Delay parameter adjustment method, device and decoy state modulation method

Abstract

The present application relates to the technical field of key distribution, and provides a delay parameter adjustment method, device and decoy state modulation method, wherein the delay parameter adjustment method first obtains a single-photon negative feedback optical signal, and then obtains a detection count signal, the detection count signal is obtained according to the single-photon negative feedback optical signal, and a first ratio is calculated based on the detection count signal, the first ratio is a ratio parameter of a signal state and a decoy state, if the first ratio is greater than or equal to a first ratio threshold, a first target parameter and a second target parameter are obtained by a counting rule or a ratio rule, so that in the optical signal corresponding to the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter, the ratio of the signal state to the decoy state is less than the first ratio threshold. The method can solve the problem of low security in the preparation of the decoy state by adjusting the ratio of the signal state to the decoy state in real time.

Description

Technical Field

[0001] The present application relates to the field of key distribution technology, and in particular to a delay parameter adjustment method, device and decoy state modulation method. Background Art

[0002] In the quantum key distribution system, the BB84 protocol for decoy states requires the sender to complete the preparation of decoy states. There are many ways to prepare decoy states, such as internal modulation and external modulation. Internal modulation uses different driving voltages to load on the laser module to produce different luminous intensities, thereby realizing the preparation of signal states and decoy states; external modulation loads modulation signals of different amplitudes on the pulse light source to adjust the light intensity and complete the preparation of signal states and decoy states.

[0003] In the process of internal modulation, different driving electrical signals are loaded into the laser. In the time domain, the delay of the two driving signals needs to be consistent. Internal modulation can make the delay of the two paths consistent through the delay chip. External modulation achieves delay through the modulator.

[0004] However, the delay chip and modulator will change with temperature, the output signal state and spoofed state of the laser will shift in the time domain, and the modulation point of the modulator will shift with temperature changes, thereby affecting the ratio of the signal state and the spoofed state, all of which lead to low safety in the preparation of the spoofed state. Summary of the invention

[0005] The present application provides a delay parameter adjustment method, device and entrapped state modulation method to solve the problem of low safety in the preparation of entrapped states.

[0006] In a first aspect, the present application provides a delay parameter adjustment method, comprising:

[0007] Acquire a single-photon negative feedback optical signal, wherein the single-photon negative feedback optical signal is obtained by splitting an optical signal output by a laser according to an input electrical signal, wherein the electrical signal is obtained according to a first electrical signal output by a first delay chip and a second electrical signal output by a second delay chip;

[0008] Acquiring a detection counting signal, wherein the detection counting signal is obtained according to the single-photon negative feedback optical signal;

[0009] Calculating a first ratio based on the detection count signal, wherein the first ratio is a ratio parameter of a signal state to a decoy state in the single-photon negative feedback optical signal;

[0010] If the first ratio is greater than or equal to a first ratio threshold, the first target parameter and the second target parameter are obtained by counting rules or ratio rules, so that in the optical signals corresponding to the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter, the ratio of the signal state to the decoy state is less than the first ratio threshold.

[0011] In some feasible embodiments, the calculating the first ratio based on the detection count signal includes:

[0012] Acquire first position information, wherein the first position information includes position information of the optical signal in the decoy state and position information of the optical signal in the signal state;

[0013] Acquire second position information based on the detection counting signal, where the second position information is time position information of the detection counting signal;

[0014] Comparing the first position information with the second position information to output a first count and a second count, wherein the first count is a signal state count and the second count is a decoy state count;

[0015] A first ratio is calculated using the first count and the second count.

[0016] In some feasible embodiments, the obtaining the first target parameter and the second target parameter by using a counting rule or a ratio rule includes:

[0017] Adjust the first delay parameter to obtain a third count, and adjust the second delay parameter to obtain a fourth count, wherein the first delay parameter is an initial parameter of the first delay chip, the second delay parameter is an initial parameter of the second delay chip, the third count is the adjusted first count, and the fourth count is the adjusted second count;

[0018] Iterate the adjustment process, if the third count is greater than or equal to a first preset value, obtain a first target parameter, and if the fourth count is greater than or equal to a second preset value, obtain a second target parameter.

[0019] In some feasible embodiments, the obtaining the first target parameter and the second target parameter by using a counting rule or a ratio rule includes:

[0020] Adjusting the first delay parameter and iterating the adjustment process;

[0021] calculating a second ratio, wherein the second ratio is the adjusted first ratio;

[0022] If the second ratio is less than or equal to a second ratio threshold, a first target parameter is obtained.

