WO2020088411A1 - 量子密钥分发相位解码方法和装置及相应系统 - Google Patents

量子密钥分发相位解码方法和装置及相应系统 Download PDF

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WO2020088411A1
WO2020088411A1 PCT/CN2019/113713 CN2019113713W WO2020088411A1 WO 2020088411 A1 WO2020088411 A1 WO 2020088411A1 CN 2019113713 W CN2019113713 W CN 2019113713W WO 2020088411 A1 WO2020088411 A1 WO 2020088411A1
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polarization
reflection
beam splitter
key distribution
quantum key
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PCT/CN2019/113713
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English (en)
French (fr)
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许华醒
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中国电子科技集团公司电子科学研究院
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Priority to US17/289,127 priority Critical patent/US20210385078A1/en
Publication of WO2020088411A1 publication Critical patent/WO2020088411A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/27—Optical coupling means with polarisation selective and adjusting means
    • G02B6/2753—Optical coupling means with polarisation selective and adjusting means characterised by their function or use, i.e. of the complete device
    • 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
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
    • G06N10/00—Quantum computing, i.e. information processing based on quantum-mechanical phenomena
    • 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
    • H04B10/548—Phase or frequency 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
    • H04B10/70—Photonic quantum communication
    • 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
    • H04L9/0819—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s)
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/27—Optical coupling means with polarisation selective and adjusting means
    • G02B6/2753—Optical coupling means with polarisation selective and adjusting means characterised by their function or use, i.e. of the complete device
    • G02B6/2773—Polarisation splitting or combining
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
    • G02B6/29349—Michelson or Michelson/Gires-Tournois configuration, i.e. based on splitting and interferometrically combining relatively delayed signals at a single beamsplitter
    • 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
    • H04B10/50—Transmitters
    • H04B10/516—Details of coding or modulation
    • H04B10/532—Polarisation 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
    • H04B10/50—Transmitters
    • H04B10/516—Details of coding or modulation
    • H04B10/548—Phase or frequency modulation
    • H04B10/556—Digital modulation, e.g. differential phase shift keying [DPSK] or frequency shift keying [FSK]
    • H04B10/5561—Digital phase modulation

Definitions

  • the invention relates to the technical field of optical transmission secure communication, and in particular to a quantum key distribution phase decoding method and device based on polarization orthogonal rotation reflection and a quantum key distribution system including the device.
  • Quantum secret communication technology is a frontier hotspot field combining quantum physics and information science. Based on the quantum key distribution technology and the principle of one-time encryption, quantum secret communication can realize the secure transmission of information in an open channel. Quantum key distribution is based on the physical principles of quantum mechanics Heisenberg uncertainty relationship, quantum non-cloning theorem, etc. It can achieve the safe sharing of keys between users and can detect potential eavesdropping behaviors. It can be used in defense, government affairs, Areas with high security information transmission requirements such as finance and electricity.
  • the encoding scheme of quantum key distribution mainly uses polarization encoding and phase encoding.
  • Terrestrial quantum key distribution is mainly based on fiber channel transmission, and the production of optical fibers has non-ideal situations such as non-circular cross-section, uneven distribution of core refractive index in the radial direction, and optical fibers are affected by temperature, strain, and bending in the actual environment. Will produce random birefringence effect.
  • phase coding uses the phase difference between the front and back optical pulses to encode information, which can be stably maintained during long-distance fiber channel transmission.
  • phase encoding scheme for the phase encoding scheme, during interference decoding, due to the influence of the birefringence of the transmission fiber and the codec interferometer fiber, there is a problem of polarization-induced fading, resulting in unstable decoding interference. Similarly, if a correction device is added, although only one polarization state needs to be corrected, it will also increase the system complexity and cost. For the quantum key distribution phase encoding scheme, how to perform interference decoding stably and efficiently is a hot spot and a difficult problem for quantum secret communication applications based on the existing optical cable infrastructure.
  • the main objective of the present invention is to propose a phase decoding method and device for quantum key distribution based on polarization orthogonal rotation reflection to solve the problem of unstable phase decoding interference caused by polarization-induced fading in the application of phase encoding quantum key distribution.
  • a phase decoding method for quantum key distribution based on polarization orthogonal rotation reflection characterized in that the method comprises:
  • One input optical pulse of any polarization state is split into two optical pulses by a beam splitter
  • At least one of the two optical pulses is phase-modulated according to a quantum key distribution protocol
  • the two orthogonal polarization states of the light pulse of the path are reflected by the polarization orthogonal rotation, so that after reflection by the corresponding reflection device, the light of the path
  • Each orthogonal polarization state of the pulse is transformed into a polarization state orthogonal thereto.
  • phase decoding method for quantum key distribution based on polarization orthogonal rotation reflection according to scheme 1, wherein the two reflection devices are circular polarization orthogonal rotation reflection devices, and each of the two reflection devices includes Reflector.
  • phase decoding method for quantum key distribution based on polarization orthogonal rotation reflection according to scheme 4, wherein the two reflection devices each include a mirror and a quarter wave plate, and the mirror is located at The rear end of the quarter wave plate is integrally formed with the quarter wave plate, wherein the polarization direction of one of the two orthogonal polarization states of each of the two optical pulses is the same as the quarter
  • the angle of the slow axis of a wave plate is 45 degrees.
  • a quantum key distribution phase decoding device based on polarization orthogonal rotation reflection characterized in that the phase decoding device includes: a beam splitter, two reflecting devices, and optical coupling with the beam splitter and respectively Two optical paths optically coupled by the two reflecting devices, wherein at least one of the two optical paths has a phase modulator,
  • the beam splitter is used to split an input optical pulse of any polarization state into two optical pulses
  • the two optical paths are used to transmit the two optical pulses respectively, and are used to realize the relative delay of the two optical pulses;
  • the two reflecting devices are respectively used to reflect the two optical pulses transmitted from the beam splitter through the two optical paths back to the beam splitter to be combined and output by the beam splitter;
  • the phase modulator is used to phase modulate the optical pulse transmitted through the optical path where it is located according to the quantum key distribution protocol
  • the two reflection devices are configured such that, for each of the two optical pulses:
  • the two orthogonal polarization states of the light pulse of the path are reflected by the polarization orthogonal rotation, so that after reflection by the corresponding reflection device, the light of the path
  • Each orthogonal polarization state of the pulse is transformed into a polarization state orthogonal thereto.
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to scheme 10, wherein the two reflection devices are circular polarization orthogonal rotation reflection devices, and each of the two reflection devices includes Reflector.
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to scheme 10, wherein the two reflection devices are linear polarization orthogonal rotation reflection devices.
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to scheme 13, wherein the two reflection devices each include a mirror and a quarter wave plate, and the mirror is located at The rear end of the quarter-wave plate is integrally formed with the quarter-wave plate, wherein the quarter-wave plate is constructed such that two orthogonal polarizations of each of the two optical pulses The angle between the polarization direction of one of the states and the slow axis of the quarter wave plate is 45 degrees.
