pre-stored full-temperature test data. It also generates corresponding digital control signals based on the data from the thermistor acquisition module and the ambient temperature sensor. The DC temperature control circuit receives the digital control signal output by the main control module and outputs a temperature control current. Based on the temperature control current, the semiconductor cooler controls the temperature of the light-emitting diode die.

[0010] Furthermore, the digital control signal includes a direction control signal and a current setting signal. The direction control signal is a digital logic level signal, including a first control signal K1 and a second control signal K2.

[0011] Furthermore, the digital-to-analog converter converts the received current setting signal into a corresponding analog voltage, which is matched with the magnitude of the temperature control current.

[0012] Furthermore, based on the direction control signal, the corresponding transistors in the full-bridge circuit are turned on and off via a logic control switch, thereby changing the direction of the current flowing through the semiconductor cooler.

[0013] Furthermore, the specific steps of controlling the conduction and cutoff of the corresponding transistors in the full-bridge circuit through a logic control switch according to the direction control signal, thereby changing the direction of the current flowing through the semiconductor cooler, include: When the first control signal K1 is low and the second control signal K2 is high, PMOS transistor Q1 is turned on, logic control switch S1 is turned off, NMOS transistor Q3 is turned off, the current of the first constant current source circuit connected to NMOS transistor Q3 is zero, PMOS transistor Q2 is turned off, logic control switch S2 is closed, NMOS transistor Q4 is turned on, and the direction of the current flowing through the semiconductor cooler is from PMOS transistor Q1 through the semiconductor cooler to NMOS transistor Q4; When the first control signal K1 is high and the second control signal K2 is low, PMOS transistor Q2 is turned on, logic control switch S2 is turned off, NMOS transistor Q4 is turned off, the current of the second constant current source circuit connected to NMOS transistor Q4 is zero, PMOS transistor Q1 is turned off, logic control switch S1 is closed, NMOS transistor Q3 is turned on, and the direction of the current flowing through the semiconductor cooler is from PMOS transistor Q2 through the semiconductor cooler to NMOS transistor Q3.

[0014] Furthermore, the temperature control current is obtained by a DC temperature control circuit based on the direction control signal. When the first control signal K1 is low and the second control signal K2 is high, the temperature control current is: When the first control signal K1 is high and the second control signal K2 is low, the temperature control current is: In the formula, For temperature control current, For analog voltage, The resistor in the first constant current source circuit. This is the resistor in the second constant current source circuit.

[0015] Furthermore, during the process of dynamically adjusting the temperature control setpoint based on the pre-stored full-temperature test data by the temperature compensation unit, the temperature control setpoint is dynamically adjusted by calling the temperature compensation mathematical model and temperature compensation parameters based on the ambient temperature collected by the ambient temperature sensor and the pre-stored full-temperature test data.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention utilizes a digital-to-analog converter to convert digital control signals into analog voltages, and combines this with a DC temperature control circuit to output a smooth DC temperature control current. This avoids high-frequency harmonics and electromagnetic interference generated by traditional PWM control methods from the source, and solves the problem of switching noise coupling and signal purity reduction caused by the close proximity of the temperature control pins of the semiconductor cooler and the detector pins in the miniaturization / integration design of fiber optic gyroscopes. This significantly improves the anti-interference capability and the accuracy of fiber optic gyroscopes.

[0017] 2. This invention integrates a temperature compensation unit within the main control module. Based on pre-stored full-temperature test data and real-time acquisition of ambient temperature, it dynamically adjusts the temperature control setpoint to compensate for the actual temperature deviation between the thermistor and the LED chip. This solves the problem of output wavelength drift caused by chip temperature inaccuracy in the full temperature range in existing technologies, and effectively improves the wavelength stability of the SLD light source in the full temperature range. Attached Figure Description

[0018] Figure 1 A schematic diagram showing the change in the output wavelength of the light source with temperature when the temperature is controlled at a constant temperature point; Figure 2 This is a schematic diagram of the low-noise DC temperature control system for fiber optic gyroscope SLD light source proposed in this invention. Figure 3 This is a flowchart illustrating the control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source proposed in this invention. Figure 4 This is a schematic diagram showing the direction of current flowing through the semiconductor cooler when the first control signal K1 is low and the second control signal K2 is high. Figure 5 This is a schematic diagram showing the direction of current flowing through the semiconductor cooler when the first control signal K1 is high and the second control signal K2 is low.

