Method, device and system for measuring temperature coefficient of avalanche voltage of avalanche photodiode

Abstract

The application discloses a kind of avalanche photodiode avalanche voltage temperature coefficient measurement method, device and system, including the initial bias voltage and initial operating temperature of initialization avalanche photodiode, and the initial voltage amplitude after receiving optical signal of reference optical fiber in constant-temperature water bath device is obtained;The operating temperature of avalanche photodiode is adjusted to target operating temperature;At target operating temperature, the voltage amplitude of reference optical fiber is restored to initial voltage amplitude by adjusting bias voltage, and the adjusted bias voltage is obtained;According to the adjusted bias voltage, initial bias voltage, initial operating temperature and target operating temperature, the avalanche voltage temperature coefficient of current temperature interval is obtained.The voltage amplitude of reference optical fiber placed in constant-temperature zone is used as reference by using existing conventional DTS system, bias voltage is dynamically adjusted, it is separated from additional constant-temperature experiment box and independent calibration test tool, without designing additional hardware and software algorithm, it is realized in system measurement and compensation.

Description

Technical Field

[0001] This invention relates to the fields of optical communication and optical sensing technology, and in particular to a method, apparatus and system for measuring the temperature coefficient of avalanche voltage of an avalanche photodiode. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Avalanche photonic diodes (APDs) are optical devices frequently used in optical communication and optical sensing. Due to their avalanche gain characteristics, a reverse bias voltage is required during use. The specific value of the reverse bias voltage depends on the APD's material and packaging process. The avalanche voltage has a clear direct proportional relationship with temperature, and the temperature coefficient is inconsistent across different temperature ranges, meaning it is not linear. Furthermore, the temperature coefficients of different APDs exhibit significant dispersion, making it difficult to accurately measure the temperature coefficient of the avalanche voltage.

[0004] Existing measurement methods generally involve designing dedicated APD test fixtures and then using separate constant temperature chambers and separate test fixtures to measure its temperature coefficient. However, this method is time-consuming and labor-intensive, and the measurement temperature coefficient is affected by the differences in other passive optical devices (such as wavelength division multiplexers), which makes it impossible to guarantee the accuracy of the measurement. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a method, device, and system for measuring the avalanche voltage temperature coefficient of an avalanche photodiode. Utilizing the software and hardware of a conventional DTS fiber optic distributed temperature measurement system, and taking the voltage amplitude of a reference fiber placed in a constant-temperature zone as a reference, the bias voltage is dynamically adjusted. This eliminates the need for separate calibration in an additional constant-temperature experimental chamber, avoids the design of a separate algorithm, and simplifies the process, enabling in-system measurement and compensation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for measuring the temperature coefficient of avalanche voltage in an avalanche photodiode, characterized in that it includes:

[0008] Initialize the initial bias voltage and initial operating temperature of the avalanche photodiode, and obtain the initial voltage amplitude of the reference fiber after receiving the optical signal in the constant temperature water bath device.

[0009] Control the operating temperature of the avalanche photodiode to adjust it to the target operating temperature;

[0010] At the target operating temperature, the bias voltage is adjusted to restore the voltage amplitude of the reference fiber to the initial voltage amplitude, thus obtaining the adjusted bias voltage.

[0011] The avalanche voltage temperature coefficient for the current temperature range is obtained based on the adjusted bias voltage, initial bias voltage, initial operating temperature, and target operating temperature.

[0012] As an alternative implementation, the avalanche voltage temperature coefficient is: CA(T)=|V bias -V| / |T3-T1|; where V bias V is the adjusted bias voltage, T1 is the initial bias voltage, and T3 is the target operating temperature.

[0013] Secondly, the present invention provides a method for temperature compensation of avalanche photodiodes, comprising:

[0014] Using the avalanche voltage temperature coefficient measurement method described in the first aspect, the avalanche voltage temperature coefficient for different temperature ranges is determined;

[0015] Temperature compensation for avalanche photodiodes is performed based on the avalanche voltage temperature coefficient in different temperature ranges.