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to scheme 10, wherein the two reflection devices are elliptical polarization orthogonal rotation reflection devices.
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to scheme 16, wherein the beam splitter is an elliptical polarization maintaining beam splitter.
  • a quantum key distribution system including:
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to scheme 10, which is provided at the receiving end of the quantum key distribution system and is used for phase decoding.
  • the invention uses polarization orthogonal rotation reflection to control the two orthogonal polarization states of the input optical pulses, and the phase difference transmitted by the two arms of the decoding interferometer is equal, so that the two orthogonal input light pulses of any polarization state are orthogonal Both polarization states can stabilize the interference output, thereby achieving unexpected beneficial effects.
  • a stable interference output at the decoding interferometer can be realized for an input light pulse of any polarization state, which solves the problem that the system cannot work stably due to polarization-induced fading in the phase-encoding quantum key distribution application.
  • the invention provides an easy-to-implement and apply anti-polarization-induced fading phase encoding quantum key distribution decoding scheme.
  • FIG. 1 is a flowchart of a quantum key distribution phase decoding method based on polarization orthogonal rotation reflection in a preferred embodiment of the present invention
  • FIG. 2 is a schematic structural diagram of a quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to a preferred embodiment of the present invention
  • FIG. 3 is a schematic structural diagram of a quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to another preferred embodiment of the present invention.
  • FIG. 4 is a schematic structural diagram of a quantum key distribution phase decoding device based on polarization orthogonal rotation reflection according to another preferred embodiment of the present invention.
  • FIG. 1 A phase decoding method for quantum key distribution based on polarization orthogonal rotation reflection in a preferred embodiment of the present invention is shown in FIG. 1 and includes the following steps:
  • Step S101 Split an input optical pulse of any polarization state into two optical pulses by a beam splitter.
  • the incident input light pulse is in any polarization state, and may be linearly polarized, circularly polarized, or elliptically polarized fully polarized light, or partially polarized light or unpolarized light.
  • the incident input light pulse can be regarded as composed of two orthogonal polarization states.
  • the two optical pulses obtained by beam splitting can also be regarded as composed of two orthogonal polarization states same as the incident input optical pulse.
  • the beam splitter may be a 50:50 fiber coupler, which splits an incident input optical pulse into two optical pulses at 50:50.
  • Step S102 Transmit the two optical pulses obtained by beam splitting along the two optical paths respectively, and after the relative delay of the two optical pulses are reflected back to the beam splitter by two reflecting devices to be separated by the beam splitter Combined output.
  • the two optical pulses are reflected by the two reflecting devices an odd number of times or respectively reflected by the two reflecting devices an even number of times (including zero times, that is, direct transmission) and combined by the beam splitter for output.
  • At least one of the two optical pulses can be distributed according to the quantum key for the input optical pulse before beam splitting or during beam splitting from the beam splitter to the beam splitter
  • the protocol performs phase modulation.
  • each of the two optical pulses obtained by beam splitting when the optical pulse of this channel is reflected by the corresponding reflecting device in the two reflecting devices, the two orthogonal polarizations of the optical pulse of the channel The state is polarized and orthogonally rotated and reflected, so that after being reflected by the corresponding reflection device, each orthogonal polarization state of the light pulse of this path is transformed into a polarization state orthogonal thereto.
  • the x polarization state transmitted to a reflection device along the optical path is transformed into the orthogonal state after being reflected by the polarization orthogonal rotation at the reflection device
  • the polarization state is the y-polarization state
  • the y-polarization state transmitted to the reflecting device along the optical path is converted into the orthogonal polarization state, that is, the x-polarizing state, after being reflected by the orthogonal polarization rotation at the reflecting device.
  • the phase difference of the x-polarization state of the input optical pulse transmitted through the two optical paths during the beam splitting of the beam splitter to the beam splitter is exactly equal to the optical pulse
  • the phase difference of the y polarization state transmitted by the two optical paths during the beam splitting of the beam splitter to the beam splitter is combined.
  • the above two reflection devices are circular polarization orthogonal rotation reflection devices.
  • the above two reflecting devices each include a reflecting mirror.
  • the above beam splitter may be a circular polarization maintaining beam splitter.
  • the circularly polarized orthogonal rotation and reflection device refers to the ability to perform polarization orthogonal rotation and reflection on the incident circularly polarized light, that is, when reflecting the incident circularly polarized light, the polarization state of the circularly polarized light is transformed to be orthogonal to it
  • the polarization device of the polarization state that is, the incident left-handed circularly polarized light is reflected by the circularly polarized orthogonal rotation reflecting device and then transformed into a right-handed circularly polarized light orthogonal thereto, and the incident right-handed circularly polarized light passes through the circle
  • the polarization orthogonal rotating reflection device is converted into left-handed circularly polarized light orthogonal to it after being reflected.
  • the above two reflecting devices are linearly polarized orthogonal rotating reflecting devices.
  • the above two reflecting devices each include a mirror and a quarter wave plate, the mirror is integrally formed with the quarter wave plate at the rear end of the quarter wave plate, wherein the The angle between the polarization direction of one of the two orthogonal polarization states of the two optical pulses and the fast or slow axis of the quarter wave plate is 45 degrees.
  • the above beam splitter may be a line polarization maintaining beam splitter.
  • Such a reflection device including a mirror and a quarter-wave plate can be referred to simply as a "quarter-wave plate mirror", which can be achieved by plating a mirror on the surface of the quarter-wave plate crystal, or by The end face of the polarization-maintaining optical fiber with a phase difference of 90 degrees in the axis transmission is plated with a mirror.
  • the linearly polarized orthogonal rotation and reflection device refers to the ability to perform polarization orthogonal rotation and reflection on the incident linearly polarized light, that is, when reflecting the incident linearly polarized light, the polarization state of the linearly polarized light is transformed to be orthogonal to it
  • the polarization device of the polarization state that is, the incident x-linear polarized light is reflected by the linearly polarized orthogonal rotating reflective device and then transformed into a y-linear polarized light orthogonal thereto.
  • the incident y-linearly polarized light is positively polarized by the linearly polarized light After being reflected by the cross-rotating reflection device, it is converted into x-ray polarized light orthogonal thereto.
  • the above two reflecting devices are elliptical polarization orthogonal rotation reflecting devices, and the above beam splitter may be an elliptical polarization maintaining beam splitter.
  • the appropriate reflecting device can be selected according to the specific elliptical polarization maintaining beam splitter.
  • the elliptical polarization orthogonal rotation and reflection device refers to the ability to perform polarization orthogonal rotation reflection on the incident elliptical polarization state light, that is, when reflecting the incident elliptical polarization state light, the polarization state of the elliptical polarization state light is converted to be orthogonal to it
  • the polarization device of the polarization state that is, the incident left-handed elliptically polarized light is reflected by the elliptically polarized orthogonal rotation and reflection device and then transformed into a right-handed elliptically polarized light orthogonal thereto, and the incident right-handed elliptically polarized light passes through the ellipse
  • the polarized orthogonal rotating reflection device is converted into left-handed elliptical polarized light orthogonal to it after being reflected.
