Measurement Device and Method for Minimum Integration Time of Avalanche Photodiode

Abstract

The present invention discloses a device and method for measuring the minimum integration time of an avalanche photodiode, and relates to the field of measurement technology. The measuring device includes: a light source, which is suitable for emitting an incident laser signal, and the avalanche photodiode to be measured detects the incident laser signal and outputs a current signal; a detection component, which is used to detect the optical power of the incident laser signal to obtain a first detection result, and is used to detect the current signal to obtain a second detection result; a processing component, including: a photon number determination module, which is used to obtain the average number of photons of the incident laser signal per unit time according to the first detection result; a mean and variance determination module, which is used to obtain the mean of the current signal and the variance of the current signal according to the second detection result; an integration time determination module, which is used to obtain the minimum integration time of the avalanche photodiode to be measured according to the average number of photons of the incident laser signal per unit time, the mean of the current signal, and the variance of the current signal.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and particularly to a measuring device for the minimum integration time of an avalanche photodiode in linear mode. Background Art

[0002] An avalanche photodiode is a high-performance photoelectric conversion device that utilizes the avalanche multiplication effect of carriers to amplify photoelectric signals for detecting optical signals. The avalanche photodiode has the advantages of small size, large current gain, high sensitivity, fast response speed, etc., and is suitable for detecting and receiving weak optical signals, and has been widely used in fields such as optical fiber communication, lidar, and optical imaging. For an avalanche photodiode operating in linear mode, the indicators for measuring its response speed mainly include response bandwidth, response time, minimum integration time, etc. These indicators jointly determine the performance of the avalanche photodiode in high-speed applications and its applicability in fast optical signal detection and communication systems. Among them, the response bandwidth refers to the frequency response of the avalanche photodetection signal and can be directly measured by devices such as a spectrum analyzer. The response time refers to the time required for an optical signal to reach the photodiode and start generating an output current, and is usually measured by the time from 10% to 90% of the falling edge (or rising edge) of the output signal when an input pulsed optical signal is applied, and can be directly measured by devices such as an oscilloscope. The minimum integration time refers to the minimum cumulative time of the optical signal that the avalanche photodiode can resolve when measuring the optical signal, which determines the optical resolution ability of the avalanche photodiode. Currently, there is no device or method that can directly measure it. Summary of the Invention

[0003] In view of this, the present invention provides a measuring device and a measuring method for the minimum integration time of an avalanche photodiode.

[0004] As a first aspect of the present invention, there is provided a measuring device for the minimum integration time of an avalanche photodiode, the measuring device comprising:

[0005] A light source, adapted to emit an incident laser signal and transmit the incident laser signal to the avalanche photodiode to be measured, so that the avalanche photodiode to be measured detects the incident laser signal and outputs a current signal; wherein, the avalanche photodiode to be measured operates in linear mode;

[0006] A detection component, adapted to detect the optical power of the incident laser signal to obtain a first detection result, and adapted to detect the current signal to obtain a second detection result;

[0007] A processing component, comprising:

[0008] A photon number determination module, adapted to obtain the average number of photons of the incident laser signal per unit time according to the first detection result;

[0009] A mean value and variance determination module, applicable to obtaining the mean value of a current signal and the variance of the current signal according to a second detection result;

[0010] An integration time determination module, applicable to obtaining the minimum integration time of an avalanche photodiode to be measured according to the average number of photons of a laser signal per unit time, the mean value of the current signal, and the variance of the current signal.

[0011] According to an embodiment of the present invention, when the avalanche photodiode to be measured is in an AC output mode or a DC output mode, the incident laser signal is a discontinuous laser signal, and the current signal output by the avalanche photodiode to be measured includes a high-level signal and a low-level signal. Among them, when the avalanche photodiode to be measured receives the incident laser signal, the avalanche photodiode to be measured outputs a high-level signal, and when the avalanche photodiode to be measured does not receive the incident laser signal, the avalanche photodiode to be measured outputs a low-level signal;

[0012] The mean value and variance determination module is applicable to obtaining the mean value of the electrical signal according to the mean value of the high-level signal and the mean value of the low-level signal, and is applicable to obtaining the variance of the current signal according to the variance of the high-level signal and the variance of the low-level signal.