[0023] In some feasible embodiments, the obtaining the first target parameter and the second target parameter by using a counting rule or a ratio rule includes:

[0024] Adjusting the second delay parameter and iterating the adjustment process;

[0025] calculating a third ratio, wherein the third ratio is the adjusted first ratio;

[0026] If the third ratio is greater than or equal to a third ratio threshold, a second target parameter is obtained.

[0027] In some feasible embodiments, the obtaining the first location information includes:

[0028] Detecting a time position, wherein the time position is a time position of the counting signal relative to a system synchronization light;

[0029] In response to the query instruction, first optical signal information and second optical signal information are acquired, wherein the first optical signal is optical signal information in a decoy state emitted by the control device, and the second optical signal is optical signal information in a signal state emitted by the control device;

[0030] Based on the first optical signal information and the second optical signal information, the time position is matched to output first position information.

[0031] In some feasible embodiments, obtaining a single-photon negative feedback optical signal includes:

[0032] Acquiring an optical signal;

[0033] Splitting the optical signal to output a system optical signal and a negative feedback optical signal;

[0034] The negative feedback optical signal is attenuated to output a single-photon negative feedback optical signal.

[0035] In a second aspect, the present application provides a delay parameter adjustment device, comprising:

[0036] A single-photon detection module, used for acquiring a single-photon negative feedback optical signal, wherein the single-photon negative feedback optical signal is obtained by splitting an optical signal output by a laser according to an input electrical signal, wherein the electrical signal is obtained according to a first electrical signal output by a first delay chip and a second electrical signal output by a second delay chip; and acquiring a detection count signal, wherein the detection count signal is obtained according to the single-photon negative feedback optical signal;

[0037] An information processing module, configured to calculate a first ratio based on the detection counting signal, wherein the first ratio is a ratio parameter of a signal state to a decoy state in the single-photon negative feedback optical signal;

[0038] If the first ratio is greater than or equal to a first ratio threshold, it also includes a modulation control unit, which is used to obtain the first target parameter and the second target parameter through a counting rule or a ratio rule, so that in the optical signals corresponding to the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter, the ratio of the signal state to the decoy state is less than the first ratio threshold.

[0039] In some feasible embodiments, it also includes:

[0040] A beam splitter, used for splitting the optical signal to output a system optical signal and a negative feedback optical signal;

[0041] The attenuator is used to attenuate the negative feedback optical signal to output a single-photon negative feedback optical signal.

[0042] In a third aspect, the present application provides a spoofed state modulation method, comprising:

[0043] Acquire a first target parameter and a second target parameter, wherein the first target parameter and the second target parameter are acquired by a counting rule or a ratio rule, and are used to make the ratio of the signal state to the decoy state in the optical signal outputted by the first delay chip according to the first electrical signal outputted according to the first target parameter smaller than a first ratio threshold, wherein the first ratio is a ratio parameter of the signal state to the decoy state in the single-photon negative feedback optical signal;

[0044] Setting the delay parameter of the first delay chip to a first target parameter to output a first electrical signal, and setting the delay parameter of the second delay chip to a second target parameter to output a second electrical signal;

[0045] Converting the first electrical signal into a first drive signal, and converting the second electrical signal into a second drive signal;

[0046] A signal state is outputted by the first driving signal, and a decoy state is outputted by the second driving signal.

[0047] It can be seen from the above technical scheme that the present application provides a delay parameter adjustment method, device and decoy state modulation method, the delay parameter adjustment method first obtains a single-photon negative feedback optical signal, the negative feedback optical signal is obtained by splitting the optical signal output by the laser according to the input electrical signal, the electrical signal is obtained according to the first electrical signal output by the first delay chip and the second electrical signal output by the second delay chip, and then obtains a detection count signal, the detection count signal is obtained according to the single-photon negative feedback optical signal; based on the detection count signal, a first ratio is calculated, and the first ratio is a ratio parameter of the signal state and the decoy state in the single-photon negative feedback optical signal; if the first ratio is greater than or equal to the first ratio threshold, the first target parameter and the second target parameter are obtained by counting rules or ratio rules, so that the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter The optical signal corresponding to the output, the ratio of the signal state to the decoy state is less than the first ratio threshold. The method can solve the problem of low safety in the preparation of the decoy state by adjusting the ratio of the signal state to the decoy state in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0049] Figure 1 A flowchart of a delay parameter adjustment method provided in an embodiment of the present application;

[0050] Figure 2 A schematic diagram of a process for generating an optical signal provided in an embodiment of the present application;

