WO2018196585A1 - 信号的接收装置和接收方法 - Google Patents

信号的接收装置和接收方法 Download PDF

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Publication number
WO2018196585A1
WO2018196585A1 PCT/CN2018/082259 CN2018082259W WO2018196585A1 WO 2018196585 A1 WO2018196585 A1 WO 2018196585A1 CN 2018082259 W CN2018082259 W CN 2018082259W WO 2018196585 A1 WO2018196585 A1 WO 2018196585A1
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Prior art keywords
pulse signal
signal
local oscillation
optical pulse
optical
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PCT/CN2018/082259
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English (en)
French (fr)
Inventor
蔡永旌
陆亮亮
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华为技术有限公司
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Priority to EP18792163.0A priority Critical patent/EP3588839B1/en
Publication of WO2018196585A1 publication Critical patent/WO2018196585A1/zh
Priority to US16/592,128 priority patent/US10749608B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
    • H04L9/0852—Quantum cryptography
    • H04L9/0858—Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/70—Photonic quantum communication
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
    • H01S5/06209—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in single-section lasers
    • H01S5/06216—Pulse modulation or generation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50—Transmitters
    • H04B10/508—Pulse generation, e.g. generation of solitons
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50—Transmitters
    • H04B10/516—Details of coding or modulation
    • H04B10/524—Pulse modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/80—Optical aspects relating to the use of optical transmission for specific applications, not provided for in groups H04B10/03 - H04B10/70, e.g. optical power feeding or optical transmission through water
    • H04B10/85—Protection from unauthorised access, e.g. eavesdrop protection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
    • H04L9/0852—Quantum cryptography

Definitions

  • the present application relates to the field of communications technologies, and in particular, to receiving a quantum optical pulse signal and a local oscillator optical pulse signal for adjusting a Self-Referenced Continuous-Variable Quantum Key Distribution (SR-CV-QKD).
  • SR-CV-QKD Self-Referenced Continuous-Variable Quantum Key Distribution
  • Quantum cryptography is a new communication technology that combines quantum characteristics and traditional cryptography. The basic principles and characteristics of quantum mechanics ensure the security of communication transmission. After more than 30 years of development, it has begun to be put into practical use in the market. .
  • Quantum cryptography is mainly used to distribute keys, also known as Quantum Key Distribution (QKD).
  • QKD Quantum Key Distribution
  • the QKD system is used to generate and distribute quantum keys, which are used to encrypt classical information and enhance the security of classical information transmission processes.
  • a unidirectional QKD system works by randomly encoding a series of information on the quantum state of the quantum optical pulse signal at the transmitting end, after being transmitted through the quantum channel, and being detected by the detector at the receiving end, and then the transmitting end and the receiving end. After processing the program through the classic channel data comparison, the two parties finally share a set of identical and secure random number keys.
  • QKD has two methods: Discrete-Variable Quantum Key Distribution (DV-QKD) and Continuous-Variable Quantum Key Distribution (CV-QKD), in which discrete and continuous It refers to whether the information randomly encoded by the quantum state is discrete or continuous.
  • DV-QKD Discrete-Variable Quantum Key Distribution
  • CV-QKD Continuous-Variable Quantum Key Distribution
  • DV-QKD implements key distribution by encoding a single photon signal, so it requires a single photon detector with high detection accuracy and requires low temperature operation.
  • the CV-QKD is not required. It uses a balanced zero-beat detector, so it is more practical, and its own characteristics make it compatible with the current WDM network.
  • FIG. 1 shows a conventional CV-QKD system.
  • a continuous laser light source of a transmitting end (referred to as Alice) generates a periodic optical pulse signal by chopping of an amplitude modulator.
  • the optical pulse signal is split into two paths by a 1:9 beam splitter, and the powerful one-way pulse signal is directly input to one end of the polarization coupler as a local oscillator pulse signal.
  • the pulse with a small light intensity will continue to be randomly parameter modulated by the amplitude and phase modulator.
  • the random number to be transmitted can be encoded onto the regular component of the weak light signal.
  • the rotating mirror is used to change the polarization of the pulse signal to rotate 90° on the basis of the original polarization (meaning that the polarization of the optical pulse signal and the polarization of the local oscillator pulse signal are orthogonal and perpendicular), and at the same time, the optical pulse signal is increased.
  • After walking for a period of optical path it is attenuated by the attenuator and becomes the other end of the quantum optical pulse signal input polarization coupler, so that it can be transmitted in the optical fiber together with the other local oscillator optical pulse signal through polarization multiplexing and time multiplexing. Because the intensity of the local oscillator is much larger than that of the quantum optical pulse signal, crosstalk is easily generated. Therefore, polarization multiplexing and time multiplexing are used to increase the isolation between the local oscillator and the signal light.
  • the polarization state of the control input signal is adjusted in real time by a dynamic polarization controller, so that when the input signal passes through the subsequent polarization beam splitter, the quantum light pulse signal is completely output from one end thereof, The local oscillation pulse signal is completely output from the other end.
  • the path-pulsing pulse signal needs to be randomly selected by the phase modulator and the same unequal-arm optical path device as the transmitting end performs time delay compensation on the local light pulse signal, thereby ensuring input to the 2 ⁇ 2 coupler.
  • the quantum light pulse signal is aligned with the local oscillator light timing.
  • the two outputs of the 2 ⁇ 2 coupler are connected to the two inputs of the balanced receiver. After the electrical signals output by the balanced receiver are collected by the data, the initial data obtained by some data processing is usually called the original code ( Raw key), or the original key.
  • the mode of the local light is used, that is, while transmitting the quantum light pulse signal, a classic light pulse signal with stronger light intensity is transmitted as the local light pulse signal.
  • the local oscillation pulse signal has a very large interference to the quantum optical pulse signal, in order to minimize the interference, the quantum light pulse signal and the local oscillation optical pulse signal are often time-multiplexed in the implementation, that is, the quantum light pulse is transmitted at the transmitting end.
  • the signal pulse is delayed for a period of time, so that it is transmitted with the associated local oscillator pulse signal in time, but this requires the same delay compensation to be applied to the local oscillator at the receiving end, thus requiring the receiving end and transmitting It is very difficult to make fiber delays of the same length at the end.
  • the local oscillator pulse signal is related to the vacuum noise measurement level of the receiver balance detector. If the intensity of the local oscillator pulse signal changes, the detection result will be affected. If the change is implemented by a third-party eavesdropper, it may cause system security to be affected (the local oscillator pulse signal attack).
  • the local oscillator generated by the transmitting end of the conventional CV-QKD system is transferred to the receiving end, and the interference result between the local oscillator optical pulse signal generated by the receiving end and the quantum optical pulse signal transmitted by the transmitting end can be analyzed,
  • a reference pulse having a strong light intensity is introduced between the quantum light pulse signals sent by the transmitting end, and the reference pulse may be referred to as a reference light for detecting the quantum light pulse signal light sent by the transmitting end and the local oscillator light pulse signal at the receiving end.
  • the frequency offset and the phase difference are such that the measuring machine in the CV-QKD system is selected to recover the information of the quantum light pulse signal.
  • the scheme does not require strict equal length control for the lengths of the two optical fibers at the transmitting end and the receiving end.
  • the intensity of the reference pulse is much weaker than that of the local oscillator optical pulse signal transmitted by the transmitting end of the conventional CV-QKD system, so the interference to the quantum optical pulse signal is small, and the local oscillator light transmitted by the local oscillator optical pulse signal can be eliminated. The hidden danger of the pulse signal being attacked.
  • the SR-CV-QKD system scheme it is estimated by measuring the phase difference between the local oscillator and the reference light, and the estimation is based on the reference light and the pulse of the quantum signal light are very close in the time domain, and both pass through
  • the transmission of the same channel can be approximated by estimating the phase of the change in the reference optical transmission and the pulse of the adjacent quantum signal light, or using the pulse phase of the reference light before the quantum signal light and after the quantum signal light. Average estimate.
  • the local oscillation pulse signal and the quantum optical pulse signal are not generated by the same laser, the delay between the two needs to be adjusted to achieve the timing alignment of the two to ensure optimal interference. At present, the optical delay line is used for timing alignment.
  • the timing of the signal pulse will be jittered, and additional delay occurs, causing the timing of the two to be inconsistent. To ensure timing alignment, it is required. Continue to mediate the optical delay line so that the timing alignment is less efficient.
  • the embodiment of the present application provides a signal receiving apparatus and a receiving method. According to a reference pulse signal in a probe optical pulse signal and an adjusted pulse signal according to a reference pulse signal, a first local oscillator having the same timing as an optical pulse signal is obtained. The optical pulse signal, and then the original key, realizes the timing alignment of the first local oscillation pulse signal and the quantum optical signal, thereby improving the efficiency of the timing alignment of the two.
  • an embodiment of the present application provides a signal receiving apparatus, where the receiving apparatus may include:
  • a signal receiving module configured to detect a reference pulse signal in the received optical pulse signal; wherein the optical pulse signal comprises a reference pulse signal and a quantum light pulse signal;
  • a synchronous clock module for obtaining a modulated pulse signal according to the reference pulse signal
  • the first intensity modulator in the signal receiving module is configured to obtain a first local oscillation pulse signal that is the same as the timing of the optical pulse signal according to the modulated pulse signal, and the signal receiving module respectively respectively uses the first local oscillation pulse signal with the reference pulse signal and the quantum The optical pulse signal interferes to obtain the original key.
  • the receiving device provided by the embodiment of the present application can efficiently match the timing of the first local oscillation pulse signal and the optical pulse signal to ensure optimal interference between the first local oscillation pulse signal and the optical pulse signal, and obtain accurate and original density. key.
  • the signal receiving module can include the first beam splitter and the first detector.
  • the first beam splitter is configured to separate the received optical pulse signals.
  • the first detector is configured to detect a reference pulse signal in the separated optical pulse signal.
  • the synchronous clock module is configured to obtain a modulated pulse signal according to the reference pulse signal, including:
  • the synchronous clock module determines clock information of the optical pulse signal according to the reference pulse signal; and obtains a modulated pulse signal according to the clock information.
  • the first intensity modulator is configured to obtain a timing of the optical pulse signal according to the modulated pulse signal
  • the same first local light pulse signal including:
  • the first intensity modulator is configured to chop the continuous laser generated by the laser according to the modulated pulse signal to form the first local oscillation pulse signal.
  • the signal receiving module further includes a signal modulating unit and a second intensity modulator;
  • the intensity modulators are coupled to the signal modulation unit and the first intensity modulator, respectively.
  • the synchronous clock module is also used to determine timing information of the reference pulse signal.
  • a signal modulation unit configured to determine modulation information according to the timing information.
  • the second intensity modulator is configured to adjust the first local oscillation pulse signal according to the modulation information.
  • the second intensity modulator is configured to adjust the first local oscillator optical pulse signal according to the modulation information, including :
  • the first intensity modulator adjusts the first local oscillation pulse signal to two intensity local oscillation pulses according to the modulation information: the second local oscillation pulse signal and the third local oscillation pulse signal.
  • the signal receiving module interferes the first local oscillation pulse signal with the reference pulse signal and the quantum optical pulse signal, include:
  • a signal receiving module configured to interfere with the second local oscillation pulse signal and the quantum optical pulse signal; and interfere with the third local oscillation pulse signal and the reference pulse signal; wherein the second local oscillation pulse signal intensity is greater than the third The intensity of the local oscillator pulse signal.
  • the second local oscillation pulse signal and the third local oscillation pulse signal of different strengths can detect the reference pulse signal and the signal light pulse signal through the same balanced zero-shoot detector, in the reference pulse signal.
  • the intensity is 1000 times the intensity of the signal pulse signal.
  • the dynamic range of the AD/DA for the collection of the quantum light pulse signal is also reasonable.
  • the signal receiving module further includes a second beam splitter and The second detector, the second beam splitter is respectively connected to the second intensity modulator, the second detector, and the phase modulator.
  • the second beam splitter is configured to separate the second local oscillation pulse signal and the third local oscillation pulse signal.
  • the second detector is configured to detect the intensity of the second local oscillation pulse signal and the intensity of the third local oscillation pulse signal.
  • the signal receiving module Includes a polarization recognizer.
  • the polarization identifier is configured to receive the optical pulse signal after the splitting of the first beam splitter, and detect polarization information of the reference pulse signal in the optical pulse signal, and generate polarization adjustment information according to the polarization information.
  • the signal receiving module further includes a third beam splitter, wherein the first beam splitter and the polarization identifier pass The third beam splitter is connected.
  • a third beam splitter for receiving the optical pulse signal separated by the first beam splitter and splitting the optical pulse signal; and the polarization identifier determining the reference pulse signal in the optical pulse signal separated by the third beam splitter Polarization information.
