Signal processing method, signal processing device and quantum communication receiving end

Abstract

The present disclosure provides a signal processing method, a signal processing device and a quantum communication receiving end. The method comprises: acquiring a single-photon quantum optical signal; performing photoelectric conversion on the quantum optical signal to obtain an avalanche signal; and outputting a detection result corresponding to the quantum optical signal when the level of the avalanche signal is greater than or equal to a dynamic discrimination level, wherein the dynamic discrimination level is generated according to a fixed bias level and a capacitively coupled alternating current signal.

Description

Technical Field

[0001] This disclosure relates to the field of quantum communication technology, and more specifically, to a signal processing method, a signal processing device, and a quantum communication receiver. Background Technology

[0002] Single-photon detectors are the core module for quantum optical detection at the receiver end of a quantum key distribution (QKD) system. After more than a decade of development, high-speed single-photon detection technology has laid an effective technical foundation for high-speed QKD systems.

[0003] In the detection of quantum optical signals, if a single-photon detector produces an output position error, there is a 50% chance of generating an erroneous bit, regardless of the transmission distance. In practical QKD systems, these error counts are included in the follow-up pulse. The increase in the number of follow-up pulses significantly affects the final secure key generation rate. As the gating frequency of the single-photon detector increases, the gating period decreases proportionally, making the output timing accuracy of the detection results crucial. Therefore, the time resolution performance of high-speed single-photon detectors constrains the core indicator of secure key generation rate in high-speed QKD systems.

[0004] In single-photon detection technology specifications, the detector count half-width, also known as the detector effective gate width, is usually used to characterize the time domain of the judgment signal and then generate the corresponding security key. If the effective gate width of a high-speed single-photon detector is too wide, the error count will be too high, resulting in a low security key generation rate. Summary of the Invention

[0005] In view of this, embodiments of the present disclosure provide a signal processing method, a signal processing apparatus, and a quantum communication receiver.

[0006] One aspect of this disclosure provides a signal processing method applied to a quantum communication receiver, the method comprising:

[0007] Acquiring quantum optical signals from single photons;

[0008] The above quantum optical signal is converted into an avalanche signal by photoelectric conversion;

[0009] When the level of the aforementioned avalanche signal is greater than or equal to the dynamic discrimination level, the detection result corresponding to the aforementioned quantum optical signal is output, wherein the aforementioned dynamic discrimination level is generated based on the fixed bias level and the capacitively coupled AC signal.

[0010] According to embodiments of this disclosure, the aforementioned dynamic discrimination level is generated in the following manner:

[0011] Obtain the fixed bias level when the single-photon detector is working normally;

[0012] An initial dynamic discrimination level is obtained, and the fixed bias level is increased. The period of the initial dynamic discrimination level is the same as the gating period, and the increase of the fixed bias level is equal to the increase of the initial dynamic discrimination level. The initial dynamic discrimination level is generated based on the increased fixed bias level and the capacitively coupled AC signal.

[0013] The above-mentioned initial dynamic discrimination level is delayed to obtain the above-mentioned dynamic discrimination level.

[0014] According to embodiments of this disclosure, the signal processing method further includes:

[0015] A first time region is determined where the timing signal distribution probability satisfies a preset probability when the single-photon detector count distribution is determined, so that the initial dynamic discrimination level is delayed according to the first time region.

[0016] According to embodiments of this disclosure, the initial dynamic discrimination level is delayed to obtain the dynamic discrimination level, including:

[0017] The delay of the initial dynamic discrimination level is adjusted to obtain the adjusted dynamic level;

[0018] Based on the adjusted dynamic level, a second time region is determined in which the timing signal distribution probability satisfies the preset probability when the single-photon detector count distribution is determined.

[0019] If the overlap between the first time region and the second time region meets the preset overlap threshold, the adjusted dynamic level is determined as the dynamic discrimination level.

[0020] According to embodiments of this disclosure, the above-mentioned quantum optical signal is photoelectrically converted to obtain an avalanche signal, including:

[0021] When a gated signal is applied to the avalanche diode, the quantum optical signal is photoelectrically converted using the avalanche diode to obtain the avalanche signal.

[0022] According to embodiments of this disclosure, the signal processing method further includes:

[0023] The avalanche signal is filtered to obtain a filtered avalanche signal, and the level of the filtered avalanche signal is used to determine whether to generate the above detection result.