[0019] Legend: 1. Thermistor acquisition module; 2. Ambient temperature sensor; 3. Main control module; 4. Digital-to-analog converter; 5. DC temperature control circuit. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0021] The following English abbreviations are involved: Super Luminescent Diode (SLD) Thermoelectric Cooler (TEC) Example 1 This embodiment provides a low-noise DC temperature control system for a fiber optic gyroscope SLD light source. The fiber optic gyroscope SLD light source includes a light-emitting diode die, a semiconductor cooler, a thermistor, a heat sink, and an optical coupling component.

[0022] Existing temperature control chips (such as MAX1978 or ADN8830) use PWM to control the semiconductor cooler. PWM regulates the average current through rapid switching, but this generates high-frequency harmonics and electromagnetic interference. In the miniaturization / integration design of fiber optic gyroscopes, the TEC temperature control pin is very close to the detector output pin. PWM control regulates the average TEC current through rapid switching, and its steep current steps generate abundant high-frequency harmonics. This PWM noise interferes with the signal of nearby detectors through spatial radiation or wire coupling, leading to a decrease in accuracy. This invention, however, converts the digital control signal into a smooth analog voltage using a digital-to-analog converter, and then outputs a continuous, non-abrupt DC current through a constant current source circuit. This current waveform has no high-frequency components, fundamentally avoiding the generation of electromagnetic interference. To achieve adjustable direction and magnitude of the DC temperature control current, a full-bridge circuit is combined with a constant current source circuit, such as... Figure 2 As shown, the low-noise DC temperature control system includes a thermistor acquisition module 1, an ambient temperature sensor 2, a main control module 3, a digital-to-analog converter 4, and a DC temperature control circuit 5. The thermistor acquisition module 1 is used to acquire the resistance value of the thermistor, and its output terminal is connected to the main control module 3 through an SPI digital interface. The ambient temperature sensor 2 is used to acquire the ambient temperature, and its output terminal is connected to the main control module 3 through a general-purpose I / O interface. The main control module 3 is used to receive data from the thermistor acquisition module 1 and the ambient temperature sensor 2. It integrates a temperature compensation unit, which dynamically adjusts the temperature control setpoint based on pre-stored full-temperature test data and generates corresponding digital control signals according to the data from the thermistor acquisition module 1 and the ambient temperature sensor 2. The digital-to-analog converter 4 is connected to the main control module 3 and is used to receive the digital control signals and convert them into corresponding analog voltages. The DC temperature control circuit 5 is used to receive the digital control signals output by the main control module 3 and output a temperature control current. Based on the temperature control current, the temperature of the LED chip is controlled by a semiconductor cooler.

[0023] The DC temperature control circuit 5 includes a full-bridge circuit and a constant current source circuit. The full-bridge circuit is connected to the semiconductor cooler, with PMOS transistors Q1 and Q2 as its upper half-bridge and NMOS transistors Q3 and Q4 as its lower half-bridge. NMOS transistor Q3 is connected to the first constant current source circuit, which includes operational amplifier U1 and resistor R1. NMOS transistor Q4 is connected to the second constant current source circuit, which includes operational amplifier U2 and resistor R2.

[0024] The DC temperature control circuit 5 is equipped with logic control switches to control the conduction and cutoff of each transistor, including logic control switch S1 and logic control switch S2.

[0025] Example 2 This embodiment provides a control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source. The fiber optic gyroscope SLD light source includes a light-emitting diode chip, a semiconductor cooler, a thermistor, a heat sink, and an optical coupling component. The low-noise DC temperature control system for the fiber optic gyroscope SLD light source, as provided in Embodiment 1, is used to control the temperature of the fiber optic gyroscope SLD light source. Figure 3 As shown, it includes the following steps: S1. The resistance value of the thermistor is collected in real time through the thermistor acquisition module 1.

[0026] Thermistors are typically mounted directly near the LED die, providing the most direct reflection of its actual temperature changes. Thermistor acquisition module 1 can use an ADS1220 to acquire the resistance value of the thermistor.