  • the signal receiving module further includes a dynamic polarization controller, a dynamic polarization controller, and a polarization identifier, The second intensity modulator and the second beam splitter are connected;
  • a dynamic polarization controller configured to adjust a polarization direction of the second local oscillation pulse signal and the third local oscillation pulse signal according to the polarization adjustment information, and adjust a second local oscillation pulse signal and a third local oscillation of the polarization direction
  • the pulse signal is output to the second beam splitter.
  • the second local oscillator pulse signal and the third local oscillator pulse signal and the reference pulse signal and the quantum light in the optical pulse signal are adjusted by the polarization identifier and the dynamic polarizer in the receiving device.
  • the polarization of the pulse signal is uniform, and the interference between the second local oscillation pulse signal and the quantum light signal, the third local oscillation pulse signal and the reference pulse signal is optimal to obtain an accurate original key.
  • an embodiment of the present application provides a method for receiving a signal, where the receiving method may include:
  • the optical pulse signal comprises a reference pulse signal and a quantum light pulse signal
  • the first local light pulse signal is interfered with the reference pulse signal and the quantum light pulse signal to obtain an original key.
  • the timing of the first local oscillation pulse signal and the optical pulse signal can be consistently ensured, and the interference between the first local oscillation pulse signal and the optical pulse signal is ensured to be optimal, and the accurate original density is obtained. key.
  • the detecting the reference pulse signal in the received optical pulse signal comprises:
  • determining the modulated pulse signal according to the reference pulse signal includes:
  • the modulated pulse signal is determined based on the clock information.
  • the first local oscillator having the same timing as the optical pulse signal is obtained according to the modulated pulse signal Pulse signals, including:
  • the continuous laser generated by the laser is chopped according to the modulated pulse signal to form a first local oscillation pulse signal.
  • the receiving method may further include:
  • the first local oscillation pulse signal is adjusted according to the timing information.
  • the adjusting the first local oscillator optical pulse signal according to the timing information includes:
  • the first local oscillation pulse signal is adjusted to two intensity local oscillation pulse signals according to timing information: a second local oscillation pulse signal and a third local oscillation pulse signal.
  • the interference between the first local oscillation pulse signal and the reference pulse signal and the quantum optical pulse signal includes:
  • the intensity of the second local oscillation pulse signal is greater than the intensity of the third local oscillation pulse signal.
  • the second local oscillation pulse signal and the third local oscillation pulse signal of different strengths can detect the reference pulse signal and the signal optical pulse signal through the same balanced zero-shoot detector, in the reference pulse signal.
  • the intensity is 1000 times the intensity of the signal pulse signal.
  • the dynamic range of the AD/DA for the collection of the quantum light pulse signal is also reasonable.
  • the receiving method may further include:
  • Polarization information of the reference pulse signal in the optical pulse signal is detected; polarization adjustment information is obtained according to the polarization information.
  • the second local oscillator pulse signal is interfered with the quantum optical pulse signal
  • the third local oscillator is Before the optical pulse signal interferes with the reference pulse signal
  • the polarization directions of the second local oscillation pulse signal and the third local oscillation pulse signal are adjusted according to the polarization adjustment information.
  • the receiving method provided by the embodiment of the present application achieves the second by adjusting the polarizations of the reference pulse signal and the quantum light pulse signal in the second local oscillation pulse signal and the third local oscillation pulse signal of the different intensity.
  • the interference between the local oscillation pulse signal and the quantum optical signal, the third local oscillation pulse signal and the reference pulse signal is optimal to obtain an accurate original key.
  • FIG. 1 is a schematic structural diagram of a conventional continuous variable quantum key distribution system
  • FIG. 2 is a structural block diagram of a one-way SR-CV-QKD system according to an embodiment of the present application
  • FIG. 3 is a schematic structural diagram of a quantum key distribution system for adjusting a self-reference continuous variable according to an embodiment of the present disclosure
  • 4(a) is a schematic diagram of a modulated pulse signal according to an embodiment of the present application.
  • 4(b) is a schematic diagram of another modulation pulse signal provided by an embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of a quantum key distribution system for adjusting a self-referential continuous variable according to an embodiment of the present disclosure
  • FIG. 6 is a schematic structural diagram of another quantum key distribution system for regulating self-reference continuous variables according to an embodiment of the present disclosure
  • FIG. 7 is a flowchart of a method for receiving a signal according to an embodiment of the present application.
  • FIG. 8 is a flowchart of another method for receiving a signal according to an embodiment of the present application.
  • the embodiment of the present application provides a signal receiving apparatus and a receiving method, and the receiving apparatus and the receiving method are applied to an SR-CV-QKD system.
  • the receiving device in the SR-CV-QKD system receives the optical pulse signal transmitted by the transmitting device, wherein the optical pulse signal includes a quantum optical pulse signal of the reference pulse signal.
  • the receiving device detects the reference pulse signal in the optical pulse signal, determines timing information of the reference pulse signal, and polarization information, and determines the first book for generating the same timing as the optical pulse signal according to the timing information of the reference pulse signal.
  • a modulated pulse signal of the oscillating pulse signal determining modulation information for adjusting the intensity of the first local oscillation pulse signal, and determining polarization adjustment information according to the polarization information of the reference pulse signal, according to the modulation pulse signal, the modulation information, and the polarization
  • the information adjusts the first local oscillation pulse signal to obtain a first local oscillation pulse aligned with the optical pulse signal timing information and the polarization information, and the first local oscillation pulse signal and the reference pulse signal and the quantum optical pulse signal respectively Interfere to get the original key.
  • the original key is the initial key detected by the receiving device.
  • the quantum key is obtained after the original key is subjected to a series of processing by the receiving device.
  • the SR-CV-QKD system is shown in Figure 2.
  • Figure 2 is a block diagram of a unidirectional SR-CV-QKD system.
  • the SR-CV-QKD system may include a transmitting end and a receiving end, or is called a transmitting device and a receiving device.
  • the transmitting device may include a first negotiation information module, a synchronous clock sending module, a signal sending module, and a first main control module.
  • the receiving device may include a second negotiation information module, a synchronous clock receiving module, a signal receiving module, and The second main control module.
  • the synchronous clock receiving module may be simply referred to as a synchronous clock module.
  • the first main control module in the sending device is configured to control the first negotiation information module, the synchronous clock sending module, and the signal sending module in the sending device to perform corresponding operations;
  • the second main control module in the receiving device is used to control receiving The second negotiation information module, the synchronous clock receiving module, and the signal receiving module in the device perform corresponding operations.
  • the solution provided by the embodiment of the present application mainly relates to a receiving device in an SR-CV-QKD system, and more particularly to a synchronous clock receiver and a quantum signal receiver in a receiving device.
  • the transmitting device is configured to transmit and transmit the optical pulse signal carrying the quantum key to the receiving device, where the optical pulse signal includes a reference pulse signal of the quantum optical pulse signal.
  • the intensity of the reference pulse signal may be approximately 1000 times the intensity of the quantum light pulse signal.
  • the reference pulse signal and the quantum light pulse signal may be set in a certain relationship, for example, one of the two reference pulse signals has one quantum light pulse signal, or one of the two reference pulse signals has a quantum light pulse signal, etc., so that After the receiving device detects the reference pulse signal in the optical pulse signal, the information of the quantum optical pulse signal is estimated according to the relationship between the reference pulse signal and the quantum optical pulse signal.
  • the signal receiving module in the receiving device receives the optical pulse signal sent by the transmitting device, detects the reference pulse signal in the optical pulse signal, recovers the timing information of the reference pulse signal by using the synchronous clock module, and recovers according to the timing information of the reference pulse signal.
  • the clock information of the light pulse signal; the receiving device generates a corresponding modulated pulse signal according to the clock information of the recovered light pulse signal, and then performs a chirp waveform cost light pulse signal on the continuous laser generated by the local laser according to the modulated pulse signal,
  • the frequency and time domain distribution of the local oscillation pulse signal are consistent with the frequency and time domain distribution of the optical pulse signal.
  • the local oscillation pulse signal is also the first local oscillation pulse signal mentioned in the present application.
  • the receiving device may further determine the modulation information according to the timing information of the reference pulse signal, and adjust the signal strength of the first local oscillation optical pulse signal according to the modulation information, so that the receiving device provided by the embodiment of the present application can pass through a balanced detector. Meet the detection requirements of pulse signals of different intensities.
  • the receiving device may further detect polarization information of the reference pulse signal to determine polarization adjustment information according to the polarization information, thereby adjusting a polarization direction of the first local oscillation pulse signal according to the polarization adjustment information, so as to adjust the polarization direction and the light pulse.
  • the polarization directions of the signals are the same to achieve optimal interference between the first local oscillator pulse signal and the optical pulse signal.
  • the timing information of the reference pulse signal is recovered by the synchronous clock module, and the signal receiving module obtains the polarization information of the reference pulse signal, and accordingly adjusts the frequency, delay, light intensity and polarization of the first local oscillation pulse signal generated by the receiving device. Therefore, it is ensured that the local oscillation pulse signal generated by the receiving device and the received optical pulse signal can be aligned in timing and polarization to achieve optimal interference to further obtain the original key.
  • FIG. 3 is a schematic structural diagram of a quantum key distribution system for adjusting self-reference continuous variables according to an embodiment of the present disclosure.
  • the receiving device may include a signal receiving module 100 and a synchronous clock module 200, and the signal receiving module includes a first intensity modulator 110.
  • the signal receiving module 100 is configured to detect a reference pulse signal in the received optical pulse signal; wherein the optical pulse signal comprises a reference pulse signal and a quantum light pulse signal.
  • the synchronous clock module 200 is configured to obtain a modulated pulse signal according to the reference pulse signal.
  • the first intensity modulator IM 1 110 in the signal receiving module 100 is configured to obtain a first local oscillator optical pulse signal that is the same as the timing of the optical pulse signal according to the modulated pulse signal, and the signal receiving module respectively respectively uses the first local oscillator optical pulse signal The reference pulse signal and the quantum light pulse signal are interfered to obtain an original key.
  • the receiving device after receiving the optical pulse signal sent by the transmitting device, the receiving device detects the reference pulse signal in the optical pulse signal, and estimates the quantum optical pulse signal according to the timing information of the reference pulse signal.
  • the reference pulse signal and the quantum light pulse signal in the optical pulse signal are transmitted according to a certain relationship, for example, there is one quantum optical pulse signal in the middle of each two reference pulse signals, or one quantum exists after every two reference pulse signals. Light pulse signal, and so on. Then, there is a simple proportional relationship between the frequency of the optical pulse signal and the frequency of the reference pulse signal. According to the proportional relationship, the timing information of the reference pulse signal can be obtained when the reference pulse signal is detected, and the clock of the optical pulse signal can be further recovered. information.
  • the synchronous clock module 200 may include a clock recovery unit that generates a corresponding modulated pulse signal according to clock information of the optical pulse signal.
  • the first intensity modulator IM 1 110 obtains a first local oscillator pulse signal having the same timing as that of the optical pulse signal according to the modulated pulse signal, so that the first local oscillator pulse signal and the optical pulse signal interfere to obtain an original key, and further Further get the quantum key.
  • the receiving device provided by the embodiment of the present application obtains a first local oscillation pulse signal by detecting a reference pulse signal in the optical pulse signal, and generates a modulated pulse signal according to the reference pulse signal, and the timing and light of the first local oscillation optical pulse signal
  • the timing of the pulse signal is consistent, and the device provided by the embodiment of the present application can be simpler and more efficient than the timing of adjusting the optical fiber delay to adjust the timing of the first local oscillation pulse signal and the optical pulse signal.
  • the timing of the first local light pulse signal and the timing of the optical pulse signal are made uniform, and the original key is further obtained, thereby obtaining the quantum key.
  • the synchronous clock module 200 is configured to obtain a modulated pulse signal according to the reference pulse signal, including:
  • the synchronous clock module 200 determines clock information of the optical pulse signal according to the reference pulse signal; and obtains a modulated pulse signal according to the clock information, so that the first intensity modulator IM 1 110 performs chopping formation on the continuous laser generated by the local laser according to the modulated pulse signal.
  • the first local light pulse signal The first local light pulse signal.
  • IM 1 110 chopping the continuous laser generated by the local laser.
  • the principle of chopping is to process the continuous laser passing through IM1 by loading the electric pulse signal. It can be visually understood as a switching operation.
  • the frequency distribution and time domain distribution of the formed pulse signal are consistent with the frequency distribution and time domain distribution of the loaded electrical pulse signal.
  • the clock information of the optical pulse signal that is, the frequency distribution and the time domain distribution information of the optical pulse signal
  • the clock synchronization module 200 is obtained from the clock synchronization module 200, and the corresponding electrical pulse signal can be generated according to the information, and the electrical pulse signal is generated.
  • the continuous laser generated by the local laser is chopped by IM1 to obtain a first local oscillation pulse signal that is consistent with the frequency distribution and time domain distribution of the optical pulse signal.
  • This method requires a specific optical path length, and the implementation process requires high precision of the optical path length and is troublesome to manufacture.