[0016] Thirdly, the present invention provides an avalanche photodiode avalanche voltage temperature coefficient measuring device, comprising:

[0017] The initialization module is configured to initialize the initial bias voltage and initial operating temperature of the avalanche photodiode, and to acquire the initial voltage amplitude of the reference fiber after receiving the optical signal in the constant temperature water bath device.

[0018] The temperature control module is configured to adjust the operating temperature of the avalanche photodiode to the target operating temperature.

[0019] The bias voltage adjustment module is configured to adjust the bias voltage at the target operating temperature to restore the voltage amplitude of the reference fiber to the initial voltage amplitude, thereby obtaining the adjusted bias voltage.

[0020] The temperature coefficient measurement module is configured to obtain the avalanche voltage temperature coefficient for the current temperature range based on the adjusted bias voltage, initial bias voltage, initial operating temperature, and target operating temperature.

[0021] Fourthly, the present invention provides an avalanche voltage temperature coefficient measurement system for an avalanche photodiode, comprising a host computer and an APD receiving and amplifying module; the APD receiving and amplifying module includes a controller, an avalanche photodiode, and the avalanche voltage temperature coefficient measuring device described in the third aspect; the controller is connected to the host computer via a serial port, and the host computer writes the initial operating temperature and the adjustment of the operating temperature to obtain the avalanche voltage temperature coefficient in different temperature ranges according to the avalanche voltage temperature coefficient measuring device.

[0022] As an alternative implementation, the avalanche photodiode includes a 1660nm channel APD diode and a 1450nm channel APD diode, which are used to receive Raman scattered light at 1660nm and 1450nm respectively. The 1660nm channel APD diode and the 1450nm channel APD diode are biased by independent high-voltage modules, and the avalanche voltage temperature coefficient is measured simultaneously in both channels.

[0023] As an alternative implementation, the avalanche photodiode is mounted on a semiconductor cooler by a clamp, the clamp being equipped with a thermistor for monitoring the clamp temperature, the thermistor and the semiconductor cooler being connected to a temperature control module, the temperature control module being controlled by a controller to control temperature changes.

[0024] As an alternative implementation, the temperature of the clamp is the same as the temperature of the avalanche photodiode.

[0025] As an alternative implementation, the avalanche photodiode avalanche voltage temperature coefficient measurement system further includes a pulsed light source. The light signal emitted by the pulsed light source enters the reference fiber after passing through a wavelength division multiplexer. Spontaneous Raman scattering light signal is generated in the reference fiber region, which is then received and amplified by the APD receiving and amplifying module.

[0026] Fifthly, the present invention provides an avalanche photodiode temperature compensation system, comprising a control system and the avalanche photodiode avalanche voltage temperature coefficient measurement system described in the fourth aspect; the control system receives the avalanche voltage temperature coefficients in different temperature ranges measured by the avalanche photodiode avalanche voltage temperature coefficient measurement system, and obtains a compensation scheme therefrom, and performs temperature compensation on the avalanche photodiode according to the compensation scheme.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention provides a method, device, and system for measuring the avalanche voltage temperature coefficient of an avalanche photodiode. It utilizes the software and hardware of a conventional DTS fiber optic distributed temperature measurement system, using the voltage amplitude of a reference fiber placed in a constant temperature zone as a reference, to dynamically adjust the bias voltage. This eliminates the need for separate calibration in an additional constant temperature test chamber, and avoids the design of separate hardware and software algorithms. The process is simple, improving measurement and production efficiency, and enabling in-system measurement and compensation.

[0029] This invention provides a method, device, and system for measuring the avalanche voltage temperature coefficient of an avalanche photodiode. Utilizing existing DTS fiber optic distributed temperature measurement system software and hardware, the avalanche voltage temperature coefficient of an APD can be measured without additional equipment or algorithms, thereby achieving a good temperature compensation scheme.

