Non-interference peak suppression device and method and quantum key distribution system

Abstract

The invention provides a non-interference peak suppression device and method and a quantum key distribution system, and relates to the technical field of quantum communication. The non-interference peak suppression device comprises a transmitting end and a receiving end, wherein the transmitting end comprises a laser pulser used for generating optical pulses at a quantum key distribution working frequency; the first unequal-arm interferometer is used for transmitting the optical pulse; the receiving end comprises a second unequal arm interferometer used for receiving the optical pulse transmitted by the transmitting end; the single-photon detector is used for obtaining the sum of photon counts, and the gating frequency of the single-photon detector is configured to be 2n times of quantum key distribution working frequency; and the polarization controller is used for calculating a non-interference peak suppression ratio according to the photon counting sum of the effective interference and the photon counting sum of the ineffective interference, and adjusting the photon polarization state of the transmitting end according to the non-interference peak suppression ratio, so that the non-interference peak suppression ratio is kept to be the lowest. According to the invention, photon counting of the interference peak and the non-interference peak can be obtained in each period, and dynamic suppression of the non-interference peak is realized in combination with real-time feedback adjustment.

Description

Technical Field

[0001] This application relates to the field of quantum communication technology, and more specifically, to a non-interference peak suppression device and method, and a quantum key distribution system. Background Technology

[0002] Quantum key distribution (QKD) systems leverage the non-cloning and measurement perturbation properties of quantum states to achieve absolutely secure key distribution. Their core structure includes a transmitter (Alice) and a receiver (Bob), both equipped with non-equilateral Mach-Zehnder interferometers (MZIs). The MZIs at the transmitter and receiver control and measure the phase difference of photons to encode and decode qubits (such as "0" and "1"), ensuring the security of key distribution.

[0003] In QKD systems, non-interfering peaks are signals without key information carrying capacity formed because photons fail to meet the coherent interference conditions. They directly affect the generation rate of secure keys. The essence of non-interfering peaks is that the temporal or spatial coherence of photons does not meet the interference requirements. Specific scenarios fall into two categories: First, a mismatch in the time difference between photons arriving at the receiver's MZI. Interference in non-equidistant MZIs depends on both beams arriving at the beam splitter at the same time. If the arm length of the receiver's MZI is not matched with that of the transmitter, the time difference between the two beams exceeds the photon coherence time, thus preventing interference. Second, polarization mismatch. During photon transmission, birefringence caused by fiber temperature fluctuations, vibrations, bending, or non-uniform fiber pulling can cause polarization drift, resulting in the polarization directions of the two beams being perpendicular, thus failing to meet the interference prerequisite.

[0004] Existing technologies for measuring and suppressing non-interference peaks have significant drawbacks: firstly, oscilloscopes have low measurement sensitivity and cannot directly detect single-photon level signals (QKD system optical power is typically ≤10). -12 W, while the minimum measurable optical power of the oscilloscope is ≥10 -6 Firstly, the time resolution is limited, making it difficult to capture details of narrow pulses in the sub-ns range. Secondly, the operation is complex and lacks real-time capability. Thirdly, the delay measurement of high-speed detectors requires changing the delay of the gating signal, which is not suitable for real-time monitoring during the dynamic operation of QKD systems. Fourthly, the code rate detection method based on QKD systems is subject to interference from multiple factors. The decrease in code rate cannot be attributed solely to the growth of non-interference peaks, and precise suppression cannot be achieved.

[0005] Therefore, there is an urgent need for a technical solution that can suppress non-interference peaks in real time and with high precision to overcome the shortcomings of existing technologies and ensure the key distribution efficiency and security of QKD systems. Summary of the Invention

[0006] To address the technical problems of poor real-time performance, low measurement accuracy, and inability to accurately adjust feedback in existing non-interference peak suppression techniques, this application provides a device, method, and quantum key distribution system that can achieve real-time monitoring and high-precision suppression of non-interference peaks.