  • This method needs to adjust the generation mode of the modulated pulse signal loaded on the IM 1 , for example, by increasing the delay generated by the delay chip to adjust the modulation pulse signal, or adding corresponding processing to the modulation pulse signal generation,
  • the frequency distribution and the time domain distribution of the modulated pulse signal loaded on the IM 1 are simulated by digital information provided by a logic function chip.
  • an electric pulse of a specific frequency distribution and a time domain distribution is simulated by the arrangement and distribution of digital information, and the modulated pulse signal determines the frequency distribution of the modulated first local oscillation pulse signal and Time domain distribution information.
  • Figure 4(b) by changing the arrangement and distribution of digital information, the time domain distribution of the modulated pulse signal will change. It can be seen from Fig. 4(a) and Fig. 4(b) that the electric pulse generated in Fig. 4(a) and Fig.
  • FIG. 4(b) has time delay in time, so that the first local oscillator generated by IM1 chopping
  • the optical pulse signal, the frequency distribution and the time domain distribution of the first local oscillation pulse signal are consistent with the frequency distribution and the time domain distribution of the optical pulse signal. According to the periodicity, the difference between FIG. 4(a) and FIG. 4(b) is equivalent to the addition of a number "0" at the initial point.
  • the precondition for obtaining the modulated pulse signal by the receiving device is that the reference pulse signal is detected as a starting point. Therefore, no matter what kind of variation occurs in the transmission optical path, the optical pulse signal transmission occurs extra time. The delay does not affect the alignment of the optical pulse signal and the first local oscillator pulse signal.
  • the timing alignment of the first local light pulse signal and the optical pulse signal can be completed with high efficiency compared with the prior art.
  • the signal receiving module 100 may further include a first beam splitter 120 and a first detector 130.
  • the signal receiving module 100 is configured to detect a reference pulse signal in the received optical pulse signal, including:
  • the first beam splitter 120 is configured to separate the received optical pulse signal; the first detector 130 is configured to detect a reference pulse signal in the separated optical pulse signal.
  • the optical pulse signal includes a reference pulse signal and a quantum light pulse signal.
  • the received optical pulse signal is spectrally processed by the first beam splitter 120, and the reference pulse signal in the split optical pulse signal is detected by the first detector 130.
  • the first detector 130 can be a classic photodetector.
  • the splitting of the first beam splitter 120 needs to be appropriately selected according to the line attenuation of the SR-CV-QKD system. Because in the SR-CV-QKD system, the light intensity of the reference pulse signal can be about 1000 times that of the quantum light pulse signal (the light intensity of the quantum light pulse signal is about 10 for each light pulse). After the first beam splitter 120 is separated by a certain ratio, it is necessary to ensure that the intensity of the reference pulse signal in the separated optical pulse signal is still detectable by the classical photodetector. At the same time, the additional attenuation generated by the first beam splitter 120 on the quantum light pulse signal in the unseparated optical pulse signal needs to be guaranteed within a certain range, which is acceptable for the SR-CV-QKD system. The scope of the SR-CV-QKD system will not result in a security key.
  • the first beam splitter 120 may select a beam splitter of 1:9, and the light intensity of the reference pulse signal in the separated optical pulse signal is still strong, and the final measurement is performed.
  • the quantum light pulse signal in the optical pulse signal introduces only 1 dB of additional attenuation, which is acceptable for SR-CV-QKD systems with short transmission distances.
  • the first detector 130 is a photodetector.
  • the first detector 130 detects the reference pulse signal of the optical signal to obtain a reference pulse signal each converted into an electrical pulse signal.
  • the first detector 130 detects the reference pulse signal in the optical pulse signal, since the light intensity of the quantum light pulse signal in the optical pulse signal is very weak, it can be considered that the first detector 130 cannot respond to it, and the corresponding signal is not generated.
  • Electric pulse signal since the light intensity of the quantum light pulse signal in the optical pulse signal is very weak, it can be considered that the first detector 130 cannot respond to it, and the corresponding signal is not generated.
  • Electric pulse signal Then, the electric pulse signal corresponding to the reference pulse signal can be obtained by synchronizing the optical pulse signal of the clock module 200, and the frequency distribution, the time domain distribution, and the frequency distribution and the time domain distribution of the reference pulse signal are consistent.
  • the receiving device may further include a signal modulating unit 140 and a second intensity modulator 150.
  • the second intensity modulator 150 is coupled to the signal modulation unit 140 and the synchronous clock module 200, respectively; the second intensity modulator IM 2 150 is coupled to the first intensity modulator 110.
  • the synchronization clock module 200 is further configured to determine timing information of the reference pulse signal; the signal modulation unit 140 is configured to determine the modulation information according to the timing information; and the second intensity modulator IM 2 150 is configured to use the first local oscillator according to the modulation information.
  • the pulse signal is adjusted.
  • the synchronization clock module 200 obtains the frequency information of the reference pulse signal and sends it to the signal modulation unit 140 for loading the second intensity modulator IM 2 150 with modulation information, which is used for adjustment from the first intensity modulator IM 1 to output a first local oscillator light intensity of this pulse signal, a second intensity modulator IM 2 150 a.
  • the second intensity modulator IM 2 adjusts the first local oscillation pulse signal to two intensity local oscillation pulses according to the modulation information: the second local oscillation pulse signal and the third local oscillator Optical pulse signal.
  • the second local oscillation pulse signal is interfered with the quantum optical pulse signal; the third local oscillation pulse signal is interfered with the reference pulse signal; wherein the second local oscillation pulse signal intensity is greater than the third The intensity of the local oscillator pulse signal.
  • the intensity of the local oscillator optical pulse signal of the two intensity local oscillator pulse signals is interfered with the received quantum optical pulse signal, and the weak local oscillator optical pulse signal is received and received.
  • the reference pulse signal interferes.
  • the signal receiving module may further include a balanced zero-beat detector.
  • the input of the balanced zero-beat detector is connected to the phase modulator PM via a second beam splitter in the signal receiving module 100, and the second beam splitter is coupled to the second intensity modulator IM 2 150.
  • the SR-CV-QKD system uses balanced zero-beat detector detection, and the result of the balanced zero-beat detector and the two-way interference light (that is, the interference light of the intensity of the local oscillator pulse signal and the quantum light pulse signal,
  • the square of the product of the intensity of the intensity of the weaker local oscillator pulse signal and the interference signal interfered with the reference pulse signal is directly related. Therefore, if the local oscillator optical pulse signal of the same intensity is interfered with the received optical pulse signal (including the stronger reference pulse signal and the weaker quantum optical pulse signal), it is detected by the balanced zero-shoot detector.
  • the intensity of the interference light corresponding to the reference pulse signal and the quantum light pulse signal may differ by about 30 times because the intensity of the reference pulse signal is approximately 1000 times the intensity of the quantum light pulse signal.
  • the output range of the balanced zero-beat detector is fixedly limited.
  • the output measured by the quantum light pulse signal only accounts for the output range of the balanced zero-shoot detector.
  • the dynamic range of the AD / DA used is not reasonable, which will be the quantum optical pulse signal.
  • the accuracy of the measurement has a certain influence, and the quantum light pulse signal is the carrier of the key information, and the measurement should be as accurate as possible.
  • the embodiment of the present application uses different intensity of the local oscillator optical pulse signal to interfere with the reference pulse signal and the quantum optical pulse signal in the optical pulse signal, for example, interference with the local oscillation optical pulse signal of the intensity I 1 and the reference pulse signal.
  • the local oscillator pulse signal of intensity I 2 is interfered with the quantum light pulse signal, and I 1 and I 2 satisfy the relationship: I 2 ⁇ 1000I 1 .
  • the reference pulse signal and the quantum light pulse signal are detected by the balanced zero-shooting detector, and the results of detecting the reference pulse signal and the quantum light pulse signal are close in size. Sampling the measured output of the quantum light pulse signal can take full advantage of the ADC's AD/DA dynamic range, and the measurement results can be more accurate.
  • the extinction ratio of the current technology intensity modulator can be about 30 dB.
  • two kinds of local oscillation pulse signals with intensity differences close to 1000 times can be modulated by an intensity modulator.
  • a part of the local oscillation pulse signal interferes with the reference pulse signal in the optical pulse signal, and another part of the local oscillation optical pulse signal interferes with the quantum optical pulse signal in the optical pulse signal.
  • the second intensity modulator IM 2 is configured to attenuate the local oscillation optical pulse signal that interferes with the reference pulse signal, and does not attenuate the local oscillation optical pulse signal of the quantum optical pulse signal when it arrives.
  • the intensity modulator IM 2 can be loaded on a second square wave signal intensity modulator IM 2, frequency and duty cycle of the square wave signal and The frequency and duty cycle of the quantum light pulse signal are in proportion to the ratio of the entire optical pulse signal.
  • the ratio of the frequency and duty cycle of the quantum optical pulse signal to the entire optical pulse signal is complementary to the ratio of the frequency and duty cycle of the reference pulse signal to the entire optical pulse signal.
  • the entire optical pulse signal has a ratio of 1:1 reference pulse signal and quantum light pulse signal mixed, then the frequency of the square wave signal is consistent with the frequency of the reference pulse signal, and the duty ratio of the square wave signal is 50%, and The magnitude of the square wave signal satisfies the low level to allow IM 2 to be in the maximum attenuation state, and the high level allows IM 2 to be in the maximum pass state.
  • the frequency of the quantum optical pulse signal can be calculated according to the frequency of the measured reference pulse signal.
  • the specific estimation method is mentioned in the foregoing, and is a prior art, and is not described here for brevity.
  • the signal receiving module 100 may further include a second beam splitter 160 and a second detector 170, respectively of the second beam splitter 160 and the second intensity modulator 150, and the second detector
  • the phase modulator 180 is connected to the unit 170.
  • the second beam splitter 160 is configured to separate the second local oscillation pulse signal and the third local oscillation pulse signal.
  • the second detector 170 is configured to detect the intensity of the second local oscillation pulse signal and the intensity of the third local oscillation pulse signal.
  • the balanced zero beat detector demodulates the signal loading information from the measurement result.
  • the light intensity information of the local oscillator pulse signal is also required.
  • the embodiment of the present application sets a combination of a beam splitter and a detector at the output end of the IM2 to detect the first local oscillation pulse signal after the IM2 modulation, that is, the second local oscillation pulse signal and the third The intensity information of the local oscillator pulse signal. Moreover, the embodiment of the present application can monitor the intensity jitter of different local oscillator optical pulse signals through a beam splitter and a detector, and then calibrate the vacuum noise level.
  • the detected intensity information is fed back to the final digital signal processor (DSP) for providing parameters of the signal pulse adjustment information for the balanced zero-beat detector.
  • DSP final digital signal processor
  • the intensity of the local oscillation pulse signal can be adjusted by the IM 2 , and the optimal gain output of the reference pulse signal and the quantum optical pulse signal can be satisfied through the same balanced detector.
  • the dynamic range of the AD/DA used is also reasonable.
  • the local oscillator optical pulse signals of different intensities are used.
  • the following describes the influence of the intensity of different local oscillator optical pulse signals on the SR-CV-QKD system, mainly from the aspects of safety and detection performance. Be explained.
  • the local oscillator light intensity is an important parameter for calibrating the vacuum noise level and must be kept constant, otherwise there will be safety hazards (for example, the local oscillator pulse signal is attacked).
  • the local oscillation pulse signal is locally generated by the receiving device, and it can be considered that there is no external attack on the local oscillation pulse signal.
  • the intensity of the local oscillator pulse signal is monitored in real time. Therefore, the embodiment of the present application uses two different intensity local oscillator optical pulse signals to have no effect on system security.
  • the vacuum noise level is proportional to the intensity of the local oscillator pulse signal.
  • the vacuum noise level needs to be significantly greater than the electrical noise level (usually considered at least 10 times larger).
  • the detection result of the quantum light pulse signal can be distinguished from the detection output.
  • the local oscillators of two intensities of I 1 and I 2 are used, and the corresponding vacuum noise levels also have two kinds of N 01 and N 02 , and the I 2 intensity local oscillator optical pulse signal is used for detecting
  • the quantum light pulse signal has a strong intensity, and the corresponding vacuum noise level N 02 is large, which can meet the above requirements.
  • the local oscillator optical pulse signal of I 1 light intensity is weak, and the corresponding vacuum noise level N 01 is very low.
  • N 02 ⁇ 1000N 01 when the reference pulse signal is detected, the vacuum noise level is flooded by the electrical noise.
  • the reference pulse signal itself has a strong light intensity (10 3 -10 4 photons per pulse), and its signal-to-noise ratio is very high, as long as the output of the detection of the reference pulse signal is sufficiently large compared to the electrical noise level, then the reference pulse signal The measurement is still feasible.
  • the technical solution of the present application is feasible to use two different intensity local oscillator pulse signals for balancing the detection of the optical signal.