  • each of the two optical pulses obtained by beam splitting maintain the two orthogonal polarization states of the optical pulses of the channel to split the beam splitter to the corresponding reflection
  • the device remains unchanged during the reflection, and remains unchanged during the reflection of the corresponding reflection device to the beam splitter.
  • This can be achieved, for example, by configuring the two optical paths as polarization maintaining optical paths and configuring the optical devices on the two optical paths as polarization maintaining optical devices and / or non-birefringent optical devices.
  • a quantum key distribution phase decoding device based on polarization orthogonal rotation reflection in a preferred embodiment of the present invention is shown in FIG. 2 and includes the following components: beam splitter 201, phase modulator 202, two reflection devices 203 and 204.
  • the beam splitter 201 is optically coupled to the two reflecting devices 203 and 204 via two optical paths, respectively.
  • the phase modulator 202 is disposed on one of the two optical paths.
  • the reflection devices 203 and 204 are each a polarization orthogonal rotation reflection device.
  • the polarization orthogonal rotation and reflection device refers to a type that can perform polarization orthogonal rotation and reflection on the two orthogonal polarization states of the reflected light pulse, that is, when reflecting the incident light pulse, each of the light pulses is orthogonal
  • a reflection device that transforms the polarization state into a polarization state orthogonal thereto.
  • the beam splitter 201 is used to split an incident input optical pulse into two optical pulses for transmission along the two optical paths.
  • the two optical paths are used to transmit the two optical pulses respectively, and used to realize the relative delay of the two optical pulses.
  • the phase modulator 202 is used to phase modulate the optical pulse (ie, one of the two optical pulses) transmitted on the optical path where it is located according to the quantum key distribution protocol.
  • the phase modulator 202 can randomly modulate a 0 degree phase or a 90 degree phase.
  • the phase modulator 202 may be a polarization-independent phase modulator or a polarization-dependent phase modulator.
  • the polarization-independent phase modulator is suitable for performing the same phase modulation on the two orthogonal polarization states of the optical pulse, so it is called polarization-independent.
  • the polarization-independent phase modulator can be implemented by two birefringent phase modulators connected in series or in parallel.
  • phase modulation can be achieved through a variety of specific means.
  • these measures may include: modulating the length of the free-space optical path, or modulating the length of the optical fiber, or using series or parallel optical waveguide phase modulators.
  • the desired phase modulation can be achieved by changing the length of the free-space optical path with a motor.
  • the length of the optical fiber can be modulated by an optical fiber stretcher using the piezoelectric effect, thereby achieving phase modulation.
  • the phase modulator may be other types suitable for voltage control. By applying an appropriate voltage to the polarization-independent phase modulator to perform the same phase modulation on the two orthogonal polarization states of the optical pulse, the desired phase modulation can be achieved.
  • a polarization-dependent phase modulator such as a birefringence phase modulator, is suitable for applying different adjustable phase modulations to the two orthogonal polarization states passing through it.
  • the birefringent phase modulator may be a lithium niobate phase modulator, and by controlling the voltage applied to the lithium niobate crystal, the phase modulation experienced by each of the two orthogonal polarization states passing through the lithium niobate phase modulator Perform control and adjustment.
  • phase modulator 202 Although only one phase modulator 202 is shown as being provided on one of the two optical paths in FIG. 2, it is also possible to configure one phase modulator on each of the two optical paths. In the case where two phase modulators are provided in this way, the difference between the phases modulated by the two phase modulators is determined by the quantum key distribution protocol. In addition, instead of providing a phase modulator on one or both of the two optical paths, a phase modulator may be provided before the beam splitter 201 to phase the input optical pulse before beam splitting according to the quantum key distribution protocol modulation.
  • the reflecting devices 203 and 204 are respectively used to reflect the two optical pulses transmitted from the beam splitter 201 through the two optical paths back to the beam splitter 201 to be combined and output by the beam splitter 201.
  • the two reflection devices 203 and 204 are polarization orthogonal rotation reflection devices, for each of the two light pulses: when the light pulse is reflected by the corresponding reflection device in the two reflection devices The two orthogonal polarization states of the path light pulse are reflected by polarization orthogonal rotation, so that after being reflected by the corresponding reflection device, each orthogonal polarization state of the path light pulse is transformed into a polarization state orthogonal thereto.
  • the reflecting devices 203 and 204 are circular polarization orthogonal rotating reflecting devices.
  • the reflecting devices 203 and 204 each include a reflecting mirror.
  • the beam splitter 201 may be a circular polarization maintaining beam splitter.
  • the reflecting devices 203 and 204 are linearly polarized orthogonal rotating reflecting devices.
  • the reflecting devices 203 and 204 each include a mirror and a quarter wave plate, the mirror is integrally formed with the quarter wave plate at the rear end of the quarter wave plate, wherein the The quarter wave plate is constructed such that the angle between the polarization direction of one of the two orthogonal polarization states of the two optical pulses and the fast axis or slow axis of the quarter wave plate is 45 degree.
  • the beam splitter 201 may be a line polarization maintaining beam splitter.
  • the reflecting devices 203 and 204 are elliptical polarization orthogonal rotation reflecting devices, and the beam splitter 201 may be an elliptical polarization maintaining beam splitter.
  • the appropriate reflecting device can be selected according to the specific elliptical polarization maintaining beam splitter.
  • the two optical paths may be configured as polarization maintaining optical paths, and the optical devices on the two optical paths may be configured as polarization maintaining optical devices and / or non-birefringent optical devices.
  • the two orthogonal polarization states of the optical pulse of this path can be kept unchanged during the beam splitter to the reflection of the corresponding reflection device, and The reflection of the corresponding reflection device to the beam splitter remains unchanged.
  • the phase decoding device in FIG. 2 constitutes an unequal-arm Michelson interferometer, which may be a polarization-maintaining unequal-arm Michelson interferometer or a non-polarization-maintaining unequal-arm Michelson interferometer, depending on the specific configuration.
  • the phase decoding device of FIG. 2 may further include an optical circulator.
  • the optical circulator may be located in front of the beam splitter 201.
  • An incident input light pulse of any polarization state can be input from the first port of the optical circulator and output from the second port of the optical circulator to the beam splitter 201, and the combined output from the beam splitter 201 is input to the optical ring
  • the second port of the circulator and output from the third port of the optical circulator is the same port.
  • a quantum key distribution phase decoding device based on polarization orthogonal rotation reflection is shown in FIG. 3, and includes the following components: a polarization maintaining beam splitter 303, a phase modulator 304, and a mirror 305 and 306.
  • the polarization maintaining beam splitter 303 is a circular polarization maintaining fiber beam splitter.
  • One of the two ports 301 and 302 on the side of the polarization maintaining beam splitter 303 serves as an input port of the phase decoding device.