[0013] According to an embodiment of the present invention, the minimum integration time of the avalanche photodiode to be measured is expressed as follows:

[0014] ;

[0015] ;

[0016] ;

[0017] Among them, is the minimum integration time of the avalanche photodiode to be measured, is the mean value of the mean current signal, is the variance of the current signal, is the mean value of the high-level signal, is the mean value of the low-level signal, is the variance of the high-level signal, is the variance of the low-level signal, is the average number of photons of the incident laser signal per unit time.

[0018] According to an embodiment of the present invention, the light source includes:

[0019] A first laser, a laser driven by direct current, applicable to emitting an initial laser signal, and the initial laser signal is a discontinuous laser signal;

[0020] An intensity modulator, which is applicable to modulate the intensity of an initial laser signal to obtain an incident laser signal; or,

[0021] The light source includes:

[0022] A second laser, which is a gated-driven laser and is applicable to emit an incident laser signal.

[0023] According to an embodiment of the present invention, the light source further includes:

[0024] An optical attenuator, which is applicable to adjust the optical power of the incident laser signal.

[0025] According to an embodiment of the present invention, when the avalanche photodiode to be measured is an avalanche photodiode in a DC output mode, the incident laser signal includes a plurality of sub-laser signals, each sub-laser signal is a continuous laser signal, and the optical powers of any two sub-laser signals are different;

[0026] The current signal output by the avalanche photodiode to be measured includes a plurality of sub-current signals; each sub-current signal corresponds to each sub-laser signal one by one;

[0027] Obtaining the minimum integration time of the avalanche photodiode to be measured according to the average number of photons of the laser signal per unit time, the mean value of the current signal, and the variance of the current signal, includes:

[0028] Obtaining the minimum integration time of the avalanche photodiode to be measured according to the average number of photons of all sub-laser signals per unit time, the mean value of all sub-current signals, and the variance of all sub-current signals.

[0029] According to an embodiment of the present invention, the minimum integration time of the avalanche photodiode to be measured satisfies the following relationship:

[0030] ;

[0031] ;

[0032] Wherein, represents the minimum integration time of the avalanche photodiode to be measured, represents the mean value of the sub-current signal, represents the variance of the sub-current signal, represents the average number of photons of the sub-laser signal per unit time, represents the mean value of the background noise of the avalanche photodiode to be measured, represents the variance of the background noise of the avalanche photodiode to be measured, and are fitting coefficients.

[0033] According to an embodiment of the present invention, the light source includes:

[0034] The first laser, a DC-driven laser, is suitable for emitting an initial laser signal, and the initial laser signal is a continuous laser signal;

[0035] The optical attenuator is suitable for adjusting the optical power of the initial laser signal multiple times to obtain multiple sub-laser signals.

[0036] According to an embodiment of the present invention, the measuring device further includes:

[0037] The amplifier is suitable for amplifying the current signal output by the avalanche photodiode to be measured and transmitting the amplified current signal to the detection component.

[0038] The detection component includes:

[0039] The optical power meter is suitable for detecting the optical power of the incident laser signal to obtain a first detection result;

[0040] The oscilloscope is suitable for detecting the current signal to obtain a second detection result.

[0041] As a second aspect of this aspect, there is also provided a method for measuring the minimum integration time of an avalanche photodiode, which is implemented by using the above-mentioned measuring device. The measuring method includes:

[0042] Making the avalanche photodiode to be measured detect the incident laser signal and output a current signal; wherein, the avalanche photodiode to be measured operates in a linear mode;

[0043] Using the detection component to detect the optical power of the incident laser signal to obtain a first detection result, and detecting the current signal to obtain a second detection result;

[0044] Obtaining the average number of photons of the incident laser signal per unit time according to the first detection result;

[0045] Obtaining the mean value and variance of the current signal according to the second detection result;

[0046] Obtaining the minimum integration time of the avalanche photodiode to be measured according to the average number of photons of the laser signal per unit time, the mean value of the current signal, and the variance of the current signal.