  • the IM1 in the present embodiment completes the timing alignment of the first local light pulse signal and the optical pulse signal by other means, the self-referential continuous variable quantum key shown in FIG. 5 can be adopted.
  • the distribution system completes the adjustment of the intensity of the first laser pulse signal to make full use of the AD/DA dynamic range of the ADC to make the measurement result of the quantum light pulse signal more accurate.
  • the signal receiving module 100 may further include a third beam splitter 175 and a polarization identifier 180, a third beam splitter 175 and a first beam splitter 120.
  • the polarization identifiers 180 are connected, or the first beam splitter 120 is coupled to the polarization identifier 180 via a third beam splitter 175.
  • the third beam splitter 175 is configured to receive the optical pulse signal separated by the first beam splitter 120 and split the optical pulse signal.
  • the polarization identifier 180 is configured to detect polarization information of the reference pulse signal in the optical pulse signal separated by the third beam splitter, and generate polarization adjustment information according to the polarization information.
  • the signal receiving module 100 may further include a Dynamic Polarization Control (DPC) 190, an input end of the dynamic polarization controller 190 and an output of the polarization identifier 180, The output of the second intensity modulator 150 is coupled, and the output of the dynamic polarization controller 190 is coupled to the input of the second beam splitter 160.
  • DPC Dynamic Polarization Control
  • the dynamic polarization controller 190 is configured to adjust a polarization direction of the second local oscillation pulse signal and the third local oscillation pulse signal according to the polarization adjustment information, and adjust a second local oscillation pulse signal and a third local oscillation of the polarization direction.
  • the optical pulse signal is output to the second beam splitter 160.
  • a dynamic polarization controller 190 is disposed after the IM2, and after the polarization identifier 180 detects the polarization information in the reference pulse signal in the optical pulse signal, corresponding polarization adjustment information is generated and fed back to the dynamic polarization controller 190.
  • the polarization of the local oscillator light modulated by IM2 is adjusted to be aligned with the polarization direction in the reference pulse signal to ensure optimal interference between the local oscillation pulse signal and the reference pulse signal and the quantum light pulse signal.
  • the dynamic polarization controller 190 is disposed in the optical path of the local oscillation optical pulse signal in order to minimize the additional attenuation of the optical pulse signal in the optical pulse signal optical path.
  • the reference pulse signal in the split optical pulse signal can be fully utilized, and the real-time polarization information of the reference pulse signal is obtained from the reference pulse signal, thereby making the polarization direction of the local oscillator optical pulse signal It can be adjusted in real time to further ensure that when the local oscillator pulse signal and the received optical pulse signal interfere, the polarization direction is also aligned, and the interference is optimal.
  • the receiving device provided by the embodiment of the present application is described below.
  • the method for receiving the signal provided by the embodiment of the present application is described below with reference to FIG. 7.
  • the executing body of the receiving method is the receiving device provided by the embodiment of the present application.
  • FIG. 7 is a schematic flowchart diagram of a signal receiving method according to an embodiment of the present application. As shown in FIG. 7, the receiving method may include the following steps:
  • S210 Detect a reference pulse signal in the received optical pulse signal; wherein the optical pulse signal includes a quantum optical pulse signal of the reference pulse signal.
  • the receiving device receives the optical pulse signal transmitted by the transmitting device in the SR-CV-QKD system, wherein the optical pulse signal includes a reference pulse signal and a quantum light pulse signal, and the intensity of the reference pulse signal is about 1000 times that of the quantum light pulse signal.
  • the receiving device receives the optical pulse signal and detects the reference pulse signal in the optical pulse signal.
  • the receiving device generates a modulated pulse signal based on the timing information of the detected reference pulse signal, and the timing information of the modulated pulse signal coincides with the timing information of the optical pulse signal.
  • the modulated pulse signal is used to modulate the local oscillator optical pulse signal, that is, the first local oscillation pulse signal described in the embodiment of the present application, so that the timing information of the modulated first local oscillation pulse signal and the timing of the optical pulse signal are modulated.
  • the information is consistent, that is, the frequency distribution and time domain distribution of the first local oscillation pulse signal are consistent with the frequency distribution and time domain distribution of the optical pulse signal.
  • the receiving device modulates the first local oscillator optical pulse signal that is consistent with the timing of the optical pulse signal according to the modulated pulse signal generated according to the timing information of the reference pulse signal, to efficiently complete the optical pulse signal of the first local oscillation pulse signal.
  • the timing alignment makes the first local oscillation pulse signal and the optical pulse signal achieve optimal interference, and further obtains a more accurate original key.
  • the first local oscillation pulse signal that is modulated in accordance with the timing of the optical pulse signal is respectively interfered with the reference pulse signal and the quantum light pulse signal in the optical pulse signal to obtain an original key, and the original key obtained by the receiving device is obtained.
  • the key performs a series of processing to obtain a quantum key.
