Quantum key distribution method, device, electronic device and storage medium

Abstract

The present disclosure provides a quantum key distribution method, device, electronic device and storage medium, which relate to the field of quantum communication technology. The method includes: determining a demodulated reference signal and a demodulated quantum signal through a composite optical signal, wherein the composite optical signal is obtained by polarization multiplexing the reference signal and the quantum signal; performing carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal; performing polarization and slow phase integrated compensation on the first reference signal and the first quantum signal to obtain a second reference signal and a second quantum signal; extracting a quantum key from the second reference signal and the second quantum signal to achieve the distribution of the quantum key. The present disclosure can improve the adaptability to environmental changes, improve the flexibility of quantum key distribution, and improve the coding rate and stability of the quantum key distribution system in a complex environment.

Description

Background Art

[0002] With the continuous development of quantum communication technology, quantum key distribution technology has been widely studied. Quantum key distribution mainly uses quantum states to transmit keys. Quantum key distribution technology includes continuous variable quantum key distribution technology. In order to ensure quantum state transmission, the local oscillator continuous variable quantum key distribution system usually works in a low signal-to-noise ratio environment and is very sensitive to damage such as polarization and phase.

[0003] In related technologies, quantum key distribution can be achieved by performing polarization and phase recovery through digital signal processing algorithms commonly used in classical coherent optical communication systems.

[0004] However, the methods provided by related technologies are not flexible enough and lack the ability to adapt to environmental changes, making it difficult to ensure the coding rate and stability of quantum key distribution systems in complex environments.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] The present disclosure provides a quantum key distribution method, device, electronic device and storage medium, which at least to a certain extent overcome the problems of insufficient flexibility of related technologies, lack of adaptability to environmental changes, and difficulty in ensuring the coding rate and stability of quantum key distribution systems in complex environments.

[0007] Other features and advantages of the present disclosure will become apparent from the following detailed description, or may be learned in part by the practice of the present disclosure.

[0008] According to one aspect of the present disclosure, a quantum key distribution method is provided, comprising: determining a demodulated reference signal and a demodulated quantum signal through a composite optical signal sent by a transmitting end, wherein the composite optical signal is obtained by polarization multiplexing the reference signal and the quantum signal; performing carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal; performing polarization and slow phase integrated compensation on the first reference signal and the first quantum signal to obtain a second reference signal and a second quantum signal; and extracting a quantum key from the second reference signal and the second quantum signal to achieve distribution of the quantum key.

[0009] In some embodiments, a demodulated reference signal and a demodulated quantum signal are determined by a composite optical signal sent by a transmitting end, including: receiving the composite optical signal sent by the transmitting end; processing the composite optical signal by a polarization beam splitter to obtain two mutually perpendicular polarization state signals; coherently demodulating the two mutually perpendicular polarization state signals and a local local oscillator signal to obtain an electrical signal; and performing analog-to-digital conversion on the electrical signal to obtain a demodulated reference signal and a demodulated quantum signal.

[0010] In some embodiments, carrier frequency offset recovery and fast phase drift recovery are performed on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal, including: estimating the carrier frequency offset in the demodulated reference signal to obtain a frequency offset estimation value; compensating the demodulated quantum signal for carrier frequency offset according to the frequency offset estimation value; estimating the fast phase drift in the demodulated reference signal to obtain a fast phase drift estimation value; and compensating the demodulated quantum signal for fast phase drift according to the fast phase drift estimation value.

[0011] In some embodiments, the first reference signal and the first quantum signal are subjected to integrated polarization and slow phase compensation to obtain a second reference signal and a second quantum signal, including: obtaining the state vector of the extended Kalman system at the previous moment; predicting the a priori state vector at the current moment based on the state vector at the previous moment; determining an observation matrix based on the a priori state vector; and determining the second reference signal and the second quantum signal based on the a priori state vector, the observation matrix, the first reference signal and the first quantum signal.

[0012] In some embodiments, the prior state vector at the current moment is predicted based on the state vector at the previous moment, including: predicting the prior state vector at the current moment and the prior estimation error covariance matrix table at the current moment based on the state vector at the previous moment; determining the observation matrix based on the prior state vector, including: determining the Kalman gain and the observation matrix based on the state vector at the current moment and the prior estimation error covariance matrix at the current moment; determining the second reference signal and the second quantum signal based on the prior state vector, the observation matrix, the first reference signal and the first quantum signal, including: determining the second reference signal and the second quantum signal based on the prior state vector, the observation matrix, the Kalman gain, the first reference signal and the first quantum signal.

[0013] In some embodiments, after determining the second reference signal and the second quantum signal according to the prior state vector, the observation matrix, the Kalman gain, the first reference signal and the first quantum signal, it also includes: performing constellation point decision on the output signal composed of the second reference signal and the second quantum signal to obtain a decision error; if the decision error meets a preset condition, updating the state vector at the current moment, the covariance of the state vector at the current moment and the Kalman gain.

[0014] In some embodiments, the transmitting end is used to process the first carrier signal through a delay device and a first attenuator to obtain a reference signal, and the reference signal is used for coarse estimation of carrier frequency deviation and phase at the receiving end; the second carrier signal is processed through a modulator and a second attenuator to obtain a quantum signal; and the quantum signal and the reference signal are polarization multiplexed through a polarization coupler to obtain the composite optical signal.