[0030] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0032] Figure 1 This is a schematic diagram of the avalanche voltage temperature coefficient measurement method for avalanche photodiodes provided in Embodiment 1 of the present invention;

[0033] Figure 2 This is a schematic diagram of the avalanche photodiode avalanche voltage temperature coefficient measurement system provided in Embodiment 4 of the present invention;

[0034] Figure 3 This is a schematic diagram of the avalanche photodiode structure provided in Embodiment 4 of the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides a method for measuring the temperature coefficient of avalanche voltage in an avalanche photodiode, including:

[0041] Initialize the initial bias voltage and initial operating temperature of the avalanche photodiode, and obtain the initial voltage amplitude of the reference fiber after receiving the optical signal in the constant temperature water bath device.

[0042] Control the operating temperature of the avalanche photodiode to adjust it to the target operating temperature;

[0043] At the target operating temperature, the bias voltage is adjusted to restore the voltage amplitude of the reference fiber to its initial voltage amplitude, thus obtaining the adjusted bias voltage.

[0044] The avalanche voltage temperature coefficient for the current temperature range is obtained based on the adjusted bias voltage, initial bias voltage, initial operating temperature, and target operating temperature, thus enabling the measurement of the avalanche voltage temperature coefficient of avalanche photodiodes in different temperature ranges.

[0045] In this embodiment, the initial bias voltage of the avalanche photodiode is V, and the initial operating temperature is T1; the temperature of the constant temperature water bath is set to T2, and the reference fiber is placed in the constant temperature water bath. At the initial operating temperature T1, the initial voltage amplitude of the reference fiber after receiving the optical signal is V1.

[0046] The operating temperature of the avalanche photodiode is adjusted to the target operating temperature T3. After the temperature stabilizes, if the bias voltage is not changed, the initial voltage amplitude V1 will decrease or increase depending on the change in operating temperature. The reference fiber area is located in a constant-temperature water bath with a constant temperature; apart from the temperature of the avalanche photodiode changing, nothing else changes, so the initial voltage amplitude should also remain unchanged. Therefore, by adjusting the bias voltage to restore the changed voltage amplitude to the initial voltage amplitude V1, the adjusted bias voltage V is obtained. bias Therefore, the avalanche voltage temperature coefficient in the temperature range from T1 to T3 is: CA(T)=|V bias -V| / |T3-T1|.

[0047] Furthermore, if the operating temperature of the avalanche photodiode is increased to the target operating temperature T... 31 Once the temperature stabilizes, if the bias voltage remains unchanged, the initial voltage amplitude V1 will decrease due to the increase in operating temperature. By adjusting the bias voltage to restore the changed voltage amplitude to the initial voltage amplitude V1, the adjusted bias voltage V is obtained. bias ; So, T 31 The avalanche voltage temperature coefficient for the temperature range up to T1 is: CA(T)=(V bias -V) / (T 31 -T1).

[0048] Furthermore, if the operating temperature of the avalanche photodiode is reduced to the target operating temperature T... 32 Once the temperature stabilizes, if the bias voltage remains unchanged, the initial voltage amplitude V1 will increase due to the decrease in operating temperature. By adjusting the bias voltage to restore the changed voltage amplitude to the initial voltage amplitude V1, the adjusted bias voltage V is obtained. bias ; So, T 32 The avalanche voltage temperature coefficient for the temperature range up to T1 is: CA(T)=(VV bias ) / (T1-T 32 ).

[0049] As an alternative implementation, the initial operating temperature can be written to the microcontroller controller in the APD receiver amplifier module by the host computer via a serial port, and the operating temperature can also be adjusted by the host computer via a serial port; generally, the initial operating temperature is set to 25°C.

[0050] As an alternative implementation, the optical signal emitted by the pulsed light source enters the reference fiber after passing through a wavelength division multiplexer. Spontaneous Raman scattering light signals are generated in the reference fiber region, which are then received and amplified by the APD receiving and amplifying module. The bias voltage is adjusted according to the initial voltage amplitude of the reference fiber.

