A single photon detector based on silicon-based avalanche diode and its temperature control method

Abstract

The present invention relates to the technical field of single-photon detectors, and provides a single-photon detector based on a silicon-based avalanche diode and a temperature control method thereof. The temperature control method of a single-photon detector based on a silicon-based avalanche diode includes: setting a target temperature of the detector and obtaining the ambient temperature of the detector; calculating a first difference between the ambient temperature and the target temperature, and if the first difference is positive, controlling the TEC module to perform heating; if the first difference is negative, controlling the TEC module to perform cooling; controlling the output capacity of the TEC module according to the absolute value of the first difference; obtaining the actual temperature of the detector according to a sampling time interval, and calculating the second difference between the actual temperature and the target temperature; and controlling the convergence speed of the actual temperature according to the absolute value of the second difference, so that the actual temperature of the detector meets the preset requirements. The present invention improves the accuracy and stability of the temperature control of the detector by dynamically adjusting the temperature of the detector.

Description

Technical Field

[0001] The present invention relates to the technical field of single-photon detectors, and in particular to a single-photon detector based on a silicon-based avalanche diode and a temperature control method thereof. Background Art

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

[0003] A single-photon detector refers to a photodetector that can respond to a single photon level, such as an avalanche photodiode (APD) based on InGaAs materials. With the development of materials, semiconductor process technology, and driving technology, photoelectric detection devices such as photomultiplier tubes, Geiger-mode avalanche photodiodes, and charge-coupled arrays (CCDs) have become the absolute mainstay of practical single-photon detectors. When the Geiger-mode APD is in a reverse bias state, when the reverse bias voltage at both ends of the APD exceeds the avalanche voltage, a single-photon-level incident light signal may trigger a self-sustaining avalanche in the APD, generating a macroscopically detectable avalanche current pulse, thereby achieving effective detection of single photons.

[0004] The performance parameters of silicon-based avalanche diode detectors, such as detection efficiency, dark counts, after-pulse time, dead time, etc., are closely related to the precise control of APD temperature. Figure 1 The relationship between the dark count of single-photon detectors and the bias voltage and temperature is demonstrated. The dark count shows a positive correlation with both temperature and bias voltage, that is, the higher the temperature and the higher the bias voltage, the higher the dark count.

[0005] However, the current prior art has the following problems when controlling the temperature of APD:

[0006] (1) The temperature control accuracy cannot be achieved with a small granularity, causing the APD to operate in a large temperature fluctuation range and the performance indicators to fluctuate greatly;

[0007] (2) The dynamic response of temperature control is poor. When faced with random fluctuations in the external ambient temperature, it cannot be adjusted dynamically in time.

[0008] (3) The response time is long. For different usage scenarios of the detector, the waiting time cannot be compressed to a smaller scale.

[0009] (4) The temperature control range is narrow, and its use is strictly limited to places with constant temperature and humidity such as laboratories.

[0010] The prior art uses a semiconductor refrigerator (TEC) to adjust the temperature of the laser. For example, the Chinese patent with application number "CN2016103295193" discloses a semiconductor laser temperature control system based on TEC, which uses a PID control algorithm. The PID control loop needs to adjust multiple control parameters. The setting of the control parameters is very complicated and requires a lot of manual experience. Different people have different experiences, which will lead to poor setting of the PID control loop parameters and time-consuming and laborious debugging. The Chinese patent with application number "CN2024104057341" discloses a temperature control device and method for a laser. The temperature change rate needs to be calculated during the control process of the method described therein, and multiple thresholds are set for the temperature change rate, making the control process complicated. Summary of the invention

[0011] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a single-photon detector based on a silicon-based avalanche diode and a temperature control method thereof. The present invention improves the accuracy and stability of temperature control of the single-photon detector based on a silicon-based avalanche diode by dynamically adjusting and providing real-time feedback on the temperature of the single-photon detector based on a silicon-based avalanche diode.