[0015] According to another aspect of the present disclosure, a quantum key distribution device is also provided, including: a signal determination module, used to determine a demodulated reference signal and a demodulated quantum signal through a composite optical signal sent by a transmitting end, wherein the composite optical signal is obtained by polarization multiplexing the reference signal and the quantum signal; a signal recovery module, used to perform carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal; an integrated compensation module, used to perform polarization and slow phase integrated compensation on the first reference signal and the first quantum signal to obtain a second reference signal and a second quantum signal; a post-processing module, used to extract a quantum key from the second reference signal and the second quantum signal to achieve distribution of the quantum key.

[0016] In some embodiments, the signal determination module is used to receive the composite optical signal sent by the transmitting end; process the composite optical signal through a polarization beam splitter to obtain two mutually perpendicular polarization state signals; coherently demodulate the two mutually perpendicular polarization state signals and a local oscillator signal to obtain an electrical signal; and perform analog-to-digital conversion on the electrical signal to obtain a demodulated reference signal and a demodulated quantum signal.

[0017] In some embodiments, the signal recovery module is used to estimate the carrier frequency offset in the demodulated reference signal to obtain a frequency offset estimation value; perform carrier frequency offset compensation on the demodulated quantum signal according to the frequency offset estimation value; estimate the fast phase drift in the demodulated reference signal to obtain a fast phase drift estimation value; and perform fast phase drift compensation on the demodulated quantum signal according to the fast phase drift estimation value.

[0018] In some embodiments, an integrated compensation module is used to obtain the state vector of the extended Kalman system at the previous moment; predict the prior state vector at the current moment based on the state vector at the previous moment; determine the observation matrix based on the prior state vector; determine the second reference signal and the second quantum signal based on the prior state vector, the observation matrix, the first reference signal and the first quantum signal.

[0019] In some embodiments, an integrated compensation module is used to predict the prior state vector at the current moment and the prior estimation error covariance matrix table at the current moment based on the state vector at the previous moment; determine the Kalman gain and the observation matrix based on the state vector at the current moment and the prior estimation error covariance matrix at the current moment; determine the second reference signal and the second quantum signal based on the prior state vector, the observation matrix, the Kalman gain, the first reference signal and the first quantum signal.

[0020] In some embodiments, the quantum key distribution device provided by the embodiments of the present disclosure may also include: an update module, configured to perform constellation point decision on the output signal composed of the second reference signal and the second quantum signal to obtain a decision error; if the decision error satisfies a preset condition, the state vector at the current moment, the covariance of the state vector at the current moment, and the Kalman gain are updated.

[0021] In some embodiments, the transmitting end is used to process the first carrier signal through a delay device and a first attenuator to obtain a reference signal, and the reference signal is used for coarse estimation of carrier frequency deviation and phase at the receiving end; the second carrier signal is processed through a modulator and a second attenuator to obtain a quantum signal; and the quantum signal and the reference signal are polarization multiplexed through a polarization coupler to obtain the composite optical signal.

[0022] According to another aspect of the present disclosure, an electronic device is also provided, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to execute any one of the above-mentioned quantum key distribution methods by executing the executable instructions.

[0023] According to another aspect of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the quantum key distribution method described above is implemented.

[0024] According to another aspect of the present disclosure, a computer program product or a computer program is provided, the computer program product or the computer program including computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device executes the quantum key distribution method provided in various optional ways in any embodiment of the present disclosure.

[0025] The technical solution provided in the embodiments of the present disclosure performs carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal, and then performs integrated polarization and slow phase compensation, thereby realizing the extraction and distribution of quantum keys. Therefore, the embodiments of the present disclosure can improve the adaptability to environmental changes, improve the flexibility of quantum key distribution, and improve the coding rate and stability of the quantum key distribution system in complex environments.

[0026] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0028] Figure 1 A schematic diagram showing a system architecture in an embodiment of the present disclosure;

[0029] Figure 2 A flow chart of a quantum key distribution method in an embodiment of the present disclosure is shown;

[0030] Figure 3 A schematic diagram showing interaction between a sending end and a receiving end in an embodiment of the present disclosure is shown;

[0031] Figure 4 A schematic diagram showing a method of performing digital signal processing on a demodulated quantum signal and a demodulated reference signal in an embodiment of the present disclosure is shown;

[0032] Figure 5 A schematic diagram of a quantum key distribution device in an embodiment of the present disclosure is shown;

[0033] Figure 6 A structural block diagram of an electronic device according to an embodiment of the present disclosure is shown;

[0034] Figure 7A schematic diagram of a computer-readable storage medium in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0035] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0036] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0037] The specific implementation of the embodiment of the present disclosure is described in detail below with reference to the accompanying drawings.

[0038] Figure 1 FIG. 1 shows an exemplary application system architecture diagram to which the quantum key distribution method in the embodiment of the present disclosure can be applied. Figure 1 As shown, the system architecture 100 may include a first electronic device 101 and a second electronic device 102. The first electronic device 101 may communicate with the second electronic device 102, the first electronic device 101 may be a transmitting end, and the second electronic device 102 may be a receiving end.

[0039] Exemplarily, the first electronic device 101 may send a composite optical signal to the second electronic device 102. The second electronic device 102 may determine a demodulated reference signal and a demodulated quantum signal through the composite optical signal sent by the first electronic device 101, where the composite optical signal is obtained by polarization multiplexing the reference signal and the quantum signal.

[0040] Then, the second electronic device 102 performs carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal.

[0041] Then, the second electronic device 102 can perform integrated polarization and slow phase compensation on the first reference signal and the first quantum signal to obtain a second reference signal and a second quantum signal.

[0042] Finally, the second electronic device 102 can extract the quantum key from the second reference signal and the second quantum signal to achieve the distribution of the quantum key.