[0051] In this embodiment, the temperature coefficient of the avalanche voltage of the avalanche photodiode in the 1450nm and 1660nm channels can be measured using the above method; specifically:

[0052] (1) Measurement of the temperature coefficient of avalanche voltage in the 1660nm channel during heating:

[0053] Temperature coefficients were measured in different temperature ranges with 25℃ as the reference. The initial operating voltage of the avalanche photodiode was set to (Vbr-2V), and the initial operating temperature was set to 25℃. Vbr_25 was given by the supplier at the time of manufacture. After the power-on was stable (including the stabilization of the constant temperature water bath temperature), the initial bias voltage was Vbr_25-2V, and the constant temperature water bath temperature was set to 30℃. The initial voltage amplitude A_1660_25 of the reference fiber was recorded at this time.

[0054] The microcontroller is controlled via RS232 serial port to write 30℃ to the bidirectional temperature control circuit, which means that the operating temperature of the avalanche photodiode is adjusted to 30℃. After the temperature stabilizes, the temperature of the temperature control fixture will be 30℃, and the temperature of the avalanche photodiode will also be 30℃. If the bias voltage remains unchanged at this time, the initial voltage amplitude A_1660_25 will inevitably decrease. However, the reference fiber is located in a constant temperature water bath and its temperature remains unchanged. In the entire DTS system, except for the temperature of the avalanche photodiode, everything else remains unchanged. Therefore, the voltage curve amplitude of the reference fiber should also remain unchanged.

[0055] Therefore, by increasing the bias voltage of the 1660nm channel through the serial port, the voltage curve amplitude of the reference fiber is restored to the initial voltage amplitude A_1660_25. The bias voltage Vbias_30_1660 at this time is recorded. Then, the temperature coefficient of the avalanche voltage is: CA1660(25~30)={Vbias_30_1660-(Vbr_25-2)} / {30-25}.

[0056] (2) The temperature coefficient of avalanche voltage in the 1450nm channel during heating is the same as that in the 1660nm channel in step (1), and will not be repeated here. The final temperature coefficient of avalanche voltage is: CA1450(25~35)={Vbias_30_1450-(Vbr_25-2)} / {30-25}.

[0057] (3) Measurement of the temperature coefficient of avalanche voltage in the 1660nm channel during cooling:

[0058] Temperature coefficient measurements were performed in different temperature ranges with 25 degrees Celsius as the reference. The initial operating voltage of the avalanche photodiode was set to (Vbr-2V), and the initial operating temperature was set to 25℃. Vbr_25 was provided by the supplier at the time of manufacture. After the power-on was stable (including the stabilization of the constant temperature water bath temperature), the initial bias voltage was Vbr_25-2V, and the constant temperature water bath temperature was set to 30℃. The initial voltage amplitude A_1660_25 of the reference fiber was recorded at this time.

[0059] The microcontroller is controlled via RS232 serial port to write 20℃ to the bidirectional temperature control circuit, which means that the operating temperature of the avalanche photodiode is adjusted to 20℃. After the temperature stabilizes, the temperature of the temperature control fixture will be 20℃, and the temperature of the avalanche photodiode will also be 20℃. If the bias voltage remains unchanged at this time, the initial voltage amplitude A_1660_25 will inevitably increase. However, the reference fiber is located in a constant temperature water bath and its temperature remains unchanged. In the entire DTS system, except for the temperature of the avalanche photodiode, everything else remains unchanged. Therefore, the voltage curve amplitude of the reference fiber should also remain unchanged.

[0060] Therefore, by reducing the bias voltage of the 1660nm channel through the serial port, the voltage curve amplitude of the reference fiber is restored to the initial voltage amplitude A_1660_25. The bias voltage Vbias_20_1660 at this time is recorded. Then, the temperature coefficient of the avalanche voltage is: CA1660(20~25)={(Vbr_25-2)-Vbias_20_1660} / {25-20}.

[0061] (4) The temperature coefficient of avalanche voltage in the 1450nm channel during cooling is the same as that in the 1660nm channel in step (3), and will not be repeated here. The final temperature coefficient of avalanche voltage is: CA1450(20~25)={(Vbr_25-2)-Vbias_20_1450} / {25-20}.