[0027] S2. The ambient temperature is collected in real time by ambient temperature sensor 2.

[0028] Ambient temperature is the main interference factor affecting the thermal load and final stability point of the temperature control system. Ambient temperature sensor 2 can be a DS18B20 to collect ambient temperature in real time.

[0029] S3. The main control module 3 receives the resistance value of the thermistor and the ambient temperature, and the temperature compensation unit dynamically adjusts the temperature control setpoint based on the pre-stored full-temperature test data, and generates corresponding digital control signals according to the resistance value of the thermistor and the ambient temperature.

[0030] The main control module 3 can use an FPGA or ARM to process the digital control signals in the temperature control process. Through its integrated SPI interface, the main control module reads data from the thermistor acquisition module 1 in real time. This data reflects the current resistance value of the thermistor inside the SLD light source. Simultaneously, the main control module 3 uses a single bus or I / O... 2 The C interface reads the current ambient temperature value measured by ambient temperature sensor 2.

[0031] Since temperature control is performed entirely digitally within the main control module 3, and considering the over-temperature control phenomenon observed in the wavelength response of the light source during full-temperature testing, a wavelength temperature compensation mechanism can be easily established within the main control chip. This improves the wavelength stability of the fiber optic gyroscope across all temperatures, and the entire temperature compensation process requires no modification or adjustment to the hardware. During the dynamic adjustment of the temperature control setpoint based on pre-stored full-temperature test data by the temperature compensation unit, the ambient temperature sensor 2 collects the ambient temperature. The temperature compensation unit then uses this data to dynamically adjust the temperature control setpoint by calling the temperature compensation mathematical model and parameters. This compensates for the deviation between the actual temperature of the LED chip and the temperature measured by the thermistor caused by changes in ambient temperature, resulting in a higher temperature control effect with greater output wavelength stability.

[0032] The steps for constructing the temperature compensation mathematical model and temperature compensation parameters include: Under the fixed temperature point temperature control mode, the fiber optic gyroscope SLD light source was tested across the entire temperature range to obtain data on the relationship between the output wavelength of the light source and the ambient temperature. The offset of the light source output wavelength is converted into a deviation matrix of the thermistor resistance value over the entire temperature range. This matrix contains the mapping relationship between ambient temperature and the thermistor measurement deviation. Based on the thermistor resistance deviation matrix and ambient temperature data, a temperature compensation mathematical model is constructed to describe the relationship between the thermistor's measured temperature and the actual core temperature deviation, and the corresponding temperature compensation parameters are calculated.

[0033] The temperature compensation unit inside the main control module 3 is activated. This unit takes the real-time ambient temperature value as input and queries the thermistor deviation matrix pre-stored in the main control module 3. Subsequently, the temperature compensation unit calculates a real-time temperature compensation parameter based on the built-in mathematical model.

[0034] The calculated temperature compensation parameters are superimposed on the initial target temperature control setpoint of the system to generate a new, dynamically corrected temperature control setpoint. This step aims to offset the wavelength drift caused by the difference between the actual temperature of the thermistor and the light source die across the entire temperature range.

[0035] The main control module 3 converts the resistance value of the thermistor into the currently measured temperature value, then calculates the temperature deviation between the current temperature value and the temperature control setpoint, and sends this temperature deviation into the digital PID control algorithm implemented inside the main control module 3. After calculation, a comprehensive control quantity is output.

[0036] The comprehensive control quantity is analyzed into two specific types of digital control signals, including direction control signals and current setting signals.

[0037] The direction control signal is a digital logic level signal. Based on the positive and negative polarities of the control quantity, a first control signal K1 and a second control signal K2 are generated and directly output to the H-bridge of the DC temperature control circuit to control the direction of the current flowing through the TEC.

[0038] The digital-to-analog converter 4 converts the received current setting signal into a corresponding analog voltage, which is matched to the magnitude of the temperature control current. This is achieved via SPI / I... 2 Small DACs with a C interface can adjust the magnitude of temperature-controlled current by changing the analog voltage, such as the DAC8551.

