CN110460428A - Quantum key distribution phase codec, corresponding coding and decoding device and system - Google Patents

Quantum key distribution phase codec, corresponding coding and decoding device and system Download PDF

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Publication number
CN110460428A
CN110460428A CN201910176940.9A CN201910176940A CN110460428A CN 110460428 A CN110460428 A CN 110460428A CN 201910176940 A CN201910176940 A CN 201910176940A CN 110460428 A CN110460428 A CN 110460428A
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port
phase
polarization
beam splitter
modulator
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CN110460428B (en
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许华醒
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China Electronics Technology Group Corp CETC
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China Electronics Technology Group Corp CETC
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0816Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
    • H04L9/0852Quantum cryptography
    • H04L9/0858Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

The present invention proposes quantum key distribution phase codec and corresponding coding and decoding device and system.The phase codec includes beam splitter and two polarized orthogonal rotary reflection devices through two arms Yu beam splitter optical coupling respectively.At least one reflection unit includes polarization beam apparatus, quarter-wave plate reflecting mirror and the phase-modulator with first port, second port, third port and the 4th port, and is coupled to corresponding arm through the first port.Polarization beam apparatus second and the 4th port by first transmission optical path coupling, phase-modulator setting first transmission optical path on.The third port of polarization beam apparatus is coupled to quarter-wave plate reflecting mirror by the second transmission optical path.The invention allows to the input optical pulses to random polarization state steadily to carry out encoding and decoding interference, solve the problems, such as in phase code and time bit-phase code quantum key distribution application polarization induction decline cause system can not steady operation, while the loss at interferometer reduces.

Description

Quantum key distribution phase codec, corresponding coding and decoding device and system
Technical field
The present invention relates to optical transport private communication technology field more particularly to a kind of amounts based on polarized orthogonal rotary reflection Quantum key distribution phase codec, corresponding coding and decoding device and quantum key distribution system including the phase codec.
Background technique
Quantum Secure Communication is the forward position focus field that quantum physics are combined with information science.Based on quantum key Distribution technology and one time cryptosystem principle, quantum secret communication can be in the safe transmissions of overt channel realization information.Quantum is close Key distribution can be realized based on physical principles such as quantum mechanics Heisenberg uncertainty relationship, quantum non-clone principles in user Between safely shared key, and can detecte potential eavesdropping behavior, it is contour to can be applied to national defence, government affairs, finance, electric power The field of security information transmission demand.
Ground quantum key distribution is based primarily upon fibre channel transmission, because phase code uses the phase of front and back light pulse Difference carrys out encoded information, can stablize holding during long-distance optical fiber transmission, so the phase based on unequal arm interferometer Position coding and time bit-phase code are the primary coding schemes of quantum key distribution application.It is cut however, optical fiber fabrication exists The non-circular symmetrical, fiber core refractive index in face radially non-idealities such as uneven distribution, and optical fiber in the actual environment by temperature, Strain, bending etc. influence, and can generate random birefringence effect.Therefore, light pulse is transmitted through long-distance optical fiber and through unequal arm After the transmission of interferometer two-arm optical fiber, asking in the presence of polarization induction decline when carrying out phase decoding interference by unequal arm interferometer Topic causes decoding interference unstable, the bit error rate is caused to increase.If it will increase system complexity and cost using correcting device, and Stable application is difficult to realize for strong jammings situations such as aerial optical cable, road and bridge optical cables.
A kind of unequal arm faraday-Michelson's interferometer is proposed in the prior art, light pulse can be made by light Fine channel random birefringence and derived from this polarization state change influence when, still keep result of interference stablize output.But it is this Interferometer loss is big, and wherein the Insertion Loss of phase-modulator is one of the principal element caused compared with lossy.Specifically, working as phase When modulator is placed in an arm of interferometer, light pulse can be by phase-modulator twice, to cause to interfere due to carrying out transmission back The loss of instrument is larger, and system effectiveness is relatively low.
For quantum key distribution phase code and time bit-phase encoding scheme, how to carry out to stability and high efficiency Interference decoding is the hot spot and problem that quantum secret communication application is carried out based on existing optical cable infrastructure.
Summary of the invention
It is a primary object of the present invention to propose a kind of quantum key distribution phase volume based on polarized orthogonal rotary reflection Decoder, corresponding coding and decoding device and quantum key distribution system including the phase codec, with solve phase code with And phase decoding caused by polarization induction decline interferes unstable difficulty in time bit-phase code quantum key distribution application Topic, while reducing the loss at interferometer.
The present invention provides at least following technical scheme:
1. a kind of quantum key distribution phase codec, comprising: beam splitter, respectively through two arms and the beam splitter light Two polarized orthogonal rotary reflection devices of coupling, wherein one of described two polarized orthogonal rotary reflection devices or each institute Stating polarized orthogonal rotary reflection device includes the polarization beam splitting with first port, second port, third port and the 4th port Device, quarter-wave plate reflecting mirror and phase-modulator, and the first port through the polarization beam apparatus is coupled to described two Respective arms in a arm, the second port of the polarization beam apparatus and the 4th port are described by the first transmission optical path optical coupling In the first transmission optical path, the third port of the polarization beam apparatus passes through the second transmission optical path coupling for phase-modulator setting It is bonded to the quarter-wave plate reflecting mirror, the quarter-wave plate reflecting mirror includes quarter-wave plate and at described four points One of the reflecting mirror that is integrally formed of wave plate rear end and the quarter-wave plate, wherein inputting the light of the quarter-wave plate The angle of the fast axle or slow axis of the polarization direction of pulse and the quarter-wave plate is 45 degree.