[0043] The disclosed embodiment does not limit the type of the first electronic device 101, and the first electronic device 101 may be a terminal device or a server. The terminal device includes but is not limited to a smart phone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, a wearable device, an augmented reality device, a virtual reality device, etc.

[0044] Optionally, the client of the application installed in different terminal devices is the same, or the client of the same type of application based on different operating systems. Based on the different terminal platforms, the specific form of the client of the application can also be different, for example, the application client can be a mobile client, a PC client, etc.

[0045] The server can be a server that provides various services, such as a background management server that provides support for devices operated by users using terminal devices. The background management server can analyze and process the received request data, and feed back the processing results to the terminal device.

[0046] Optionally, the server can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN (Content Delivery Network), as well as big data and artificial intelligence platforms.

[0047] Similarly, the embodiment of the present disclosure does not limit the type of the second electronic device 102 , and the second electronic device 102 may also be a terminal device or a server.

[0048] Those skilled in the art will know that Figure 1 The number of the first electronic device 101 and the second electronic device 102 is only illustrative, and any number of the first electronic device 101 and the second electronic device 102 may be provided according to actual needs. This is not limited in the embodiments of the present disclosure.

[0049] Under the above system architecture, a quantum key distribution method is provided in an embodiment of the present disclosure, which can be executed by any electronic device with computing and processing capabilities.

[0050] In some embodiments, the quantum key distribution method provided in the embodiments of the present disclosure can be executed by a terminal device of the above-mentioned system architecture; in other embodiments, the quantum key distribution method provided in the embodiments of the present disclosure can be executed by a server in the above-mentioned system architecture; in other embodiments, the quantum key distribution method provided in the embodiments of the present disclosure can be implemented by the terminal device and the server in the above-mentioned system architecture through interaction.

[0051] Figure 2 A flow chart of a quantum key distribution method in an embodiment of the present disclosure is shown as follows: Figure 2 As shown, the quantum key distribution method provided in the embodiment of the present disclosure includes the following steps S202 to S208.

[0052] S202, determining a demodulated reference signal and a demodulated quantum signal through a composite optical signal sent by a transmitting end, wherein the composite optical signal is obtained by performing polarization multiplexing on the reference signal and the quantum signal.

[0053] Exemplarily, the transmitting end may be the transmitting end of any local local oscillator CV-QKD (Continuous-Variable QuantumKey Distribution) system. The transmitting end sends the composite optical signal for quantum key distribution to the receiving end of the local local oscillator CV-QKD system, and the receiving end is used to process the composite optical signal through the method provided in the embodiment of the present disclosure, so as to obtain the corresponding quantum key to realize the distribution of quantum key.

[0054] Exemplarily, the composite optical signal may include a quantum signal and a reference signal, wherein the reference signal is used at the receiving end to perform coarse estimation of carrier frequency offset and phase to calibrate the quantum signal, and the quantum signal is used to carry information of the quantum key.

[0055] In some embodiments, the transmitting end can be used to process the first carrier signal through a delay device and a first attenuator to obtain a reference signal, and the reference signal is used for coarse estimation of carrier frequency deviation and phase at the receiving end; process the second carrier signal through a modulator and a second attenuator to obtain a quantum signal; and polarization multiplex the quantum signal and the reference signal through a polarization coupler to obtain the composite optical signal.

[0056] In a possible implementation, the transmitting end can use a pulse light source as a carrier signal, and can divide the carrier signal into two paths, namely, a first carrier signal and a second carrier signal, through a first beam splitter. The first carrier signal can pass through a delay device and a first attenuator to form a reference signal. The second carrier signal can be modulated by a modulator and a second attenuator to obtain a quantum signal.

[0057] For example, after obtaining the modulated quantum signal and the reference signal, the polarization multiplexing of the quantum signal and the reference signal can be realized through a polarization coupler to obtain a composite optical signal. Then, the composite optical signal can be transmitted to the receiving end through a quantum channel, which can be an optical fiber link.

[0058] The embodiment of the present disclosure does not limit the attenuation of the first attenuator and the second attenuator, and the attenuation of the first attenuator and the second attenuator can be determined based on experience or application scenarios.

[0059] In an exemplary embodiment, a polarization coupler can be used to process the modulated quantum signal and the reference signal to realize polarization multiplexing, thereby improving the capacity and transmission efficiency of the channel. The quantum signal and the reference signal can be encoded in different polarization states through the polarization coupler, and these polarization states carrying different information can be coupled together to obtain a composite optical signal. Exemplarily, the quantum signal and the reference signal can be encoded in the polarization states of horizontal polarization and vertical polarization, respectively.

[0060] In some exemplary embodiments, a demodulated reference signal and a demodulated quantum signal are determined by a composite optical signal sent by a transmitting end, including: receiving the composite optical signal sent by the transmitting end; processing the composite optical signal by a polarization beam splitter to obtain two mutually perpendicular polarization state signals; coherently demodulating the two mutually perpendicular polarization state signals with a local local oscillator signal to obtain an electrical signal; and performing analog-to-digital conversion on the electrical signal to obtain a demodulated reference signal and a demodulated quantum signal.

[0061] Exemplarily, after receiving the composite optical signal, the composite optical signal can be processed by a polarization beam splitter to obtain two mutually perpendicular polarization state signals, that is, a quantum signal and a reference signal coupled in different polarization states. In addition, the receiving end can also split the local local oscillator signal into two paths through a second beam splitter, and input the two local local oscillator signals and the two mutually perpendicular polarization state signals into a coherent receiver to achieve coherent demodulation of the quantum signal and the reference signal to obtain an electrical signal. Finally, the receiving end can perform analog-to-digital conversion on the electrical signal to obtain a demodulated reference signal and a demodulated quantum signal.