[0039] S4. The DC temperature control circuit 5 receives the digital control signal output by the main control module 3 and outputs the temperature control current. Based on the temperature control current, the semiconductor cooler controls the temperature of the LED chip.

[0040] Based on the direction control signal, the logic control switch controls the on and off of the corresponding transistors in the full-bridge circuit, thereby changing the direction of the current flowing through the thermoelectric cooler. The specific steps include: like Figure 4 As shown, when the first control signal K1 is low and the second control signal K2 is high, PMOS transistor Q1 is turned on, logic control switch S1 is turned off, NMOS transistor Q3 is turned off, the current in the first constant current source circuit connected to NMOS transistor Q3 is zero, PMOS transistor Q2 is turned off, logic control switch S2 is closed, and NMOS transistor Q4 is turned on. The direction of the current flowing through the thermoelectric cooler is from PMOS transistor Q1 through the thermoelectric cooler to NMOS transistor Q4. This current in this direction causes the TEC to cool the attached light-emitting diode die.

[0041] like Figure 5 As shown, when the first control signal K1 is high and the second control signal K2 is low, PMOS transistor Q2 is turned on, logic control switch S2 is turned off, NMOS transistor Q4 is turned off, the current in the second constant current source circuit connected to NMOS transistor Q4 is zero, PMOS transistor Q1 is turned off, logic control switch S1 is closed, NMOS transistor Q3 is turned on, and the direction of the current flowing through the thermoelectric cooler is from PMOS transistor Q2 through the thermoelectric cooler to NMOS transistor Q3. This current in this direction causes the TEC to heat the attached LED die.

[0042] The temperature control current is obtained through the DC temperature control circuit 5 based on the direction control signal.

[0043] When the first control signal K1 is low and the second control signal K2 is high, the temperature control current is: When the first control signal K1 is high and the second control signal K2 is low, the temperature control current is: In the formula, For temperature control current, For analog voltage, The resistor in the first constant current source circuit. This is the resistor in the second constant current source circuit.

[0044] By using two sets of resistors, R1 and R2, different maximum current limits can be set for the cooling and heating modes, allowing for independent configuration based on the efficiency of cooling and heating.

[0045] This precise control over the direction and magnitude of the current ensures that the LED chip temperature can quickly and stably reach and maintain the target set point, meeting the stringent requirements of fiber optic gyroscopes for light source stability. The rest is the same as in Example 1.

[0046] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A low-noise DC temperature control system for a fiber optic gyroscope SLD light source, the fiber optic gyroscope SLD light source comprising a light-emitting diode die, a semiconductor cooler, a thermistor, a heat sink, and an optical coupling component, characterized in that, The low-noise DC temperature control system includes a thermistor acquisition module (1), an ambient temperature sensor (2), a main control module (3), a digital-to-analog converter (4), and a DC temperature control circuit (5). The thermistor acquisition module (1) is used to acquire the resistance value of the thermistor, and its output terminal is connected to the main control module (3) through the SPI digital interface; The ambient temperature sensor (2) is used to collect ambient temperature, and its output is connected to the main control module (3) through a general I / O interface; The main control module (3) is used to receive the resistance value of the thermistor and the ambient temperature. It integrates a temperature compensation unit, which dynamically adjusts the temperature control set point based on the pre-stored full-temperature test data and generates corresponding digital control signals according to the data of the thermistor acquisition module (1) and the ambient temperature sensor (2). The digital-to-analog converter (4) is signal-connected to the main control module (3) and is used to receive the digital control signal and convert it into the corresponding analog voltage; The DC temperature control circuit (5) is used to receive the digital control signal output by the main control module (3) and output the temperature control current, and control the temperature of the light-emitting diode die through the semiconductor cooler according to the temperature control current.

2. The low-noise DC temperature control system for fiber optic gyroscope SLD light source according to claim 1, characterized in that, The DC temperature control circuit (5) includes a full-bridge circuit and a constant current source circuit. The full-bridge circuit is connected to the semiconductor cooler, with PMOS transistors Q1 and Q2 as its upper half-bridge and NMOS transistors Q3 and Q4 as its lower half-bridge. The NMOS transistor Q3 is connected to a first constant current source circuit, which includes an operational amplifier U1 and a resistor R1. The NMOS transistor Q4 is connected to a second constant current source circuit, which includes an operational amplifier U2 and a resistor R2.