  • the polarization maintaining beam splitter 303 and the reflecting mirrors 305 and 306 constitute a polarization maintaining unequal-arm Michelson interferometer, and the two optical paths therebetween are polarization maintaining fiber optical paths.
  • the phase modulator 304 is inserted into either arm of the polarization maintaining unequal-arm Michelson interferometer.
  • the port 301 or 302 of the polarization maintaining beam splitter 303 serves as the output port of the device.
  • the optical pulse enters the polarization maintaining beam splitter 303 through the port 301 or 302 of the polarization maintaining beam splitter 303 and is split into two optical pulses by the polarization maintaining beam splitter 303.
  • One optical pulse from the polarization-maintaining beam splitter 303 is phase-modulated by the phase modulator 304 and reflected back by the mirror 305, and the other optical pulse is directly transmitted to the mirror 306 through the polarization-maintaining fiber and reflected by the mirror 306.
  • the two optical pulses reflected by the relatively delayed reflection are output by the port 301 or 302 after being combined by the polarization maintaining beam splitter 303.
  • the device may further include an optical circulator.
  • the optical circulator may be located in front of the polarization maintaining beam splitter 303.
  • An incident input light pulse of any polarization state can be input from the first port of the optical circulator and output from the second port of the optical circulator to the polarization maintaining beam splitter 303, and the combined output from the polarization maintaining beam splitter 303 is Input to the second port of the optical circulator and output from the third port of the optical circulator.
  • a quantum key distribution phase decoding device based on polarization orthogonal rotation reflection is shown in FIG. 4 and includes the following components: a polarization maintaining beam splitter 403, a phase modulator 404, and a quarter One wave plate reflectors 405 and 406.
  • the polarization maintaining beam splitter 403 is a line polarization maintaining optical fiber beam splitter.
  • the quarter-wave plate mirrors 405 and 406 can be realized by mirror-coated quarter-wave plate crystals, or can be realized by polarization-maintaining fiber end-faced mirrors with a phase difference of 90 degrees between the fast and slow axis transmission phases.
  • the angle between the fast axis or slow axis of the polarization-maintaining fiber connected to the quarter-wave plate mirrors 405 and 406 and the corresponding fast axis or slow axis of the quarter-wave plate is 45 degrees.
  • One of the two ports 401 and 402 on the side of the polarization maintaining beam splitter 403 serves as an input port of the phase decoding device.
  • the polarization-maintaining beam splitter 403 and the quarter-wave plate mirrors 405 and 406 form a polarization-maintaining unequal-arm Michelson interferometer, and the two optical paths therebetween are polarization-maintaining fiber optical paths.
  • the phase modulator 404 is inserted into either arm of the polarization maintaining unequal-arm Michelson interferometer.
  • the port 401 or 402 of the polarization maintaining beam splitter 403 serves as the output port of the device.
  • the optical pulse enters the polarization maintaining beam splitter 403 through the port 401 or 402 of the polarization maintaining beam splitter 403 and is split into two optical pulses by the polarization maintaining beam splitter 403.
  • One optical pulse from the polarization-maintaining beam splitter 403 is phase-modulated by the phase modulator 404 and reflected back by the quarter-wave plate mirror 405, and the other optical pulse is directly transmitted to the quarter-wave plate through the polarization-maintaining fiber
  • the mirror 406 is reflected back by the quarter-wave plate mirror 406.