2. phase codec according to scheme 1, wherein described two polarized orthogonal rotary reflection devices are identical The polarized orthogonal rotary reflection device of construction, or the polarized orthogonal rotary reflection device for different configuration.
3. phase codec according to scheme 1, wherein the first transmission optical path and/or second transmission Optical path is that polarization keeps optical path.
4. phase codec according to scheme 1, wherein the beam splitter is polarization-maintaining beam splitter.
5. phase codec according to scheme 1, wherein described two arms are respectively to polarize to keep optical path, described two Optical device on a arm is that polarization keeps optical device and/or non-birefringent optical device.
6. a kind of HVDC Modulation quantum key distribution phase coding and decoding device, including preposition beam splitter and two are according to scheme Any phase codec in 1-5, two phase codecs are optically coupled to through two strip optical paths described respectively Preposition beam splitter, wherein the beam splitter of each phase codec is not coupled to the described two of the phase codec One of port of arm is optically coupled to the corresponding sub-light road in the two strips optical path, and every sub-light road is provided with a light Circulator, wherein the phase-modulator is direct current phase-modulator.
7. a kind of quantum key distribution time bit-phase coding and decoding device, including preposition beam splitter and one are according to side Any phase codec, the phase codec are optically coupled to described preposition point through a strip optical path in case 1-5 Beam device, wherein one of the port for not being coupled to described two arms of the beam splitter of the phase codec is optically coupled to described one Strip optical path.
8. a kind of HVDC Modulation quantum key distribution time bit-phase coding and decoding device, including preposition beam splitter and one A phase codec according to any in scheme 1-5, the phase codec are optically coupled to institute through a strip optical path Preposition beam splitter is stated, wherein one of port for not being coupled to described two arms of beam splitter of phase codec optical coupling To the strip optical path, wherein being provided with an optical circulator in the strip optical path, the phase-modulator is direct current Phase-modulator.
9. the coding and decoding device according to scheme 7 or 8 further includes being coupled to the preposition beam splitting through another strip optical path The beam splitter of device.
10. a kind of quantum key distribution system, comprising:
According to the phase codec any in scheme 1~5 or according to the encoding and decoding any in scheme 6~9 The receiving end of the quantum key distribution system is arranged in, for decoding in device;And/or
According to the phase codec any in scheme 1~5 or according to the encoding and decoding any in scheme 6~9 The transmitting terminal of the quantum key distribution system is arranged in, for encoding in device.
The present invention makes it possible to steadily carry out volume solution to the input optical pulse of random polarization state by creative construction Code interference, it is thus achieved that unexpected beneficial effect.Using the solution of the present invention, for the input light arteries and veins of random polarization state Punching may be implemented to stablize interference output at phase decoding interferometer, solves phase code and time bit-phase is compiled Code amount quantum key distribution application in polarization induction decline cause system can not steady operation the problem of.In addition, due to phase-modulation Device is placed in the reflection unit of interferometer, and it is primary that light pulse need to only be transferred through phase-modulator, to reduce at interferometer Loss.The present invention provides a kind of phase code of efficient anti-polarization induction decline for being easily achieved and applying and times Bit-phase code quantum key distribution decoding scheme.
Detailed description of the invention
Fig. 1 is the quantum key distribution phase encoding and decoding based on polarized orthogonal rotary reflection of one embodiment of the present invention The composed structure schematic diagram of device;
Fig. 2 is that a kind of composed structure of polarized orthogonal rotary reflection device of phase codec for use in the present invention is shown It is intended to;
Fig. 3 is the composed structure of another polarized orthogonal rotary reflection device of phase codec for use in the present invention Schematic diagram;
Fig. 4 is the composed structure of another polarized orthogonal rotary reflection device of phase codec for use in the present invention Schematic diagram;
Fig. 5 is the composed structure of another polarized orthogonal rotary reflection device of phase codec for use in the present invention Schematic diagram;
Fig. 6 is the HVDC Modulation quantum key distribution phase based on polarized orthogonal rotary reflection of one embodiment of the present invention The composed structure schematic diagram of position coding and decoding device;
Fig. 7 is the quantum key distribution time bit-based on polarized orthogonal rotary reflection of one embodiment of the present invention The composed structure schematic diagram of phase coding and decoding device;
When Fig. 8 is the HVDC Modulation quantum key distribution based on polarized orthogonal rotary reflection of one embodiment of the present invention Between bit-phase coding and decoding device composed structure schematic diagram;
Fig. 9 is the quantum key distribution phase encoding and decoding based on polarized orthogonal rotary reflection of one embodiment of the present invention The composed structure schematic diagram of device.