[0047] According to an embodiment of the present invention, the processing component uses the average number of photons of the incident laser signal per unit time, the mean value of the current signal, and the variance of the current signal to obtain the minimum integration time of the avalanche photodiode to be measured, realizing the measurement of the minimum integration time of the avalanche photodiode operating in a linear mode, and further realizing the accurate and comprehensive measurement of the response speed of the avalanche photodiode in the linear mode. Description of the Drawings

[0048] Through the following description of the embodiments of the present invention with reference to the accompanying drawings, the above and other objects, features, and advantages of the present invention will become clearer. In the drawings:

[0049] Figure 1 A schematic diagram of a measuring device for the minimum integration time of an avalanche photodiode provided according to an embodiment of the present invention is shown;

[0050] Figure 2 A schematic diagram of a measuring device with a continuous light source provided according to an embodiment of the present invention is shown;

[0051] Figure 3 A schematic diagram of a measuring device with a gated light source provided according to an embodiment of the present invention is shown;

[0052] Figure 4 A schematic diagram of another measuring device with a gated light source provided according to an embodiment of the present invention is shown.

[0053] Description of the reference numerals

[0054] 1 - Light source; 2 - Detection component; 3 - Processing component; 4 - Avalanche photodiode to be measured; 11 - First laser; 12 - Optical attenuator; 13 - Intensity modulator; 14 - Second laser; 21 - Optical power meter; 22 - Oscilloscope; 31 - Photon number determination module; 32 - Mean and variance determination module; 33 - Integration time determination module. Detailed embodiments

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following further describes the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0056] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0057] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0058] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.

[0059] It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "rear", "left", "right", etc., are only references to the directions in the accompanying drawings and are not used to limit the protection scope of the present invention. Throughout the accompanying drawings, the same elements are denoted by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, the conventional structures or configurations will be omitted.

[0060] Figure 1 A measuring device for the minimum integration time of an avalanche photodiode according to an embodiment of the present invention is shown.

[0061] As Figure 1 shown, the measuring device includes: a light source 1, a detection component 2, and a processing component 3.

[0062] The light source 1 is adapted to emit an incident laser signal and transmit the incident laser signal to the avalanche photodiode 4 to be measured, so that the avalanche photodiode 4 to be measured detects the incident laser signal and outputs a current signal; wherein, the avalanche photodiode 4 to be measured operates in a linear mode. The detection component 2 is adapted to detect the optical power of the incident laser signal to obtain a first detection result, and is adapted to detect the current signal to obtain a second detection result. The processing component 3 includes a photon number determination module 31, a mean and variance determination module 32, and an integration time determination module 33. The photon number determination module 31 is adapted to obtain the average number of photons of the incident laser signal per unit time according to the first detection result. The mean and variance determination module 32 is adapted to obtain the mean value of the current signal according to the second detection result, and is adapted to obtain the variance of the current signal according to the second detection result. The integration time determination module 33 is adapted to obtain the minimum integration time of the avalanche photodiode to be measured according to the average number of photons of the incident laser signal per unit time, the mean value of the current signal, and the variance of the current signal. The mean value of the current signal is the average value of the current signals detected by the detection component during the detection time of the detection component 2. The variance of the current signal refers to the measure of the degree of dispersion of the current signals measured by the detection component 2 deviating from its average value during the detection time of the detection component 2.

[0063] According to an embodiment of the present invention, the processing component 3 obtains the minimum integration time of the avalanche photodiode by using the average number of photons of the incident laser signal per unit time, the mean value of the current signal, and the variance of the current signal, realizes the measurement of the minimum integration time of the avalanche photodiode operating in the linear mode, and further realizes the accurate and comprehensive measurement of the response speed of the avalanche photodiode in the linear mode.

[0064] According to an embodiment of the present invention, the avalanche photodiode 4 to be measured can be an avalanche photodiode in an AC output mode or an avalanche photodiode in a DC output mode. For avalanche photodiodes to be measured with different output modes, the incident laser signals output by the light source 1 are also different.