[0062] S204, performing carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal.

[0063] In one possible implementation, the demodulated reference signal and the demodulated quantum signal may be first subjected to carrier frequency offset recovery, and then the demodulated reference signal and the demodulated quantum signal may be subjected to fast phase drift recovery. In another possible implementation, the demodulated reference signal and the demodulated quantum signal may be first subjected to fast phase drift recovery, and then the demodulated reference signal and the demodulated quantum signal may be subjected to carrier frequency offset recovery. The disclosed embodiments are not limited to this. After performing carrier frequency offset recovery and fast phase drift recovery, the first reference signal and the first quantum signal may be obtained.

[0064] It should be noted that the frequency deviation value refers to the center frequency difference between the transmitting light source and the local oscillator light source, which will introduce system noise. The frequency deviation value can be extracted based on the reference signal for frequency deviation compensation of quantum signals. In addition, fast phase drift recovery is to compensate for the rapidly changing phase noise caused by the carrier and the line width of the local oscillator light source.

[0065] In some exemplary embodiments, carrier frequency offset recovery and fast phase drift recovery are performed on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal, including: estimating the carrier frequency offset in the demodulated reference signal to obtain a frequency offset estimation value; compensating the demodulated quantum signal for carrier frequency offset according to the frequency offset estimation value; estimating the fast phase drift in the demodulated reference signal to obtain a fast phase drift estimation value; and compensating the demodulated quantum signal for fast phase drift according to the fast phase drift estimation value.

[0066] In an exemplary embodiment, the frequency offset value between the carrier signal and the local oscillator signal can be extracted from the demodulated reference signal, and the frequency offset value can be used as a frequency offset estimation value. The carrier frequency offset of the demodulated quantum signal can then be compensated by the frequency offset estimation value, thereby realizing carrier frequency offset recovery.

[0067] In an exemplary embodiment, the phase information of the demodulated reference signal and the demodulated quantum signal can be extracted, and the fast phase drift value caused by the carrier line width can be estimated to obtain a fast phase drift estimation value. Then, the fast phase drift compensation can be performed on the demodulated quantum signal according to the fast phase drift estimation value, thereby realizing fast phase drift recovery.

[0068] Exemplarily, the carrier frequency offset recovery and fast phase drift recovery process is mainly used to compensate the carrier frequency offset and fast phase drift of the demodulated quantum signal to obtain a second quantum signal. The first reference signal may be the same as or different from the demodulated reference signal.

[0069] S206, performing integrated polarization and slow phase compensation on the first reference signal and the first quantum signal to obtain a second reference signal and a second quantum signal.

[0070] Exemplarily, after completing the carrier frequency offset recovery and the fast phase drift recovery, the stage of integrated compensation of polarization and slow phase can be entered. In this stage, the integrated parallel compensation of polarization and slow phase can be realized by adopting the extended Kalman structure.

[0071] In some exemplary embodiments, the first reference signal and the first quantum signal are subjected to integrated polarization and slow phase compensation to obtain a second reference signal and a second quantum signal, including: obtaining the state vector of the extended Kalman system at the previous moment; predicting the a priori state vector at the current moment based on the state vector at the previous moment; determining an observation matrix based on the a priori state vector; and determining the second reference signal and the second quantum signal based on the a priori state vector, the observation matrix, the first reference signal and the first quantum signal.

[0072] In an exemplary embodiment, the input signal of the polarization and slow phase integrated compensation algorithm can be represented by Z(k), where Z(k)=[Z x (k), Z y (k)],Z x (k) can represent the first quantum signal, Z y (k) may represent the first reference signal, and k may represent a time. In addition, the output signal of the polarization and slow phase integrated compensation algorithm may be represented by U(k), where U(k)=[U x (k), U y (k)],U x (k) can represent the second quantum signal, U y (k) may represent a second reference signal.

[0073] Exemplarily, U(k) may be expressed as shown in formula (1).

[0074] (1)

[0075] Among them, H(k) can be used to represent the observation matrix, S(k) can be used to represent the state vector, and v(k) can be used to represent the measurement noise vector of the extended Kalman system, which has a mean of zero and a covariance of R k Gaussian distribution.

[0076] Exemplarily, the state vector can be used to describe the internal state of the extended Kalman system. In one possible implementation, the state vector at the previous moment can be used as the prior state vector at the current moment. In addition, the observation matrix H(k) can be used to describe the relationship between the output signal and the state vector of the extended Kalman system. Therefore, by determining the observation matrix and the prior state vector at the current moment, the first reference signal and the first quantum signal can be compensated for polarization and slow phase integration to obtain a second reference signal and a second quantum signal.

[0077] In an exemplary embodiment, the state conversion process of S(k) may be as shown in formula (2).

[0078] (2)

[0079] Among them, S(k-1) can represent the state vector of the previous moment, and w(k) can represent the process noise of the extended Kalman system, which has a mean of zero and a variance of Q k Gaussian distribution.

[0080] Exemplarily, H(k) may be expressed as shown in formula (3).

[0081] (3)

[0082] Among them, Z x (k) can represent the first quantum signal, Z y (k) may represent a first reference signal, k may represent a time, j may represent an imaginary unit, and a, b, c, and d may be parameters for controlling the polarization state of a signal. k For example, the state vector of the extended Kalman system at the current moment can be represented by S(k), S(k)=[a,b,c,d,θ k ] T .