Specific embodiment
Specifically describing the preferred embodiment of the present invention with reference to the accompanying drawing, wherein attached drawing constitutes the application a part, and Together with embodiments of the present invention for illustrating the principle of the present invention.For purpose of clarity and simplification, when it may make the present invention Theme it is smudgy when, illustrating and omitting in detail to the known function and structure of device described herein.
The quantum key distribution phase codec based on polarized orthogonal rotary reflection of one embodiment of the present invention is such as Shown in Fig. 1, including consisting of part: 101, two reflection units 102 and 103 of beam splitter.
Two reflection units 102 and 103 are respectively through two arms (upper and lower arms in Fig. 1) and 101 optical coupling of beam splitter.
According to the present invention, two reflection units 102 and 103 are polarized orthogonal rotary reflection device, and the two are anti- At least one of injection device includes phase-modulator.
Here, polarized orthogonal rotary reflection device refers to that one kind can be to two orthogonal polarisation states of the light pulse reflected Make polarized orthogonal rotary reflection, i.e. in the incident light pulse of reflection by each orthogonal polarisation state of the light pulse be transformed into and its The reflection unit of orthogonal polarization state.For example, it is assumed that the two orthogonal polarisation states are respectively x-polarisation state and y-polarisation state, edge The x-polarisation state of optic path to a polarized orthogonal rotary reflection device becomes after polarized orthogonal rotary reflection at reflection unit It changes orthogonal to that polarization state i.e. y-polarisation state into, is passed through at reflection unit along the y-polarisation state of optic path to the reflection unit inclined It shakes and is transformed into orthogonal to that polarization state i.e. x-polarisation state after orthogonal rotary reflection.
Here, the polarized orthogonal rotary reflection device including phase-modulator is properly termed as " having phase-modulation function Polarized orthogonal rotary reflection device ".
Beam splitter 101 is used to the beam splitting of input optical pulse all the way of incident random polarization state be two-way light pulse with respectively It is transmitted along two arms.
Two arms for transmitting the two-way light pulse respectively.
Each phase-modulator is used to carry out phase-modulation according to quantum key distribution agreement to the light pulse by it.Phase The phase-modulation that position modulator carries out is determined by quantum key distribution agreement, depends on specific application.For example, in a kind of possibility Application in, phase-modulator can 0 degree of phase of Stochastic Modulation or 90 degree of phases.In each of two reflection units 102 and 103 In the case where including phase-modulator, the difference for the phase that the two phase-modulators are modulated is true by quantum key distribution agreement It is fixed, depend on specific application.
Phase-modulator can be single polarization phase modulator or birefringent phase modulator.Single polarization phase modulator Phase-modulation is applied to a polarization state, another polarization state is ended.Birefringent phase modulator is suitable for by its two A orthogonal polarisation state applies different adjustable phase-modulations.For example, birefringent phase modulator can be lithium niobate phase tune Device processed is applied to the voltage of lithium columbate crystal by controlling, can be orthogonal inclined to two for passing through the lithium niobate phase modulator The phase-modulation that polarization state is respectively subjected to is controlled and is adjusted.
Reflection unit 102 and 103 is respectively used to will be from the two-way of beam splitter 101 come through the transmission of described two arms Light pulse reflected back into beam splitter 101 is to close beam output by beam splitter 101.
Since two reflection units 102 and 103 are polarized orthogonal rotary reflection device, in the two-way light pulse Per light pulse all the way: the road light pulse is through the corresponding reflection unit reflection road the Shi Gai light pulse in described two reflection units Two orthogonal polarisation states make polarized orthogonal rotary reflection, so that after the reflection via the corresponding reflection unit, the road light pulse Each orthogonal polarisation state be transformed into orthogonal to that polarization state.In this way, for the phase codec of Fig. 1, just using polarization The polarized orthogonal rotary reflection at rotary reflection device is handed over, the x-polarisation state of input optical pulse is closed in beam splitter beam splitting to beam splitter The phase difference transmitted during beam through described two arms is exactly equal to the y-polarisation state of the light pulse in beam splitter beam splitting to beam splitting The phase difference that device transmits during closing beam through described two arms.
The invention proposes four kinds of creative polarized orthogonal rotary reflection device constructions, i.e. configurations discussed below 1, structure Make 2, construction 3 and construction 4.
According to construction 1, polarized orthogonal rotary reflection device includes polarization beam apparatus, which has input port , transmission optical path optically coupled to one another through a transmission optical path with two output ports of two output ports, the polarization beam apparatus On be provided with half-wave plate, the angle for inputting the polarization direction of the light pulse of the half-wave plate and the fast axle of the half-wave plate or slow axis is 45 Degree.Polarized orthogonal rotary reflection device with construction 1, can be by being polarized when for phase codec of the invention The reflection unit is couple the arm by the arm that the input port of beam splitter is coupled to phase codec.