[0012] In order to achieve the above object, the present invention adopts the following technical solution:

[0013] A first aspect of the present invention provides a temperature control method for a single-photon detector based on a silicon-based avalanche diode.

[0014] A temperature control method for a single-photon detector based on a silicon-based avalanche diode, comprising:

[0015] Set the target temperature of the detector and obtain the ambient temperature of the detector;

[0016] Calculate a first difference between the ambient temperature and the target temperature, and if the first difference is positive, control the TEC module to perform heating; if the first difference is negative, control the TEC module to perform cooling;

[0017] controlling the output capacity of the TEC module according to the absolute value of the first difference;

[0018] The actual temperature of the detector is obtained at the sampling time interval, and the second difference between the actual temperature and the target temperature is calculated; according to the absolute value of the second difference, the convergence speed of the actual temperature is controlled so that the actual temperature of the detector meets the preset requirements.

[0019] Furthermore, the method of controlling the output capacity of the TEC module according to the absolute value of the first difference includes: the larger the absolute value of the first difference is, the stronger the output capacity of the TEC module is controlled.

[0020] Furthermore, the method of controlling the output capacity of the TEC module according to the absolute value of the first difference comprises:

[0021] When |T2 – T1|≥20℃, the output capacity of the TEC module is regulated at 100%;

[0022] When 15℃≤|T2 – T1|<20℃, the output capacity of the TEC module is regulated at 70%;

[0023] When 10℃≤|T2 – T1|<15℃, the output capacity of the TEC module is regulated by 50%;

[0024] When 5℃≤|T2 – T1|<10℃, the output capacity of the TEC module is adjusted by 30%;

[0025] When 0℃≤|T2 – T1|<5℃, the output capacity of the TEC module is adjusted by 10%;

[0026] Wherein, |T2 – T1| represents the absolute value of the first difference, T2 represents the ambient temperature of the detector, and T1 represents the target temperature of the detector.

[0027] Furthermore, the method of controlling the convergence speed of the actual temperature according to the absolute value of the second difference includes: the greater the absolute value of the second difference, the greater the convergence speed of the actual temperature.

[0028] Furthermore, the method of controlling the convergence speed of the actual temperature according to the absolute value of the second difference includes:

[0029] When |T3 – T1|≥10℃, the convergence speed is ≥1℃ / S and remains unchanged. If the convergence speed does not meet expectations, it is adjusted in the direction of increasing the convergence speed.

[0030] When 5℃≤|T3 – T1|<10℃, 0.5℃ / S≤ convergence speed<1℃ / S, remain unchanged. If the convergence speed does not meet expectations and the convergence speed is ≥1℃ / S, adjust in the direction of reducing the convergence speed. If the convergence speed is ≤0.5℃ / S, adjust in the direction of increasing the convergence speed.

[0031] When 3℃≤|T3 – T1|<5℃, the convergence speed is <0.5℃ / S and remains unchanged. If the convergence speed does not meet expectations, adjust in the direction of reducing the convergence speed.

[0032] Wherein, |T3 – T1| represents the absolute value of the second difference, T2 represents the actual temperature of the detector, and T1 represents the target temperature of the detector.

[0033] Furthermore, when the absolute value of the second difference is less than the set value, the actual temperature at the current sampling moment and the previous sampling moment is obtained, and the third difference is calculated; and the temperature control strategy is adjusted according to the third difference.

[0034] Furthermore, the method of adjusting the temperature control strategy according to the third difference includes:

[0035] When 0.3℃≤ T3 (t-1) - T3 (t) When <0.5℃, reduce the convergence speed;

[0036] When 0.1℃≤ T3 (t-1) - T3 (t) <0.3℃, keep it unchanged and start timing. If the timing is up and the convergence threshold falls within this interval, reduce the convergence speed.