[0083] In some exemplary embodiments, predicting the a priori state vector at the current moment based on the state vector at the previous moment includes predicting the a priori state vector at the current moment and the a priori estimation error covariance matrix table at the current moment based on the state vector at the previous moment.

[0084] In this case, determining the observation matrix according to the prior state vector includes: determining the Kalman gain and the observation matrix according to the state vector at the current moment and the prior estimation error covariance matrix at the current moment. And, determining the second reference signal and the second quantum signal according to the prior state vector, the observation matrix, the first reference signal and the first quantum signal includes: determining the second reference signal and the second quantum signal according to the prior state vector, the observation matrix, the Kalman gain, the first reference signal and the first quantum signal.

[0085] In an exemplary embodiment, the workflow of the extended Kalman algorithm can be represented by the following formulas (4) to (9).

[0086] (4)

[0087] (5)

[0088] (6)

[0089] (7)

[0090] (8)

[0091] (9)

[0092] Among them, S - (k) can represent the prior state vector at time k. - (k) can represent the prior estimation error covariance matrix at time k, so the P - (k) can represent the covariance between the true state and the prior estimated state of the extended Kalman system. k It can represent the variance of the process noise of the extended Kalman system. K can represent the Kalman gain. R k It can represent the covariance of the measurement noise vector of the extended Kalman system. C represents the vector of U(k) after the constellation diagram is judged, dU k Indicates decision error.

[0093] In an exemplary embodiment, the kth moment can be taken as the current moment and the k-1th moment can be taken as the previous moment. k , Q k Then, S can be determined according to S(k-1). - (k), P - (k) is estimated, where S - The value of (k) can be used as the prior state vector of the system.

[0094] Then, we can use formula (6) to calculate S - (k), P - (k) to obtain the current observation matrix H(k), and based on S - (k) and H(k) are used to perform integrated polarization and slow phase compensation.

[0095] In some exemplary embodiments, after determining the second reference signal and the second quantum signal according to the prior state vector, the observation matrix, the Kalman gain, the first reference signal and the first quantum signal, the quantum key distribution method provided by the embodiments of the present disclosure may also include: performing constellation point decision on the output signal composed of the second reference signal and the second quantum signal to obtain a decision error; if the decision error satisfies a preset condition, updating the state vector at the current moment, the covariance of the state vector at the current moment and the Kalman gain.

[0096] Exemplarily, the preset condition may be that the decision error is not less than a preset threshold. Exemplarily, the preset threshold may be determined based on experience or application scenarios, and the embodiments of the present disclosure do not limit it.

[0097] In some embodiments, after the integrated compensation of polarization and slow phase is completed, constellation point decision is performed on the compensated output signal to obtain a decision error dU k Among them, dU k It can be expressed based on the following formula (10).

[0098] (10)

[0099] In formula (10), U C It can represent the vector after U(k) is judged by the constellation diagram. U(k) can represent the output signal of the polarization and slow phase integrated compensation algorithm.

[0100] After that, dU can be adjusted according to the preset threshold β. k Make a judgment, if dU k ≥β, then the variance Q of the process noise of the extended Kalman system can be k Perform adaptive update. k <β, then Q k For example, Q k The adaptive update formula of can be shown as formula (11).

[0101] (11)

[0102] In the formula (11), E may represent an expectation operation, K may represent a Kalman gain, and T may represent a matrix transposition operation.

[0103] In an exemplary embodiment, when Q k After the adaptive update, the state vector at the current moment, the covariance of the state vector at the current moment, and the Kalman gain can also be updated accordingly. The updated state vector at the current moment, the covariance of the state vector at the current moment, and the Kalman gain can be used for Kalman prediction at the next moment and applied to the integrated compensation of polarization and slow phase at the next moment. In addition, the steps of the integrated compensation of polarization and slow phase can be executed in a loop until the signal compensation at all moments is completed, after which the quantum key negotiation and confidentiality enhancement stage can be performed based on the compensated information to realize the screening and distribution of quantum keys.

[0104] S208, extracting a quantum key from the second reference signal and the second quantum signal to achieve quantum key distribution.

[0105] In some embodiments, quantum key negotiation and confidentiality enhancement can be performed, wherein the sender and the receiver can authenticate each other to prevent man-in-the-middle attacks. Then, quantum key exchange can be performed. Finally, quantum key determination can be performed, for example, when both parties calculate the same quantum key, it can be determined that the quantum key is correct.

[0106] Exemplarily, confidentiality enhancement is a series of measures taken to improve the security of quantum key negotiation and the entire communication process. The confidentiality enhancement operations in the disclosed embodiments may include: forward secrecy, integrity protection, key update, key isolation, etc.

[0107] In an exemplary embodiment, a schematic diagram of interaction between a transmitting end and a receiving end provided by an embodiment of the present disclosure can be as follows: Figure 3 shown.

[0108] Among them, the transmitting end can divide the optical signal emitted by the pulse light source into two paths through the first beam splitter, one path passes through the delay device and the first attenuator to form a reference signal, and the other path passes through the modulator and the second attenuator to realize the modulation of the quantum signal. Then, the polarization multiplexing of the quantum signal and the reference signal is performed through the polarization coupler to obtain a composite optical signal. Finally, the transmitting end can transmit the composite optical signal to the receiving end through the quantum channel.

[0109] The receiving end can divide the composite optical signal after passing through the quantum channel into two mutually perpendicular polarization state signals through a polarization beam splitter, and divide the local oscillator signal into two signals through a second beam splitter. Then, the receiving end can input the above four signals into a coherent receiver for coherent demodulation, realize photoelectric conversion, and obtain an electrical signal. Finally, the receiving end can perform analog-to-digital conversion on the demodulated electrical signal to obtain a demodulated quantum signal and a demodulated reference signal, and enter the subsequent digital signal processing link.