[0062] Since the 1660nm and 1450nm avalanche photodiodes are biased by independent high-voltage modules, the temperature coefficient measurements of the 1660nm and 1450nm are performed simultaneously, meaning that the avalanche voltage temperature coefficient of the two diodes can be calculated simultaneously in one heating or cooling process.

[0063] Understandably, after obtaining the adjusted bias voltage, initial bias voltage, initial operating temperature, and target operating temperature, the avalanche voltage temperature coefficient for each temperature range can be calculated manually, or it can be automatically calculated according to the formula for calculating the avalanche voltage temperature coefficient, so as to achieve automatic measurement.

[0064] Example 2

[0065] This embodiment provides a method for temperature compensation of avalanche photodiodes, including:

[0066] The avalanche voltage temperature coefficient measurement method described in Example 1 was used to determine the avalanche voltage temperature coefficient in different temperature ranges.

[0067] Temperature compensation for avalanche photodiodes is performed based on the avalanche voltage temperature coefficient in different temperature ranges.

[0068] As an alternative implementation method, the avalanche voltage temperature coefficient is measured in different temperature ranges with 25℃ as the reference. When the temperature is increased, the avalanche voltage temperature coefficient is calculated in 10℃ or 5℃ intervals, such as 25-35, 35-45, 45-55, etc. The corresponding bias voltage compensation can be performed according to the avalanche voltage temperature coefficient to achieve a good compensation effect.

[0069] As an alternative implementation method, the avalanche voltage temperature coefficient is measured in different temperature ranges with 25°C as the reference. When cooling down, the avalanche voltage temperature coefficient can be obtained in multiple temperature ranges in the same way as when heating up.

[0070] Example 3

[0071] This embodiment provides an avalanche photodiode avalanche voltage temperature coefficient measuring device, including:

[0072] The initialization module is configured to initialize the initial bias voltage and initial operating temperature of the avalanche photodiode, and to acquire the initial voltage amplitude of the reference fiber after receiving the optical signal in the constant temperature water bath device.

[0073] The temperature control module is configured to adjust the operating temperature of the avalanche photodiode to the target operating temperature.

[0074] The bias voltage adjustment module is configured to adjust the bias voltage at the target operating temperature to restore the voltage amplitude of the reference fiber to the initial voltage amplitude, thereby obtaining the adjusted bias voltage.

[0075] The temperature coefficient measurement module is configured to obtain the avalanche voltage temperature coefficient for the current temperature range based on the adjusted bias voltage, initial bias voltage, initial operating temperature, and target operating temperature.

[0076] It should be noted that the above modules correspond to the steps described in Embodiment 1, and the examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the content disclosed in Embodiment 1. It should also be noted that the above modules, as part of the system, can be executed in a computer system such as a set of computer-executable instructions.

[0077] Example 4

[0078] like Figure 2 As shown, this embodiment provides an avalanche voltage temperature coefficient measurement system for an avalanche photodiode, including a host computer and an APD receiving and amplifying module; the APD receiving and amplifying module includes a controller, an avalanche photodiode, and the avalanche voltage temperature coefficient measuring device described in Embodiment 3; the controller is connected to the host computer via a serial port, and the host computer writes the initial operating temperature and the adjustment of the operating temperature through the serial port, so as to obtain the avalanche voltage temperature coefficient in different temperature ranges according to the avalanche voltage temperature coefficient measuring device.

[0079] In this embodiment, the initial operating temperature is written to the microcontroller controller in the APD receiver amplifier module by the host computer via a serial port, and the operating temperature is also adjusted by the host computer via a serial port; generally, the initial operating temperature is set to 25°C.

[0080] In this embodiment, as Figure 3 As shown, the avalanche photodiode is mounted on a semiconductor cooler via a temperature control clamp. The temperature control clamp is equipped with a thermistor for monitoring the temperature of the temperature control clamp. The thermistor and the semiconductor cooler are connected to a bidirectional temperature control module. The bidirectional temperature control module precisely controls the operating temperature of the avalanche photodiode. This temperature can be written to the APD receiving and amplifying module by the host computer via an RS232 serial port.