[0051] Figure 3 A comparison diagram of signals a1 and b1 provided in an embodiment of the present application;

[0052] Figure 4 A comparison diagram of signals a2 and b2 provided in an embodiment of the present application;

[0053] Figure 5 A comparison diagram of the affected signals a2 and b2 provided in an embodiment of the present application;

[0054] Figure 6 A diagram of the generation process of an optical signal provided in an embodiment of the present application;

[0055] Figure 7 A schematic diagram of an optical signal after being affected provided in an embodiment of the present application;

[0056] Figure 8A schematic diagram of a process for obtaining a first target parameter through a counting rule provided in an embodiment of the present application;

[0057] Fig. 9 A schematic diagram of a process for obtaining a first target parameter through a ratio rule provided in an embodiment of the present application;

[0058] Fig.10 A schematic diagram of a process for obtaining a second target parameter by using a ratio rule provided in an embodiment of the present application;

[0059] Fig.11 A schematic diagram of a delay parameter adjustment device provided in an embodiment of the present application;

[0060] Fig.12 A schematic flow chart of the induced state modulation method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0061] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following embodiments do not represent all embodiments consistent with the present application.

[0062] In the quantum key distribution system, the preparation of the decoy state is more important for the security of the system. However, whether internal modulation or external modulation is used, the impact of temperature changes will occur. Among them, internal modulation relies on the delay chip to maintain the consistency of the two-way drive signal, but is greatly affected by temperature. External modulation relies on the stability and delay control of the modulator, and is also affected by temperature changes. Temperature changes will significantly affect the characteristics of the delay chip and modulator, resulting in an imbalance in the ratio of the signal state and the decoy state. These changes will cause the characteristics of the delay chip and modulator to drift, which in turn affects the time synchronization and ratio accuracy of the signal state and the decoy state, thereby reducing the security of the preparation of the decoy state.

[0063] To solve the problem of low security of decoy state preparation, such as Figure 1 As shown, some embodiments of the present application provide a delay parameter adjustment method, including:

[0064] S100: Acquire a single-photon negative feedback optical signal.

[0065] The single-photon negative feedback optical signal is obtained by splitting the optical signal output by the laser according to the input electrical signal, and the electrical signal is obtained according to the first electrical signal output by the first delay chip and the second electrical signal output by the second delay chip. Specifically, in order to obtain the single-photon negative feedback optical signal, in some embodiments, it includes: first obtaining the optical signal, then splitting the optical signal to output the system optical signal and the negative feedback optical signal, and then outputting the single-photon negative feedback optical signal through the attenuator.

[0066] The optical signal is loaded into the laser through different driving electrical signals to generate an optical signal including a signal state and a decoy state. In order to obtain the optical signal, in some embodiments, a random number sequence is first generated, and then the random number sequence is allocated to determine the signal state or the decoy state, and then two signals with random number sequence information are generated. After the delay chip receives the signal, it performs delay processing, and the driving unit receives the signal after delay processing, converts it into a driving signal, and then drives the laser to output the optical signal through capacitive coupling.

[0067] The control device has a built-in random number generator, which is used to generate a random number sequence. The random number generator can be a hardware-based random number generator, such as a quantum random number generator, or a software-based pseudo-random number generator, that is, these random numbers can be true random numbers, such as those generated by a quantum random number generator, or pseudo-random numbers, such as those generated by an algorithm. The generated random number sequence is assigned to each pulse to determine its type, where the type includes a signal state and a decoy state. For example, 0 represents a signal state and 1 represents a decoy state.

[0068] like Figure 2 As shown, the control device generates signal a1 and signal b1, and signal a1 and signal b1 contain information of random number sequence. Delay chip A, i.e., the first delay chip, receives signal a1, and delay chip B, i.e., the second delay chip, receives signal b1, wherein delay chip A and delay chip B include programmable delay units, which can adjust delay parameters and perform delay processing on the signal according to preset delay parameters to align the accuracy of the signal state with the decoy state.

[0069] Delay chip A receives signal a1, performs delay processing according to preset delay parameters, and outputs signal a2, i.e., the first electrical signal. Delay chip B receives signal b1, performs delay processing according to preset delay parameters, and outputs signal b2, i.e., the second electrical signal.

[0070] The driving unit A receives the signal a2 and converts it into a driving signal a3 for driving the laser. The driving unit B receives the signal b2 and converts it into a driving signal b3 for driving the laser. The driving unit converts the delayed signal into a driving signal for driving the laser. The driving unit may include an amplifier, a modulator, etc., so that the signal can effectively drive the laser.