  • the two optical pulses reflected by the relatively delayed reflection are combined by the polarization maintaining beam splitter 403 and output by the port 401 or 402.
  • the device may further include an optical circulator.
  • the optical circulator may be located in front of the polarization maintaining beam splitter 403.
  • An incident input light pulse of any polarization state can be input from the first port of the optical circulator and output from the second port of the optical circulator to the polarization maintaining beam splitter 403, and the combined output from the polarization maintaining beam splitter 403 is Input to the second port of the optical circulator and output from the third port of the optical circulator.
  • polarization-maintaining optical fiber optical path refers to an optical path that uses polarization-maintaining optical fibers to transmit optical pulses or an optical path formed by connecting polarization-maintaining optical fibers.
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection of the present invention can be configured at the receiving end of the quantum key distribution system for phase decoding.
  • the quantum key distribution phase decoding device based on polarization orthogonal rotation reflection of the present invention may also be arranged at the transmitting end of the quantum key distribution system for phase encoding.

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Abstract

本发明提出一种基于偏振正交旋转反射的量子密钥分发相位解码方法、装置及相应系统。该方法包括：将任意偏振态的输入光脉冲经分束器分束为两路光脉冲；分别沿两条光路传输两路光脉冲并将它们进行相对延时后分别经两个反射装置反射回分束器以由分束器合束输出，其中对两路光脉冲中的至少一路光脉冲按照量子密钥分发协议进行相位调制，且对于两路光脉冲中的每一路光脉冲：该路光脉冲经两个反射装置中的相应反射装置反射时其两个正交偏振态作偏振正交旋转反射，使得经由相应反射装置的反射后该路光脉冲的每个正交偏振态变换成与其正交的偏振态。本发明提供了一种易于实现和应用的抗偏振诱导衰落的相位编码量子密钥分发解码方案。

Description

量子密钥分发相位解码方法和装置及相应系统 技术领域
本发明涉及光传输保密通信技术领域，尤其涉及一种基于偏振正交旋转反射的量子密钥分发相位解码方法、装置及包括该装置的量子密钥分发系统。
背景技术
量子保密通信技术是量子物理与信息科学相结合的前沿热点领域。基于量子密钥分发技术和一次一密密码原理，量子保密通信可在公开信道实现信息的安全传输。量子密钥分发基于量子力学海森堡不确定关系、量子不可克隆定理等物理原理，能够实现在用户之间安全地共享密钥，并可以检测到潜在的窃听行为，可应用于国防、政务、金融、电力等高安全信息传输需求的领域。
目前，量子密钥分发的编码方案主要采用偏振编码和相位编码。地面量子密钥分发主要基于光纤信道传输，而光纤制作存在截面非圆对称、纤芯折射率沿径向不均匀分布等非理想情况，并且光纤在实际环境中受温度、应变、弯曲等影响，会产生随机双折射效应。采用偏振编码时，受光纤随机双折射的影响，偏振编码的量子态经长距离光纤传输后到达接收端时，光脉冲偏振态会发生随机变化，造成误码率升高，导致需要增加纠偏设备，增加了系统复杂度和成本，且对于架空光缆、路桥光缆等强干扰情况难以实现稳定应用。相比偏振编码，相位编码采用前后光脉冲的相位差来编码信息，在长距离光纤信道传输过程中能够稳定保持。然而对于相位编码方案，在干涉解码时，因传输光纤和编解码干涉仪光纤双折射的影响，存在偏振诱导衰落的问题，导致解码干涉不稳定。同样，若增加纠偏设备，虽然只需要对一种偏振态进行纠偏，但也会增加系统复杂度和成本。对于量子密钥分发相位编码方案，如何稳定高效地进行干涉解码是基于现有光缆基础设施进行量子保密通信应用的热点和难题。
发明内容
本发明的主要目的在于提出一种基于偏振正交旋转反射的量子密钥分发相位解码方法和装置，以解决相位编码量子密钥分发应用中偏振诱导衰落引起的相位解码干涉不稳定的难题。
本发明提供至少以下技术方案：
1.一种基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述方法包括：
将任意偏振态的一路输入光脉冲经分束器分束为两路光脉冲；
分别沿两条光路传输所述两路光脉冲，并将所述两路光脉冲进行相对延时后分别经两个反射装置反射回所述分束器以由所述分束器合束输出；
其中，在所述分束器分束至所述分束器合束的过程中对所述两路光脉冲中的至少一路光脉冲按照量子密钥分发协议进行相位调制，并且
其中，对于所述两路光脉冲中的每一路光脉冲：
该路光脉冲经所述两个反射装置中的相应反射装置反射时该路光脉冲的两个正交偏振态作偏振正交旋转反射，使得经由所述相应反射装置的反射后，该路光脉冲的每个正交偏振态变换成与其正交的偏振态。
2.根据方案1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置为圆偏振正交旋转反射装置，所述两个反射装置各包括反射镜。
3.根据方案2所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述分束器是圆保偏分束器。
4.根据方案1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置为线偏振正交旋转反射装置。
5.根据方案4所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置各包括反射镜和四分之一波片，所述反射镜在所述四分之一波片后端与所述四分之一波片一体地形成，其中所述两路光脉冲各自的两个正交偏振态之一的极化方向与所述四分之一波片的慢轴的夹角为45度。
6.根据方案4所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述分束器是线保偏分束器。
7.根据方案1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置为椭圆偏振正交旋转反射装置。
8.根据方案7所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述分束器是椭圆保偏分束器。
9.根据方案1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，对于所述两路光脉冲中的每一路光脉冲：
保持该路光脉冲的两个正交偏振态在所述分束器分束至所述相应反射装置反射期间保持不变，且在所述相应反射装置反射至所述分束器合束期间保持不变。
10.一种基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述相位解码装置包括：分束器、两个反射装置以及与所述分束器光耦合并分别与所述两个反射装置光耦合的两条光路，其中所述两条光路中的至少一条光路上具有一个相位调制器，
所述分束器用于将任意偏振态的一路输入光脉冲分束为两路光脉冲；
所述两条光路用于分别传输所述两路光脉冲，并用于实现所述两路光脉冲的相对延时；
所述两个反射装置用于分别将来自所述分束器的经所述两条光路传输来的所述两路光脉冲反射回所述分束器以由所述分束器合束输出；