[0007] According to a first aspect of this application, at least one embodiment of this application provides a non-interference peak suppression device, comprising: a transmitting end, including: a laser pulser for generating optical pulses at a quantum key distribution operating frequency; a first unequal-arm interferometer for transmitting the optical pulses, such that the optical pulses form a long-arm transmission path and a short-arm transmission path; a receiving end, including: a second unequal-arm interferometer for providing a long-arm receiving path and a short-arm receiving path to receive the optical pulses transmitted by the transmitting end; and a single-photon detector connected to the second unequal-arm interferometer for acquiring the sum of photon counts of effective interference and the sum of photon counts of ineffective interference within a first period, wherein the single-photon detector... The gating frequency of the sub-detector is configured to be 2n times the quantum key distribution operating frequency, wherein the effective interference is the case where the optical pulse selects different arm lengths during transmission at the transmitting end and the receiving end, and the ineffective interference is the case where the optical pulse selects the same arm length during transmission at the transmitting end and the receiving end, where n is an integer greater than or equal to 1; a polarization controller, connected to the transmitting end and the receiving end respectively, is used to calculate the non-interference peak suppression ratio based on the sum of photon counts of the effective interference and the sum of photon counts of the ineffective interference, and adjust the photon polarization state of the transmitting end according to the non-interference peak suppression ratio to keep the non-interference peak suppression ratio at its lowest.

[0008] For example, in some embodiments of this application, the single-photon detector includes: a first single-photon detector connected to the second unequal-arm interferometer to obtain the photon counts of effective interference and ineffective interference of the second unequal-arm interferometer; and a second single-photon detector connected to the second unequal-arm interferometer to obtain the photon counts of effective interference and ineffective interference of the second unequal-arm interferometer.

[0009] For example, in some embodiments of this application, the polarization controller calculates the non-interference peak suppression ratio according to the following formula:

[0010] Wherein, R is the non-interference peak suppression ratio. The sum of the effective interference photon counts obtained by the first single-photon detector and the second single-photon detector. This is the sum of the invalid interference photon counts obtained by the first single-photon detector and the second single-photon detector.

[0011] For example, in some embodiments of this application, the first single-photon detector and the second single-photon detector include: an avalanche single-photon detector and / or a superconducting detector.

[0012] For example, in some embodiments of this application, the formula for calculating the first period is:

[0013] in, For the first cycle, The operating frequency for the quantum key distribution is specified.

[0014] For example, in some embodiments of this application, the light pulses generated by the pulsed laser include single-photon and / or weakly coherent light pulses.

[0015] According to a second aspect of this application, at least one embodiment of this application provides a non-interference peak suppression method, the non-interference peak suppression method being performed by a non-interference peak suppression device as described in any of the first aspects, the non-interference peak suppression method comprising: generating an optical pulse at a quantum key distribution operating frequency; transmitting the optical pulse to generate an interference peak and a non-interference peak; detecting photon signals corresponding to the interference peak and the non-interference peak at 2n times the quantum key distribution operating frequency to obtain the sum of photon counts of effective interference and the sum of photon counts of ineffective interference within a first period; calculating a non-interference peak suppression ratio based on the sum of photon counts of effective interference and the sum of photon counts of ineffective interference; and adjusting the photon polarization state at the receiving end of the non-interference peak suppression device according to the non-interference peak suppression ratio to keep the non-interference peak suppression ratio at its lowest.

[0016] For example, in some embodiments of this application, the non-interference peak suppression ratio is calculated according to the following formula:

[0017] in, To obtain the total number of photons for effective interference, The sum of photon counts for obtaining invalid interference.

[0018] For example, in some embodiments of this application, the first period is calculated according to the following formula:

[0019] in, For the first cycle, The operating frequency for the quantum key distribution is specified.

[0020] According to a third aspect of this application, at least one embodiment of this application provides a quantum key distribution system, including: a non-interference peak suppression device as described in any one of the first aspects.

[0021] Through the above exemplary embodiments, the non-interference peak suppression device and method, and quantum key distribution system provided in this application have at least one of the following beneficial effects: High real-time performance: The single-photon detector adopts a gating configuration with a working frequency of 2n times that of QKD, which can synchronously acquire the photon counts of interference peaks and non-interference peaks in each cycle. Combined with the real-time feedback adjustment of the polarization controller, dynamic suppression of non-interference peaks can be achieved.