[0024] According to embodiments of this disclosure, the signal processing method further includes:

[0025] The filtered avalanche signal is amplified to obtain an amplified avalanche signal. The level of the amplified avalanche signal is used to determine whether to generate the detection result. The threshold range of the dynamic discrimination level is determined based on the amplification factor and the fixed bias level.

[0026] According to an embodiment of this disclosure, the level of the avalanche signal includes a first region and a second region, wherein the division of the first region and the second region is determined based on the distribution probability of the timing signal, and the distribution probability in the first region is greater than the distribution probability in the second region.

[0027] According to embodiments of this disclosure, when the level of the avalanche signal is greater than or equal to the dynamic discrimination level, a detection result corresponding to the quantum optical signal is output, including:

[0028] For the first region mentioned above, when the level in the first region is greater than or equal to the dynamic discrimination level, a detection result corresponding to the quantum optical signal is output, wherein the dynamic discrimination level is reduced based on the level distribution probability value in the first region.

[0029] For the second region, when the level in the second region is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output, wherein the dynamic discrimination level is increased based on the level distribution probability value in the second region.

[0030] Another aspect of this disclosure provides a signal processing apparatus, including:

[0031] The acquisition module is used to acquire quantum optical signals of single photons;

[0032] Avalanche diodes are used to perform photoelectric conversion on the aforementioned quantum optical signals to obtain avalanche signals.

[0033] A comparator is used to output a detection result corresponding to the quantum light signal using a single-photon detector when the level of the avalanche signal is greater than or equal to the dynamic discrimination level, wherein the dynamic discrimination level is generated based on a fixed bias level and a capacitively coupled AC signal.

[0034] Another aspect of this disclosure provides a quantum communication receiver, comprising:

[0035] Single-photon detectors, including:

[0036] A signal processing device is used to output a detection result corresponding to the quantum optical signal when the comparator of the signal processing device determines that the level of the avalanche signal is greater than or equal to the dynamic discrimination level.

[0037] According to embodiments of this disclosure, a dynamic discrimination level generated based on a fixed bias level and a capacitively coupled AC signal is compared in real time with the level of the current avalanche signal. If the level of the avalanche signal is greater than or equal to the dynamic discrimination level, a detection result corresponding to the quantum optical signal is output. The dynamic discrimination level technology introduces a time component into the discrimination level amplitude, increasing the count rate in time regions with high avalanche probability and decreasing the count rate in time regions with low avalanche probability. This improves the temporal resolution of the single-photon detector, thereby reducing false counts. Especially in quantum key distribution systems, it can reduce the bit error rate and increase the generation rate of secure keys. Attached Figure Description

[0038] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0039] Figure 1 A flowchart illustrating a signal processing method according to an embodiment of the present disclosure is shown schematically.

[0040] Figure 2 A flowchart illustrating the acquisition of dynamic discrimination levels according to an embodiment of the present disclosure is shown schematically;

[0041] Figure 3 The schematic diagram illustrates the principle of a signal processing method according to an embodiment of the present disclosure;

[0042] Figure 4 This illustration schematically shows a loading diagram of the dynamic discrimination level according to an embodiment of the present disclosure;

[0043] Figure 5 A schematic block diagram of a signal processing apparatus according to an embodiment of the present disclosure is shown.

[0044] Figure 6 A schematic block diagram of a quantum communication receiver according to an embodiment of the present disclosure is shown. Detailed Implementation

[0045] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0047] 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 are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0048] When using expressions such as "at least one of A, B, and C", they should generally be interpreted in accordance with the meaning that is commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0049] Current methods for extracting avalanche signals using single-photon detection typically employ a fixed discrimination level comparison method. This means the discrimination level remains constant across all avalanche signal time regions. However, as the gate frequency of the single-photon detector increases, the gate period decreases proportionally. This method causes the discrimination timing signal to fall outside the period, resulting in numerous false counts. Furthermore, constant-ratio timing techniques can reduce the variation in decision time caused by amplitude changes under a fixed discrimination level. However, in single-photon detection, the avalanche signal amplitude is very weak, becoming a millivolt-level pulse signal after multiple amplification stages. Its signal-to-noise ratio is inherently low. In constant-ratio timing techniques, the signal to be timed is amplified by a delay ratio and used as the discrimination level. Due to the high noise of the avalanche signal, the discrimination level still results in significant time-determination noise, thus affecting the security key generation rate.