  • the timing information (ie, frequency distribution and time domain distribution) of the first local oscillation pulse signal and the timing of the optical pulse signal can be modulated. Modulating the pulse signal with the information (that is, the frequency distribution and the time domain distribution), and modulating, so that the time series information of the modulated first local oscillation pulse signal is consistent with the timing information of the optical pulse signal, so that the modulated first
  • the local oscillator pulse signal and the optical pulse signal can achieve optimal interference, resulting in a more accurate original key.
  • detecting a reference pulse signal in the received optical pulse signal includes:
  • the received optical pulse signal may be separated by a first beam splitter in the receiving device, and detected by the first detector connected to the output end of the first beam splitter.
  • Reference pulse signal For a detailed description, reference may be made to the specific description of the operation performed by the first beam splitter and the first detector in FIG. 3, which will not be further described herein for brevity.
  • the optical pulse signal includes a reference pulse signal and a quantum light pulse signal.
  • determining the modulated pulse signal according to the reference pulse signal includes:
  • the processes of S221, S222, and S223 may be completed by a synchronous receiving module in the receiving device.
  • the synchronous receiving module can include a clock recovery unit, the input of the clock recovery unit being coupled to the output of the first detector.
  • the clock recovery unit recovers the timing information of the reference pulse signal, and determines the clock information of the optical pulse signal according to the relationship between the reference pulse signal and the quantum optical pulse signal, and generates the adjusted second information according to the clock information of the optical pulse signal, so that The frequency distribution and the time domain distribution of the first local oscillation pulse signal are adjusted to be local oscillator optical pulse signals that are consistent with the frequency distribution and the time domain distribution of the optical pulse signal.
  • the first local oscillator optical pulse signal having the same timing as the optical pulse signal is obtained according to the modulated pulse signal, including:
  • the first intensity modulator IM 1 in the receiving device chops the continuous laser light generated by the laser according to the modulated pulse signal to form a first local oscillator light pulse signal, and the timing and light of the pulse signal of the first local oscillator light pulsed out
  • the timing of the pulse signal is consistent, that is, the frequency distribution of the first local oscillation pulse signal is consistent with the frequency distribution of the optical pulse signal, so that the first local oscillation pulse signal and the optical pulse signal are optimally interfered to obtain an accurate original key.
  • the receiving method may further include:
  • the first local oscillation pulse signal can be adjusted by the second intensity modulator IM 2 in the receiving device.
  • the IM 2 adjusts the first local oscillation pulse signal to two intensity local oscillation pulse signals according to the timing information of the reference pulse signal: the second local oscillation pulse signal and the third local oscillation pulse signal, and the specific adjustment process is referred to
  • the description process of the adjustment of the first local oscillation pulse signal by the IM 2 in FIG. 3 is for brevity and will not be described herein.
  • the first local light pulse signal is interfered with the reference pulse signal and the quantum light pulse signal, and includes:
  • the IM 2 adjusts the first local oscillation pulse signal to the local oscillation pulse signal of different intensity: the second local oscillation pulse signal and the third local oscillation pulse signal can be detected by the same balanced zero-shoot detector
  • the dynamic range of the AD/DA corresponding to the data acquisition of the quantum light pulse is also reasonable.
  • the receiving method may further include:
  • S250 and S260 can be completed by the polarization identifier and the dynamic polarizer shown in FIG.
  • the specific implementation process please refer to the working description process of the polarization identifier and the dynamic polarizer in FIG. 3, which will not be repeated here for brevity.
  • the receiving method may further include:

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Abstract

本申请实施例涉及一种信号的接收装置和接收方法，该接收装置包括：信号接收模块，用于探测接收到的光脉冲信号中的参考脉冲信号；其中，光脉冲信号包括参考脉冲信号和量子光脉冲信号；同步时钟模块，用于根据参考脉冲信号得到调制脉冲信号；信号接收模块中的第一强度调制器用于根据调制脉冲信号得到与光脉冲信号的时序相同的第一本振光脉冲信号，信号接收模块将所述第一本振光脉冲信号分别与参考脉冲信号、量子光脉冲信号进行干涉，以得到原始密钥。采用本申请实施例提供的接收装置可以高效率的将第一本振光脉冲信号与光脉冲信号的时序一致，保证第一本振光脉冲信号与光脉冲信号干涉最优，得到精确地原始密钥。

Description

信号的接收装置和接收方法
本申请要求于2017年04月24日提交国家知识产权局、申请号为201710271787.9、申请名称为“信号的接收装置和接收方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，尤其涉及一种调控自参考连续变量量子密钥分配(Self-Referenced Continuous-Variable Quantum Key Distribution，SR-CV-QKD)的量子光脉冲信号和本振光脉冲信号的接收装置和接收方法。
背景技术
随着通信技术的不断成熟，通信速率不断加快，人们开始越来越多地关注通信的安全性能。量子密码通信是结合了量子特性与传统密码的新型通信技术，由量子力学的基本原理和特性来确保通信传输过程中的安全性，经过最近三十多年的发展，目前已经开始走向市场实用化。
量子密码通信主要用于分配密钥，也被称为量子密钥分配(Quantum Key Distribution，QKD)。QKD系统用于产生并分配量子密钥，该量子密钥被用于对经典信息进行加密，增强经典信息传输过程的安全性。比如一个单向的QKD系统，其工作原理是通过在发送端对量子光脉冲信号的量子态上随机编码一串信息，经过量子信道传输后被接收端的探测器检测，然后发送端和接收端再通过经典信道的数据比对等处理程序后，最终使得双方共享一组相同并且安全的随机数密钥。
目前QKD有两种方式：离散变量量子密钥分配(Discrete-Variable Quantum Key Distribution，DV-QKD)和连续变量量子密钥分配(Continuous-Variable Quantum Key Distribution，CV-QKD)，其中，离散和连续是指对量子态随机编码信息是离散型还是连续型。
DV-QKD是通过编码单光子信号来实现密钥分配，因此需要探测精度高并且要求工作于低温的单光子探测器。而CV-QKD则不需要，它使用平衡零拍探测器，因此更具有实用性，而且其自身的特性也让它和目前的波分复用网络具有良好的兼容性。
图1为一个传统的CV-QKD系统。如图1所示，在传统CV-QKD系统方案中，发送端(称为Alice)的连续激光光源通过振幅调制器的斩波，产生周期性的光脉冲信号。由一个1:9分束器将光脉冲信号分成两路，光强大的一路脉冲信号作为随路的本振光脉冲信号直接输入到偏振耦合器的一端。而光强小的一路脉冲会继续经过振幅和相位调制器进行随机参数调制，通过在调制器加载相应电压，可以将要发送的随机数编码到弱光信号的正则分量上，该调制线路上的法拉第旋转镜用于改变脉冲信号的偏振使其在原本的偏振基础上旋转90°(意味着光脉冲信号的偏振和本振光脉冲信号的偏振是正交垂直的)，同时让该光脉冲信号多行走一段光程，再通过衰减器衰减后成为量子光脉冲信号输入偏振耦合器的 另一端，这样就可以与另一路的本振光脉冲信号通过偏振复用和时间复用一起在光纤中传输。因为本振光的强度要比量子光脉冲信号大很多，容易对其产生串扰，所以这里的偏振复用和时间复用就是用来增加本振光和信号光的隔离度。
在接收端(通常称为Bob)中，通过一个动态偏振控制器来实时调整控制输入信号的偏振状态，使得输入信号经过随后的偏振分光器时，量子光脉冲信号完全从其中一端输出，随路本振光脉冲信号则完全从另外一端输出。随路本振光脉冲信号需要经过相位调制器进行测量基的随机选择以及与发送端相同的不等臂光路装置对本振光脉冲信号进行时间延迟补偿，从而保证在输入到2×2的耦合器的量子光脉冲信号和本振光时序上是对齐的。2×2耦合器的两个输出端接入到平衡接收机的两个输入端，通过平衡接收机输出的电信号被数据采集之后，通过一些数据处理方式得到的初始数据通常称为原始码(raw key)，或称为原始密钥。