According to construction 2, polarized orthogonal rotary reflection device includes polarization beam apparatus, which has input port , the transmission light optically coupled to one another through a transmission optical path with two output ports of two output ports, the polarization beam apparatus Routing polarization maintaining optical fibre is formed, and the slow axis and fast axle of the polarization maintaining optical fibre keep inputting respectively two of the light pulse of the polarization maintaining optical fibre Orthogonal polarisation state stablizes transmission --- and i.e. polarization state is constant, and two output ports of the polarization beam apparatus and the polarization maintaining optical fibre structure Cause so that, by the polarization beam apparatus two output ports export light pulse be all coupled to the polarization maintaining optical fibre slow axis carry out The fast axle for transmitting or being all coupled to the polarization maintaining optical fibre is transmitted.Here, it is exported by two output ports of the polarization beam apparatus Light pulse be all coupled to the polarization maintaining optical fibre slow axis transmitted or be all coupled to the polarization maintaining optical fibre fast axle carry out transmission can It turn 90 degrees or reverses (90+n*180) degree by polarization maintaining optical fibre torsion to realize, wherein n is integer.No matter polarization maintaining optical fibre torsion or It does not reverse, the light pulse inputted from the slow axis of polarization maintaining optical fibre (is stablized along slow axis and transmitted) along slow axis transmission always, from polarization-maintaining The light pulse of the fast axle input of optical fiber (is stablized along fast axle and is transmitted) along fast axle transmission always.Polarized orthogonal with construction 2 Rotary reflection device, can be by coupling the input port of its polarization beam apparatus to when for phase codec of the invention The reflection unit is couple the arm by one arm of phase codec.
According to construction 3, polarized orthogonal rotary reflection device includes polarization beam apparatus, which has input port , the transmission light optically coupled to one another through a transmission optical path with two output ports of two output ports, the polarization beam apparatus Routing is formed comprising the polarization maintaining optical fibre of 90 degree of fusion points of odd number, and each 90 degree of fusion points are by polarization maintaining optical fibre slow axis and polarization maintaining optical fibre Fast axle alignment welding forms.With construction 3 polarized orthogonal rotary reflection device when for phase codec of the invention, It can be coupled the reflection unit to by an arm for coupleeing phase codec for the input port of its polarization beam apparatus The arm.
According to construction 4, polarized orthogonal rotary reflection device includes: with first port, second port, third port and the The polarization beam apparatus of four ports;With the reflection unit of the third port optical coupling of the polarization beam apparatus;And phase-modulator, The second port of the polarization beam apparatus and the 4th port pass through the first transmission optical path optical coupling, the third of the polarization beam apparatus Port is coupled to the reflection unit by the second transmission optical path, and the phase-modulator setting is in the first transmission optical path On, the reflection unit is quarter-wave plate reflecting mirror." quarter-wave plate reflecting mirror " includes reflecting mirror and a quarter Wave plate, the reflecting mirror are integrally formed in the quarter-wave plate rear end with the quarter-wave plate, wherein input should The angle of the polarization direction of the light pulse of quarter-wave plate and the fast axle of the quarter-wave plate or slow axis is 45 degree.Four/ One wave plate reflecting mirror can be by plating reflecting mirror realization in quarter-wave plate plane of crystal, also can be by transmitting phase in fast and slow axis 90 degree of phase difference of polarization maintaining optical fibre end face plating reflecting mirror is realized.First transmission optical path can be polarization maintaining optical fibre optical path;Second transmission Optical path can be polarization maintaining optical fibre optical path, and form the slow axis and the quarter-wave plate of the polarization maintaining optical fibre of the second transmission optical path Slow axis or fast axle angle are 45 degree.Polarized orthogonal rotary reflection device with construction 4 is for phase encoding and decoding of the invention It, can be by coupling the first port of its polarization beam apparatus on an arm of phase codec for the reflection unit coupling when device It is bonded to the arm.
For the polarized orthogonal rotary reflection device of any configuration in above-mentioned construction 1, construction 2 and construction 3, polarized orthogonal rotation Turn to be inserted with a phase-modulator in the transmission optical path between two output ports of polarization beam apparatus in reflection unit.
Return to the phase codec of Fig. 1, at least one of reflection unit 102 and 103 can for using above-mentioned construction 1, The polarized orthogonal rotary reflection device of one of construction 2, construction 3 and construction 4.A reflection in reflection unit 102 and 103 When device is the polarized orthogonal rotary reflection device using one of above-mentioned construction 1, construction 2, construction 3 and construction 4, another is anti- Injection device can be the polarized orthogonal rotary reflection device for using one of above-mentioned construction 1, construction 2, construction 3 and construction 4, can also Think the polarized orthogonal rotary reflection device of other constructions.The polarized orthogonal rotary reflection device of other constructions can be example Such as quarter-wave plate reflecting mirror.
One or two of reflection unit 102 and 103 may include phase-modulator.For example, in 102 He of reflection unit When only one reflection unit in 103 is the polarized orthogonal rotary reflection device using above-mentioned construction 4, reflection unit 102 and 103 In another reflection unit can be for using the polarized orthogonal rotary reflection of above-mentioned construction 1, construction 2 and construction one of 3 dress It sets, and another reflection unit may include or not comprising another in phase-modulator or reflection unit 102 and 103 A reflection unit can be for using the polarized orthogonal rotary reflection device such as quarter-wave plate reflecting mirror of other constructions.Again Such as, two reflection units in reflection unit 102 and 103 can be to be filled using the polarized orthogonal rotary reflection of above-mentioned construction 4 It sets.For another example, two reflection units in reflection unit 102 and 103 are respectively using any in above-mentioned construction 1, construction 2 and construction 3 Polarized orthogonal rotary reflection device when, one or two of the two reflection units may include phase-modulator.