[0037] When 0℃≤ T3 (t-1) - T3 (t) <0.1℃, keep it unchanged and start timing. If the timing is up and the convergence threshold falls within this interval, keep it unchanged.

[0038] When T3 (t-1) - T3 (t) When <0℃, the convergence speed increases;

[0039] Among them, T3 (t-1) Indicates the actual temperature at the previous sampling time t-1, T3 (t) Represents the actual temperature at the current sampling time t.

[0040] A second aspect of the present invention provides a single photon detector based on a silicon-based avalanche diode.

[0041] A single-photon detector of a silicon-based avalanche diode comprises: a main control module, and an intelligent temperature control module, a real-time sampling module, a communication module and a power supply module all connected thereto;

[0042] A main control module, used to interact with each module and process data, and execute the steps in the temperature control method of the single-photon detector of the silicon-based avalanche diode described in the first aspect;

[0043] Temperature control module, used to adjust the temperature of the detector;

[0044] Real-time sampling module, used to collect the real-time temperature of the detector;

[0045] Communication module, used to communicate with the host computer and external devices;

[0046] The power supply module is used to supply power to the main control module, intelligent temperature control module, real-time sampling module and communication module.

[0047] Furthermore, the temperature control module includes a TEC module, one side of the TEC module is in close contact with the detector housing, and the other side is in close contact with a silicon-based avalanche diode. A temperature sensor is provided in the silicon-based avalanche diode for collecting the real-time temperature of the detector.

[0048] Furthermore, the TEC module is connected to a TEC driving circuit, and the TEC driving circuit is used to control the current direction of the TEC module to cool or heat the silicon-based avalanche diode.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] The present invention provides a single-photon detector based on a silicon-based avalanche diode and a temperature control method thereof. The temperature control strategy adopted by the detector can adapt to complex changes in the external environment, and has significant characteristics such as fast convergence speed, timely dynamic response, and a wide temperature control range. It improves the reliability and stability of the detector and provides stable performance indicators.

[0051] The present invention provides detailed instructions for the setting of thresholds, specific temperature control strategies and parameter selection in the temperature control process, and the implementation process is simple. The complicated PID parameter setting process is avoided during use, thereby achieving precise control of the detector's operating temperature, enabling it to operate under stable temperature conditions, and improving the performance and stability of the detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0053] Figure 1 It is a schematic diagram showing the influence of APD temperature and bias voltage on dark counts according to the present invention;

[0054] Figure 2 It is a flow chart of a temperature control method of a single photon detector based on a silicon-based avalanche diode shown in the present invention;

[0055] Figure 3 1 is a structural diagram of a single-photon detector of a silicon-based avalanche diode shown in the present invention. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0057] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0058] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0059] Embodiment 1

[0060] like Figure 2 As shown, this embodiment provides a temperature control method for a single photon detector based on a silicon-based avalanche diode, comprising:

[0061] Step 1: Set the control unit to sample the temperature of the temperature control body for 1 second, and set the detector target temperature T1;

[0062] Step 2: Obtain the ambient temperature T2 of the detector;

[0063] Step 3: Get the actual temperature T3 of the detector;

[0064] Step 4: Calculate the difference between the ambient temperature and the detector target temperature, T2 – T1. If it is a positive value, heating is performed; if it is a negative value, cooling is performed.

[0065] Step 5: Calculate the absolute value of the difference between the ambient temperature and the detector target temperature |T2 – T1|, and control the execution unit to adjust the temperature according to the output capacity of 0-100%;

[0066] (1) When the absolute value |T2 – T1| ≥ 20°C, the output capacity is 100% controlled;

[0067] (2) When the absolute value is 15℃≤|T2 – T1|<20℃, the output capacity is adjusted to 70%;

[0068] (3) When the absolute value is 10℃≤|T2 – T1|<15℃, the output capacity is 50% controlled;

[0069] (4) When the absolute value is 5℃≤|T2 – T1|<10℃, the output capacity is adjusted to 30%;