在传统CV-QKD系统方案中采用随路本振光的方式，即在传输量子光脉冲信号的同时还传输一束光强更强的经典光脉冲信号作为本振光脉冲信号。由于该本振光脉冲信号对量子光脉冲信号干扰非常大，为了尽量减小干扰，实施中往往采用量子光脉冲信号和本振光脉冲信号时间复用的方式，即在发送端将量子光脉冲信号脉冲延时一段时间的方式，使其与随路本振光脉冲信号在时间上错开进行传输，但这就要求在接收端需要对本振光施加相同的延时补偿，因此要求接收端和发送端都要制作同样长度的光纤延时，其难度很大。另外本振光脉冲信号会关系到接收端平衡探测器的真空噪声测量水平，本振光脉冲信号的强度如果发生变化会对探测结果产生影响。若是该变化是由第三方窃听者实施，则有可能会导致系统安全性受到影响(本振光脉冲信号攻击)。
2015年3月份Bing Qi等在“Generating the local oscillator"locally"in continuous-variable quantum key distribution based on coherent detection”和Daniel B.S.Soh等在“Self-referenced continuous-variable quantum key distribution”中都提出自参考连续变量量子密钥分配(SR-CV-QKD)的方案。将传统CV-QKD系统发送端产生的本振光转移到接收端，且为了保证接收端产生的本振光脉冲信号和发送端发送过来的量子光脉冲信号光之间的干涉结果可以被解析，在发送端发送的量子光脉冲信号之间引入一个光强较强的参考脉冲，该参考脉冲可以称为参考光，用于检测发送端发送的量子光脉冲信号光与接收端的本振光脉冲信号的频偏与相差，从而实现CV-QKD系统中的测量机选择，恢复出量子光脉冲信号的信息。采用本方案不需要对发送端和接收端的两路光纤长度进行严格的等长控制。另外，参考脉冲的强度比传统CV-QKD系统发送端发送的本振光脉冲信号强度弱很多，因此对量子光脉冲信号的干扰较小，可以消除发送本振光脉冲信号带来的本振光脉冲信号被攻击的隐患。
其中，在SR-CV-QKD系统方案中，是通过测量本振光和参考光的相位差来估算，估算是基于参考光和量子信号光的脉冲在时域上非常接近，而且两者都经过了同一段信道的传输，可以近似的认为参考光传输过程中变化的相位和相邻的量子信号光的脉冲一致来估算，或者采用量子信号光之前和量子信号光之后的参考光的脉冲相位的平均值估算。但由于本振光脉冲信号和量子光脉冲信号不是同一个激光器产生的，两者之间的时延需要通过调整才能做到两者的时序对齐一致，才能保证干涉最优。而目前，采用光延时线来进行时序对齐，但若传输光路出现一点波动将导致信号脉冲的时序出现抖动，则出现额外的时延，造 成两者时序不一致，若要保证时序对齐，则需要继续调解光延时线，以至于时序对齐的效率比较低。
发明内容
本申请实施例提供了一种信号的接收装置和接收方法，通过根据探测光脉冲信号中的参考脉冲信号，并根据参考脉冲信号得到调节脉冲信号，得到与光脉冲信号时序相同的第一本振光脉冲信号，进而得到原始密钥，实现了第一本振光脉冲信号与量子光信号的时序对齐，提高了两者时序对齐的效率。
第一方面，本申请实施例提供了一种信号的接收装置，该接收装置可以包括：
信号接收模块，用于探测接收到的光脉冲信号中的参考脉冲信号；其中，光脉冲信号包括参考脉冲信号和量子光脉冲信号；
同步时钟模块，用于根据参考脉冲信号得到调制脉冲信号；
信号接收模块中的第一强度调制器用于根据调制脉冲信号得到与光脉冲信号的时序相同的第一本振光脉冲信号，信号接收模块将第一本振光脉冲信号分别与参考脉冲信号、量子光脉冲信号进行干涉，以得到原始密钥。
采用本申请实施例提供的接收装置可以高效率的将第一本振光脉冲信号与光脉冲信号的时序一致，保证第一本振光脉冲信号与光脉冲信号干涉最优，得到精确地原始密钥。
结合第一方面，在第一方面的第一种可能实现的方式中，信号接收模块可以包括第一分束器和第一探测器。
第一分束器，用于分离接收到的光脉冲信号。
第一探测器，用于探测分离后光脉冲信号中的参考脉冲信号。
结合第一方面或第一方面的第一种可能实现的方式，在第一方面的第二种可能实现的方式中，同步时钟模块，用于根据参考脉冲信号得到调制脉冲信号，包括：
同步时钟模块根据参考脉冲信号确定光脉冲信号的时钟信息；根据时钟信息得到调制脉冲信号。
结合第一方面或者第一方面的上述任一可能实现的方式之一，在第一方面的第三种可能实现的方式中，第一强度调制器用于根据调制脉冲信号得到与光脉冲信号的时序相同的第一本振光脉冲信号，包括：
第一强度调制器，用于根据调制脉冲信号对激光器产生的连续激光进行斩波形成第一本振光脉冲信号。
结合第一方面或者第一方面的上述任一可能实现的方式之一，在第一方面的第四种可能实现的方式中，信号接收模块还包括信号调制单元和第二强度调制器；第二强度调制器分别与信号调制单元和第一强度调制器相连。
同步时钟模块，还用于确定参考脉冲信号的时序信息。
信号调制单元，用于根据时序信息确定调制信息。
第二强度调制器，用于根据调制信息对第一本振光脉冲信号进行调整。
结合第一方面的第四种可能实现的方式，在第一方面的第五种可能实现的方式中，第二强度调制器，用于根据调制信息对第一本振光脉冲信号进行调整，包括：
第一强度调制器根据调制信息将第一本振光脉冲信号调整为两种强度的本振光脉冲： 第二本振光脉冲信号和第三本振光脉冲信号。
结合第一方面的第五种可能实现的方式，在第一方面的第六种可能实现的方式中，信号接收模块将第一本振光脉冲信号与参考脉冲信号、量子光脉冲信号进行干涉，包括：
信号接收模块，用于将第二本振光脉冲信号与量子光脉冲信号进行干涉；将第三本振光脉冲信号与参考脉冲信号进行干涉；其中，第二本振光脉冲信号强度大于第三本振光脉冲信号强度。
采用本申请实施例提供的接收装置，不同强度的第二本振光脉冲信号和第三本振光脉冲信号可以通过同一平衡零拍探测器探测参考脉冲信号和信号光脉冲信号，在参考脉冲信号强度是信号脉冲信号强度的1000倍，满足对参考脉冲信号的探测不饱和的情况下，对量子光脉冲信号的采集的AD/DA的动态范围也合理。
结合第一方面的第五种可能实现的方式或者第一方面的第六种可能实现的方式，在第一方面的第七种可能实现的方式中，信号接收模块还包括第二分束器和第二探测器，第二分束器分别与第二强度调制器、第二探测器、相位调制器相连。
第二分束器，用于将第二本振光脉冲信号和第三本振光脉冲信号进行分离。
第二探测器，用于探测第二本振光脉冲信号的强度和第三本振光脉冲信号的强度。
结合第一方面的第五种可能实现的方式至第一方面的第七种可能实现的方式中的任一可能实现的方式，在第一方面的第八种可能实现的方式中，信号接收模块包括偏振识别器。
偏振识别器，用于接收第一分束器分束后的光脉冲信号，并探测光脉冲信号中的参考脉冲信号的偏振信息，并根据偏振信息产生偏振调节信息。
结合第一方面的第八种可能实现的方式，在第一方面的第九种可能实现的方式中，信号接收模块还包括第三分束器，其中，第一分束器与偏振识别器通过第三分束器相连接。
第三分束器，用于接收第一分束器分离出的光脉冲信号，并对光脉冲信号进行分束；偏振识别器确定第三分束器分离的光脉冲信号中的参考脉冲信号的偏振信息。
结合第一方面的第八种或者第九种可能实现的方式，在第一方面的第十种可能实现的方式中，信号接收模块还包括动态偏振控制器，动态偏振控制器与偏振识别器、第二强度调制器、第二分束器相连接；
动态偏振控制器，用于根据偏振调节信息调整第二本振光脉冲信号与第三本振光脉冲信号的偏振方向，并将调整偏振方向的第二本振光脉冲信号和第三本振光脉冲信号输出到第二分束器。
采用本申请实施例提供的接收装置，通过接收装置中的偏振识别器和动态偏振器调整第二本振光脉冲信号和第三本振光脉冲信号与光脉冲信号中的参考脉冲信号和量子光脉冲信号的偏振一致，达到第二本振光脉冲信号与量子光信号、第三本振光脉冲信号与参考脉冲信号的干涉最优，以得到精确地原始密钥。
第二方面，本申请实施例提供了一种信号的接收方法，该接收方法可以包括：
探测接收到的光脉冲信号中的参考脉冲信号；其中，光脉冲信号包括参考脉冲信号和量子光脉冲信号；
根据参考脉冲信号确定调制脉冲信号；
根据调制脉冲信号得到与光脉冲信号时序相同的第一本振光脉冲信号；
将第一本振光脉冲信号与参考脉冲信号、量子光脉冲信号进行干涉，以得到原始密钥。
采用本申请实施例提供的接收方法可以高效率的将第一本振光脉冲信号与光脉冲信号的时序一致，保证第一本振光脉冲信号与光脉冲信号干涉最优，得到精确地原始密钥。
结合第二方面，在第二方面的第一种可能实现的方式中，探测接收到的光脉冲信号中的参考脉冲信号，包括：
分离接收到的光脉冲信号；探测分离后的光脉冲信号中的参考脉冲信号。
结合第二方面或者第二方面的第一种可能实现的方式，在第二方面的第二种可能实现的方式中，根据参考脉冲信号确定调制脉冲信号，包括：
确定参考脉冲信号的时序信息；
根据时序信息确定光脉冲信号的时钟信息；
根据时钟信息确定调制脉冲信号。
结合第二方面或者第一方面的上述任一可能实现的方式之一，在第二方面的第三种可能实现的方式中，根据调制脉冲信号得到与光脉冲信号时序相同的第一本振光脉冲信号，包括：
根据调制脉冲信号对对激光器产生的连续激光进行斩波形成第一本振光脉冲信号。
结合第二方面的第二种或者第三种可能实现的方式，在第二方面的第四种可能实现的方式中，该接收方法还可以包括：
根据时序信息调整第一本振光脉冲信号。
结合第二方面的第四种可能实现的方式，在第二方面的第五种可能实现的方式中，根据时序信息调整第一本振光脉冲信号，包括：
根据时序信息将第一本振光脉冲信号调整为两种强度的本振光脉冲信号：第二本振光脉冲信号和第三本振光脉冲信号。
结合第二方面的第五种可能实现的方式，在第二方面的第六种可能实现的方式中，将第一本振光脉冲信号与参考脉冲信号、量子光脉冲信号进行干涉，包括：
将第二本振光脉冲信号与量子光脉冲信号进行干涉；
将第三本振光脉冲信号与参考脉冲信号进行干涉；
其中，第二本振光脉冲信号强度大于第三本振光脉冲信号强度。
采用本申请实施例提供的接收方法，不同强度的第二本振光脉冲信号和第三本振光脉冲信号可以通过同一平衡零拍探测器探测参考脉冲信号和信号光脉冲信号，在参考脉冲信号强度是信号脉冲信号强度的1000倍，满足对参考脉冲信号的探测不饱和的情况下，对量子光脉冲信号的采集的AD/DA的动态范围也合理。
结合第二方面或者第二方面的上述任一可能实现的方式，在第二方面的第七种可能实现的方式中，该接收方法还可以包括：
探测光脉冲信号中参考脉冲信号的偏振信息；根据偏振信息得到偏振调节信息。
结合第二方面的第八种可能实现的方式，在第二方面的第九种可能实现的方式中，在将第二本振光脉冲信号与量子光脉冲信号进行干涉，以及将第三本振光脉冲信号与参考脉冲信号进行干涉之前，方法还包括：
根据偏振调节信息调整第二本振光脉冲信号和第三本振光脉冲信号的偏振方向。
本申请实施例提供的接收方法，通过调整不同强度的第二本振光脉冲信号和第三本振光脉冲信号与光脉冲信号中的参考脉冲信号和量子光脉冲信号的偏振一致，达到第二本振光脉冲信号与量子光信号、第三本振光脉冲信号与参考脉冲信号的干涉最优，以得到精确地原始密钥。
附图说明
图1提供了一种传统的连续变量量子密钥分发系统的结构示意图；
图2为本申请实施例提供的一个单向SR-CV-QKD系统的结构框图；
图3为本申请实施例提供的一种调控自参考连续变量量子密钥分配系统的结构示意图；
图4(a)为本申请实施例提供的一种调制脉冲信号示意图；
图4(b)为本申请实施例提供的另一种调制脉冲信号示意图；
图5为本申请实施例提供的一种调控自参考连续变量量子密钥分配系统的结构示意图；
图6为本申请实施例提供的另一种调控自参考连续变量量子密钥分配系统的结构示意图；
图7为本申请实施例提供的一种信号的接收方法流程图；
图8为本申请实施例提供的另一种信号的接收方法流程图。
具体实施方式
本申请实施例提供了一种信号的接收装置和接收方法，该接收装置和接收方法应用于SR-CV-QKD系统。SR-CV-QKD系统中的接收装置接收发送装置发送的光脉冲信号，其中，光脉冲信号中包括参考脉冲信号的量子光脉冲信号。通过接收装置检测光脉冲信号中的参考脉冲信号，确定出参考脉冲信号的时序信息和偏振信息等信息，并根据参考脉冲信号的时序信息确定出用于产生与光脉冲信号时序相同的第一本振光脉冲信号的调制脉冲信号，确定出用于调整第一本振光脉冲信号的强度的调制信息，以及根据参考脉冲信号的偏振信息确定出偏振调节信息，根据调制脉冲信号、调制信息和偏振信息对第一本振光脉冲信号进行调整，获得与光脉冲信号时序信息和偏振信息对齐的第一本振光脉冲，通过将第一本振光脉冲信号分别与参考脉冲信号、量子光脉冲信号进行干涉，得到原始密钥。
其中，原始密钥为接收装置探测到的最初的密钥。原始密钥通过接收装置进行一系列的处理之后可得到量子密钥。
SR-CV-QKD系统如图2所示，图2为一个单向SR-CV-QKD系统的结构框图。如图2所示，该SR-CV-QKD系统可以包括发送端和接收端，或者称为发送装置和接收装置。从逻辑功能上划分，发送装置可以包括第一协商信息模块、同步时钟发送模块、信号发送模块和第一主控制模块；接收装置可以包括第二协商信息模块，同步时钟接收模块、信号接收模块和第二主控制模块。在本申请实施例中，为描述简便，可以将同步时钟接收模块简称为同步时钟模块。
其中，发送装置中的第一主控模块用于控制发送装置中的第一协商信息模块、同步时钟发送模块、信号发送模块执行相应的操作；接收装置中的第二主控模块用于控制接收装置中的第二协商信息模块、同步时钟接收模块、信号接收模块执行相应的操作。
本申请实施例提供的方案主要涉及SR-CV-QKD系统中的接收装置，尤其涉及接收装置中的同步时钟接收机和量子信号接收机。
发送装置用于将携带量子密钥的光脉冲信号发送输出到接收装置，该光脉冲信号中包括量子光脉冲信号的参考脉冲信号。在本申请实施例中，参考脉冲信号的强度可以大约为量子光脉冲信号的强度的1000倍。而且参考脉冲信号和量子光脉冲信号可以按照一定的关系进行设置，例如，两个参考脉冲信号中有一个量子光脉冲信号，或者两个参考脉冲信号中间有一个量子光脉冲信号，等等，以便于接收装置检测到光脉冲信号中的参考脉冲信号后，根据参考脉冲信号与量子光脉冲信号的关系估计量子光脉冲信号的信息。
接收装置中的信号接收模块接收到发送装置发送输出的光脉冲信号，检测光脉冲信号中的参考脉冲信号；采用同步时钟模块恢复出参考脉冲信号的时序信息，并根据参考脉冲信号的时序信息恢复出光脉冲信号的时钟信息；接收装置根据恢复出的光脉冲信号的时钟信息产生相应的调制脉冲信号，再根据调制脉冲信号对本地的激光器产生的连续的激光进行斩波形成本振光脉冲信号，得到本振光脉冲信号的频率、时域分布与光脉冲信号的频率、时域分布一致。该本振光脉冲信号也就是本申请中提到的第一本振光脉冲信号。
接收装置还可以根据参考脉冲信号的时序信息确定出调制信息，根据调制信息调整第一本振光脉冲信号的信号强度，以使本申请实施例提供的接收装置，可以通过一个平衡探测器即可以满足不同强度的脉冲信号的探测需求。
另外，接收装置还可以检测参考脉冲信号的偏振信息，以根据偏振信息确定偏振调节信息，从而根据偏振调节信息调整第一本振光脉冲信号的偏振方向，以使调整后的偏振方向与光脉冲信号的偏振方向相同，以达到第一本振光脉冲信号与光脉冲信号的最优干涉。
采用同步时钟模块恢复出参考脉冲信号的时序信息，信号接收模块得到参考脉冲信号的偏振信息，并依此调节接收装置生成的第一本振光脉冲信号的频率、时延、光强度和偏振，从而保证接收装置生成的本振光脉冲信号和接收到的光脉冲信号可以在时序和偏振对齐，达到最优干涉，以进一步得到原始密钥。
下面结合附图对本申请实施例的方案进行详细说明。需要说明的是，本申请实施例中提到的“第一”和“第二”仅仅是为了区分，并不对其进行限定。