[0022] High measurement accuracy: It adopts an avalanche single-photon detector, which can directly detect single-photon level signals, avoiding the problem of insufficient sensitivity of classic tools such as oscilloscopes. Furthermore, it accurately reflects the amplitude of non-interference peaks through dual-detector counting summation and suppression ratio calculation.

[0023] Reduced bit error rate: When n=1 (gating frequency is twice the QKD operating frequency), the non-interference peak detection period can absorb the after-pulse effect of the avalanche single-photon detector, avoiding the influence of the after-pulse on the detection results of the interference peak (including key information), and significantly reducing the system bit error rate.

[0024] Wide adaptability: It supports integer configuration of n≥1, which can be flexibly adjusted according to the working frequency, optical pulse width and other parameters of the QKD system to adapt to the non-interference peak suppression requirements in different scenarios.

[0025] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0026] The above and other objects, features, and advantages of this application will become more apparent from the detailed description of exemplary embodiments with reference to the accompanying drawings. The drawings described below are merely some embodiments of this application and are not intended to limit the scope of this application.

[0027] Figure 1 This is a schematic diagram of the non-interference peak suppression device according to an embodiment of this application; Figure 2 A schematic diagram illustrating photon counting by an exemplary single-photon detector is shown.

[0028] Explanation of reference numerals in the attached figures: 1-Sender, 11-Laser pulser; 12-First unequal-arm interferometer; 2-Receiver, 21-Second unequal arm interferometer, 22-Single photon detector: 221-First single photon detector, 222-Second single photon detector; 3-Polarization controller. Detailed Implementation

[0029] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0030] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0031] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0032] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0033] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, and therefore cannot be used to limit the scope of protection of this application.

[0034] Figure 1 This is a schematic diagram of the non-interference peak suppression device according to an embodiment of this application.

[0035] like Figure 1 As shown, the non-interference peak suppression device includes: a transmitter 1, a receiver 2, and a polarization controller 3.

[0036] The transmitting end 1 includes a laser pulser 11 and a first unequal arm interferometer 12.

[0037] Laser pulser 11 is used for quantum key distribution at a frequency (f QKD The light pulse is generated. The light pulse is a single-photon and / or weakly coherent light pulse with a pulse width in the sub-ns range (e.g., 100 ps and below).

[0038] The first unequal-arm interferometer 12 is connected to the laser pulser 11 and is used to transmit the light pulse, so that the light pulse forms a long-arm transmission path and a short-arm transmission path, which provides a basis for the generation of subsequent interference effects.

[0039] The receiver 2 includes a second unequal arm interferometer 21 and a single-photon detector 22.

[0040] The second unequal-arm interferometer 21 is used to provide a long-arm receiving path and a short-arm receiving path to receive the light pulses transmitted by the transmitter 1. The selection of its arm length, together with the selection of the arm length of the transmitter, determines whether the interference is effective.

[0041] A single-photon detector 22 is connected to a second unequal-arm interferometer 21 to obtain the total photon counts of effective interference (C_2n-1) and the total photon counts of ineffective interference (C_2n) within the first period, respectively. The gate frequency of the single-photon detector is configured to be 2n times the quantum key distribution operating frequency (2n×f). QKD ).

[0042] Where n is an integer greater than or equal to 1. Effective interference is the case where the light pulses are transmitted at the transmitting and receiving ends with different arm lengths (e.g., the transmitting end selects a long arm and the receiving end selects a short arm, or vice versa). Ineffective interference is the case where the light pulses are transmitted at the transmitting and receiving ends with the same arm length (both select long arms or both select short arms).

[0043] Furthermore, the formula for calculating the first cycle is:

[0044] in, For the first cycle, The operating frequency for quantum key distribution.

[0045] Furthermore, the single-photon detector 22 includes a first single-photon detector 221 and a second single-photon detector 222.