所述相位调制器用于对经其所在的光路传输的光脉冲按照量子密钥分发协议进行相位调制，
其中，所述两个反射装置被构造成使得，对于所述两路光脉冲中的每一路光脉冲：
该路光脉冲经所述两个反射装置中的相应反射装置反射时该路光脉冲的两个正交偏振态作偏振正交旋转反射，使得经由所述相应反射装置的反射后，该路光脉冲的每个正交偏振态变换成与其正交的偏振态。
11.根据方案10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置为圆偏振正交旋转反射装置，所述两个反射装置各包括反射镜。
12.根据方案11所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述分束器是圆保偏分束器。
13.根据方案10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置为线偏振正交旋转反射装置。
14.根据方案13所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置各包括反射镜和四分之一波片，所述反射镜在所述四分之一波片后端与所述四分之一波片一体地形成，其中所述四分之一波片被构造成使得，所述两路光脉冲各自的两个正交偏振态之一的极化方向与所述四分之一波片的慢轴的夹角为45度。
15.根据方案13所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述分束器是线保偏分束器。
16.根据方案10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置为椭圆偏振正交旋转反射装置。
17.根据方案16所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述分束器是椭圆保偏分束器。
18.根据方案10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两条光路为偏振保持光路。
19.一种量子密钥分发系统，包括：
根据方案10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其设置在所述量子密钥分发系统的接收端，用于相位解码。
本发明通过创造性的配置，利用偏振正交旋转反射控制输入光脉冲的两个正交偏振态各自在解码干涉仪两臂传输的相位差相等，使得任意偏振态的输入光脉冲的两个正交偏振态均能稳定干涉输出，由此实现了意想不到的有益效果。利用本发明的方案，对于任意偏振态的输入光脉冲可以实现在解码干涉仪处的稳定干涉输出，解决了相位编码量子密钥分发应用中偏振诱导衰落造成系统无法稳定工作的问题。本发明提供了一种易于实现和应用的抗偏振诱导衰落的相位编码量子密钥分发解码方案。
附图说明
图1为本发明一优选实施例的基于偏振正交旋转反射的量子密钥分发相位解码方法的流程图；
图2为本发明一优选实施例的基于偏振正交旋转反射的量子密钥分发相位解码装置的组成结构示意图；
图3为本发明另一优选实施例的基于偏振正交旋转反射的量子密钥分发相位解码装置的组成结构示意图；
图4为本发明另一优选实施例的基于偏振正交旋转反射的量子密钥分发相位解码装置的组成结构示意图。
具体实施方式
下面结合附图来具体描述本发明的优选实施例，其中，附图构成本申请一部分，并与本发明的实施例一起用于阐释本发明的原理。为了清楚和简化目的，当其可能使本发明的主题模糊不清时，对本文所描述的器件的已知功能和结构的详细具体说明将省略。
本发明一优选实施例的一种基于偏振正交旋转反射的量子密钥分发相位解码方法如图1所示，包括以下步骤：
步骤S101：将任意偏振态的一路输入光脉冲经分束器分束为两路光脉冲。
入射的输入光脉冲是任意偏振态的，可以是线偏振的、圆偏振的或者椭圆偏振的完全偏振光，也可以是部分偏振光或者非偏振光。
入射的输入光脉冲可以看成由两个正交偏振态组成。自然地，分束得到的两路光脉冲也可以同样看成由与入射的输入光脉冲相同的两个正交偏振态组成。
分束器可以为50:50光纤耦合器，其将入射的一路输入光脉冲按50:50分束为两路光脉冲。
步骤S102：分别沿两条光路传输分束得到的两路光脉冲，并将这两路光脉冲进行相对延时后分别经两个反射装置反射回所述分束器以由所述分束器合束输出。
在该方法中，两路光脉冲分别经两个反射装置反射奇数次或者分别经两个反射装置反射偶数次(含零次，即直接透射)后由所述分束器合束输出。
在该方法中，可以对分束前的所述输入光脉冲或者在分束器分束至分束器合束的过程中对所述两路光脉冲中的至少一路光脉冲按照量子密钥分发协议进行相位调制。
这里，相对延时和相位调制按照量子密钥分发协议的要求和规定进行，本文不作详细说明。
根据本发明的方法，对于分束得到的两路光脉冲中的每一路光脉冲：该路光脉冲经所述两个反射装置中的相应反射装置反射时该路光脉冲的两个正交偏振态作偏振正交旋转反射，使得经由所述相应反射装置的反射后，该路光脉冲的每个正交偏振态变换成与其正交的偏振态。
举例而言，假设这两个正交偏振态分别为x偏振态和y偏振态，沿光路传输到一个反射装置的x偏振态在反射装置处经偏振正交旋转反射后变换成与其正交的偏振态即y偏振态，沿光路传输到该反射装置的y偏振态在反射装置处经偏振正交旋转反射后变换成与其正交的偏振态即x偏振态。
如此，利用反射装置处的偏振正交旋转反射，输入光脉冲的x偏振态在分束器分束至分束器合束的过程中经所述两条光路传输的相位差恰好等于该光脉冲的y偏振态在分束器分束至分束器合束的过程中经所述两条光路传输的相位差。
根据一种可能的配置，上述两个反射装置为圆偏振正交旋转反射装置。例如，上述两个反射装置各包括反射镜。在这种情况下，上述分束器可以是圆保偏分束器。这里，圆偏振正交旋转反射装置是指能够对入射的圆偏振态光作偏振正交旋转反射、即在反射入射的圆偏振态光时将该圆偏振态光的偏振态变换成与其正交的偏振态的反射装置，即：入射的左旋圆偏振光经所述圆偏振正交旋转反射装置反射后变换成与其正交的右旋圆偏振光，入射的右旋圆偏振光经所述圆偏振正交旋转反射装置反射后变换成与其正交的左旋圆偏振光。
根据另一种可能的配置，上述两个反射装置为线偏振正交旋转反射装置。例如，上述两个反射装置各包括反射镜和四分之一波片，所述反射镜在所述四分之一波片后端与所述四分之一波片一体地形成，其中所述两路光脉冲各自的两个正交偏振态之一的极化方向与所述四分之一波片的快轴或慢轴的夹角为45度。在这种情况下，上述分束器可以是线保偏分束器。这种包括反射镜和四分之一波片的反射装 置可以简称为“四分之一波片反射镜”，可以通过在四分之一波片晶体表面镀反射镜实现，亦可通过在快慢轴传输相位相差90度的保偏光纤端面镀反射镜实现。这里，线偏振正交旋转反射装置是指能够对入射的线偏振态光作偏振正交旋转反射、即在反射入射的线偏振态光时将该线偏振态光的偏振态变换成与其正交的偏振态的反射装置，即：入射的x线偏振光经所述线偏振正交旋转反射装置反射后变换成与其正交的y线偏振光，入射的y线偏振光经所述线偏振正交旋转反射装置反射后变换成与其正交的x线偏振光。
根据又一种可能的配置，上述两个反射装置为椭圆偏振正交旋转反射装置，上述分束器可以是椭圆保偏分束器。在这种情况下，可以根据具体的椭圆保偏分束器，选择适合的反射装置。这里，椭圆偏振正交旋转反射装置是指能够对入射的椭圆偏振态光作偏振正交旋转反射、即在反射入射的椭圆偏振态光时将该椭圆偏振态光的偏振态变换成与其正交的偏振态的反射装置，即：入射的左旋椭圆偏振光经所述椭圆偏振正交旋转反射装置反射后变换成与其正交的右旋椭圆偏振光，入射的右旋椭圆偏振光经所述椭圆偏振正交旋转反射装置反射后变换成与其正交的左旋椭圆偏振光。
对于以上几种配置，有利地，对于分束得到的两路光脉冲中的每一路光脉冲：保持该路光脉冲的两个正交偏振态在所述分束器分束至所述相应反射装置反射期间保持不变，且在所述相应反射装置反射至所述分束器合束期间保持不变。这可以例如通过将所述两条光路配置为偏振保持光路且将所述两条光路上的光器件配置为偏振保持光器件和/或非双折射光器件来实现。
本发明一优选实施例的一种基于偏振正交旋转反射的量子密钥分发相位解码装置如图2所示，包括以下组成部分：分束器201、相位调制器202、两个反射装置203和204。
分束器201分别经由两条光路光耦合至两个反射装置203和204。相位调制器202配置于所述两条光路之一上。反射装置203和204各为一个偏振正交旋转反射装置。
这里，偏振正交旋转反射装置是指一种能够对所反射的光脉冲的两个正交偏振态作偏振正交旋转反射、即在反射入射的光脉冲时将该光脉冲的每个正交偏振态变换成与其正交的偏振态的反射装置。
分束器201用于将入射的一路输入光脉冲分束为两路光脉冲以分别沿两条光路传输。
两条光路用于分别传输所述两路光脉冲，并用于实现所述两路光脉冲的相对延时。
相位调制器202用于对其所在的光路传输的光脉冲(即，两路光脉冲之一)按照量子密钥分发协议进行相位调制。相位调制器202可随机调制0度相位或90度相位。
相位调制器202可以为偏振无关相位调制器或者偏振相关相位调制器。