[0071] The driving signal output by the driving unit is AC coupled through a capacitor. AC coupling can eliminate DC bias in the driving signal, which helps to make the laser more stable. In addition, AC coupling can isolate the DC component in the signal to prevent the DC component from affecting subsequent circuits. It can also suppress low-frequency noise, retain high-frequency signals, and improve signal purity.

[0072] The driving signal a3 is AC coupled through capacitor C1, and the signal b3 is AC coupled through capacitor C2. The capacitor can remove the DC component in the signal and only allow the AC component to pass. Then the AC coupled signal a3 and signal b3 are combined to generate a driving signal. The optical signal is generated through the driving signal. The optical signal is a light pulse containing a signal state and a decoy state.

[0073] like Figure 3 As shown, when the controller generates signal a1 and signal b1, only signal a1 or signal b1 is output at a certain moment, and they will not appear at the same time. The amplitudes of signal a1 and signal b1 are the same, and there is a phase difference in phase.

[0074] like Figure 4 As shown in the figure, after passing through delay chip A and delay chip B, the amplitude and phase of signal a1 and signal b1 are exactly the same. However, in actual applications, due to the individual differences of delay chips and the influence of temperature, signal a2 and signal b2 will have a certain uncertain phase difference, such as Figure 5 As shown in the figure, the phase difference caused by temperature will cause the ratio of the signal state to the decoy state to change, which will cause the system to fail to work normally and stably.

[0075] like Figure 6 As shown, the timing shows the generation process of the optical signal. Due to the different driving amplitudes of signal a3 and signal b3 being loaded on it, an optical signal is obtained, that is, a quantum state optical signal containing a decoy state and a signal state.

[0076] Since the delay chip A and the delay chip B are affected by temperature, their delay positions will drift. Therefore, Figure 7 As shown in the figure, the position of the optical signal may change in the actual system. When affected by temperature, the decoy state moves from the original position of the dotted line to a new position. In other words, when the detector detects single photons at the position of the dotted line, its count will drop significantly, resulting in a change in the ratio of the signal state to the decoy state.

[0077] In this embodiment, after obtaining the optical signal, it is split by a beam splitter, one of which is used as a system optical signal for the normal operation of the system, and the other is used as a negative feedback optical signal for monitoring and adjustment inside the system. For the sake of convenience, in this embodiment, the system optical signal is defined as the first light, and the negative feedback optical signal is defined as the second light. The splitting ratio of the beam splitter can be 50:50, 40:60, 30:70, 20:80, 10:90, 1:99, 1:999, etc. According to actual needs, a suitable splitting ratio can be selected to balance the intensities of the system optical signal and the negative feedback optical signal.

[0078] In some embodiments, the second path of light passes through an attenuator and is converted into a single-photon negative feedback optical signal. After the conversion, the number of photons in the optical signal is controlled or limited to a single photon. In an optical signal system, a negative feedback mechanism is used to stabilize parameters such as the intensity, frequency, or phase of an optical signal. When the optical signal passes through an attenuator, the attenuator reduces the intensity of the optical signal according to preset parameters. If the attenuation of the attenuator is large enough so that the intensity of the optical signal at the output end is reduced to a level close to or lower than the energy level of a single photon, the output optical signal is a negative feedback optical signal (single photon).

[0079] S200: Acquire a detection count signal.

[0080] The detection count signal is obtained according to the single-photon negative feedback light signal. After the single-photon negative feedback light signal is obtained, the single-photon negative feedback light signal is detected by a detector to output the detection count signal. The single-photon negative feedback light signal is an optical signal, which is difficult to directly perform subsequent information processing and analysis.

[0081] When a photon passes through the detector, it will cause the number of charge carriers in the detector to change. This change can be detected and converted into an electrical signal. The electrical signal output by the detector is the detection count signal. Each detection count signal represents a detected photon. By converting it into a detection count signal, the count data of the electrical signal can be obtained. For example, the detector can calculate the number of photons detected within a certain period of time based on the intensity and appearance time of the light signal. These count data are easy to store, process and transmit.

[0082] S300: Calculate a first ratio based on the detection count signal.

[0083] Every time a single photon is successfully detected, the detector generates a detection count signal. Measuring the time position of each detection count signal relative to the system synchronization light, that is, the reference signal, helps to determine the specific moment when each detection event occurs.