3. The low-noise DC temperature control system for fiber optic gyroscope SLD light source according to claim 2, characterized in that, The DC temperature control circuit (5) is equipped with logic control switches for controlling the conduction and cutoff of each transistor, including logic control switch S1 and logic control switch S2.

4. A control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source, wherein the fiber optic gyroscope SLD light source includes a light-emitting diode die, a semiconductor cooler, a thermistor, a heat sink, and an optical coupling component, and the low-noise DC temperature control system for a fiber optic gyroscope SLD light source as described in claim 3 is used to control the temperature of the fiber optic gyroscope SLD light source, characterized in that... Includes the following steps: The resistance value of the thermistor is acquired in real time by the thermistor acquisition module (1); The ambient temperature is collected in real time by an ambient temperature sensor (2); The main control module (3) receives the resistance value of the thermistor and the ambient temperature, and the temperature compensation unit dynamically adjusts the temperature control set point based on the pre-stored full-temperature test data. It also generates corresponding digital control signals based on the data from the thermistor acquisition module (1) and the ambient temperature sensor (2). The DC temperature control circuit (5) receives the digital control signal output by the main control module (3) and outputs a temperature control current. The temperature control current is used to control the temperature of the light-emitting diode chip through the semiconductor cooler.

5. The control method for the low-noise DC temperature control system for a fiber optic gyroscope SLD light source according to claim 4, characterized in that, The digital control signal includes a direction control signal and a current setting signal. The direction control signal is a digital logic level signal, including a first control signal K1 and a second control signal K2.

6. The control method for the low-noise DC temperature control system for a fiber optic gyroscope SLD light source according to claim 5, characterized in that, The digital-to-analog converter (4) converts the received current setting signal into a corresponding analog voltage, which is matched with the magnitude of the temperature control current.

7. The control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source according to claim 6, characterized in that, According to the direction control signal, the corresponding transistors in the full-bridge circuit are turned on and off by a logic control switch, thereby changing the direction of the current flowing through the semiconductor cooler.

8. The control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source according to claim 7, characterized in that, The specific steps for changing the direction of the current flowing through the semiconductor cooler by controlling the on and off of the corresponding transistors in the full-bridge circuit through a logic control switch according to the direction control signal include: When the first control signal K1 is low and the second control signal K2 is high, PMOS transistor Q1 is turned on, logic control switch S1 is turned off, NMOS transistor Q3 is turned off, the current of the first constant current source circuit connected to NMOS transistor Q3 is zero, PMOS transistor Q2 is turned off, logic control switch S2 is closed, NMOS transistor Q4 is turned on, and the direction of the current flowing through the semiconductor cooler is from PMOS transistor Q1 through the semiconductor cooler to NMOS transistor Q4; When the first control signal K1 is high and the second control signal K2 is low, PMOS transistor Q2 is turned on, logic control switch S2 is turned off, NMOS transistor Q4 is turned off, the current of the second constant current source circuit connected to NMOS transistor Q4 is zero, PMOS transistor Q1 is turned off, logic control switch S1 is closed, NMOS transistor Q3 is turned on, and the direction of the current flowing through the semiconductor cooler is from PMOS transistor Q2 through the semiconductor cooler to NMOS transistor Q3.

9. The control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source according to claim 4, characterized in that, The temperature control current is obtained by the DC temperature control circuit (5) according to the direction control signal. When the first control signal K1 is low and the second control signal K2 is high, the temperature control current is: When the first control signal K1 is high and the second control signal K2 is low, the temperature control current is: In the formula, For temperature control current, For analog voltage, The resistor in the first constant current source circuit. This is the resistor in the second constant current source circuit.

10. The control method for a low-noise DC temperature control system for a fiber optic gyroscope SLD light source according to claim 4, characterized in that, During the process of dynamically adjusting the temperature control setpoint based on the pre-stored full-temperature test data by the temperature compensation unit, the temperature control setpoint is dynamically adjusted by calling the temperature compensation mathematical model and temperature compensation parameters based on the ambient temperature collected by the ambient temperature sensor (2) and the pre-stored full-temperature test data.

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