偏振无关相位调制器适于对光脉冲的两个正交偏振态进行相同的相位调制，所以被称为偏振无关的。举例而言，偏振无关相位调制器可以由两个双折射相位调制器串联或并联实现。根据情况，可以通过多种具体手段来实现相位调制。例如，这些手段可包括：调制自由空间光路的长度，或者调制光纤的长度，或者利用串联或并联光波导相位调制器等。例如，可通过用电机改变自由空间光路的长度来实现期望的相位调制。再如，可通过利用压电效应的光纤拉伸器来调制光纤的长度，由此实现相位调制。另外，相位调制器可以是适于电压控制的其他类型，通过施加合适的电压至偏振无关相位调制器来对光脉冲的两个正交偏振态进行相同的相位调制，可实现期望的相位调制。
偏振相关相位调制器例如双折射相位调制器，适于对通过其的两个正交偏振态施加不同的可调的相位调制。例如，双折射相位调制器可以为铌酸锂相位调制器，通过控制施加至铌酸锂晶体的电压，可以对通过该铌酸锂相位调制器的两个正交偏振态各自所经受的相位调制进行控制和调整。
尽管图2中，仅一个相位调制器202被示出为设置于两条光路之一上，但在两条光路上各配置一个相位调制器也是可能的。在如此设置有两个相位调制器的情况下，两个相位调制器所调制的相位之差由量子密钥分发协议确定。另外，代替在 两条光路之一或两者上设置相位调制器，可以在分束器201之前设置相位调制器，用于对分束前的所述输入光脉冲按照量子密钥分发协议进行相位调制。
反射装置203和204分别用于将来自分束器201的经所述两条光路传输来的所述两路光脉冲反射回分束器201以由分束器201合束输出。
由于两个反射装置203和204均为偏振正交旋转反射装置，对于所述两路光脉冲中的每一路光脉冲：该路光脉冲经所述两个反射装置中的相应反射装置反射时该路光脉冲的两个正交偏振态作偏振正交旋转反射，使得经由所述相应反射装置的反射后，该路光脉冲的每个正交偏振态变换成与其正交的偏振态。
根据一种可能的配置，反射装置203和204为圆偏振正交旋转反射装置。例如，反射装置203和204各包括反射镜。在这种情况下，分束器201可以是圆保偏分束器。
根据另一种可能的配置，反射装置203和204为线偏振正交旋转反射装置。例如，反射装置203和204各包括反射镜和四分之一波片，所述反射镜在所述四分之一波片后端与所述四分之一波片一体地形成，其中所述四分之一波片被构造成使得，所述两路光脉冲各自的两个正交偏振态之一的极化方向与所述四分之一波片的快轴或慢轴的夹角为45度。在这种情况下，分束器201可以是线保偏分束器。
根据又一种可能的配置，反射装置203和204为椭圆偏振正交旋转反射装置，分束器201可以是椭圆保偏分束器。在这种情况下，可以根据具体的椭圆保偏分束器，选择适合的反射装置。
对于以上几种配置，有利地，可以将所述两条光路配置为偏振保持光路，且将所述两条光路上的光器件配置为偏振保持光器件和/或非双折射光器件。如此，对于分束得到的两路光脉冲中的每一路光脉冲：可以保持该路光脉冲的两个正交偏振态在分束器分束至相应反射装置反射期间保持不变，且在所述相应反射装置反射至所述分束器合束期间保持不变。
图2的相位解码装置构成不等臂迈克尔逊干涉仪，可以为保偏不等臂迈克尔逊干涉仪或非保偏不等臂迈克尔逊干涉仪，取决于具体配置。
尽管未示出，图2的相位解码装置还可以包括光环形器。该光环形器可以位于分束器201前端。入射的任意偏振态的一路输入光脉冲可从光环形器的第一端口 输入并从光环形器的第二端口输出至分束器201，来自分束器201的合束输出被输入至光环形器的第二端口并从光环形器的第三端口输出。在此情况下，图2的不等臂迈克尔逊干涉仪的输入端口和输出端口之一为同一端口。
本发明另一优选实施例的一种基于偏振正交旋转反射的量子密钥分发相位解码装置如图3所示，包括以下组成部分：保偏分束器303、相位调制器304，以及反射镜305和306。
保偏分束器303为圆保偏光纤分束器。
保偏分束器303一侧的两个端口301和302之一作为相位解码装置的输入端口。保偏分束器303与反射镜305和306构成保偏不等臂迈克尔逊干涉仪，其间的两条光路为保偏光纤光路。相位调制器304插入保偏不等臂迈克尔逊干涉仪的两臂中的任一臂。保偏分束器303的端口301或302作为装置的输出端口。
工作时，光脉冲经保偏分束器303的端口301或302进入保偏分束器303并由保偏分束器303分成两路光脉冲。来自保偏分束器303的一路光脉冲经相位调制器304进行相位调制后由反射镜305反射回来，另一路光脉冲直接经保偏光纤传输至反射镜306并由反射镜306反射回来。经相对延时的反射回来的两路光脉冲经保偏分束器303合束后由端口301或302输出。
在保偏分束器303的输入端口和输出端口之一为同一端口的情况下，装置还可以包括光环形器。该光环形器可以位于保偏分束器303前端。入射的任意偏振态的一路输入光脉冲可从光环形器的第一端口输入并从光环形器的第二端口输出至保偏分束器303，来自保偏分束器303的合束输出被输入至光环形器的第二端口并从光环形器的第三端口输出。
本发明另一优选实施例的一种基于偏振正交旋转反射的量子密钥分发相位解码装置如图4所示，包括以下组成部分：保偏分束器403、相位调制器404，以及四分之一波片反射镜405和406。
保偏分束器403为线保偏光纤分束器。
四分之一波片反射镜405和406可以为四分之一波片晶体表面镀反射镜实现，亦可由快慢轴传输相位相差90度的保偏光纤端面镀反射镜实现。与四分之一波片 反射镜405、406相连的保偏光纤的快轴或慢轴与相应的四分之一波片的快轴或者慢轴的夹角为45度。
保偏分束器403一侧的两个端口401和402之一作为相位解码装置的输入端口。保偏分束器403与四分之一波片反射镜405和406构成保偏不等臂迈克尔逊干涉仪，其间的两条光路为保偏光纤光路。相位调制器404插入保偏不等臂迈克尔逊干涉仪的两臂中的任一臂。保偏分束器403的端口401或402作为装置的输出端口。
工作时，光脉冲经保偏分束器403的端口401或402进入保偏分束器403并由保偏分束器403分成两路光脉冲。来自保偏分束器403的一路光脉冲经相位调制器404进行相位调制后由四分之一波片反射镜405反射回来，另一路光脉冲直接经保偏光纤传输至四分之一波片反射镜406并由四分之一波片反射镜406反射回来。经相对延时的反射回来的两路光脉冲经保偏分束器403合束后由端口401或402输出。
在保偏分束器403的输入端口和输出端口之一为同一端口的情况下，装置还可以包括光环形器。该光环形器可以位于保偏分束器403前端。入射的任意偏振态的一路输入光脉冲可从光环形器的第一端口输入并从光环形器的第二端口输出至保偏分束器403，来自保偏分束器403的合束输出被输入至光环形器的第二端口并从光环形器的第三端口输出。
本文中，术语“分束器”和“合束器”可互换使用，分束器亦可称为和用作合束器，反之亦然。本文中，“保偏光纤光路”是指采用保偏光纤传输光脉冲的光路或保偏光纤连接形成的光路。
可以在量子密钥分发系统的接收端配置本发明的基于偏振正交旋转反射的量子密钥分发相位解码装置，用于相位解码。另外，也可以在量子密钥分发系统的发射端配置本发明的基于偏振正交旋转反射的量子密钥分发相位解码装置，用于相位编码。
通过具体实施方式的说明，应当可对本发明为达成预定目的所采取的技术手段及功效有更加深入且具体的了解，然而所附图示仅是提供参考与说明之用，并非用来对本发明加以限制。

Claims (19)

  1. 一种基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述方法包括：
    将任意偏振态的一路输入光脉冲经分束器分束为两路光脉冲；
    分别沿两条光路传输所述两路光脉冲，并将所述两路光脉冲进行相对延时后分别经两个反射装置反射回所述分束器以由所述分束器合束输出；
    其中，在所述分束器分束至所述分束器合束的过程中对所述两路光脉冲中的至少一路光脉冲按照量子密钥分发协议进行相位调制，并且
    其中，对于所述两路光脉冲中的每一路光脉冲：
    该路光脉冲经所述两个反射装置中的相应反射装置反射时该路光脉冲的两个正交偏振态作偏振正交旋转反射，使得经由所述相应反射装置的反射后，该路光脉冲的每个正交偏振态变换成与其正交的偏振态。
  2. 根据权利要求1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置为圆偏振正交旋转反射装置，所述两个反射装置各包括反射镜。
  3. 根据权利要求2所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述分束器是圆保偏分束器。
  4. 根据权利要求1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置为线偏振正交旋转反射装置。
  5. 根据权利要求4所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置各包括反射镜和四分之一波片，所述反射镜在所述四分之一波片后端与所述四分之一波片一体地形成，其中所述两路光脉冲各自的两个正交偏振态之一的极化方向与所述四分之一波片的慢轴的夹角为45度。
  6. 根据权利要求4所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述分束器是线保偏分束器。