[0070] (5) When the absolute value is 0℃≤|T2 – T1|<5℃, the output capacity is adjusted to 10%;

[0071] Step 6: According to the strategy of sampling once every 1S, calculate the absolute value of the difference between the actual temperature T3 of the detector and the target temperature T1 of the detector |T3–T1|;

[0072] (1) When the absolute value |T3 – T1| is ≥10°C, the convergence speed is ≥1°C / S, the temperature control strategy remains unchanged, the convergence speed does not meet expectations, and the temperature control strategy is adjusted to increase the convergence speed;

[0073] (2) When the absolute value is 5℃≤|T3 – T1|<10℃, 0.5℃ / S≤convergence speed<1℃ / S, the temperature control strategy remains unchanged. If the convergence speed does not meet expectations, the convergence speed is ≥1℃ / S, the temperature control strategy is adjusted to reduce the convergence speed. If the convergence speed is ≤0.5℃ / S, the temperature control strategy is adjusted to increase the convergence speed.

[0074] (3) When the absolute value is 3℃≤|T3 – T1|<5℃, the convergence speed is <0.5℃ / S, the temperature control strategy remains unchanged, the convergence speed does not meet expectations, and the temperature control strategy is adjusted to increase the convergence speed;

[0075] (4) When the absolute value |T3 – T1| is less than 3°C, proceed to step 7;

[0076] Step 7: According to the strategy of sampling once every 1S, compare the actual temperature T3 value of the detector between the two samplings:

[0077] (1) When "0.3℃≤ T3 (t-1) - T3 (t) <0.5℃”: the temperature control strategy is adjusted to the adjacent segment that reduces the convergence speed; t represents the current adoption time, and t-1 represents the previous adoption time;

[0078] (2) When "0.1℃≤ T3 (t-1) - T3 (t) <0.3℃”: the temperature control strategy remains unchanged and starts counting for 10s. If the convergence threshold falls within this interval after 10s, the temperature control strategy is adjusted to the adjacent segment that reduces the convergence speed;

[0079] (3) When "0℃≤ T3 (t-1) - T3 (t) <0.1℃”: The temperature control strategy remains unchanged and starts counting for 10 seconds. If the convergence threshold falls within this range after 10 seconds, the temperature control strategy remains unchanged;

[0080] (4) When “T3 (t-1) - T3 (t) <0℃; the temperature control strategy is adjusted to the adjacent segment that increases the convergence speed.

[0081] Based on the above temperature control method, the difference between the temperature inside the avalanche diode in the single-photon detector and the target temperature can be controlled within + / -0.1°C, meeting the temperature requirements for stable operation of the detector.

[0082] The present invention provides detailed instructions for setting the threshold value, specific temperature control strategy and parameter selection in the temperature control process, and the implementation process is simple, and the complex PID parameter setting process is avoided during use. Accordingly, the working temperature of the detector can be accurately controlled, so that it can operate under stable temperature conditions, and the performance and stability of the detector can be improved.

[0083] Embodiment 2

[0084] like Figure 3 As shown, this embodiment provides a single-photon detector of a silicon-based avalanche diode, including: a main control module, and an intelligent temperature control module, a real-time sampling module, a communication module and a power supply module all connected thereto;

[0085] A main control module, used for interacting with each module and processing data, and executing the steps in the temperature control method of the single-photon detector of the silicon-based avalanche diode described in the first embodiment;

[0086] Temperature control module, used to adjust the temperature of the detector;

[0087] Real-time sampling module, used to collect the real-time temperature of the detector;

[0088] Communication module, used to communicate with the host computer and external devices;

[0089] The power supply module is used to supply power to the main control module, intelligent temperature control module, real-time sampling module and communication module.

[0090] In some embodiments, the main control module further includes: a main control module, a storage module, and a clock module. The main control module is the core of the entire single-photon detector, responsible for real-time interaction with each sub-module and external communication; the storage module is responsible for storing system programs, important parameters, instructions, operating data, etc.; the clock module provides a reference clock source for the main control module and is the core of the entire system.