[0110] The method provided by the embodiment of the present disclosure performs carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal, and then performs integrated polarization and slow phase compensation, thereby realizing the extraction and distribution of quantum keys. Therefore, the embodiment of the present disclosure can improve the adaptability to environmental changes, improve the flexibility of quantum key distribution, and improve the coding rate and stability of the quantum key distribution system in complex environments.

[0111] In an exemplary embodiment, a schematic diagram of performing digital signal processing on a demodulated quantum signal and a demodulated reference signal provided by the embodiment of the present disclosure can be as follows: Figure 4 shown.

[0112] Among them, the carrier frequency offset estimation can be performed by the demodulated reference signal to obtain the frequency offset estimation value. Then, the carrier frequency offset compensation of the demodulated quantum signal can be performed by the frequency offset estimation value. And, the fast phase drift estimation can be performed according to the reference signal to obtain the fast phase drift estimation value. Then, the fast phase drift compensation can be performed on the demodulated quantum signal according to the fast phase drift estimation value to obtain the first reference signal and the first quantum signal.

[0113] Then, the first reference signal and the first quantum signal can be subjected to polarization and slow phase integrated compensation to obtain a second reference signal and a second quantum signal. Among them, Z(k) can be input into an extended Kalman system for polarization demultiplexing and quadratic phase compensation to obtain U(k). And the constellation point decision can be made according to U(k) to obtain the decision error U C , then the decision error can be obtained by the above formula (10) to make error decisions. k ≥β, then Q k Perform adaptive update, if dU k <β, then Q k to update.

[0114] Then, the current state vector, the covariance of the current state vector, and the Kalman gain can be updated accordingly. - (k), P -(k) and H(k) update the values ​​of Kalman augmentation K, S(k) and P(k), and the values ​​of S(k) and P(k) can be used for Kalman prediction at the next moment and applied to polarization and phase compensation at the next moment. Furthermore, the above steps can be iterated continuously until the signal compensation at all moments is completed, and the original quantum key can be extracted from the signal after polarization and phase integrated compensation, and the original quantum key can be subjected to quantum key negotiation and confidentiality enhancement operations to achieve key distribution.

[0115] The disclosed embodiments provide a polarization phase integrated compensation structure and method based on the extended Kalman structure, which can improve the compensation accuracy of polarization and phase damage of the local local oscillator CV-QKD system and improve the system coding rate. In addition, the disclosed embodiments provide a polarization compensation method based on an adaptive Kalman filter algorithm, which can effectively cope with the rapid changes in polarization and phase caused by changes in the system working environment through adaptive updating of the process noise variance, thereby improving the anti-interference ability of the CV-QKD system. In addition, the polarization and slow phase integrated compensation system provided by the disclosed embodiments can be applied to existing CV-QKD equipment and networks to improve equipment performance.

[0116] It should be noted that the acquisition, storage, use, and processing of data in the technical solution disclosed in this disclosure are in compliance with the relevant provisions of national laws and regulations, and various types of data such as personal identity data, operation data, behavioral data, etc. related to individuals, customers, and groups obtained in the embodiments of this disclosure have all been authorized.

[0117] Based on the same inventive concept, the embodiments of the present disclosure also provide a quantum key distribution device, as described in the following embodiments. Since the principle of solving the problem in the device embodiment is similar to that in the above method embodiment, the implementation of the device embodiment can refer to the implementation of the above method embodiment, and the repeated parts will not be repeated.

[0118] Figure 5 A schematic diagram of a quantum key distribution device in an embodiment of the present disclosure is shown as follows: Figure 5 As shown, the device comprises:

[0119] A signal determination module 501 is used to determine a demodulated reference signal and a demodulated quantum signal through a composite optical signal sent by a transmitting end, where the composite optical signal is obtained by polarization multiplexing the reference signal and the quantum signal;

[0120] A signal recovery module 502 is used to perform carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal;

[0121] An integrated compensation module 503 is used to perform integrated polarization and slow phase compensation on the first reference signal and the first quantum signal to obtain a second reference signal and a second quantum signal;

[0122] The post-processing module 504 is used to extract the quantum key from the second reference signal and the second quantum signal to achieve the distribution of the quantum key.

[0123] In some embodiments, the signal determination module 501 is used to receive the composite optical signal sent by the transmitting end; process the composite optical signal through a polarization beam splitter to obtain two mutually perpendicular polarization state signals; coherently demodulate the two mutually perpendicular polarization state signals and a local oscillator signal to obtain an electrical signal; perform analog-to-digital conversion on the electrical signal to obtain a demodulated reference signal and a demodulated quantum signal.

[0124] In some embodiments, the signal recovery module 502 is used to estimate the carrier frequency offset in the demodulated reference signal to obtain a frequency offset estimation value; perform carrier frequency offset compensation on the demodulated quantum signal according to the frequency offset estimation value; perform fast phase drift estimation on the demodulated reference signal to obtain a fast phase drift estimation value; and perform fast phase drift compensation on the demodulated quantum signal according to the fast phase drift estimation value.

[0125] In some embodiments, the integrated compensation module 503 is used to obtain the state vector of the extended Kalman system at the previous moment; predict the prior state vector at the current moment based on the state vector at the previous moment; determine the observation matrix based on the prior state vector; determine the second reference signal and the second quantum signal based on the prior state vector, the observation matrix, the first reference signal and the first quantum signal.