It, can be by adjusting the length of two arms and/or adjusting two reflection units for the phase codec of Fig. 1 Using the transmission in one or two reflection unit of the construction selected from construction 1, construction 2, construction 3 and construction 4 in 102 and 103 Optical path realizes the relative time delay of above-mentioned two-way light pulse.
In the case where reflection unit uses selected from construction 1, construction 2, construction 3 and constructs 4 construction, phase can be compiled Two arms of decoder are configured to polarization and keep optical path, and configure polarization for the optical device on described two arms and keep optical device And/or non-birefringent optical device.In this way, every light pulse all the way in the two-way light pulse obtained for beam splitting: this can be kept Two orthogonal polarisation states of road light pulse are remained unchanged in beam splitter beam splitting to during the reflection of corresponding reflection unit, and in the phase It answers reflection unit to reflex to during the beam splitter closes beam to remain unchanged.In general, polarization keeps optical path to can be free space optical Road or polarization maintaining optical fibre optical path.Herein, " non-birefringent optical device " refers to for different polarization states (for example, two orthogonal inclined Polarization state) optical device with identical refractive index.In addition, polarization keeps optical device to be alternatively referred to as polarization-maintaining optical device.
In addition, the beam splitter 101 of phase codec can be polarization-maintaining beam splitter.
Fig. 2 shows a kind of polarized orthogonal rotations with phase-modulation function of phase codec for use in the present invention Turn the composed structure schematic diagram of reflection unit.
Polarized orthogonal rotary reflection device shown in Fig. 2 with phase-modulation function includes consisting of part: polarization Beam splitter 202, quarter-wave plate reflecting mirror 203, phase-modulator 204.
Polarization beam apparatus 202 includes port A, port B, port C and port D, and port A, port B, port C and port D can It is referred to as first port, second port, third port and the 4th port.The port 201 of 202 side of polarization beam apparatus, namely Port A is the input terminal and output end of device.The port E phase of the port B of polarization beam apparatus 202 and 204 side of phase-modulator Even, the port D of polarization beam apparatus 202 is connected with the port F of 204 other side of phase-modulator;That is, phase-modulator 204 is located at In the transmission optical path for connecting the port B and port D of polarization beam apparatus 202.The port C and quarter-wave of polarization beam apparatus 202 Piece reflecting mirror 203 is connected.Quarter-wave plate reflecting mirror 203 can be real by plating reflecting mirror in quarter-wave plate plane of crystal It is existing, also reflecting mirror realization can be plated by transmitting 90 degree of phase phase difference of polarization maintaining optical fibre end face in fast and slow axis.Phase-modulator 204 is Single polarization phase modulator or birefringent phase modulator.By the end of the port B of polarization beam apparatus 202 and phase-modulator 204 The transmission optical path of mouthful E connection, the transmission optical path for connecting the port D of polarization beam apparatus 202 with the port F of phase-modulator 204, The transmission optical path that the port C of polarization beam apparatus 202 is connect with quarter-wave plate reflecting mirror 203 is that polarization keeps optical path for example Polarization maintaining optical fibre keeps the polarization state (consistent with two orthogonal polarization eigen states of polarization beam apparatus) of the light pulse through its transmission no Become.
When work, input optical pulse is inputted by port 201 through the port A of polarization beam apparatus 202, and by polarization beam apparatus 202 polarization beam splittings are the mutually orthogonal first via light pulse and the second tunnel light pulse of polarization state.First via light pulse is by polarization point The port B of beam device 202 is exported and after the port E input phase modulator 204 of phase modulated device 204 progress phase-modulation by phase The port F output of position modulator 204.The first via light pulse exported from the port F of phase-modulator 204 is by polarization beam apparatus 202 port D input polarization beam splitter 202, and exported by the port C of polarization beam apparatus 202 to quarter-wave plate reflecting mirror 203.The first via light pulse for inputting it is reflected back polarization beam apparatus 202 and is divided by polarization by quarter-wave plate reflecting mirror 203 The port A of beam device 202 is exported.Second tunnel light pulse is exported by the port C of polarization beam apparatus 202 to quarter-wave plate reflecting mirror 203, the second tunnel light pulse for inputting it is reflected back polarization beam apparatus 202 and is divided by polarization by quarter-wave plate reflecting mirror 203 The port D of beam device 202 is exported.The phase modulated device 204 of the second tunnel light pulse exported from the port D of polarization beam apparatus 202 Port F input phase modulator 204 is exported after carrying out phase-modulation by the port E of phase-modulator 204.From phase-modulator Second tunnel light pulse of 204 port E output is by the port B input polarization beam splitter 202 of polarization beam apparatus 202 and by polarization point The port A of beam device 202 is exported.Each of first via light pulse and the second tunnel light pulse are through quarter-wave plate reflecting mirror 203 Reflection retrodeviates polarization state and is transformed to orthogonal to that polarization state.Phase-modulator 204 is to first via light pulse and the second tunnel light pulse Carry out identical phase-modulation.Advantageously, the first via light pulse obtained by 202 polarization beam splitting of polarization beam apparatus is from polarization beam splitting Device 202 is transmitted to time of phase-modulator 204 and the second tunnel pulse for being obtained by 202 polarization beam splitting of polarization beam apparatus from polarization The time that beam splitter 202 is transmitted to phase-modulator 204 is identical, i.e., the first via obtained by 202 polarization beam splitting of polarization beam apparatus Light pulse and the second tunnel light pulse reach phase-modulator 204 simultaneously --- in this case, the modulation of phase-modulator 204 one It is secondary to complete identical phase-modulation to first via light pulse and the second tunnel light pulse.By the polarization point of polarization beam apparatus 202 The first via light pulse and the second tunnel light pulse that beam obtains do not reach simultaneously phase-modulator 204 be also it is possible, only at this In the case of kind, the needs of phase-modulator 204 are respectively modulated first via light pulse and the second tunnel light pulse and adjust to them The phase of system need to keep identical.