[0046] The first single-photon detector 221 is connected to the second unequal-arm interferometer 21 to obtain the photon counts of effective interference and ineffective interference from the second unequal-arm interferometer 21. The second single-photon detector 222 is connected to the second unequal-arm interferometer 22 to obtain the photon counts of effective interference and ineffective interference from the second unequal-arm interferometer 21.

[0047] Furthermore, the first and second single-photon detectors include avalanche single-photon detectors (APD), superconducting detectors, etc., which have high sensitivity and can accurately detect single-photon level signals.

[0048] The polarization controller 3 is signal-connected to the transmitter 1 and the receiver 2. It is used to calculate the non-interference peak suppression ratio based on the sum of photon counts of effective interference and the sum of photon counts of ineffective interference, and adjust the photon polarization state of the transmitter based on the suppression ratio. This is used to compensate for the photon polarization state drift generated during optical fiber link transmission, so as to keep the non-interference peak suppression ratio at the lowest level, ensure that the photon polarization state of the transmitter matches the decoding requirements, and thus suppress the amplitude of the non-interference peak.

[0049] Furthermore, the polarization controller calculates the non-interference peak suppression ratio R according to the following formula:

[0050] Where R is the non-interference peak suppression ratio, The sum of the effective interference photon counts obtained by the first and second single-photon detectors. The sum of the invalid interference photon counts obtained by the first and second single-photon detectors.

[0051] This application also provides a non-interference peak suppression method, executed by the non-interference peak suppression device described above, comprising the following steps: S1: The laser pulser operates at the quantum key distribution frequency (f... QKD It generates light pulses.

[0052] The optical pulse is a single-photon and / or weakly coherent optical pulse; S2: The first unequal-arm interferometer at the transmitting end transmits the light pulse, forming a long-arm transmission path and a short-arm transmission path. After transmission, the light pulse reaches the second unequal-arm interferometer at the receiving end. Based on the selection of the arm lengths at the transmitting and receiving ends, interference peaks (effective interference) and non-interference peaks (ineffective interference) are generated.

[0053] S3: Single-photon detectors operate at 2n times the quantum key distribution frequency (2n×f). QKD ) Detect the photon signals corresponding to the interference peak and non-interference peak in the first period The total number of photons with effective interference (C_2n-1) and the total number of photons with ineffective interference (C_2n) are obtained respectively.

[0054] S4: The polarization controller is based on the formula Calculate the non-interference peak suppression ratio R.

[0055] S5: The polarization controller adjusts the photon polarization state at the receiving end according to the non-interference peak suppression ratio R, so that R is always kept at the lowest level, thereby suppressing the amplitude of the non-interference peak.

[0056] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0057] Example 1 In this embodiment, n=1 (preferred embodiment), the quantum key distribution operating frequency f QKD =1.25GHz, the gate frequency of the single-photon detector f_detector=2×1.25GHz=2.5GHz, the first period Δt=1 / 1.25GHz=800ps.

[0058] like Figure 1 As shown, the non-interference peak suppression device includes: a transmitter 1, a receiver 2, and a polarization controller 3. The laser pulser 11 of the transmitter 1 generates weak coherent optical pulses with a pulse width of less than 100ps at a repetition frequency of 1.25GHz. After the optical pulses enter the first unequal arm interferometer 12, they are divided into a long arm transmission path and a short arm transmission path.

[0059] The second unequal arm interferometer 21 of receiver 2 provides a long arm receiving path and a short arm receiving path to receive optical pulses transmitted via a transmission link (fiber optic link).

[0060] The first single-photon detector 221 (APD) and the second single-photon detector 222 (APD) are both connected to the output end of the second unequal-arm interferometer 21. Both of them count photons at a gate frequency of 2.5 GHz and record the counting result once every 800 ps.

[0061] like Figure 2 As shown, when transmitter 1 selects the long arm and receiver 2 selects the short arm, or when transmitter 1 selects the short arm and receiver 2 selects the long arm, effective interference is formed, and the sum of the counts of the first single-photon detector 221 and the second single-photon detector 222 is C_2n-1; when both transmitter 1 and receiver 2 select the long arm or both select the short arm, ineffective interference is formed, and the counts of the two detectors are approximately equal, and the sum of the two counts is C_2n.