[0084] Among them, the first ratio is a ratio parameter of the signal state and the decoy state in the single-photon negative feedback light signal. To obtain the first ratio, in some embodiments, the first position information is first obtained, and then the second position information is obtained based on the detection count signal, the first position information is compared with the second position information, and the first count and the second count are output. The first ratio is calculated through the first count and the second count.

[0085] The first position information includes position information of the optical signal in a decoy state and position information of the optical signal in a signal state. To obtain the first position information, in some embodiments, the time position is first detected, wherein the time position is the time position of the counting signal relative to the system synchronization light; in response to the query instruction, the first optical signal information and the second optical signal information are obtained, wherein the first optical signal is the optical signal information in a decoy state emitted by the control device, and the second optical signal is the optical signal information in a signal state emitted by the control device; based on the first optical signal information and the second optical signal information, the first position information is matched with the time position and output.

[0086] The control device stores information about the light signal emitted at each time point. For example, the control device stores this information in an internal memory or database. That is, by interacting with the control device, it can be obtained whether the light signal emitted at a time point is in a decoy state or a signal state.

[0087] When an optical signal is received and a counting signal is generated, the time position of each detected counting signal relative to the system synchronization light, such as a clock signal, is measured. In order to obtain the position information of each optical signal in a decoy state and a signal state, this is achieved by communicating with a control device. The control device extracts the optical signal state information corresponding to the query time point, i.e., the signal state or the decoy state, from an internal memory or a database based on the received query request.

[0088] By communicating with the controller, the position information of the light signal in the decoy state and the position information of the light signal in the signal state can be obtained. The first position information includes the emission time, duration, intensity and other parameters of the light signal in the signal state or the decoy state.

[0089] Each detection count signal carries its time position information relative to the system synchronization light, that is, the second position information. The first position information is associated with the second position information, and then compared. Through the comparison, it can be determined whether each detection count signal corresponds to a signal state light signal or a decoy state light signal. For each determined signal state light signal or decoy state light signal, the number of corresponding detection count signals is counted to output a first count and a second count, wherein the first count is a signal state count and the second count is a decoy state count, and then a first ratio is calculated through the first count and the second count.

[0090] S400: If the first ratio is greater than or equal to the first ratio threshold, the first target parameter and the second target parameter are obtained by a counting rule or a ratio rule, so that in the optical signal corresponding to the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter, the ratio of the signal state to the decoy state is less than the first ratio threshold.

[0091] Among them, the first ratio threshold is the initial ratio threshold. When the first ratio is greater than or equal to the first ratio threshold, it indicates that the delay parameters of the first delay chip and the second delay chip need to be adjusted. When the first ratio is less than the first ratio threshold, it indicates that the delay parameters of the first delay chip and the second delay chip are the optimal delay parameters and no further adjustment is required.

[0092] In some embodiments, the delay parameters of the first delay chip and the delay parameters of the second delay chip are adjusted first, and then the first target parameters and the second target parameters are obtained. The first target parameters and the second target parameters can be obtained through two rules. The counting rule is to obtain them through the counting of the deceptive state and the signal state, and the ratio rule is to obtain them through the real-time acquisition of the ratio of the deceptive state to the signal state.

[0093] like Figure 8 As shown, in some embodiments, the first target parameter and the second target parameter are obtained through counting rules, including: adjusting the first delay parameter to obtain a third count, and adjusting the second delay parameter to obtain a fourth count, wherein the first delay parameter is an initial parameter of the first delay chip, the second delay parameter is an initial parameter of the second delay chip, the third count is the adjusted first count, and the fourth count is the adjusted second count; iterating the adjustment process, if the third count is greater than or equal to the first preset value, the first target parameter is obtained, and if the fourth count is greater than or equal to the second preset value, the second target parameter is obtained.

[0094] Taking the first delay chip as an example, according to the needs of signal detection and the pre-set standards, the delay parameters of the first delay chip are gradually adjusted. For example, the delay time can be increased or decreased in an incremental manner, and fine-tuned according to the feedback mechanism. After the adjustment is completed, the adjusted first count, that is, the third count, is obtained through the detector. The third count reflects the number of detection photons of the received signal state after the adjustment.

[0095] Through multiple iterations to optimize the delay parameters and through continuous adjustment and testing, more accurate first target parameters and second target parameters can be obtained to ensure that the ratio of the signal state to the decoy state reaches the desired level.

[0096] In a quantum key distribution system using the decoy state method, the main purpose of the decoy state method is to improve the security of quantum communication by introducing light pulses of different intensities, namely, signal state and decoy state, to detect potential eavesdropping. When the decoy state count reaches the maximum value, the decoy state can be used to the maximum extent to monitor and prevent eavesdropping under the current delay parameters. Therefore, the first preset value is the maximum value of the decoy state count, and the second preset value is the maximum value of the signal state count.