[0091] The power supply module mainly provides power support for the detector. Since the power supply of the single-photon detector covers a large range, the minimum power supply is 1.2V and the maximum high-voltage power supply is more than 200V. The stability of the power supply module is very important. The power supply module mainly provides different power supply levels for each single-photon detection to ensure reliable load, low ripple noise, high response, high stability and other requirements.

[0092] The temperature control module is the core of the detector. Its importance lies in accurately and quickly meeting the temperature control requirements according to environmental changes in real time, laying the foundation for the long-term stable operation of the detector and its applicability to various working conditions. The core of intelligent temperature control is the dynamic adjustment closed-loop strategy of the main control module. This strategy has made system-level improvements to the problems of low adjustment accuracy and slow convergence speed in previous products. The effects that can be achieved are as follows:

[0093] (1) The temperature control accuracy is extremely small, which allows the APD to operate within the range of ±0.1℃;

[0094] (2) The temperature control dynamic response range is large, which allows the APD to operate within the external ambient temperature range of ±20℃ / min;

[0095] (3) Short response time. For different usage scenarios of the detector, the waiting time is controlled within 1 minute.

[0096] (4) Wide temperature control range, covering -40℃-40℃ usage scenarios;

[0097] The main function of the real-time sampling module is to collect the temperature of the avalanche diode in real time and transmit the temperature to the main control module through the analog-to-digital converter in real time. In this process, the real-time sampling and analog-to-digital conversion need to have low latency and strong anti-interference. As the starting point of the dynamic adjustment of the entire system, the sampling must ensure authenticity, which requires data support and some algorithms to ensure this accuracy.

[0098] As a device for single photon detection, the single photon detector can be strictly regarded as a bridge between light and electricity. The optical path is connected to the detector through a specific device, while the electrical path depends on the communication module. The main function of the communication module is to provide a medium and path for the communication between the main control module and the host computer and the external device. It mainly includes a USB communication unit, a pulse output unit, and a signal indication unit. The USB communication unit provides a connection path between the main control module and the host computer; the pulse output unit provides a path for the main control module to communicate with the external device; the signal indication unit provides users with alarms, information output, status indication, etc.

[0099] The temperature control module includes a TEC module, one side of which is in close contact with the detector housing, and the other side is in close contact with a silicon-based avalanche diode. A temperature sensor is provided inside the silicon-based avalanche diode for collecting the real-time temperature of the detector. The temperature sensor can be an integrated thermistor. The TEC module is connected to a TEC drive circuit, and the TEC drive circuit is used to control the current direction of the TEC module to cool or heat the silicon-based avalanche diode. The heating or cooling power can be controlled by controlling the magnitude of the current flowing through the TEC module.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A temperature control method for a single-photon detector based on a silicon-based avalanche diode, characterized in that: include: Set the target temperature of the detector and obtain the ambient temperature of the detector; Calculating a first difference between the ambient temperature and the target temperature, and if the first difference is positive, controlling the TEC module to perform heating; If the first difference is negative, the TEC module is controlled to perform cooling; controlling the output capacity of the TEC module according to the absolute value of the first difference; Acquire the actual temperature of the detector according to the sampling time interval, and calculate the second difference between the actual temperature and the target temperature; According to the absolute value of the second difference, the convergence speed of the actual temperature is controlled so that the actual temperature of the detector meets the preset requirements; controlling the output capacity of the TEC module according to the absolute value of the first difference; The method includes: the larger the absolute value of the first difference is, the stronger the output capacity of the TEC module is controlled. The specific method includes: when |T2 - T1|≥20°C, the output capacity of the TEC module is regulated by 100%; When 15℃≤|T2 – T1|<20℃, the output capacity of the TEC module is regulated at 70%; When 10℃≤|T2 – T1|<15℃, the output capacity of the TEC module is regulated by 50%; When 5℃≤|T2 – T1|<10℃, the output capacity of the TEC module is adjusted by 30%; When 0℃≤|T2 – T1|<5℃, the output capacity of the TEC module is adjusted by 10%; Wherein, |T2 – T1| represents the absolute value of the first difference, T2 represents the ambient temperature of the detector, and T1 represents the target temperature of the detector; The method of controlling the convergence speed of the actual temperature according to the absolute value of the second difference includes: the greater the absolute value of the second difference, the greater the convergence speed of the actual temperature, and the specific method includes: when |T3 - T1|≥10°C, the convergence speed is ≥1°C / S, remains unchanged, and if the convergence speed does not meet expectations, adjust in the direction of increasing the convergence speed; When 5℃≤|T3 – T1|<10℃, 0.5℃ / S≤ convergence speed<1℃ / S, remain unchanged. If the convergence speed does not meet expectations and the convergence speed is ≥1℃ / S, adjust in the direction of reducing the convergence speed. If the convergence speed is ≤0.5℃ / S, adjust in the direction of increasing the convergence speed. When 3℃≤|T3 – T1|<5℃, the convergence speed is <0.5℃ / S and remains unchanged. If the convergence speed does not meet expectations, adjust in the direction of reducing the convergence speed. Wherein, |T3 – T1| represents the absolute value of the second difference, T3 represents the actual temperature of the detector, and T1 represents the target temperature of the detector.