[0065] According to an embodiment of the present invention, when the avalanche photodiode 4 to be measured is an avalanche photodiode in a DC output mode, the incident laser signal generated by the light source 1 includes a plurality of sub-laser signals, each sub-laser signal is a continuous laser signal, and the optical powers of any two sub-laser signals are different. The current signal output by the avalanche photodiode to be measured includes a plurality of sub-current signals; each sub-current signal corresponds to each sub-laser signal one by one. Obtaining the minimum integration time of the avalanche photodiode to be measured according to the average number of photons of the incident laser signal per unit time, the mean value of the current signal, and the variance of the current signal includes: obtaining the minimum integration time of the avalanche photodiode to be measured according to the average number of photons of all sub-laser signals per unit time, the mean value of all sub-current signals, and the variance of all sub-current signals.

[0066] According to an embodiment of the present invention, the light source 1 capable of generating multiple sub-laser signals is a continuous light source.

[0067] Figure 2 The schematic diagram of a measuring device with a continuous light source provided according to an embodiment of the present invention is shown.

[0068] As Figure 2 shown, the light source 1 includes a first laser 11 and an optical attenuator 12. The first laser 11 is a laser driven by direct current and is suitable for emitting an initial laser signal, and the initial laser signal is a continuous laser signal. The optical attenuator 12 is suitable for adjusting the optical power of the initial laser signal multiple times to obtain multiple sub-laser signals.

[0069] According to an embodiment of the present invention, when the avalanche photodiode 4 to be measured is in the direct current output mode, how the integration time determination module 33 obtains the minimum integration time of the avalanche photodiode to be measured by using the average number of photons of multiple sub-laser signals per unit time, the mean value of all sub-current signals, and the variance of all sub-current signals will be described in detail below.

[0070] For a sub-laser signal, its optical power is a constant, and the corresponding average number of photons per unit time is also a constant, denoted as . Since the avalanche photodiode to be measured in this direct current output mode operates in the linear mode, its minimum integration time is denoted as , then the average number of photons of the sub-laser signal within the minimum integration time of the avalanche photodiode to be measured in this direct current output mode is expressed as Equation (1).

[0071] (1);

[0072] When is relatively large ( ≥ 10), the number of photons of the sub-laser signal within the minimum integration time can be approximated by a one-dimensional Gaussian distribution and is expressed as Equation (2).

[0073] (2);

[0074] It can be seen from Equation (2) that the mean value of the number of photons of the sub-laser signal within the minimum integration time of the avalanche photodiode to be measured in this direct current output mode (that is, the average number of photons of the sub-laser signal within the minimum integration time of the avalanche photodiode to be measured in this direct current output mode) and the variance are both equal to .

[0075] The sub - current signal output by the avalanche photodiode under test operating in the linear mode is represented by and satisfies Equation (3). Satisfies Equation (3).

[0076] (3);

[0077] Wherein, is the photoelectric conversion coefficient of the avalanche photodiode under test, is the background noise of the avalanche photodiode under test, and the sub - current signal is the current value at each detection moment within the detection time period, and this detection time period refers to the time period during which the avalanche photodiode under test detects the sub - laser signal.

[0078] According to Equation (3), within the detection time period, the mean value of the sub - current signal is expressed as Equation (4), and the variance of the sub - current signal is expressed as Equation (5)

[0079] (4);

[0080] Wherein, represents the mean value of the sub - current signal, represents the mean value of the number of photons within the minimum integration time of this avalanche photodiode under test, that is, the average number of photons within the minimum integration time of this sub - current signal in this avalanche photodiode under test, represents the mean value of the background noise.

[0081] (5);

[0082] Wherein, represents the variance of the sub - current signal, represents the variance of the number of photons within the minimum integration time of the avalanche photodiode under test in this DC output mode, represents the variance of the background noise.

[0083] Let , then there is:

[0084] (6).

[0085] According to an embodiment of the present invention, the first laser 11 can be adjusted by using the optical attenuator 12, and multiple sub-laser signals can be obtained. Since the optical powers of the obtained multiple sub-laser signals are different, the average number of photons of the sub-laser signals per unit time can be adjusted by adjusting the optical attenuator 12 (the adjustment range of is 100~10000 / 100ps).

[0086] It can be seen from Equation (6) that by performing data fitting on the average number of photons of all sub-laser signals per unit time, the mean value of all sub-current signals, and the variance of all sub-current signals (for example, MATLAB can be used for data fitting), the fitting coefficients and can be obtained, and then the minimum integration time of the avalanche photodiode to be measured can be obtained.