[0081] As an alternative implementation, the avalanche photodiode includes a 1660nm channel APD diode and a 1450nm channel APD diode, which are used to receive Raman scattered light at 1660nm and 1450nm respectively. The 1660nm and 1450nm channel avalanche photodiodes are biased by independent high-voltage modules, so the avalanche voltage temperature coefficient can be measured simultaneously for both channels. The avalanche voltage temperature coefficient measurement process for the 1660nm and 1450nm channels is the same as in Example 1, and will not be repeated here. The operating temperature is controlled by a serial port to be written to the bidirectional temperature control module.

[0082] This embodiment uses a heat dissipation temperature control fixture + thermistor + controlled temperature object (avalanche photodiode) + TEC temperature control module. The thermistor and the heat dissipation temperature control fixture are tightly coupled. The TEC temperature control module achieves bidirectional temperature control by controlling the current flowing through the TEC. The target temperature is written into the TEC temperature control module by the controller through the DAC.

[0083] This embodiment uses a conventional DTS system combined with an APD receiver amplification module with bidirectional temperature control to measure the temperature compensation coefficient of the avalanche photodiode within the DTS system. After the measurement is completed, compensation is then implemented, and existing solutions can be used for the specific compensation.

[0084] In this embodiment, the avalanche photodiode is located inside the APD receiver amplification module, and the built-in avalanche photodiode has bidirectional precise temperature control. The bias voltage is adjusted via RS232 serial port, and precise temperature control is achieved through the max1978 bidirectional temperature control circuit. The specific temperature value can also be written via RS232 serial port.

[0085] As an alternative implementation, the temperature of the temperature-controlled fixture is the same as the temperature of the avalanche photodiode.

[0086] As an alternative implementation, the temperature control module is controlled by the controller to control temperature changes. Through the connection between the controller and the temperature control module, the set operating voltage, bias voltage and operating temperature are written through the serial port to precisely control the operating temperature and bias voltage of the avalanche photodiode.

[0087] In this embodiment, the avalanche voltage temperature coefficient measurement system further includes a pulsed light source; the optical signal emitted by the pulsed light source is transmitted to the reference optical fiber via a wavelength division multiplexer, and there is a spontaneous Raman scattered light signal in the reference optical fiber region, which is then received and amplified by the APD receiving and amplifying module, and the bias voltage is adjusted according to the initial voltage amplitude of the reference optical fiber.

[0088] In this embodiment, the avalanche voltage temperature coefficient measurement system further includes a data acquisition module. The data acquisition module acquires parameters such as the operating voltage, operating temperature, and bias voltage of the avalanche photodiode and transmits them to a host computer. The avalanche voltage temperature coefficient can be calculated on the host computer. Alternatively, the avalanche voltage temperature coefficient can be calculated in the APD receiving and amplifying module, and then the data acquisition module collects the avalanche voltage temperature coefficients in different temperature ranges for use in temperature compensation of the avalanche photodiode.

[0089] In this embodiment, the avalanche voltage temperature coefficient measurement system further includes a constant temperature water bath device, which contains a reference optical fiber.

[0090] Example 5

[0091] This embodiment provides an avalanche photodiode temperature compensation system, including a control system and the avalanche photodiode avalanche voltage temperature coefficient measurement system described in Embodiment 4; the control system receives the avalanche voltage temperature coefficients of different temperature ranges measured by the avalanche photodiode avalanche voltage temperature coefficient measurement system, and obtains a compensation scheme based on the compensation scheme to perform temperature compensation on the avalanche photodiode.

[0092] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for measuring the temperature coefficient of avalanche voltage in an avalanche photodiode, characterized in that, include: Initialize the initial bias voltage and initial operating temperature of the avalanche photodiode, and obtain the initial voltage amplitude of the reference fiber after receiving the optical signal in the constant temperature water bath device. Control the operating temperature of the avalanche photodiode to adjust it to the target operating temperature; At the target operating temperature, the bias voltage is adjusted to restore the voltage amplitude of the reference fiber to the initial voltage amplitude, thus obtaining the adjusted bias voltage. The avalanche voltage temperature coefficient for the current temperature range is obtained based on the adjusted bias voltage, initial bias voltage, initial operating temperature, and target operating temperature.