The another kind that Fig. 3 shows phase codec for use in the present invention has the polarized orthogonal of phase-modulation function The composed structure schematic diagram of rotary reflection device.
Polarized orthogonal rotary reflection device shown in Fig. 3 with phase-modulation function includes consisting of part: polarization Beam splitter 302, polarization maintaining optical fibre 303, phase-modulator 304.
Polarization beam apparatus 302 includes port A, port B, tri- ports port C.Port A, port B, port C can claim respectively For input port, the first output port, second output terminal mouth.The a port 301 namely port A of polarization beam apparatus 302 are made For the input port and output port of device.The port B and port C of polarization beam apparatus 302 are connected by polarization maintaining optical fibre 303.By The light pulse of port B and port the C output of polarization beam apparatus 302 is all coupled to the slow axis transmission of polarization maintaining optical fibre 303 or couples Fast axle to the polarization maintaining optical fibre is transmitted.The polarization-maintaining of the port B and port C of the insertion connection polarization beam apparatus 302 of phase-modulator 304 In the optical path of optical fiber 303.
When work, port A input polarization beam splitter 302 of the input optical pulse through port 301 namely polarization beam apparatus 302. Input optical pulse is considered as being made of two orthogonal polarisation states, and described two orthogonal polarisation states can be denoted as x-polarisation state and y respectively Polarization state.Polarization beam apparatus 302 is by the of first via light pulse and y-polarisation state that input optical pulse polarization beam splitting is x-polarisation state Two tunnel light pulses, to be exported respectively by the port B of polarization beam apparatus 302 and port C.It is exported by the port B of polarization beam apparatus 302 The first via light pulse of x-polarisation state be coupled to the slow axis transmission of polarization maintaining optical fibre 303, and it is defeated by the port D of phase-modulator 304 Applying aspect modulator 304 carries out phase-modulation.First via light pulse after phase modulated by phase-modulator 304 port E The port C of polarization beam apparatus 302 is exported and is transmitted to along the slow axis of polarization maintaining optical fibre 303, first via light pulse is by protecting at the C of port The slow axis of polarisation fibre 303 is coupled to polarization beam apparatus 302, is coupled to the first via light pulse of the port C of polarization beam apparatus 302 Polarization state is y-polarisation state;The first via light pulse of y-polarisation state is exported by the port A of polarization beam apparatus 302.Namely it realizes by holding The x-polarisation state component of the input optical pulse of mouth A input is transformed to y-polarisation state when being exported after being reflected by reflection unit by port A. The slow axis transmission of polarization maintaining optical fibre 303 is coupled to by the second tunnel light pulse of the port C of the polarization beam apparatus 302 y-polarisation state exported, And phase-modulation is carried out by the port E input phase modulator 304 of phase-modulator 304.The second road light after phase modulated Pulse is transmitted to the port of polarization beam apparatus 302 by the port D output of phase-modulator 304 and along the slow axis of polarization maintaining optical fibre 303 B, the second tunnel light pulse is coupled to polarization beam apparatus 302 by the slow axis of polarization maintaining optical fibre 303 at the B of port, is coupled to polarization beam splitting The polarization state of the second tunnel light pulse of the port B of device 302 is x-polarisation state;Second tunnel light pulse of x-polarisation state is by polarization beam apparatus 302 port A output.Namely it realizes by the y-polarisation state component of the port A input optical pulse inputted after being reflected by reflection unit X-polarisation state is transformed to when being exported by port A.It is defeated by the first via light pulse of port D input phase modulator 304 and by port E Second tunnel light pulse of applying aspect modulator 304 is with identical polarization state input phase modulator 304 and is subjected to identical phase Modulation is realized and polarizes unrelated phase-modulation.And when two orthogonal polarisation states of input optical pulse reflect output by reflection unit Each orthogonal polarisation state is transformed to orthogonal to that polarization state.Using above-mentioned polarization maintaining optical fibre 303 to two orthogonal polarisation states Make polarized orthogonal rotation, so that the y-polarisation of phase and output optical pulse between the x-polarisation state and y-polarisation state of input optical pulse Phase between state and x-polarisation state keeps identical.