[0062] The polarization controller 3 receives C_2n-1 and C_2n in real time and calculates the suppression ratio R according to the formula R=C_2n / (C_2n+C_2n-1). When R increases, it indicates that the photon polarization state mismatch leads to an increase in the amplitude of the non-interference peak. The polarization controller 23 performs reverse compensation on the photon polarization state by adjusting the internal waveplate angle until R stabilizes at the lowest level, ensuring that the two beams of light meet the interference premise of polarization consistency.

[0063] In this embodiment, the gate frequency is twice the QKD operating frequency, which not only ensures the accurate distinction between interference peaks and non-interference peaks (the counting interval matches the natural interval between the two peaks), but also utilizes the non-interference peak detection period to carry over the pulse effect, thereby reducing the system bit error rate and achieving real-time suppression of non-interference peaks.

[0064] Example 2 In this embodiment, n=2, and the quantum key distribution operating frequency f QKD =1GHz, the gate frequency of the single-photon detector f_detector=4GHz, the first period Δt=1 / 1GHz=1000ps.

[0065] The device structure is consistent with that of Embodiment 1. The laser pulser generates single-photon pulses with a pulse width of 80 ps. The first and second single-photon detectors count at a gate frequency of 4 GHz. The polarization controller calculates the suppression ratio R based on C₂ⁿ⁻¹ and C₂ⁿ and adjusts the polarization state accordingly. This embodiment is suitable for QKD systems with narrower optical pulse widths, enabling high-frequency monitoring and suppression of non-interference peaks and ensuring system stability at high operating frequencies.

[0066] This application is not limited to the above embodiments. Without departing from the core idea of ​​this invention, those skilled in the art can adjust the gating frequency multiple, QKD operating frequency, optical pulse type, etc. according to actual needs. All improvements and modifications based on the technical solutions of this application fall within the protection scope of this invention.

[0067] This application also provides a quantum key distribution system, including the non-interference peak suppression device described above. The device enables real-time, high-precision suppression of non-interference peaks. By adjusting the photon phase difference between the transmitting and receiving ends, the encoding and decoding of quantum bits ("0" and "1") are achieved. At the same time, the security and code rate of key distribution are ensured by utilizing the non-cloning nature of quantum states and the measurement perturbation characteristics.

[0068] Through the above example embodiments, the non-interference peak suppression device, method, and quantum key distribution system provided in this application have the following beneficial effects: The single-photon detector adopts a gating configuration of 2n times the QKD operating frequency, which can synchronously acquire the photon counts of interference peaks and non-interference peaks in each cycle. Combined with the real-time feedback adjustment of the polarization controller, dynamic suppression of non-interference peaks is achieved, with strong real-time performance. At the same time, the avalanche single-photon detector can directly detect single-photon level signals, avoiding the sensitivity problem of classical tools such as oscilloscopes. Moreover, by summing the counts of the two detectors and calculating the suppression ratio, the amplitude of the non-interference peak can be accurately reflected, and the measurement accuracy is greatly improved. When n=1 (the gating frequency is 2 times the QKD operating frequency), the non-interference peak detection period can inherit the after-pulse effect of the avalanche single-photon detector, avoiding the influence of the after-pulse on the detection result of the interference peak containing key information, and significantly reducing the system bit error rate. In addition, this application supports integer configurations of n≥1, which can be flexibly adjusted according to the operating frequency of the QKD system, the optical pulse width, and other parameters to adapt to the non-interference peak suppression requirements in different scenarios, with wide adaptability.

[0069] It should be clearly understood that this application describes how specific examples are formed and used, but this application is not limited to any details of these examples. Rather, based on the teachings of the disclosure of this application, these principles can be applied to many other embodiments.

[0070] Furthermore, it should be noted that the above figures are merely illustrative representations of the processes included in the method according to exemplary embodiments of this application, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0071] Exemplary embodiments of this application have been specifically shown and described above. It should be understood that this application is not limited to the detailed structures, arrangements, or implementation methods described herein; rather, this application is intended to cover various modifications and equivalent arrangements that fall within the objectives and scope of the appended claims.