2. The temperature control method of the single-photon detector based on the silicon-based avalanche diode according to claim 1, characterized in that: When the absolute value of the second difference is less than the set value, the actual temperature at the current sampling time and the previous sampling time is obtained, and the third difference is calculated; and the temperature control strategy is adjusted according to the third difference.

3. The temperature control method of the single photon detector based on silicon-based avalanche diode according to claim 2, characterized in that: The method of adjusting the temperature control strategy according to the third difference includes: When 0.3℃≤ T3 (t-1) - T3 (t) When < 0.5℃, reduce the convergence speed; When 0.1℃≤ T3 (t-1) - T3 (t) < 0.3℃, keep it unchanged and start timing. If the timing is up and the convergence threshold falls within this interval, reduce the convergence speed. When 0℃≤ T3 (t-1) - T3 (t) < 0.1℃, keep it unchanged and start timing. If the timing is up and the convergence threshold falls within this interval, keep it unchanged. When T3 (t-1) - T3 (t) < 0℃, the convergence speed increases; Among them, T3 (t-1) Indicates the actual temperature at the previous sampling time t-1, T3 (t) Represents the actual temperature at the current sampling time t.

4. A single photon detector of a silicon-based avalanche diode, characterized in that: include: A main control module, and an intelligent temperature control module, a real-time sampling module, a communication module and a power supply module connected thereto; A main control module, used to interact with each module and process data, and execute the steps in the temperature control method of the single-photon detector of the silicon-based avalanche diode according to any one of claims 1 to 3; Temperature control module, used to adjust the temperature of the detector; Real-time sampling module, used to collect the real-time temperature of the detector; Communication module, used to communicate with the host computer and external devices; The power supply module is used to supply power to the main control module, intelligent temperature control module, real-time sampling module and communication module.

5. The single photon detector of silicon-based avalanche diode according to claim 4, characterized in that: The temperature control module includes a TEC module, one side of the TEC module is close to the detector housing, and the other side is close to the silicon-based avalanche diode; the real-time sampling module includes a temperature sensor, which is arranged inside the silicon-based avalanche diode and is used to collect the real-time temperature of the detector.

6. The single photon detector of silicon-based avalanche diode according to claim 4, characterized in that: The TEC module is connected to a TEC driving circuit, and the TEC driving circuit is used to control the current direction of the TEC module to cool or heat the silicon-based avalanche diode.

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