[0126] In some embodiments, the integrated compensation module 503 is used to predict the prior state vector at the current moment and the prior estimation error covariance matrix table at the current moment based on the state vector at the previous moment; determine the Kalman gain and the observation matrix based on the state vector at the current moment and the prior estimation error covariance matrix at the current moment; determine the second reference signal and the second quantum signal based on the prior state vector, the observation matrix, the Kalman gain, the first reference signal and the first quantum signal.

[0127] In some embodiments, the quantum key distribution device provided by the embodiments of the present disclosure may further include:

[0128] An updating module is used to perform constellation point decision on an output signal composed of the second reference signal and the second quantum signal to obtain a decision error; if the decision error meets a preset condition, the state vector at the current moment, the covariance of the state vector at the current moment, and the Kalman gain are updated.

[0129] In some embodiments, the transmitting end is used to process the first carrier signal through a delay device and a first attenuator to obtain a reference signal, and the reference signal is used for coarse estimation of carrier frequency deviation and phase at the receiving end; the second carrier signal is processed through a modulator and a second attenuator to obtain a quantum signal; and the quantum signal and the reference signal are polarization multiplexed through a polarization coupler to obtain the composite optical signal.

[0130] It should be noted that the signal determination module 501, signal recovery module 502, integrated compensation module 503, and post-processing module 504 correspond to S202 to S208 in the method embodiment, and the examples and application scenarios implemented by the above modules and corresponding steps are the same, but are not limited to the contents disclosed in the above method embodiment. It should be noted that the above modules, as part of the device, can be executed in a computer system such as a set of computer executable instructions.

[0131] The device provided by the embodiment of the present disclosure performs carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal, and then performs integrated polarization and slow phase compensation, thereby realizing the extraction and distribution of quantum keys. Therefore, the embodiment of the present disclosure can improve the adaptability to environmental changes, improve the flexibility of quantum key distribution, and improve the coding rate and stability of the quantum key distribution system in complex environments.

[0132] Those skilled in the art will appreciate that various aspects of the present disclosure may be implemented as systems, methods or program products. Therefore, various aspects of the present disclosure may be specifically implemented in the following forms, namely: complete hardware implementation, complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software, which may be collectively referred to herein as "circuits", "modules" or "systems".

[0133] The embodiment of the present disclosure provides an electronic device, which exemplarily includes: a processor and a memory. The memory can be used to store executable instructions of the processor. The processor is configured to perform the quantum key distribution method provided by the embodiment of the present disclosure by executing the above executable instructions.

[0134] Refer to the following Figure 6 The electronic device 600 according to this embodiment of the present disclosure is described. Figure 6 The electronic device 600 shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0135] like Figure 6As shown, the electronic device 600 is in the form of a general computing device. The components of the electronic device 600 may include but are not limited to: at least one processing unit 610, at least one storage unit 620, and a bus 630 connecting different system components (including the storage unit 620 and the processing unit 610).

[0136] The storage unit stores a program code, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps of various exemplary embodiments of the present disclosure described in the above “Exemplary Method” section of this specification. For example, the processing unit 610 can perform the following steps of the above method embodiment:

[0137] The demodulated reference signal and the demodulated quantum signal are determined by the composite optical signal sent by the transmitting end, and the composite optical signal is obtained by polarization multiplexing the reference signal and the quantum signal; the demodulated reference signal and the demodulated quantum signal are subjected to carrier frequency offset recovery and fast phase drift recovery to obtain a first reference signal and a first quantum signal; the first reference signal and the first quantum signal are subjected to integrated polarization and slow phase compensation to obtain a second reference signal and a second quantum signal; the quantum key is extracted from the second reference signal and the second quantum signal to realize the distribution of the quantum key.

[0138] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0139] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0140] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0141] The electronic device 600 may also communicate with one or more external devices 640 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). This communication may be performed through an input / output (I / O) interface 650. In addition, the electronic device 600 may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) through a network adapter 660. As shown, the network adapter 660 communicates with other modules of the electronic device 600 through a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0142] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes a number of instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the implementation of the present disclosure.

[0143] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart may be implemented as a computer program product, which includes: a computer program, which implements the above-mentioned quantum key distribution method when executed by a processor.

[0144] In an exemplary embodiment of the present disclosure, a computer-readable storage medium is also provided, on which a computer program is stored, and when the computer program is executed by a processor, the quantum key distribution method provided in the embodiment of the present disclosure can be implemented. The computer-readable storage medium can be a readable signal medium or a readable storage medium.

[0145] Figure 7 A schematic diagram of a computer-readable storage medium in an embodiment of the present disclosure is shown. Figure 7As shown, a program product capable of implementing the above method of the present disclosure is stored on the computer-readable storage medium 700. In some possible implementations, various aspects of the present disclosure may also be implemented in the form of a program product, which includes a program code. When the program product is run on a terminal device, the program code is used to enable the terminal device to execute the steps according to various exemplary implementations of the present disclosure described in the above “Exemplary Method” section of this specification.

[0146] More specific examples of computer-readable storage media in the present disclosure may include, but are not limited to, an electrical connection having one or more conductors, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0147] In the present disclosure, a computer readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, wherein a readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A readable signal medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0148] Alternatively, the program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the foregoing.

[0149] In specific implementation, the program code for performing the operation of the present disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages, such as Java, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as an independent software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0150] It should be noted that, although several modules or units of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into multiple modules or units to be embodied.

[0151] In addition, although the steps of the method in the present disclosure are described in a specific order in the drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc.