[0050] In view of this, the present disclosure provides a signal processing method, a signal processing device, and a quantum communication receiver. The method includes acquiring a single-photon quantum optical signal; performing photoelectric conversion on the quantum optical signal to obtain an avalanche signal; and outputting a detection result corresponding to the quantum optical signal when the level of the avalanche signal is greater than or equal to the dynamic discrimination level, wherein the dynamic discrimination level is generated based on a fixed bias level and an AC signal coupled by capacitive coupling.

[0051] Figure 1 A flowchart illustrating a signal processing method according to an embodiment of the present disclosure is shown schematically.

[0052] like Figure 1 As shown, the signal processing method applied to the quantum communication receiver includes operations S101 to S103.

[0053] By operating S101, a quantum light signal of a single photon is obtained;

[0054] By operating S102, the quantum optical signal is converted into an avalanche signal through photoelectric conversion.

[0055] When operating S103, if the level of the avalanche signal is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum light signal is output. The dynamic discrimination level is generated based on the fixed bias level and the AC signal coupled by the capacitor.

[0056] According to embodiments of this disclosure, a single-photon quantum optical signal can be transmitted by a transmitter and enter the receiver through a channel.

[0057] According to an embodiment of this disclosure, an avalanche diode is used to perform photoelectric conversion on the quantum optical signal to obtain an avalanche signal. A comparator is used to determine the magnitude of the level of the avalanche signal and the set dynamic discrimination level. If the level of the avalanche signal is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output.

[0058] According to embodiments of this disclosure, a dynamic discrimination level generated based on a fixed bias level and a capacitively coupled AC signal is compared in real time with the level of the current avalanche signal. If the level of the avalanche signal is greater than or equal to the dynamic discrimination level, a detection result corresponding to the quantum optical signal is output. The dynamic discrimination level technology introduces a time component into the discrimination level amplitude, increasing the count rate in time regions with high avalanche probability and decreasing the count rate in time regions with low avalanche probability. This improves the temporal resolution of the single-photon detector, thereby reducing false counts. Especially in quantum key distribution systems, it can reduce the bit error rate and increase the generation rate of secure keys.

[0059] According to embodiments of this disclosure, the dynamic discrimination level is generated in the following manner:

[0060] Obtain the fixed bias level when the single-photon detector is working normally;

[0061] The initial dynamic discrimination level is obtained, and the fixed bias level is increased. The period of the initial dynamic discrimination level is the same as the gating period, and the increase of the fixed bias level is equal to the increase of the initial dynamic discrimination level. The initial dynamic discrimination level is generated based on the increased fixed bias level and the AC signal coupled by the capacitor.

[0062] The initial dynamic discrimination level is delayed to obtain the dynamic discrimination level.

[0063] According to embodiments of this disclosure, the fixed bias level remains fixed once set; the dynamic discrimination level refers to the discrimination level changing over time during the operation of the quantum communication receiver.

[0064] According to embodiments of this disclosure, a basic fixed bias level is first applied, and the amplitude of the fixed bias is adjusted to enable the single-photon detector to operate normally. Then, an initial dynamic discrimination level with the same gating period is applied, and the fixed bias level is increased by an amount comparable to the initial dynamic discrimination level. Finally, the initial dynamic discrimination level is delayed to obtain the dynamic discrimination level.

[0065] According to embodiments of this disclosure, the signal processing method further includes:

[0066] A first time region is determined where the timing signal distribution probability satisfies a preset probability when the single-photon detector count distribution is determined, so that the initial dynamic discrimination level is delayed based on the first time region.

[0067] According to embodiments of this disclosure, before loading the dynamic discrimination level, the distribution of single-photon detector counts is first statistically analyzed, and a first time region where the timing signal distribution probability satisfies a preset probability is recorded. The signal distribution within the first time region is relatively concentrated, and the preset probability can be adjusted according to actual conditions, for example, it can be 80%. Then, the initial dynamic discrimination level is loaded to obtain the dynamic discrimination level.

[0068] Figure 2 A flowchart illustrating the acquisition of dynamic discrimination levels according to an embodiment of the present disclosure is shown schematically.