Claims

1. A non-interference peak suppression device, characterized in that, include: The sending end includes: Laser pulsers are used to generate optical pulses at quantum key distribution operating frequencies. The first unequal-arm interferometer is used to transmit the optical pulse, so that the optical pulse forms a long-arm transmission path and a short-arm transmission path. The receiving end includes: The second unequal-arm interferometer is used to provide a long-arm receiving path and a short-arm receiving path to receive the light pulses transmitted by the transmitting end; A single-photon detector, connected to the second unequal-arm interferometer, is used to obtain the total number of photons with effective interference and the total number of photons with ineffective interference within the first period, respectively. The gate frequency of the single-photon detector is configured to be 2n times the quantum key distribution operating frequency. The effective interference is the case where the light pulse selects different arm lengths during transmission at the transmitting end and the receiving end, and the ineffective interference is the case where the light pulse selects the same arm length during transmission at the transmitting end and the receiving end, where n is an integer greater than or equal to 1. A polarization controller, connected to the transmitting end and the receiving end respectively, is used to calculate the non-interference peak suppression ratio based on the sum of photon counts of effective interference and the sum of photon counts of ineffective interference, and to adjust the photon polarization state of the transmitting end based on the non-interference peak suppression ratio so that the non-interference peak suppression ratio is kept to the minimum.

2. The non-interference peak suppression device as described in claim 1, characterized in that, The single-photon detector includes: A first single-photon detector is connected to the second unequal-arm interferometer to obtain the photon counts of effective interference and ineffective interference of the second unequal-arm interferometer. The second single-photon detector is connected to the second unequal-arm interferometer to obtain the photon counts of effective interference and ineffective interference of the second unequal-arm interferometer.

3. The non-interference peak suppression device as described in claim 2, characterized in that, The polarization controller calculates the non-interference peak suppression ratio according to the following formula: Wherein, R is the non-interference peak suppression ratio. The sum of the effective interference photon counts obtained by the first single-photon detector and the second single-photon detector. This is the sum of the invalid interference photon counts obtained by the first single-photon detector and the second single-photon detector.

4. The non-interference peak suppression device as described in claim 2, characterized in that, The first single-photon detector and the second single-photon detector include: an avalanche single-photon detector and / or a superconducting detector.

5. The non-interference peak suppression device as described in claim 1, characterized in that, The formula for calculating the first cycle is: in, For the first cycle, The operating frequency for the quantum key distribution is specified.

6. The non-interference peak suppression device as described in claim 1, characterized in that, The optical pulses generated by the pulsed laser include single-photon and / or weakly coherent optical pulses.

7. A non-interference peak suppression method, characterized in that, The non-interference peak suppression method is performed by the non-interference peak suppression device as described in any one of claims 1-6, and the non-interference peak suppression method includes: Generate light pulses at the quantum key distribution operating frequency; The optical pulses are transmitted, generating interference peaks and non-interference peaks; The photon signals corresponding to the interference peak and the non-interference peak are detected at a quantum key distribution operating frequency of 2n times, so as to obtain the sum of photon counts of effective interference and the sum of photon counts of ineffective interference within the first period; The non-interference peak suppression ratio is calculated based on the sum of photon counts of effective interference and the sum of photon counts of ineffective interference; The photon polarization state at the receiving end of the non-interference peak suppression device is adjusted according to the non-interference peak suppression ratio to keep the non-interference peak suppression ratio at its lowest.

8. The non-interference peak suppression method as described in claim 7, characterized in that, The non-interference peak suppression ratio is calculated according to the following formula: in, To obtain the total number of photons for effective interference, The sum of photon counts for obtaining invalid interference.

9. The non-interference peak suppression method as described in claim 7, characterized in that, The first cycle is calculated using the following formula: in, For the first cycle, The operating frequency for the quantum key distribution is specified.

10. A quantum key distribution system, characterized in that, include: The non-interference peak suppression device as described in any one of claims 1-6.

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