Phase-modulator 304 can be birefringent phase modulator or single polarization phase modulator.
The port B and port C of polarization beam apparatus 302 can be all coupled to the fast axle of polarization maintaining optical fibre 303, and the above results are not at this time It is impacted.
The another kind that Fig. 4 shows phase codec for use in the present invention has the polarized orthogonal of phase-modulation function The composed structure schematic diagram of rotary reflection device.
Polarized orthogonal rotary reflection device shown in Fig. 4 with phase-modulation function includes consisting of part: polarization Beam splitter 402, polarization maintaining optical fibre 403, phase-modulator 404 and 90 degree of fusion points 405.
Polarization beam apparatus 402 includes port A, port B, tri- ports port C.Port A, port B, port C can claim respectively For input port, the first output port, second output terminal mouth.The a port 401 namely port A of polarization beam apparatus 402 are made For the input port and output port of device.The port B and port C of polarization beam apparatus 402 are connected by polarization maintaining optical fibre 403.By The light pulse of the port B output of polarization beam apparatus 402 is coupled to the slow axis of polarization maintaining optical fibre 403 and by the end of polarization beam apparatus 402 The light pulse of mouth C output is coupled to the fast axle of polarization maintaining optical fibre 403, or the light pulse exported by the port B of polarization beam apparatus 402 It is coupled to the fast axle of polarization maintaining optical fibre 403 and polarization maintaining optical fibre 403 is coupled to by the light pulse that the port C of polarization beam apparatus 402 is exported Slow axis.Polarization maintaining optical fibre 403 includes 90 degree of fusion points, 405,90 degree of fusion points 405 by polarization maintaining optical fibre slow axis and polarization maintaining optical fibre fast axle Alignment welding forms.The polarization maintaining optical fibre 403 of the port B and port C of the insertion connection polarization beam apparatus 402 of phase-modulator 404 In optical path.
When work, port A input polarization beam splitter 402 of the input optical pulse through port 401 namely polarization beam apparatus 402. Input optical pulse is considered as being made of two orthogonal polarisation states, and described two orthogonal polarisation states can be denoted as x-polarisation state and y respectively Polarization state.Polarization beam apparatus 402 is by the of first via light pulse and y-polarisation state that input optical pulse polarization beam splitting is x-polarisation state Two tunnel light pulses, to be exported respectively by the port B of polarization beam apparatus 402 and port C.It is exported by the port B of polarization beam apparatus 402 The first via light pulse of x-polarisation state be coupled to the slow axis transmission of polarization maintaining optical fibre 403, and it is defeated by the port D of phase-modulator 404 Applying aspect modulator 404 carries out phase-modulation.First via light pulse after phase modulated by phase-modulator 404 port E It exports and is transmitted to 90 degree of fusion points 405 along the slow axis of polarization maintaining optical fibre 403, along polarization maintaining optical fibre 403 after 90 degree of fusion points 405 Fast axle is transmitted to the port C of polarization beam apparatus 402, and first via light pulse is coupled to by the fast axle of polarization maintaining optical fibre 403 at the C of port Polarization beam apparatus 402;The polarization state for being coupled to the first via light pulse of the port C of polarization beam apparatus 402 is y-polarisation state, y-polarisation The first via light pulse of state is exported by the port A of polarization beam apparatus 402.Namely realization is by the x of the port A input optical pulse inputted Polarization state component is transformed to y-polarisation state when being exported after being reflected by device by port A.It is exported by the port C of polarization beam apparatus 402 Y-polarisation state the second tunnel light pulse be coupled to polarization maintaining optical fibre 403 fast axle transmission, and along the fast axle of polarization maintaining optical fibre 403 transmit To 90 degree of fusion points 405, the slow axis after 90 degree of fusion points 405 along polarization maintaining optical fibre 403 is transmitted to the port of phase-modulator 404 E, and phase-modulation is carried out by the port E input phase modulator 404 of phase-modulator 404.The second tunnel after phase modulated Light pulse is transmitted to the end of polarization beam apparatus 402 by the port D output of phase-modulator 404 and along the slow axis of polarization maintaining optical fibre 403 Mouth B, the second tunnel light pulse is coupled to polarization beam apparatus 402 by the slow axis of polarization maintaining optical fibre 403 at the B of port;It is coupled to polarization point The polarization state of the second tunnel light pulse of the port B of beam device 402 is x-polarisation state, and the second tunnel light pulse of x-polarisation state is by polarization beam splitting The port A of device 402 is exported.Namely realize by the y-polarisation state component of the port A input optical pulse inputted after being reflected by device by Port A is transformed to x-polarisation state when exporting.
First via light pulse by port D input phase modulator 404 and by port E input phase modulator 404 Two tunnel light pulses are with identical polarization state input phase modulator 404 and are subjected to identical phase-modulation, realize and polarize unrelated phase Position modulation.Two orthogonal polarisation states of input optical pulse reflected by reflection unit each orthogonal polarisation state when exporting be transformed to Its orthogonal polarization state.