[0069] like Figure 2 As shown, the initial dynamic discrimination level is delayed to obtain the dynamic discrimination level, including operations S201 to S203.

[0070] In operation S201, the delay of the initial dynamic discrimination level is adjusted to obtain the adjusted dynamic level;

[0071] In operation S202, based on the adjusted dynamic level, a second time region is determined in which the timing signal distribution probability satisfies the preset probability when the single-photon detector count distribution is determined.

[0072] In operation S203, if the overlap between the first time region and the second time region meets the preset overlap threshold, the adjusted dynamic level is determined as the dynamic discrimination level.

[0073] According to embodiments of this disclosure, in order to obtain good technical indicators, the amplitude and delay of the initial dynamic discrimination level can be appropriately adjusted to find parameters that provide a good combination of indicators such as detection efficiency, post-pulse probability, and dark count, thereby enabling the detection of quantum optical signals using the adjusted dynamic discrimination level.

[0074] According to embodiments of this disclosure, the initial dynamic discrimination level delay is adjusted, and the statistical count of single-photon detectors is observed. When the overlap between the second time region (where the signal distribution is relatively concentrated) and the first time region of the single-photon detector count distribution, where the timing signal distribution probability satisfies a preset probability, meets a preset overlap threshold, the delay adjustment is stopped, thereby obtaining the dynamic discrimination level. The preset overlap threshold can be adjusted according to actual conditions, for example, it can be 90%.

[0075] According to embodiments of this disclosure, a quantum optical signal is photoelectrically converted to obtain an avalanche signal, including:

[0076] By applying a gating signal to the avalanche diode, the quantum optical signal is photoelectrically converted using the avalanche diode to obtain the avalanche signal.

[0077] According to embodiments of this disclosure, when a gating signal is applied to an avalanche diode, the avalanche diode is used to perform photoelectric conversion on a quantum optical signal to obtain an avalanche signal of current or voltage type.

[0078] According to embodiments of this disclosure, the signal processing method further includes:

[0079] The avalanche signal is filtered to obtain a filtered avalanche signal, and the level of the filtered avalanche signal is used to determine whether to generate a detection result.

[0080] According to embodiments of this disclosure, since there are many interference signals in the avalanche signal, such as noise signals and interference signals caused by gating signals, the actual avalanche signal is weak in amplitude in the signal output by the avalanche diode. Therefore, the avalanche signal output by the avalanche diode can be filtered to remove interference signals, thereby obtaining the required filtered avalanche signal.

[0081] According to embodiments of this disclosure, the signal processing method further includes:

[0082] The filtered avalanche signal is amplified to obtain an amplified avalanche signal. The level of the amplified avalanche signal is used to determine whether to generate a detection result. The threshold range of the dynamic discrimination level is determined based on the amplification factor and the fixed bias level.

[0083] According to the embodiments of this disclosure, since the amplitude of the avalanche signal is small, the filtered avalanche signal can be amplified by a signal amplifier to obtain an amplified avalanche signal. It should be noted that after signal amplification, the threshold range of the dynamic discrimination level is determined based on the amplification factor and the fixed bias level.

[0084] Figure 3The schematic diagram illustrates the principle of a signal processing method according to an embodiment of the present disclosure. Figure 4 A schematic diagram illustrating the loading of dynamic discrimination levels according to an embodiment of the present disclosure is shown.

[0085] According to embodiments of this disclosure, the level of the avalanche signal includes a first region and a second region, wherein the division of the first region and the second region is determined based on the distribution probability of the timing signal, and the distribution probability in the first region is greater than the distribution probability in the second region.

[0086] According to embodiments of this disclosure, when the level of the avalanche signal is greater than or equal to the dynamic discrimination level, a detection result corresponding to the quantum light signal is output, including:

[0087] For the first region, when the level in the first region is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output. The dynamic discrimination level is reduced based on the level distribution probability value in the first region.

[0088] For the second region, if the level in the second region is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output. The dynamic discrimination level is increased based on the level distribution probability value in the second region.

[0089] According to embodiments of this disclosure, such as Figure 3 As shown, the dynamic discrimination level increases in the time region (second region) where the probability of the discrimination timing signal distribution is relatively low during the gating cycle, and decreases in the time region (first region) where the probability of the discrimination timing signal distribution is relatively high. By changing the discrimination level within the gating cycle, the distribution of the discrimination timing signal in the time domain is altered, thereby compressing the half-width at half-maximum (WHM) of the detection count and improving the time resolution.