[0097] If the third count is greater than or equal to the first preset value, stop adjusting the first delay parameter and record the first target parameter at this time. If the fourth count is greater than or equal to the second preset value, stop adjusting the second delay parameter and record the second target parameter at this time. If the preset value is not reached, continue the iterative adjustment process until the condition is met.

[0098] like Fig. 9 As shown, in some embodiments, obtaining the first target parameter and the second target parameter through the ratio rule includes: adjusting the first delay parameter, iterating the adjustment process, and then calculating the second ratio, the second ratio is the adjusted first ratio, and if the second ratio is less than or equal to the second ratio threshold, the first target parameter is obtained. Fig.10 As shown, the second delay parameter is adjusted, and the adjustment process is iterated, and then the third ratio is calculated, and the third ratio is the adjusted first ratio. If the third ratio is greater than or equal to the third ratio threshold, the second target parameter is obtained.

[0099] First, the delay parameters of the first delay chip and the second delay chip are adjusted respectively. These parameters determine the transmission or processing time of the optical signal, thereby affecting the ratio of the signal state to the decoy state. After adjusting the delay parameters, it is necessary to observe and calculate the change in the ratio. Since the change in the ratio may not be linear, it may take multiple iterations of the adjustment process to find the delay parameter value that meets the conditions. After each iteration of adjustment, new ratios need to be calculated, which reflect the proportional relationship between the adjusted signal state and the decoy state.

[0100] Among them, the second ratio threshold is the minimum ratio value, and the third ratio threshold is the maximum ratio value. The second ratio threshold is the minimum value to ensure that the ratio of the signal state to the decoy state will not be too low, thereby maintaining a certain level of security. The third ratio threshold is the maximum value to optimize the performance of the system, such as increasing the bit rate or reducing the bit error rate.

[0101] If the second ratio is less than or equal to the preset second ratio threshold, it indicates that the first target parameter that meets the condition has been obtained. If the third ratio is greater than or equal to the preset third ratio threshold, it indicates that the second target parameter that meets the condition has been obtained.

[0102] The method provided in this application can realize the modulation of the decoy state preparation of the sender without sharing the ratio parameter of the signal state and the decoy state through the receiver, and can adjust the signal state and the decoy state in real time online without stopping the QKD (Quantum Key Distribution) system for calibration, thus ensuring the security of the system and the effective operation time. By adjusting the ratio of the signal state and the decoy state in real time, the security of the preparation of the decoy state can be improved.

[0103] Based on the above delay parameter adjustment method, Fig.11 As shown, some embodiments of the present application also provide a delay parameter adjustment device, including:

[0104] A single-photon detection module is used to obtain a single-photon negative feedback optical signal, wherein the negative feedback optical signal is obtained by splitting an optical signal output by a laser according to an input electrical signal, wherein the electrical signal is obtained according to a first electrical signal output by a first delay chip and a second electrical signal output by a second delay chip; and to obtain a detection count signal, wherein the detection count signal is obtained according to the single-photon negative feedback optical signal;

[0105] An information processing module, configured to calculate a first ratio based on the detection counting signal, wherein the first ratio is a ratio parameter of a signal state to a decoy state in the single-photon negative feedback optical signal;

[0106] If the first ratio is greater than or equal to a first ratio threshold, it also includes a modulation control unit, which is used to obtain the first target parameter and the second target parameter through a counting rule or a ratio rule, so that in the optical signals corresponding to the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter, the ratio of the signal state to the decoy state is less than the first ratio threshold.

[0107] In some embodiments, it also includes:

[0108] A beam splitter, used for splitting the optical signal to output a system optical signal and a negative feedback optical signal;

[0109] The attenuator is used to attenuate the negative feedback optical signal to output a single-photon negative feedback optical signal.

[0110] It can be understood that this embodiment corresponds to the embodiment of the delay parameter adjustment method and can correspond to each other, and will not be described in detail here.