[0087] According to an embodiment of the present invention, based on the above content, it can be seen that for the avalanche photodiode to be measured in the DC output mode, multiple continuous sub-laser signals can be used to measure the minimum integration time of the avalanche photodiode. However, for the avalanche photodiode in the AC output mode, when continuous laser signals are used, the mean value of the output current signal always remains near 0. Therefore, the above method is not applicable to the avalanche photodiode operating in the AC output mode.

[0088] According to an embodiment of the present invention, a non-continuous laser signal can be generated by using the light source 1 to measure the avalanche photodiode operating in the AC output mode or the avalanche photodiode operating in the DC output mode. The light source 1 capable of generating a non-continuous laser signal can be a gated light source, and the gated light source can have two forms, which will be introduced separately below.

[0089] Figure 3 FIG. shows a schematic diagram of a measuring device with a gated light source according to an embodiment of the present invention.

[0090] As Figure 3As shown, it is a gated light source in the first form. The gated light source may include, for example, a first laser 11 and an intensity modulator 13. The first laser 11 is a DC-driven laser, suitable for emitting an initial laser signal, and the initial laser signal is a continuous laser signal. The intensity modulator 13 is suitable for modulating the intensity of the initial laser signal to obtain an incident laser signal. The intensity modulator 13 can achieve the light source outputting a discontinuous incident laser signal (gated light signal) by changing the amplitude or intensity of the incident laser signal. When the intensity modulator 13 is in the "on" state (i.e., when the gate is open), it allows the incident laser signal to pass through and maintains a certain intensity; when the intensity modulator 13 is in the "off" state (i.e., when the gate is closed), it blocks the passage of the incident laser signal.

[0091] Figure 4 The schematic diagram of another measuring device with a gated light source provided according to an embodiment of the present invention is shown.

[0092] As Figure 4 shown, it is a gated light source in the second form. The gated light source includes a second laser 14. The second laser 14 is a gated-driven laser, suitable for emitting an incident laser signal. When the second laser 14 is a gated-driven laser, the generated incident laser signal is a discontinuous laser signal. Therefore, when the second laser 14 is a gated-driven laser, there is no need to use an intensity modulator 13.

[0093] According to an embodiment of the present invention, when the gate is open, the light source 1 emits an incident laser signal, and when the gate is closed, the light source 1 does not output an incident laser signal. When the light source 1 outputs an incident current signal, the avalanche photodiode under test operating in the AC output mode or the DC output mode outputs a high-level signal , when the light source 1 does not output a signal, the avalanche photodiode under test operating in the AC output mode or the DC output mode outputs a low-level signal . The mean and variance determination module 32 is suitable for obtaining the mean of the current signal according to the mean of the high-level signal and the mean of the low-level signal and for obtaining the variance of the current signal according to the variance of the high-level signal and the variance of the low-level signal.

[0094] The mean of the current signal is expressed as Equation (7), and the variance of the current signal is expressed as Equation (8).

[0095] (7);

[0096] (8);

[0097] Wherein, is the mean of the high-level signal, is the variance of the high-level signal, is the mean value of the low-level signal, is the variance of the low-level signal, is the average number of photons of the incident laser signal per unit time, is the mean value of the current signal (the mean value of the peak-to-peak value), is the variance of the current signal (the variance of the peak-to-peak value). is the incident laser signal at the minimum integration time The average number of photons within.

[0098] Equation (9) can be obtained by using Equations (7) to (8).

[0099] (9).

[0100] According to Equation (9), the minimum integration time of the avalanche photodiode under test operating in the AC output mode or the DC output mode can be obtained .

[0101] According to an embodiment of the present invention, when the light source 1 generates a discontinuous laser signal, the light source 1 further includes: an optical attenuator 12, and the optical attenuator 12 is suitable for adjusting the optical power of the incident laser signal. By adjusting the optical power of the incident laser signal through the optical attenuator 12, the minimum integration time of the avalanche photodiode under test operating in the AC output mode or the DC output mode can be measured Multiple measurements can be carried out, and thus the measurement accuracy can be guaranteed. The optical attenuator 12 is also used to ensure that the incident laser signal has an appropriate optical power, so as not to damage the detection component 2.