图3为本申请实施例提供的一种调控自参考连续变量量子密钥分配系统的结构示意图。如图3所示，该接收装置可以包括信号接收模块100和同步时钟模块200，信号接收模块中包括第一强度调制器110。
信号接收模块100，用于探测接收到的光脉冲信号中的参考脉冲信号；其中，光脉冲信号包括参考脉冲信号和量子光脉冲信号。
同步时钟模块200，用于根据参考脉冲信号得到调制脉冲信号。
信号接收模块100中的第一强度调制器IM 1 110用于根据调制脉冲信号得到与光脉冲信号的时序相同的第一本振光脉冲信号，信号接收模块将第一本振光脉冲信号分别与参考脉冲信号、量子光脉冲信号进行干涉，以得到原始密钥。
在本申请实施例中，接收装置接收到发送装置发送的光脉冲信号后，检测光脉冲信号中参考脉冲信号，根据参考脉冲信号的时序信息估计量子光脉冲信号。
另外，由于光脉冲信号中的参考脉冲信号和量子光脉冲信号按照一定的关系进行传输，比如：每两个参考脉冲信号中间有一个量子光脉冲信号，或者每两个参考脉冲信号后存在一个量子光脉冲信号，等等。那么光脉冲信号的频率和参考脉冲信号的频率之间存在一个简单的比例关系，根据该比例关系，就可以在检测参考脉冲信号时，获取参考脉冲信号的时序信息，进一步恢复出光脉冲信号的时钟信息。
在本申请实施例中，同步时钟模块200可以包括时钟恢复单元，根据光脉冲信号的时钟信息产生相应的调制脉冲信号。第一强度调制器IM 1 110根据调制脉冲信号得到与光脉冲信号的时序相同的第一本振光脉冲信号，以使第一本振光脉冲信号和光脉冲信号产生干涉，得到原始密钥，进而进一步得到量子密钥。
采用本申请实施例提供的接收装置，通过检测光脉冲信号中的参考脉冲信号，根据参考脉冲信号产生调制脉冲信号获得第一本振光脉冲信号，该第一本振光脉冲信号的时序与光脉冲信号的时序一致，与现有技术中通过调整光纤时延来调整第一本振光脉冲信号与光脉冲信号的时序一致相比，本申请实施例提供的装置，可以更简单的，高效率的使第一本振光脉冲信号时序和光脉冲信号的时序一致，进一步得到原始密钥，从而获得量子密钥。
可选地，同步时钟模块200用于根据参考脉冲信号得到调制脉冲信号，包括：
同步时钟模块200根据参考脉冲信号确定光脉冲信号的时钟信息；根据时钟信息得到调制脉冲信号，以便于第一强度调制器IM 1 110根据调制脉冲信号对本地激光器产生的连续的激光进行斩波形成第一本振光脉冲信号。
IM 1 110对本地激光器产生的连续的激光进行斩波，其斩波的原理为通过加载电脉冲信号对通过IM1的连续激光在时间上做一个处理，可以形象的理解为进行一个开关操作，最终形成的脉冲信号的频率分布和时域分布与所加载的电脉冲信号的频率分布和时域分布一致。
在本申请实施例中，从时钟同步模块200得到光脉冲信号的时钟信息，即光脉冲信号的频率分布和时域分布的信息，就可以根据此信息产生对应的电脉冲信号，该电脉冲信号通过IM1对本地激光器产生的连续激光进行斩波得到与光脉冲信号的频率分布和时域分布一致的第一本振光脉冲信号。
同时，因为接收装置接收到的光脉冲信号从第一分束器120到2*2耦合器的时间T1是已知的，分束后探测参考脉冲信号得到调制脉冲信号到IM 1的时间T2已知，本振光脉冲信号从IM 1到2*2耦合器的时间T3是已知的，如果没有额外的调制，斩波形成的本地本振光脉冲和接收到的光脉冲信号的在到达2*2耦合器干涉时，两者在时域上会错开T1-T2-T3时间。如果使本振光脉冲信号和量子光脉冲信号的时序对其，那么就只要让T1-T2-T3＝0即可。
而本申请实施例可以通过以下两种方式实现T1-T2-T3＝0。
方式一：由于时间T2是由电路决定的，通过设计光脉冲信号的光路长度和第一本振光脉冲信号的光路来选择合适的T1和T3，使得满足T1-T2-T3＝0。
该方式需要特定的光路长度，实现过程对光路长度的精度要求高，制作较麻烦。
方式二：在不改变光路的情况下，即T1和T3不变，通过调整IM 1上加载的调制脉冲信号来调节T2，使得满足T1-T2-T3＝0。
该方式需要对加载在IM 1上的调制脉冲信号的生成方式做相应的调整，比如，通过增加延时芯片调节调制脉冲信号生成的延时，或者在调制脉冲信号生成上增加相应的处理，本申请实施例采用方式二相对方式一完成T1-T2-T3＝0较为易实现。
在本申请实施例中，加载在IM 1上的调制脉冲信号的频率分布和时域分布是由一个逻辑功能芯片提供的数字信息模拟出来的。如图4(a)所示，通过数字信息的排列和分布模拟出一个特定频率分布、时域分布的电脉冲，该调制脉冲信号决定了调制出的第一本振光脉冲信号的频率分布和时域分布的信息。如图4(b)所示，通过改变数字信息的排布和分布，调制脉冲信号的时域分布将会发生改变。从图4(a)和图4(b)可以看出，图4(a)和图4(b)产生的电脉冲在时间上存在时延，以此通过IM1斩波产生的第一本振光脉冲信号，第一本振光脉冲信号的频率分布和时域分布与与光脉冲信号的频率分布和时域分布一致。根据周期性，图4(a)和图4(b)的不同相当于在初始点增加了若干数字“0”。
需要说明的是，本申请实施例提供接收装置得到调制脉冲信号的前提条件是以探测到一个参考脉冲信号为起点，因此，无论传输光路中出现何种变动，导致光脉冲信号传输出现额外的时延都不会对光脉冲信号和第一本振光脉冲信号的对齐产生影响。
采用本申请实施例提供的接收装置，相对现有技术，可以高效率的完成第一本振光脉冲信号与光脉冲信号的时序对齐。
可选地，如图3所示，该信号接收模块100还可以包括第一分束器120和第一探测器130。信号接收模块100，用于探测接收到的光脉冲信号中的参考脉冲信号，包括：
第一分束器120，用于分离接收到的光脉冲信号；第一探测器130，用于探测分离后光脉冲信号中的参考脉冲信号。
其中，光脉冲信号包括参考脉冲信号和量子光脉冲信号。
在接收装置的输入光纤接口处，通过第一分束器120，对接收到的光脉冲信号进行分光处理，并利用第一探测器130探测分光后的光脉冲信号中的参考脉冲信号。其中，第一探测器130可以为经典的光电探测器。
第一分束器120的分束配需要根据SR-CV-QKD系统的线路衰减情况来适当的选择。因为在SR-CV-QKD系统中，参考脉冲信号的光强度可以大约为量子光脉冲信号的1000倍，(量子光脉冲信号的光强度约为每个光脉冲包含光子数为10个左右)经过第一分束器120分离出一定的比例后，需要保证分离出的光脉冲信号中的参考脉冲信号的强度仍然是可以被经典的光电探测器检测到的。同时，第一分束器120对未分离出的光脉冲信号中的量子光脉冲信号产生的额外衰减需要保证在一定的范围内，这个范围为对于SR-CV-QKD系统来讲是一个可接受的范围，否则会导致SR-CV-QKD系统不能产生安全密钥。
例如，在本申请的一个实施例中，第一分束器120可以选择1:9的分束器，分离出的光脉冲信号中的参考脉冲信号的光强度仍然较强，同时对最终被测量的光脉冲信号中的量子光脉冲信号只引入1dB的额外衰减，对于短传输距离情况下的SR-CV-QKD系统来讲是可以接受的。
第一探测器130为光电探测器。第一探测器130探测为光信号的参考脉冲信号得到每 个转换为电脉冲信号的参考脉冲信号。在第一探测器130探测光脉冲信号中的参考脉冲信号时，由于光脉冲信号中的量子光脉冲信号的光强非常的弱，可以认为第一探测器130无法对其响应，也产生不了相应的电脉冲信号。那么通过同步时钟模块200的光脉冲信号就可以得到和参考脉冲信号对应的电脉冲信号，其频率分布、时域分布和参考脉冲信号的频率分布、时域分布一致。
可选地，如图3所示，该接收装置还可以包括信号调制单元140和第二强度调制器150。第二强度调制器150分别与信号调制单元140和同步时钟模块200相连；第二强度调制器IM 2 150与第一强度调制器110相连。
同步时钟模块200，还用于确定参考脉冲信号的时序信息；信号调制单元140，用于根据时序信息确定调制信息；第二强度调制器IM 2 150，用于根据调制信息对第一本振光脉冲信号进行调整。
在本申请实施例中，同步时钟模块200得到参考脉冲信号的频率信息后发送给信号调制单元140，用于给第二强度调制器IM 2 150加载调制信息，该调制信息用于调整从第一强度调制器IM 1输出到第二强度调制器IM 2 150的第一本振光脉冲信号的强度。
在本申请的一个实施例中，第二强度调制器IM 2根据调制信息将第一本振光脉冲信号调整为两种强度的本振光脉冲：第二本振光脉冲信号和第三本振光脉冲信号。
在本申请实施中，将第二本振光脉冲信号与量子光脉冲信号进行干涉；将第三本振光脉冲信号与参考脉冲信号进行干涉；其中，第二本振光脉冲信号强度大于第三本振光脉冲信号强度。
或者说，将调制出的两种强度的本振光脉冲信号中强度较强的本振光脉冲信号与接收到的量子光脉冲信号发生干涉，强度较弱的本振光脉冲信号与接收到的参考脉冲信号发生干涉。
在本申请实施例中，如图3所示，该信号接收模块还可以包括平衡零拍探测器。平衡零拍探测器的输入端通过信号接收模块100中的第二分束器和相位调制器PM相连接，第二分束器与第二强度调制器IM 2 150相连接。
SR-CV-QKD系统中采用平衡零拍探测器探测，而平衡零拍探测器探测的结果与两路干涉光(即强度较强的本振光脉冲信号与量子光脉冲信号干涉的干涉光，强度较弱的本振光脉冲信号与参考脉冲信号干涉的干涉光)的强度的乘积的平方有直接关系。因此，若是采用同一个强度的本振光脉冲信号与接收到的光脉冲信号(包括强度较强的参考脉冲信号和强度较弱的量子光脉冲信号)干涉，则通过平衡零拍探测器探测得到的参考脉冲信号和量子光脉冲信号对应的干涉光的强度会相差约30倍，因为参考脉冲信号的强度大约为量子光脉冲信号强度的1000倍。
而事实上，平衡零拍探测器的输出范围是固定有限的，在满足参考脉冲信号的测量输出不饱和的情况下，对量子光脉冲信号测量的输出就只占了平衡零拍探测器输出范围的不到1/30，再通过模数转换器A/D转换器或者称为ADC(analog to digital converter)数据采样，利用到的AD/DA的动态范围不合理，这会对量子光脉冲信号测量的精度带来一定影响，而对量子光脉冲信号才是密钥信息的载体，对其测量应该是越精确越好。
因此，本申请实施例采用不同强度的本振光脉冲信号与光脉冲信号中的参考脉冲信号、 量子光脉冲信号进行干涉，比如用强度为I 1的本振光脉冲信号和参考脉冲信号干涉，用强度为I 2的本振光脉冲信号和量子光脉冲信号干涉，且I 1和I 2，满足关系：I 2≈1000I 1。这样通过平衡零拍探测器对参考脉冲信号和量子光脉冲信号进行探测，探测参考脉冲信号和量子光脉冲信号的结果大小接近。对量子光脉冲信号的测量输出的采样就可以充分利用ADC的AD/DA动态范围，测量结果可以更加精确。
且目前的技术强度调制器的消光比可以做到30dB左右，从原理上讲，可以通过一个强度调制器就可以调制出强度相差接近1000倍的两种本振光脉冲信号。
在本申请实施例中，本振光脉冲信号中的一部分与光脉冲信号中的参考脉冲信号进行干涉，本振光脉冲信号中的另一部分与光脉冲信号中的量子光脉冲信号进行干涉。第二强度调制器IM 2用于在与参考脉冲信号进行干涉的本振光脉冲信号达到时，对其进行衰减，在与量子光脉冲信号的本振光脉冲信号到达时，不对其进行衰减。
可选地，在本申请实施例中，实现第二强度调制器IM 2的上述功能，可以在第二强度调制器IM 2上加载一个方波信号，该方波信号的频率和占空比与量子光脉冲信号的频率和占空比占整个光脉冲信号的比例一致。量子光脉冲信号的频率和占空比占整个光脉冲信号的比例与参考脉冲信号的频率和占空比占整个光脉冲信号的比例是互补的。例如，整个光脉冲信号有比例为1:1的参考脉冲信号和量子光脉冲信号混合，那么该方波信号的频率与参考脉冲信号的频率一致，方波信号的占空比为50％，且方波信号的幅值大小满足低电平可以让IM 2处于最大衰减状态，高电平让IM 2处于最大通过状态。
需要说明的是，量子光脉冲信号的频率可以根据测量到的参考脉冲信号的频率推算，具体推算方法在前文中提到，且为现有技术，为简洁描述，在这里不再赘述。
可选地，如图3所示，该信号接收模块100还可以包括第二分束器160和第二探测器170，第二分束器160的分别与第二强度调制器150，第二探测器170，相位调制器180相连接。
第二分束器160，用于将第二本振光脉冲信号和第三本振光脉冲信号进行分离。
第二探测器170，用于探测第二本振光脉冲信号的强度和第三本振光脉冲信号的强度。
由于不同强度的本振光脉冲信号会影响到真空噪声水平，且平衡零拍探测器与本振光脉冲信号的强度有关，另外，平衡零拍探测器从测量结果中解调出信号加载信息，也需要本振光脉冲信号的光强信息。
因此，本申请实施例在IM2的输出端设置一个分束器和一个探测器的组合，以此来检测经过IM2调制后第一本振光脉冲信号，即第二本振光脉冲信号和第三本振光脉冲信号的强度信息。且本申请实施例通过一个分束器和探测器还可以监控不同本振光脉冲信号的光强抖动，进而标定真空噪声水平。
并将探测到的强度信息反馈给最终的数字信号处理器(Digital Signal Processor，DSP)，用于为平衡零拍探测器提供信号脉冲调节信息的参数。需要说明的是，DSP与平衡零拍探测器相连接，如图3所示。
采用本申请实施例提供的接收装置，可以通过IM 2对本振光脉冲信号的强度进行调节，且经过同一个平衡探测器就可以满足对参考脉冲信号和量子光脉冲信号的最优增益输出，通过ADC数据采集参考脉冲信号和量子光脉冲信号的探测数据时，使用的AD/DA的动态范 围也比较合理。
在本申请实施例中，采用了不同强度的本振光脉冲信号，下面对不同本振光脉冲信号的强度对SR-CV-QKD系统的影响进行说明，主要从安全性和探测性能两方面进行说明。
在传统CVQKD系统中，本振光光强是标定真空噪声水平的重要参数，必须保持恒定，否则会存在安全性隐患(例如本振光脉冲信号被攻击)。在本申请的技术方案中，由于是SR-CV-QKD系统，本振光脉冲信号是接收装置本地产生，可以认为不存在外界对本振光脉冲信号的攻击。另外在本申请的技术方案中，对本振光脉冲信号的强度进行实时监控，因此，本申请实施例采用两种不同强度的本振光脉冲信号对系统安全性没有影响。
对于CVQKD系统，平衡探测的输出有3种：电噪声，真空噪声，信号探测结果。真空噪声水平正比于本振光脉冲信号的强度，对量子光脉冲信号(光强很弱，接近单光子级别)的测量需要真空噪声水平显著大于电噪声水平(通常认为至少大10倍)，这样才能从探测输出中分辨出量子光脉冲信号的探测结果。在本申请的技术方案中，采用了I 1、I 2两种强度的本振光，对应的真空噪声水平也有两种N 01和N 02，I 2强度的本振光脉冲信号是用于探测量子光脉冲信号，其强度较强，对应的真空噪声水平N 02较大，可以满足上述要求。而I 1光强的本振光脉冲信号较弱，对应的真空噪声水平N 01很低，其中，N 02≈1000N 01，在探测参考脉冲信号时，其真空噪声水平会被电噪声淹没。但是参考脉冲信号本身光强较强(每脉冲10 3-10 4光子)，其信噪比很高，只要满足对参考脉冲信号的探测的输出相比电噪声水平足够大，那么对参考脉冲信号的测量仍然是可行的。
综合上面的分析，本申请的技术方案采用两种不同强度的本振光脉冲信号用于平衡探测光信号是可行的。
另外，需要说明的是，如果本发送实施例中的IM1通过其他方式完成了第一本振光脉冲信号和光脉冲信号的时序对齐，则可以通过图5所示的调控自参考连续变量量子密钥分配系统完成第一本振光脉冲信号强度的调整，以充分利用ADC的AD/DA动态范围，使对量子光脉冲信号的测量结果更加精确。
可选地，如图6所示，在本申请实施例中，信号接收模块100还可以包括第三分束器175和偏振识别器180，第三分束器175与第一分束器120和偏振识别器180相连接，或者说第一分束器120与偏振识别器180通过第三分束器175相连接。