[0111] Based on the above delay parameter adjustment method, Fig.12 As shown, some embodiments of the present application also provide a decoy state modulation method, including:

[0112] Acquire a first target parameter and a second target parameter, wherein the first target parameter and the second target parameter are acquired by a counting rule or a ratio rule, and are used to make the ratio of a signal state to a decoy state in an optical signal outputted by the first delay chip according to the first electrical signal outputted by the first target parameter smaller than a first ratio threshold, wherein the first ratio is a ratio parameter of a signal state to a decoy state in a single-photon negative feedback optical signal;

[0113] Setting the delay parameter of the first delay chip to a first target parameter to output a first electrical signal, and setting the delay parameter of the second delay chip to a second target parameter to output a second electrical signal;

[0114] Converting the first electrical signal into a first drive signal, and converting the second electrical signal into a second drive signal;

[0115] A signal state is outputted by the first driving signal, and a decoy state is outputted by the second driving signal.

[0116] After obtaining the optimal delay parameters, i.e., the first target parameters and the second target parameters, based on the delay parameter adjustment method, two electrical signals are output, and the electrical signals are amplified or otherwise processed by the driving unit to be converted into a driving signal suitable for driving the laser. The laser generates a sequence of light pulses in different states according to different driving signals. Among them, the signal state light pulse is used for actual key generation, and the decoy state light pulse is used to monitor the security of the channel. The method improves the performance and security of the QKD system by dynamically adjusting the delay parameters to ensure that the ratio of the signal state to the decoy state is within the optimal range. Efficient quantum key distribution can be achieved through precise time position measurement, data analysis and parameter adjustment.

[0117] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A delay parameter adjustment method, characterized in that: include: Acquire a single-photon negative feedback optical signal, wherein the single-photon negative feedback optical signal is obtained by splitting an optical signal output by a laser according to an input electrical signal, wherein the electrical signal is obtained according to a first electrical signal output by a first delay chip and a second electrical signal output by a second delay chip; Acquiring a detection counting signal, wherein the detection counting signal is obtained according to the single-photon negative feedback optical signal; Calculating a first ratio based on the detection count signal, wherein the first ratio is a ratio parameter of a signal state to a decoy state in the single-photon negative feedback optical signal; If the first ratio is greater than or equal to a first ratio threshold, the first target parameter and the second target parameter are obtained by a counting rule or a ratio rule, so that in the optical signals corresponding to the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter, the ratio of the signal state to the decoy state is less than the first ratio threshold, the counting rule is obtained by counting the decoy state and the signal state, and the ratio rule is obtained by obtaining the ratio of the decoy state to the signal state in real time; The first target parameter and the second target parameter are obtained by using the counting rule, including: Adjust the first delay parameter to obtain a third count, and adjust the second delay parameter to obtain a fourth count, wherein the first delay parameter is an initial parameter of the first delay chip, the second delay parameter is an initial parameter of the second delay chip, the third count is the adjusted first count, and the fourth count is the adjusted second count; Iterate the adjustment process, if the third count is greater than or equal to a first preset value, obtain a first target parameter, and if the fourth count is greater than or equal to a second preset value, obtain a second target parameter; The first target parameter is obtained by using a ratio rule, including: Adjusting the first delay parameter and iterating the adjustment process; calculating a second ratio, wherein the second ratio is the adjusted first ratio; If the second ratio is less than or equal to a second ratio threshold, obtaining a first target parameter; The second target parameter is obtained by using a ratio rule, including: Adjusting the second delay parameter and iterating the adjustment process; calculating a third ratio, wherein the third ratio is the adjusted first ratio; If the third ratio is greater than or equal to a third ratio threshold, a second target parameter is obtained.

2. The delay parameter adjustment method according to claim 1, characterized in that: The calculating the first ratio based on the detection count signal comprises: Acquire first position information, wherein the first position information includes position information of the optical signal in the decoy state and position information of the optical signal in the signal state; Acquire second position information based on the detection counting signal, where the second position information is time position information of the detection counting signal; Comparing the first position information with the second position information to output a first count and a second count, wherein the first count is a signal state count and the second count is a decoy state count; A first ratio is calculated using the first count and the second count.

3. The delay parameter adjustment method according to claim 2, characterized in that: The obtaining of the first location information includes: Detecting a time position, wherein the time position is a time position of the counting signal relative to a system synchronization light; In response to the query instruction, first optical signal information and second optical signal information are acquired, wherein the first optical signal is optical signal information in a decoy state emitted by the control device, and the second optical signal is optical signal information in a signal state emitted by the control device; Based on the first optical signal information and the second optical signal information, the time position is matched to output first position information.

4. The delay parameter adjustment method according to claim 1, characterized in that: The step of obtaining a single-photon negative feedback optical signal comprises: Acquiring an optical signal; Splitting the optical signal to output a system optical signal and a negative feedback optical signal; The negative feedback optical signal is attenuated to output a single-photon negative feedback optical signal.