2. The method for measuring the avalanche voltage temperature coefficient of an avalanche photodiode as described in claim 1, characterized in that, The avalanche voltage temperature coefficient is: CA(T)=|V bias -V| / |T3-T1|; Among them, V bias V is the adjusted bias voltage, T1 is the initial bias voltage, and T3 is the target operating temperature.

3. A method for temperature compensation of avalanche photodiodes, characterized in that, include: Using the avalanche voltage temperature coefficient measurement method according to any one of claims 1-2, the avalanche voltage temperature coefficient in different temperature ranges is determined; Temperature compensation for avalanche photodiodes is performed based on the avalanche voltage temperature coefficient in different temperature ranges.

4. An avalanche photodiode avalanche voltage temperature coefficient measuring device, characterized in that, include: The initialization module is configured to initialize the initial bias voltage and initial operating temperature of the avalanche photodiode, and to acquire the initial voltage amplitude of the reference fiber after receiving the optical signal in the constant temperature water bath device. The temperature control module is configured to adjust the operating temperature of the avalanche photodiode to the target operating temperature. The bias voltage adjustment module is configured to adjust the bias voltage at the target operating temperature to restore the voltage amplitude of the reference fiber to the initial voltage amplitude, thereby obtaining the adjusted bias voltage. The temperature coefficient measurement module is configured to obtain the avalanche voltage temperature coefficient for the current temperature range based on the adjusted bias voltage, initial bias voltage, initial operating temperature, and target operating temperature.

5. An avalanche photodiode avalanche voltage temperature coefficient measurement system, characterized in that, It includes a host computer and an APD receiving and amplifying module; the APD receiving and amplifying module includes a controller, an avalanche photodiode, and the avalanche voltage temperature coefficient measuring device as described in claim 4; the controller is connected to the host computer via a serial port, and the host computer writes the initial operating temperature and the adjustment of the operating temperature to obtain the avalanche voltage temperature coefficient in different temperature ranges according to the avalanche voltage temperature coefficient measuring device.

6. The avalanche photodiode avalanche voltage temperature coefficient measurement system as described in claim 5, characterized in that, The avalanche photodiode includes a 1660nm channel APD diode and a 1450nm channel APD diode, which are used to receive Raman scattered light at 1660nm and 1450nm respectively. The 1660nm channel APD diode and the 1450nm channel APD diode are biased by independent high-voltage modules, and the avalanche voltage temperature coefficient is measured simultaneously in both channels.

7. The avalanche photodiode avalanche voltage temperature coefficient measurement system as described in claim 5, characterized in that, The avalanche photodiode is mounted on a semiconductor cooler by a clamp. The clamp is equipped with a thermistor for monitoring the temperature of the clamp. The thermistor and the semiconductor cooler are connected to a temperature control module, and the temperature control module is controlled by a controller to control temperature changes.

8. The avalanche photodiode avalanche voltage temperature coefficient measurement system as described in claim 7, characterized in that, The temperature of the clamp is the same as the temperature of the avalanche photodiode.

9. The avalanche photodiode avalanche voltage temperature coefficient measurement system as described in claim 5, characterized in that, The avalanche photodiode avalanche voltage temperature coefficient measurement system also includes a pulsed light source. The light signal emitted by the pulsed light source enters the reference fiber after passing through a wavelength division multiplexer. There is a spontaneous Raman scattered light signal in the reference fiber region, which is then received and amplified by the APD receiving and amplifying module.

10. An avalanche photodiode temperature compensation system, characterized in that, The system includes a control system and an avalanche voltage temperature coefficient measurement system for avalanche photodiodes as described in any one of claims 5-9; the control system receives the avalanche voltage temperature coefficients in different temperature ranges measured by the avalanche photodiode avalanche voltage temperature coefficient measurement system, and obtains a compensation scheme based on these, and performs temperature compensation on the avalanche photodiodes according to the compensation scheme.

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