  7. 根据权利要求1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述两个反射装置为椭圆偏振正交旋转反射装置。
  8. 根据权利要求7所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，所述分束器是椭圆保偏分束器。
  9. 根据权利要求1所述的基于偏振正交旋转反射的量子密钥分发相位解码方法，其特征在于，对于所述两路光脉冲中的每一路光脉冲：
    保持该路光脉冲的两个正交偏振态在所述分束器分束至所述相应反射装置反射期间保持不变，且在所述相应反射装置反射至所述分束器合束期间保持不变。
  10. 一种基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述相位解码装置包括：分束器、两个反射装置以及与所述分束器光耦合并分别与所述两个反射装置光耦合的两条光路，其中所述两条光路中的至少一条光路上具有一个相位调制器，
    所述分束器用于将任意偏振态的一路输入光脉冲分束为两路光脉冲；
    所述两条光路用于分别传输所述两路光脉冲，并用于实现所述两路光脉冲的相对延时；
    所述两个反射装置用于分别将来自所述分束器的经所述两条光路传输来的所述两路光脉冲反射回所述分束器以由所述分束器合束输出；
    所述相位调制器用于对经其所在的光路传输的光脉冲按照量子密钥分发协议进行相位调制，
    其中，所述两个反射装置被构造成使得，对于所述两路光脉冲中的每一路光脉冲：
    该路光脉冲经所述两个反射装置中的相应反射装置反射时该路光脉冲的两个正交偏振态作偏振正交旋转反射，使得经由所述相应反射装置的反射后，该路光脉冲的每个正交偏振态变换成与其正交的偏振态。
  11. 根据权利要求10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置为圆偏振正交旋转反射装置，所述两个反射装置各包括反射镜。
  12. 根据权利要求11所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述分束器是圆保偏分束器。
  13. 根据权利要求10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置为线偏振正交旋转反射装置。
  14. 根据权利要求13所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置各包括反射镜和四分之一波片，所述反射镜在所述四分之一波片后端与所述四分之一波片一体地形成，其中所述四分之一波片被构造成使得，所述两路光脉冲各自的两个正交偏振态之一的极化方向与所述四分之一波片的慢轴的夹角为45度。
  15. 根据权利要求13所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述分束器是线保偏分束器。
  16. 根据权利要求10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两个反射装置为椭圆偏振正交旋转反射装置。
  17. 根据权利要求16所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述分束器是椭圆保偏分束器。
  18. 根据权利要求10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其特征在于，所述两条光路为偏振保持光路。
  19. 一种量子密钥分发系统，包括：
    根据权利要求10所述的基于偏振正交旋转反射的量子密钥分发相位解码装置，其设置在所述量子密钥分发系统的接收端，用于相位解码。
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Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109150525B (zh) * 2018-10-29 2023-08-22 中国电子科技集团公司电子科学研究院 量子密钥分发相位解码方法和装置及相应系统
CN111478767B (zh) * 2019-01-23 2022-01-28 科大国盾量子技术股份有限公司 用于诱骗态编码和偏振编码的发送端、编码方法及量子密钥分发系统
CN110460432A (zh) * 2019-03-08 2019-11-15 中国电子科技集团公司电子科学研究院 量子密钥分发相位编解码器、相应的编解码装置及系统
CN110460427A (zh) * 2019-03-08 2019-11-15 中国电子科技集团公司电子科学研究院 量子密钥分发相位编解码器、相应的编解码装置及系统
CN110456518B (zh) * 2019-03-08 2023-08-15 中国电子科技集团公司电子科学研究院 偏振无关双光束干涉方法和装置
CN110460430A (zh) * 2019-03-08 2019-11-15 中国电子科技集团公司电子科学研究院 量子密钥分发相位编解码器、相应的编解码装置及系统
CN110460429A (zh) * 2019-03-08 2019-11-15 中国电子科技集团公司电子科学研究院 量子密钥分发相位编解码器、相应的编解码装置及系统
CN110460434A (zh) * 2019-06-18 2019-11-15 中国电子科技集团公司电子科学研究院 时间相位解码装置和包括其的量子密钥分发系统
CN110545180A (zh) * 2019-09-23 2019-12-06 中国科学技术大学 偏振编码装置及量子密钥分发光源
CN110572263A (zh) * 2019-09-23 2019-12-13 中国电子科技集团公司电子科学研究院 连续变量量子密钥分发解码方法、装置和系统
CN110572264A (zh) * 2019-09-23 2019-12-13 中国电子科技集团公司电子科学研究院 连续变量量子密钥分发解码方法、装置和系统
CN114448617B (zh) * 2021-12-31 2023-07-21 华南师范大学 一种逆向调制自由空间qkd系统和密钥分发方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101150371A (zh) * 2006-09-22 2008-03-26 中国科学院物理研究所 一种相位编码偏振检测的量子密钥分配系统
CN101571612A (zh) * 2004-02-02 2009-11-04 中国科学技术大学 一种偏振控制编码方法、编码器和量子密钥分配系统
US20130258453A1 (en) * 2012-03-29 2013-10-03 Oki Electric Industry Co., Ltd. Quantum entangled photon pair generator
CN109150525A (zh) * 2018-10-29 2019-01-04 中国电子科技集团公司电子科学研究院 量子密钥分发相位解码方法和装置及相应系统

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7534990B2 (en) * 2006-09-05 2009-05-19 General Photonics Corporation Compact optical delay devices
CN108650091B (zh) * 2018-07-18 2024-04-19 中国电子科技集团公司电子科学研究院 相位解码方法、相位解码接收装置和量子密钥分发系统
CN107612690B (zh) * 2017-10-26 2021-05-07 中国电子科技集团公司电子科学研究院 一种相位解码方法、装置和量子密钥分发系统
CN110620652B (zh) * 2018-07-19 2023-03-24 科大国盾量子技术股份有限公司 一种量子密钥分发系统及其通信方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101571612A (zh) * 2004-02-02 2009-11-04 中国科学技术大学 一种偏振控制编码方法、编码器和量子密钥分配系统
CN101150371A (zh) * 2006-09-22 2008-03-26 中国科学院物理研究所 一种相位编码偏振检测的量子密钥分配系统
US20130258453A1 (en) * 2012-03-29 2013-10-03 Oki Electric Industry Co., Ltd. Quantum entangled photon pair generator
CN109150525A (zh) * 2018-10-29 2019-01-04 中国电子科技集团公司电子科学研究院 量子密钥分发相位解码方法和装置及相应系统

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