[0152] Through the description of the above implementation modes, it is easy for those skilled in the art to understand that the example implementation modes described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation mode of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a mobile terminal, or a network device, etc.) to execute the method according to the implementation mode of the present disclosure.

[0153] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The description and examples are to be regarded as exemplary only, and the true scope of the present disclosure is indicated by the appended claims.

Claims

1. A quantum key distribution method, characterized in that: include: Determine a demodulated reference signal and a demodulated quantum signal by using a composite optical signal sent by a transmitting end, wherein the composite optical signal is obtained by performing polarization multiplexing on the reference signal and the quantum signal; Performing carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal; Performing integrated polarization and slow phase compensation on the first reference signal and the first quantum signal through an extended Kalman system to obtain a second reference signal and a second quantum signal; performing constellation point decision on an output signal composed of the second reference signal and the second quantum signal to obtain a decision error, and if the decision error is not less than a preset threshold, adaptively updating the variance of the process noise of the extended Kalman system; A quantum key is extracted from the second reference signal and the second quantum signal to achieve distribution of the quantum key.

2. The quantum key distribution method according to claim 1, characterized in that: The method of determining the demodulated reference signal and the demodulated quantum signal by using the composite optical signal sent by the transmitting end includes: Receiving the composite optical signal sent by the transmitting end; Processing the composite optical signal through a polarization beam splitter to obtain two mutually perpendicular polarization state signals; Performing coherent demodulation on the two mutually perpendicular polarization state signals and the local oscillator signal to obtain an electrical signal; The electrical signal is subjected to analog-to-digital conversion to obtain a demodulated reference signal and a demodulated quantum signal.

3. The quantum key distribution method according to claim 1, characterized in that: The performing carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal includes: Estimating the carrier frequency offset of the demodulated reference signal to obtain a frequency offset estimation value; Performing carrier frequency offset compensation on the demodulated quantum signal according to the frequency offset estimation value; Performing fast phase drift estimation on the demodulated reference signal to obtain a fast phase drift estimation value; The fast phase drift compensation is performed on the demodulated quantum signal according to the fast phase drift estimation value.

4. The quantum key distribution method according to any one of claims 1 to 3, characterized in that: The step of performing integrated polarization and slow phase compensation on the first reference signal and the first quantum signal to obtain a second reference signal and a second quantum signal includes: Get the state vector of the extended Kalman system at the previous moment; Predicting the prior state vector at the current moment according to the state vector at the previous moment; Determine an observation matrix according to the prior state vector; The second reference signal and the second quantum signal are determined according to the prior state vector, the measurement matrix, the first reference signal and the first quantum signal.

5. The quantum key distribution method according to claim 4, characterized in that: The predicting of the prior state vector at the current moment according to the state vector at the previous moment includes: Predicting the a priori state vector at the current moment and the a priori estimation error covariance matrix table at the current moment according to the state vector at the previous moment; The determining of the observation matrix according to the prior state vector comprises: Determine the Kalman gain and the observation matrix according to the state vector at the current moment and the prior estimation error covariance matrix at the current moment; The determining the second reference signal and the second quantum signal according to the prior state vector, the measurement matrix, the first reference signal and the first quantum signal comprises: The second reference signal and the second quantum signal are determined according to the prior state vector, the observation matrix, the Kalman gain, the first reference signal and the first quantum signal.

6. The quantum key distribution method according to claim 5, characterized in that: After determining the second reference signal and the second quantum signal according to the prior state vector, the measurement matrix, the Kalman gain, the first reference signal and the first quantum signal, the method further includes: Performing constellation point decision on an output signal composed of the second reference signal and the second quantum signal to obtain a decision error; If the decision error satisfies a preset condition, the state vector at the current moment, the covariance of the state vector at the current moment, and the Kalman gain are updated.

7. The quantum key distribution method according to claim 1, characterized in that: The transmitting end is used to process the first carrier signal through a delay device and a first attenuator to obtain a reference signal, and the reference signal is used for coarse estimation of carrier frequency deviation and phase at the receiving end; process the second carrier signal through a modulator and a second attenuator to obtain a quantum signal; and perform polarization multiplexing on the quantum signal and the reference signal through a polarization coupler to obtain the composite optical signal.

8. A quantum key distribution device, characterized in that: include: A signal determination module, used to determine a demodulated reference signal and a demodulated quantum signal through a composite optical signal sent by a transmitting end, wherein the composite optical signal is obtained by polarization multiplexing the reference signal and the quantum signal; A signal recovery module, used to perform carrier frequency offset recovery and fast phase drift recovery on the demodulated reference signal and the demodulated quantum signal to obtain a first reference signal and a first quantum signal; An integrated compensation module is used to perform polarization and slow phase integrated compensation on the first reference signal and the first quantum signal through an extended Kalman system to obtain a second reference signal and a second quantum signal; perform constellation point decision on an output signal composed of the second reference signal and the second quantum signal to obtain a decision error, and if the decision error is not less than a preset threshold, adaptively update the variance of the process noise of the extended Kalman system; A post-processing module is used to extract a quantum key from the second reference signal and the second quantum signal to achieve distribution of the quantum key.

9. An electronic device, characterized in that: include: processor; as well as A memory, configured to store executable instructions of the processor; The processor is configured to execute the quantum key distribution method described in any one of claims 1 to 7 by executing the executable instructions.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the quantum key distribution method described in any one of claims 1 to 7 is implemented.

11. A computer program product, characterized in that The computer program product includes computer instructions, which are stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device executes the quantum key distribution method as described in any one of claims 1 to 7.

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