[0090] According to embodiments of this disclosure, a time component is introduced into the discrimination level of the avalanche signal. The discrimination level is lowered in time regions with a high probability of the discrimination timing signal distribution, increasing the avalanche signal discrimination count; conversely, the discrimination level is raised in time regions with a low probability of the discrimination timing signal distribution, decreasing the avalanche signal discrimination count. This disclosure aims to suppress the time jitter of the avalanche signal caused by random avalanche processes and reduce the time dispersion of the detection output. This method can improve the time resolution performance of single-photon detectors.

[0091] According to embodiments of this disclosure, such as Figure 4 As shown, the period of the dynamic discrimination level is consistent with the gating period. Since square wave frequency components are numerous and difficult to generate in practical single-photon detectors, while a sine wave with the same gating frequency can be obtained by filtering the gating signal, it is most convenient to use a sine wave generated by directly processing the gating signal for dynamic discrimination in practical single-photon detectors. Figure 4The diagram in the middle shows the loading of a sinusoidal dynamic discrimination level, where the negative half-axis of the sine wave is aligned with the first region where the probability of the discrimination timing signal distribution is high, and the positive half-axis is aligned with the second regions on both sides where the probability of the discrimination timing signal distribution is low.

[0092] Figure 5 A schematic block diagram of a signal processing apparatus according to an embodiment of the present disclosure is shown.

[0093] like Figure 5 As shown, the signal processing device 500 includes:

[0094] Acquisition module 510 is used to acquire quantum optical signals of single photons;

[0095] The avalanche diode 520 is used for photoelectric conversion of quantum optical signals to obtain avalanche signals;

[0096] Comparator 530 is used to output a detection result corresponding to the quantum light signal using a single-photon detector when the level of the avalanche signal is greater than or equal to the dynamic discrimination level, wherein the dynamic discrimination level is generated based on a fixed bias level and a capacitively coupled AC signal.

[0097] According to embodiments of this disclosure, the avalanche diode 520 may be made of InGaAs / InP material.

[0098] According to embodiments of this disclosure, a filter and an amplifier may also be provided after the avalanche diode 520 to filter and amplify the avalanche signal.

[0099] According to embodiments of this disclosure, a dynamic discrimination level generated based on a fixed bias level and a capacitively coupled AC signal is compared in real time with the level of the current avalanche signal. If the level of the avalanche signal is greater than or equal to the dynamic discrimination level, a detection result corresponding to the quantum optical signal is output. The dynamic discrimination level technology introduces a time component into the discrimination level amplitude, increasing the count rate in time regions with high avalanche probability and decreasing the count rate in time regions with low avalanche probability. This improves the temporal resolution of the single-photon detector, thereby reducing false counts. Especially in quantum key distribution systems, it can reduce the bit error rate and increase the generation rate of secure keys.

[0100] It should be noted that the signal processing device part in the embodiments of this disclosure corresponds to the signal processing method part in the embodiments of this disclosure. The specific description of the signal processing device part is referred to in the signal processing method part, and will not be repeated here.

[0101] Figure 6 A schematic block diagram of a quantum communication receiver according to an embodiment of the present disclosure is shown.

[0102] like Figure 6As shown, the quantum communication receiver 600 includes:

[0103] The single-photon detector 610 includes:

[0104] Signal processing device 500; used to output the detection result corresponding to the quantum light signal when the comparator 530 of the signal processing device 500 determines that the level of the avalanche signal is greater than or equal to the dynamic discrimination level.

[0105] According to embodiments of this disclosure, a dynamic discrimination level generated based on a fixed bias level and a capacitively coupled AC signal is compared in real time with the level of the current avalanche signal. If the level of the avalanche signal is greater than or equal to the dynamic discrimination level, a detection result corresponding to the quantum optical signal is output. The dynamic discrimination level technology introduces a time component into the discrimination level amplitude, increasing the count rate in time regions with high avalanche probability and decreasing the count rate in time regions with low avalanche probability. This improves the temporal resolution of the single-photon detector, thereby reducing false counts. Especially in quantum key distribution systems, it can reduce the bit error rate and increase the generation rate of secure keys.