5. A delay parameter adjustment device, characterized in that: include: A single-photon detection module, used for acquiring a single-photon negative feedback optical signal, wherein the single-photon negative feedback optical signal is obtained by splitting an optical signal output by a laser according to an input electrical signal, wherein the electrical signal is obtained according to a first electrical signal output by a first delay chip and a second electrical signal output by a second delay chip; and acquiring a detection count signal, wherein the detection count signal is obtained according to the single-photon negative feedback optical signal; An information processing module, configured to calculate a first ratio based on the detection counting signal, wherein the first ratio is a ratio parameter of a signal state to a decoy state in the single-photon negative feedback optical signal; If the first ratio is greater than or equal to a first ratio threshold, a modulation control unit is further included, which is used to obtain a first target parameter and a second target parameter through a counting rule or a ratio rule, so that in the optical signals corresponding to the first electrical signal output by the first delay chip according to the first target parameter and the second electrical signal output by the second delay chip according to the second target parameter, the ratio of the signal state to the decoy state is less than the first ratio threshold, the counting rule is obtained by counting the decoy state and the signal state, and the ratio rule is obtained by obtaining the ratio of the decoy state to the signal state in real time; The first target parameter and the second target parameter are obtained by using the counting rule, including: Adjust the first delay parameter to obtain a third count, and adjust the second delay parameter to obtain a fourth count, wherein the first delay parameter is an initial parameter of the first delay chip, the second delay parameter is an initial parameter of the second delay chip, the third count is the adjusted first count, and the fourth count is the adjusted second count; Iterate the adjustment process, if the third count is greater than or equal to a first preset value, obtain a first target parameter, and if the fourth count is greater than or equal to a second preset value, obtain a second target parameter; The first target parameter is obtained by using a ratio rule, including: Adjusting the first delay parameter and iterating the adjustment process; calculating a second ratio, wherein the second ratio is the adjusted first ratio; If the second ratio is less than or equal to a second ratio threshold, obtaining a first target parameter; The second target parameter is obtained by using a ratio rule, including: Adjusting the second delay parameter and iterating the adjustment process; calculating a third ratio, wherein the third ratio is the adjusted first ratio; If the third ratio is greater than or equal to a third ratio threshold, a second target parameter is obtained.

6. The delay parameter adjustment device according to claim 5, characterized in that: Also includes: A beam splitter, used for splitting the optical signal to output a system optical signal and a negative feedback optical signal; The attenuator is used to attenuate the negative feedback optical signal to output a single-photon negative feedback optical signal.

7. A decoy state modulation method, characterized in that: include: Obtaining a first target parameter and a second target parameter, wherein the first target parameter and the second target parameter are obtained by a counting rule or a ratio rule, and are used to make the ratio of the signal state to the decoy state in the optical signal outputted by the first delay chip according to the first target parameter corresponding to the first electrical signal outputted, be less than a first ratio threshold, wherein the first ratio is a ratio parameter of the signal state to the decoy state in the single-photon negative feedback optical signal, the counting rule is obtained by counting the decoy state and the signal state, and the ratio rule is obtained by obtaining the ratio of the decoy state to the signal state in real time; The first target parameter and the second target parameter are obtained by using the counting rule, including: Adjust the first delay parameter to obtain a third count, and adjust the second delay parameter to obtain a fourth count, wherein the first delay parameter is an initial parameter of the first delay chip, the second delay parameter is an initial parameter of the second delay chip, the third count is the adjusted first count, and the fourth count is the adjusted second count; Iterate the adjustment process, if the third count is greater than or equal to a first preset value, obtain a first target parameter, and if the fourth count is greater than or equal to a second preset value, obtain a second target parameter; The first target parameter is obtained by using a ratio rule, including: Adjusting the first delay parameter and iterating the adjustment process; calculating a second ratio, wherein the second ratio is the adjusted first ratio; If the second ratio is less than or equal to a second ratio threshold, obtaining a first target parameter; The second target parameter is obtained by using a ratio rule, including: Adjusting the second delay parameter and iterating the adjustment process; calculating a third ratio, wherein the third ratio is the adjusted first ratio; If the third ratio is greater than or equal to a third ratio threshold, obtaining a second target parameter; Setting the delay parameter of the first delay chip to a first target parameter to output a first electrical signal, and setting the delay parameter of the second delay chip to a second target parameter to output a second electrical signal; Converting the first electrical signal into a first drive signal, and converting the second electrical signal into a second drive signal; A signal state is outputted by the first driving signal, and a decoy state is outputted by the second driving signal.

Images