第三分束器175，用于接收第一分束器120分离出的光脉冲信号，并对光脉冲信号进行分束。
偏振识别器180，用于探测第三分束器分离的光脉冲信号中的参考脉冲信号的偏振信息，并根据偏振信息产生偏振调节信息。
在本申请实施例中，如图6所示，信号接收模块100还可以包括动态偏振控制(Dynamic Polarization Control，DPC)器190，动态偏振控制器190的输入端与偏振识别器180的输出端、第二强度调制器150的输出端相连接，动态偏振控制器190的输出端与第二分束器160的输入端相连接。
动态偏振控制器190，用于根据偏振调节信息调整第二本振光脉冲信号与第三本振光脉冲信号的偏振方向，并将调整偏振方向的第二本振光脉冲信号和第三本振光脉冲信号输 出到第二分束器160。
在IM2之后设置一个动态偏振控制器190，偏振识别器180探测到光脉冲信号中的参考脉冲信号中的偏振信息后，产生相应的偏振调节信息，并反馈给动态偏振控制器190，以此来调节经过IM2调制后的本振光的偏振，使其与参考脉冲信号中的偏振方向对齐，以保证本振光脉冲信号与参考脉冲信号和量子光脉冲信号达到干涉最优。
另外，需要说明的是，在本申请实施例中，将动态偏振控制器190设置在本振光脉冲信号的光路中是为了尽量减小光脉冲信号光路中光脉冲信号的额外衰减。
采用本申请实施例提供的接收装置，可以充分利用分束后的光脉冲信号中的参考脉冲信号，从参考脉冲信号中得到参考脉冲信号的实时偏振信息，从而使得本振光脉冲信号的偏振方向可以实时调控，进一步保证本振光脉冲信号和接收到的光脉冲信号进行干涉时，其偏振方向也是对齐的，达到其干涉最优。
上述对本申请实施例提供的接收装置进行了说明，下面结合附图7对本申请实施例提供的信号的接收方法进行说明，该接收方法的执行主体为本申请实施例提供的接收装置。
图7为本申请实施例提供的一种信号接收方法的流程示意图。如图7所示，该接收方法可以包括以下步骤：
S210，探测接收到的光脉冲信号中的参考脉冲信号；其中，光脉冲信号中包括参考脉冲信号的量子光脉冲信号。
接收装置接收SR-CV-QKD系统中的发送装置发送的光脉冲信号，其中，光脉冲信号中包括参考脉冲信号和量子光脉冲信号，参考脉冲信号的强度为量子光脉冲信号的大约1000倍。接收装置接收到光脉冲信号，检测光脉冲信号中的参考脉冲信号。
S220，根据参考脉冲信号确定调制脉冲信号。
接收装置根据检测到的参考脉冲信号的时序信息产生调制脉冲信号，该调制脉冲信号的时序信息与光脉冲信号的时序信息一致。调制脉冲信号用于调制本振光脉冲信号，即本申请实施例中所描述的第一本振光脉冲信号，以使调制后的第一本振光脉冲信号的时序信息与光脉冲信号的时序信息一致，即第一本振光脉冲信号的频率分布、时域分布与光脉冲信号的频率分布、时域分布一致。
S230，根据调制脉冲信号得到与光脉冲信号时序相同的第一本振光脉冲信号。
接收装置根据依据参考脉冲信号的时序信息产生的调制脉冲信号，调制得到与光脉冲信号时序一致的第一本振光脉冲信号，以高效率的完成第一本振光脉冲信号的光脉冲信号的时序对齐，使第一本振光脉冲信号和光脉冲信号达到最优干涉，进一步得到更精确的原始密钥。
S240，将第一本振光脉冲信号与参考脉冲信号、量子光脉冲信号进行干涉，以得到原始密钥。
将经过调制后的与光脉冲信号时序一致的第一本振光脉冲信号分别与光脉冲信号中的参考脉冲信号、量子光脉冲信号进行干涉，得到原始密钥，经接收装置对得到的原始密钥进行一系列的处理得到量子密钥。
采用本申请实施例提供的接收方法，通过探测光脉冲信号中的参考脉冲信号，得到能调制使第一本振光脉冲信号的时序信息(即频率分布和时域分布)与光脉冲信号的时序信 息(即频率分布和时域分布)一致的调制脉冲信号，并进行调制，使调制后的第一本振光脉冲信号的时序信息与光脉冲信号的时序信息一致，以使调制后的第一本振光脉冲信号与光脉冲信号可以达到最优干涉，得到更精确地原始密钥。
需要说明的是，在本申请实施例中，所描述的“第一”和“第二”只是为了区分，并不对其进行限定。
可选地，在本申请的一个实施例中，如图8所示，探测接收到的光脉冲信号中的参考脉冲信号，包括：
S211，分离接收到的光脉冲信号。
S212，探测分离后的光脉冲信号中的参考脉冲信号。
在本申请实施例中，可以通过接收装置中的第一分束器分离接收到的光脉冲信号，并通过与第一分束器的输出端相连接的第一探测器探测光脉冲信号中的参考脉冲信号。具体描述可参见图3中第一分束器和第一探测器执行操作的具体描述，为简洁描述，在这里不再赘述。
需要说明的是，光脉冲信号中包括参考脉冲信号和量子光脉冲信号。
可选地，在本申请实施例中，如图8所示，根据参考脉冲信号确定调制脉冲信号，包括：
S221，确定参考脉冲信号的时序信息。
S222，根据所述时序信息确定光脉冲信号的时钟信息。
S223，根据所述时钟信息确定调制脉冲信号。
在本申请实施例中，S221，S222，S223的过程可以通过接收装置中的同步接收模块完成。该同步接收模块可以包括时钟恢复单元，时钟恢复单元的输入端与第一探测器的输出端相连接。时钟恢复单元恢复出参考脉冲信号的时序信息，并根据参考脉冲信号与量子光脉冲信号所存在的关系，确定出光脉冲信号的时钟信息，并根据光脉冲信号的时钟信息产生调节秒钟信息，以便于将第一本振光脉冲信号的频率分布和时域分布调整为与光脉冲信号的频率分布和时域分布一致的本振光脉冲信号。
可选地，在本申请实施例中，根据所述调制脉冲信号得到与光脉冲信号时序相同的第一本振光脉冲信号，包括：
接收装置中的第一强度调制器IM 1根据调制脉冲信号对对激光器产生的连续激光进行斩波形成第一本振光脉冲信号，斩波出的第一本振光的脉冲信号的时序与光脉冲信号的时序一致，即第一本振光脉冲信号的频率分布与光脉冲信号的频率分布一致，以使第一本振光脉冲信号与光脉冲信号达到最优干涉，得到精确地原始密钥。具体描述请参见图3中IM 1执行具体操作的描述，为简洁描述，在这里不再赘述。
可选地，在本申请的另一实施例中，如图8所示，该接收方法还可以包括：
S240，根据参考脉冲信号的时序信息调整第一本振光脉冲信号。
在本申请实施例中，可以通过接收装置中的第二强度调制器IM 2对第一本振光脉冲信号进行调整。IM 2根据参考脉冲信号的时序信息将第一本振光脉冲信号调整为两种强度的本 振光脉冲信号：第二本振光脉冲信号和第三本振光脉冲信号，具体调整过程请参见图3中IM 2对第一本振光脉冲信号进行调整的描述过程，为简洁描述，在这里不再赘述。
可选地，在本申请实施例中，将第一本振光脉冲信号与参考脉冲信号、量子光脉冲信号进行干涉，包括：
将第二本振光脉冲信号与所述量子光脉冲信号进行干涉；将第三本振光脉冲信号与参考脉冲信号进行干涉；其中，第二本振光脉冲信号强度大于第三本振光脉冲信号强度。
将IM 2将第一本振光脉冲信号调整为不同强度的本振光脉冲信号：第二本振光脉冲信号和第三本振光脉冲信号后，可以通过同一个平衡零拍探测器进行探测，以使参考脉冲信号的强度是量子光脉冲信号的强度的1000倍，满足对参考脉冲信号探测不饱和的情况下，对应量子光脉冲的数据采集的AD/DA的动态范围也合理。
可选地，在本申请的另一实施例中，该接收方法还可以包括：
S250，探测光脉冲信号中参考脉冲信号的偏振信息；
S260，根据所述偏振信息得到偏振调节信息。
在本申请实施例中，可以通过图3所示的偏振识别器和动态偏振器完成S250和S260。具体实现过程请参见图3中偏振识别器和动态偏振器的工作描述过程，为简洁描述，在这里不再赘述。
在将第二本振光脉冲信号与量子光脉冲信号进行干涉，以及将第三本振光脉冲信号与所述参考脉冲信号进行干涉之前，该接收方法还可以包括：
S270，根据偏振调节信息调整第二本振光脉冲信号和第三本振光脉冲信号的偏振方向，以使调整后的第二本振光脉冲信号偏振方向与量子光脉冲信号的偏振方向一致，第三本振光脉冲信号的偏振方向与参考脉冲信号的偏振方向一致，实现干涉最优，得到精确地原始密钥。
专业人员应该还可以进一步意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
以上所述的具体实施方式，对本申请的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本申请的具体实施方式而已，并不用于限定本申请的保护范围，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。

Claims (20)

  1. 一种信号的接收装置，其特征在于，所述接收装置包括：
    信号接收模块，用于探测接收到的光脉冲信号中的参考脉冲信号；其中，所述光脉冲信号包括所述参考脉冲信号和量子光脉冲信号；
    同步时钟模块，用于根据所述参考脉冲信号得到调制脉冲信号；
    所述信号接收模块中的第一强度调制器用于根据所述调制脉冲信号得到与所述光脉冲信号的时序相同的第一本振光脉冲信号，所述信号接收模块将所述第一本振光脉冲信号分别与所述参考脉冲信号、所述量子光脉冲信号进行干涉，以得到原始密钥。
  2. 根据权利要求1所述的接收装置，其特征在于，所述信号接收模块包括第一分束器和第一探测器，
    所述第一分束器，用于分离接收到的光脉冲信号；
    所述第一探测器，用于探测分离后所述光脉冲信号中的参考脉冲信号。
  3. 根据权利要求1或2所述的接收装置，其特征在于，所述同步时钟模块，用于根据所述参考脉冲信号得到调制脉冲信号，包括：
    所述同步时钟模块根据所述参考脉冲信号确定所述光脉冲信号的时钟信息；
    根据所述时钟信息得到所述调制脉冲信号。
  4. 根据权利要求1至3任一项所述的接收装置，其特征在于，所述第一强度调制器用于根据所述调制脉冲信号得到与所述光脉冲信号的时序相同的第一本振光脉冲信号，包括：
    所述第一强度调制器，用于根据所述调制脉冲信号对激光器产生的连续激光进行斩波形成所述第一本振光脉冲信号。
  5. 根据权利要求1至4任一项所述的接收装置，其特征在于，所述信号接收模块还包括信号调制单元和第二强度调制器；所述第二强度调制器分别与所述信号调制单元和所述第一强度调制器相连；
    所述同步时钟模块，还用于确定所述参考脉冲信号的时序信息；
    所述信号调制单元，用于根据所述时序信息确定调制信息；
    所述第二强度调制器，用于根据所述调制信息对第一本振光脉冲信号进行调整。
  6. 根据权利要求5所述的接收装置，其特征在于，所述第二强度调制器，用于根据所述调制信息对第一本振光脉冲信号进行调整，包括：
    所述第一强度调制器根据所述调制信息将所述第一本振光脉冲信号调整为两种强度的本振光脉冲：第二本振光脉冲信号和第三本振光脉冲信号。
  7. 根据权利要求6所述的接收装置，其特征在于，所述信号接收模块将所述第一光脉冲信号与所述参考脉冲信号、所述量子光脉冲信号进行干涉，包括：
    所述信号接收模块，用于将所述第二本振光脉冲信号与所述量子光脉冲信号进行干涉；
    所述信号接收模块，用于将所述第三本振光脉冲信号与所述参考脉冲信号进行干涉；
    其中，所述第二本振光脉冲信号强度大于所述第三本振光脉冲信号强度。
  8. 根据权利要求6或7所述的接收装置，其特征在于，所述信号接收模块还包括第二分束器和第二探测器，所述第二分束器分别与所述第二强度调制器、所述第二探测器、相位调制器相连；
    所述第二分束器，用于将所述第二本振光脉冲信号和所述第三本振光脉冲信号进行分离；
    所述第二探测器，用于探测所述第二本振光脉冲信号的强度和所述第三本振光脉冲信号的强度。
  9. 根据权利要求6至8任一项所述的接收装置，其特征在于，所述信号接收模块包括偏振识别器；
    所述偏振识别器，用于接收所述第一分束器分束后的光脉冲信号，并探测光脉冲信号中的所述参考脉冲信号的偏振信息，并根据所述偏振信息产生偏振调节信息。
  10. 根据权利要求9所述的接收装置，其特征在于，所述信号接收模块还包括第三分束器，其中，所述第一分束器与所述偏振识别器通过所述第三分束器相连接；
    所述第三分束器，用于接收所述第一分束器分离出的所述光脉冲信号，并对所述光脉冲信号进行分束；
    所述偏振识别器确定所述第三分束器分离的光脉冲信号中的参考脉冲信号的偏振信息。
  11. 根据权利要求9或10所述的接收装置，其特征在于，所述信号接收模块还包括动态偏振控制器，所述动态偏振控制器与所述偏振识别器、所述第二强度调制器、所述第二分束器相连接；
    所述动态偏振控制器，用于根据所述偏振调节信息调整所述第二本振光脉冲信号与所述第三本振光脉冲信号的偏振方向，并将调整偏振方向的第二本振光脉冲信号和第三本振光脉冲信号输出到所述第二分束器。
  12. 一种信号的接收方法，其特征在于，所述接收方法包括：
    探测接收到的光脉冲信号中的参考脉冲信号；其中，所述光脉冲信号包括参考脉冲信号和量子光脉冲信号；
    根据所述参考脉冲信号确定调制脉冲信号；
    根据所述调制脉冲信号得到与所述光脉冲信号时序相同的第一本振光脉冲信号；
    将所述第一本振光脉冲信号与所述参考脉冲信号、所述量子光脉冲信号进行干涉，以得到原始密钥。
  13. 根据权利要求12所述的接收方法，其特征在于，所述探测接收到的光脉冲信号中的参考脉冲信号，包括：
    分离接收到的光脉冲信号；
    探测分离后的光脉冲信号中的参考脉冲信号。
  14. 根据权利要求12或13所述的接收方法，其特征在于，所述根据所述参考脉冲信号确定调制脉冲信号，包括：
    确定所述参考脉冲信号的时序信息；
    根据所述时序信息确定所述光脉冲信号的时钟信息；
    根据所述时钟信息确定调制脉冲信号。
  15. 根据权利要求12至14任一项所述的接收方法，其特征在于，所述根据所述调制脉冲信号得到与所述光脉冲信号时序相同的第一本振光脉冲信号，包括：
    根据所述调制脉冲信号对对激光器产生的连续激光进行斩波形成所述第一本振光脉冲信号。
  16. 根据权利要求14或15所述的接收方法，其特征在于，所述方法还包括：
    根据所述时序信息调整所述第一本振光脉冲信号。
  17. 根据权利要求16所述的接收方法，其特征在于，所述根据所述时序信息调整所述第一本振光脉冲信号，包括：
    根据所述时序信息将所述第一本振光脉冲信号调整为两种强度的本振光脉冲信号：第二本振光脉冲信号和第三本振光脉冲信号。
  18. 根据权利要求17所述的接收方法，其特征在于，所述将第一本振光脉冲信号与所述参考脉冲信号、所述量子光脉冲信号进行干涉，包括：
    将所述第二本振光脉冲信号与所述量子光脉冲信号进行干涉；
    将所述第三本振光脉冲信号与所述参考脉冲信号进行干涉；
    其中，所述第二本振光脉冲信号强度大于所述第三本振光脉冲信号强度。
  19. 根据权利要求12至18任一项所述的接收方法，其特征在于，所述方法还包括：
    探测所述光脉冲信号中所述参考脉冲信号的偏振信息；
    根据所述偏振信息得到偏振调节信息。
  20. 根据权利要求19所述的方法，其特征在于，在将所述第二本振光脉冲信号与所述量子光脉冲信号进行干涉，以及将所述第三本振光脉冲信号与所述参考脉冲信号进行干涉之前，所述方法还包括：
    根据所述偏振调节信息调整所述第二本振光脉冲信号和所述第三本振光脉冲信号的偏振方向。
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