[0106] It should be noted that the quantum communication receiver part in the embodiments of this disclosure corresponds to the signal processing method part in the embodiments of this disclosure. The specific description of the quantum communication receiver part is referred to in the signal processing method part, and will not be repeated here.

[0107] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A signal processing method applied to a quantum communication receiver, the method comprising: Acquiring quantum optical signals from single photons; The quantum optical signal is photoelectrically converted to obtain an avalanche signal; When the level of the avalanche signal is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output. The dynamic discrimination level is generated as follows: a fixed bias level is obtained when the single-photon detector is operating normally; the fixed bias level is increased; an AC signal with the same period as the gating period is introduced through capacitive coupling, and the AC signal is superimposed on the increased fixed bias level to obtain an initial dynamic discrimination level, wherein the increase in the fixed bias level is equal to the increase in the initial dynamic discrimination level; the initial dynamic discrimination level is then delayed to obtain the dynamic discrimination level. The avalanche signal level includes a first region and a second region. The division between the first region and the second region is determined based on the distribution probability of the timing signal when the single-photon detector counts. The distribution probability in the first region is greater than the distribution probability in the second region. When the level of the avalanche signal is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output, including: For the first region, when the level in the first region is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output; For the second region, when the level in the second region is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output.

2. The method according to claim 1, further comprising: A first time region is determined in which the timing signal distribution probability satisfies a preset probability when the single-photon detector count distribution is determined, so that the initial dynamic discrimination level is delayed according to the first time region.

3. The method according to claim 2, wherein, The initial dynamic discrimination level is delayed to obtain the dynamic discrimination level, including: The delay of the initial dynamic discrimination level is adjusted to obtain the adjusted dynamic level; Based on the adjusted dynamic level, a second time region is determined in which the timing signal distribution probability satisfies the preset probability when the single-photon detector count distribution is determined. If the overlap between the first time region and the second time region meets a preset overlap threshold, the adjusted dynamic level is determined as the dynamic discrimination level.

4. The method according to claim 1, wherein, The quantum optical signal is photoelectrically converted to obtain an avalanche signal, including: When a gating signal is applied to the avalanche diode, the quantum optical signal is photoelectrically converted using the avalanche diode to obtain the avalanche signal.

5. The method according to claim 1 or 4, further comprising: The avalanche signal is filtered to obtain a filtered avalanche signal, and the level of the filtered avalanche signal is used to determine whether to generate the detection result.

6. The method according to claim 5, further comprising: The filtered avalanche signal is amplified to obtain an amplified avalanche signal. The level of the amplified avalanche signal is used to determine whether to generate the detection result. The threshold range of the dynamic discrimination level is determined based on the amplification factor and the fixed bias level.

7. A signal processing apparatus, comprising: The acquisition module is used to acquire quantum optical signals of single photons; An avalanche diode is used to perform photoelectric conversion on the quantum optical signal to obtain an avalanche signal; A comparator is used to output a detection result corresponding to the quantum light signal using a single-photon detector when the level of the avalanche signal is greater than or equal to the dynamic discrimination level. The dynamic discrimination level is generated as follows: obtaining a fixed bias level when the single-photon detector is operating normally; increasing the fixed bias level; introducing an AC signal with the same period as the gating period through capacitive coupling, and superimposing the AC signal onto the increased fixed bias level to obtain an initial dynamic discrimination level, wherein the increase in the fixed bias level is equal to the magnitude of the initial dynamic discrimination level; and delaying the initial dynamic discrimination level to obtain the final dynamic discrimination level. The avalanche signal level includes a first region and a second region. The division between the first region and the second region is determined based on the distribution probability of the timing signal when the single-photon detector counts. The distribution probability in the first region is greater than the distribution probability in the second region. When the level of the avalanche signal is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output, including: For the first region, when the level in the first region is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output; For the second region, when the level in the second region is greater than or equal to the dynamic discrimination level, the detection result corresponding to the quantum optical signal is output.

8. A quantum communication receiver, comprising: Single-photon detectors, including: The signal processing apparatus as described in claim 7 is configured to output a detection result corresponding to the quantum optical signal when the comparator of the signal processing apparatus determines that the level of the avalanche signal is greater than or equal to the dynamic discrimination level.

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