[0102] According to an embodiment of the present invention, the above measurement device further includes: an amplifier (not shown in the figure) suitable for amplifying the current signal output by the avalanche photodiode under test and transmitting the amplified current signal to the detection component 2.

[0103] According to an embodiment of the present invention, the detection component 2 includes: an optical power meter 21 and an oscilloscope 22.

[0104] The optical power meter 21 is suitable for detecting the optical power of the incident laser signal to obtain a first detection result, and the oscilloscope 22 is suitable for detecting the current signal to obtain a second detection result.

[0105] According to an embodiment of the present invention, the photon number determination module 31, the mean value and variance determination module 32, and the integration time determination module 33 can be combined and implemented in one module, or any one of them can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present invention, at least one of the photon number determination module 31, the mean value and variance determination module 32, and the integration time determination module 33 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on chip, a system on substrate, a system on package, an application specific integrated circuit (ASIC), or can be implemented by any other reasonable means such as hardware or firmware for integrating or packaging circuits, or can be implemented in any one of the three implementation manners of software, hardware, and firmware or in any appropriate combination of several of them. Alternatively, at least one of the photon number determination module 31, the mean value and variance determination module 32, and the integration time determination module 33 can be at least partially implemented as a computer program module, and when the computer program module is run, the corresponding functions can be executed.

[0106] As a second aspect of the present invention, a method for measuring the minimum integration time of an avalanche photodiode is further provided, which is implemented by using the above measurement device, and the measurement method includes operations S1 to S5.

[0107] In operation S1, the avalanche photodiode to be measured is made to detect the incident laser signal and output a current signal; wherein, the avalanche photodiode to be measured operates in a linear mode.

[0108] In operation S2, the detection component is used to detect the optical power of the incident laser signal to obtain a first detection result, and to detect the current signal to obtain a second detection result.

[0109] In operation S3, the average number of photons of the incident laser signal per unit time is obtained according to the first detection result.

[0110] In operation S4, the mean value of the current signal and the variance of the current signal are obtained according to the second detection result.

[0111] In operation S5, the minimum integration time of the avalanche photodiode to be measured is obtained according to the average number of photons of the laser signal per unit time, the mean value of the current signal, and the variance of the current signal.

[0112] The measurement device provided according to the embodiment of the present invention can effectively measure the performance index of the minimum integration time of an avalanche photodiode operating in a linear mode, thereby promoting the application of an avalanche photodiode operating in a linear mode in fields such as fast optical signal detection and communication systems.

[0113] The embodiments of the present invention have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should fall within the scope of the present invention.

Claims

1. A device for measuring the minimum integration time of an avalanche photodiode, characterized in that: include: A light source, adapted to emit an incident laser signal and transmit the incident laser signal to an avalanche photodiode to be tested, so that the avalanche photodiode to be tested detects the incident laser signal and outputs a current signal; wherein the avalanche photodiode to be tested operates in a linear mode; the avalanche photodiode to be tested is in an AC output mode or a DC output mode, and the incident laser signal is a discontinuous laser signal; A detection component, adapted to detect the optical power of the incident laser signal to obtain a first detection result, and adapted to detect the current signal to obtain a second detection result; Processing components, including: A photon number determination module, adapted to obtain an average photon number of the incident laser signal per unit time according to the first detection result; a mean and variance determination module, adapted to obtain a mean of the current signal and a variance of the current signal according to the second detection result; An integration time determination module, adapted to obtain a minimum integration time of the avalanche photodiode to be tested according to an average number of photons of the incident laser signal per unit time, a mean value of the current signal and a variance of the current signal; Wherein, the minimum integration time is expressed as follows: ； is the minimum integration time, is the mean value of the current signal, is the variance of the current signal, is the average number of photons of the incident laser signal per unit time.

2. The measuring device according to claim 1, characterized in that The second detection result includes a high level signal and a low level signal, wherein when the avalanche photodiode to be tested receives the incident laser signal, the avalanche photodiode to be tested outputs a high level signal, and when the avalanche photodiode to be tested does not receive the incident laser signal, the avalanche photodiode to be tested outputs a low level signal; The mean and variance determination module is adapted to obtain the mean of the current signal according to the mean of the high level signal and the mean of the low level signal, and is adapted to obtain the variance of the current signal according to the variance of the high level signal and the variance of the low level signal.

3. The measuring device according to claim 2, characterized in that The mean value of the current signal and the variance of the current signal are expressed as follows: ； ； in, is the mean value of the high level signal, is the mean value of the low level signal, is the variance of the high level signal, is the variance of the low level signal.

4. The measuring device according to claim 2, characterized in that The light source comprises: The first laser is a direct current driven laser, and is suitable for emitting an initial laser signal, wherein the initial laser signal is a discontinuous laser signal; an intensity modulator, adapted to modulate the intensity of the initial laser signal to obtain the incident laser signal; or The light source comprises: The second laser is a gate-driven laser, adapted to emit the incident laser signal.

5. The measuring device according to claim 4, characterized in that The light source also includes: The optical attenuator is suitable for adjusting the optical power of the incident laser signal.

6. A device for measuring the minimum integration time of an avalanche photodiode, characterized in that: include: A light source, adapted to emit an incident laser signal and transmit the incident laser signal to an avalanche photodiode to be tested, so that the avalanche photodiode to be tested detects the incident laser signal and outputs a current signal; wherein the avalanche photodiode to be tested operates in a linear mode; the avalanche photodiode to be tested is in a DC output mode, the incident laser signal includes a plurality of sub-laser signals, each of which is a continuous laser signal, and the optical powers of any two sub-laser signals are different; the current signal includes a plurality of sub-current signals; each sub-current signal corresponds one-to-one to each sub-laser signal; A detection component, adapted to detect the optical power of the incident laser signal to obtain a first detection result, and adapted to detect the current signal to obtain a second detection result; Processing components, including: A photon number determination module, adapted to obtain the average photon number of all sub-laser signals per unit time according to the first detection result; a mean and variance determination module, adapted to obtain the mean of all sub-current signals and the variance of all sub-current signals according to the second detection result; An integration time determination module, adapted to obtain the minimum integration time of the avalanche photodiode to be tested according to the average number of photons of all sub-laser signals per unit time, the mean of all sub-current signals and the variance of all sub-current signals; Wherein, the minimum integration time satisfies the following relationship: ； ； represents the minimum integration time, represents the mean value of the sub-current signal, represents the variance of the sub-current signal, represents the average number of photons per unit time of the sub-laser signal, represents the mean value of the background noise of the avalanche photodiode to be tested, represents the variance of the background noise of the avalanche photodiode to be measured, and is the fitting coefficient.

7. The measuring device according to claim 6, characterized in that The light source comprises: The first laser is a direct-current driven laser, and is adapted to emit an initial laser signal, wherein the initial laser signal is a continuous laser signal; The optical attenuator is adapted to adjust the optical power of the initial laser signal multiple times to obtain the multiple sub-laser signals.

8. The measuring device according to claim 1 or 6, characterized in that: The measuring device further comprises: an amplifier adapted to amplify the current signal output by the avalanche photodiode to be measured and transmit the amplified current signal to the detection component; The detection component comprises: An optical power meter, adapted to detect the optical power of the incident laser signal to obtain a first detection result; The oscilloscope is suitable for detecting the current signal to obtain a second detection result.

9. A method for measuring the minimum integration time of an avalanche photodiode, implemented by using the measuring device according to any one of claims 1 to 8, characterized in that: The measuring method comprises: The avalanche photodiode to be tested detects the incident laser signal and outputs a current signal; wherein the avalanche photodiode to be tested operates in a linear mode; Using a detection component to detect the optical power of the incident laser signal to obtain a first detection result, and detecting the current signal to obtain a second detection result; Obtaining the average number of photons of the incident laser signal per unit time according to the first detection result; Obtaining a mean value of the current signal and a variance of the current signal according to the second detection result; The minimum integration time of the avalanche photodiode to be measured is obtained according to the average number of photons of the laser signal per unit time, the mean value of the current signal and the variance of the current signal.

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