Although showing 90 degree of fusion points 405 of only one in Fig. 4, this is exemplary, and polarization maintaining optical fibre 403 can wrap Containing 90 degree of fusion points of arbitrary odd number.Each 90 degree of fusion points welding is directed at polarization maintaining optical fibre fast axle by polarization maintaining optical fibre slow axis and At.Polarization maintaining optical fibre 403 include more than one 90 degree of fusion points of odd number in the case where, the above results are unaffected, only by The first via light pulse and the second tunnel light pulse of port B and port the C output of polarization beam apparatus 402 are respectively along polarization maintaining optical fibre 403 It is transmitting along polarization maintaining optical fibre slow axis and is being converted between the transmission of polarization maintaining optical fibre fast axle more times when transmission, the number of transformation is equal to 90 Spend the number of fusion point.
Polarized orthogonal is made to two orthogonal polarisation states using the above-mentioned polarization maintaining optical fibre 403 comprising 90 degree of fusion points of odd number Rotation, so that the y-polarisation state and x-polarisation state of phase and output optical pulse between the x-polarisation state and y-polarisation state of input optical pulse Between phase keep it is identical.
Phase-modulator 404 can be birefringent phase modulator or single polarization phase modulator.
The port B of polarization beam apparatus 402 is coupled to the port C coupling of the fast axle of polarization maintaining optical fibre 403 and polarization beam apparatus 402 To polarization maintaining optical fibre 403 slow axis when, the above results are unaffected.
The position of phase-modulator 404 and 90 degree fusion point 405 and the order of connection change, and the above results are unaffected.
The another kind that Fig. 5 shows phase codec for use in the present invention has the polarized orthogonal of phase-modulation function The composed structure schematic diagram of rotary reflection device.
Polarized orthogonal rotary reflection device shown in fig. 5 with phase-modulation function includes consisting of part: polarization Beam splitter 502, phase-modulator 503, half-wave plate 504.
Polarization beam apparatus 502 includes port A, port B, tri- ports port C.Port A, port B, port C can claim respectively For input port, the first output port, second output terminal mouth.The a port 501 namely port A of polarization beam apparatus 502 are made For the input port and output port of device.The port B and port C of polarization beam apparatus 502 are connected by transmitting optical path;More specifically Ground, the port B of polarization beam apparatus 502 are connect by transmitting optical path with the port D of phase-modulator 503, phase-modulator 503 Port E is connect by transmitting optical path with half-wave plate 504, the port C that half-wave plate 504 passes through transmission optical path and polarization beam apparatus 502 Connection.Transmission optical path, phase-modulator 503 between the port B of polarization beam apparatus 502 and the port D of phase-modulator 503 Transmission optical path between transmission optical path, half-wave plate 504 between port E and half-wave plate 504 and the port C of polarization beam apparatus 502 It is that polarization keeps optical path, such as polarization maintaining optical fibre optical path.By the light pulse of the port input half-wave plate 504 of 504 two sides of half-wave plate The polarization direction of polarization state and the angle of the slow axis of half-wave plate 504 or fast axle be 45 degree.
When work, port A input polarization beam splitter 502 of the input optical pulse through port 501 namely polarization beam apparatus 502. Input optical pulse is considered as being made of two orthogonal polarisation states, and described two orthogonal polarisation states can be denoted as x-polarisation state and y respectively Polarization state.Polarization beam apparatus 502 is by the of first via light pulse and y-polarisation state that input optical pulse polarization beam splitting is x-polarisation state Two tunnel light pulses, to be exported respectively by the port B of polarization beam apparatus 502 and port C.It is exported by the port B of polarization beam apparatus 502 X-polarisation state first via optical pulse propagation to phase-modulator 503, modulated by the port D input phase of phase-modulator 503 Device 503 is simultaneously subjected to phase-modulation.First via light pulse after phase modulated is exported by the port E of phase-modulator 503 to half Wave plate 504.After half-wave plate 504 carries out polarized orthogonal rotation, it is inclined that polarization state by x-polarisation state is transformed to y for first via light pulse Polarization state.The first via optical pulse propagation of the y-polarisation state exported by half-wave plate 504 to polarization beam apparatus 502 port C, by polarizing The port C input polarization beam splitter 502 of beam splitter 502, and exported by the port A of polarization beam apparatus 502.In this way, realizing by holding The x-polarisation state component of the input optical pulse of mouth A input is transformed to y-polarisation state when being exported after being reflected by device by port A.By inclined Second tunnel optical pulse propagation of the y-polarisation state of the port C output of vibration beam splitter 502 is made partially to half-wave plate 504 through half-wave plate 504 The orthogonal postrotational second tunnel light pulse polarization conversion that shakes is x-polarisation state.By the second of the x-polarisation state that half-wave plate 504 exports Road optical pulse propagation to phase-modulator 503 port E, by phase-modulator 503 port E input phase modulator 503 simultaneously It is subjected to phase-modulation.The second tunnel light pulse after phase modulated is exported by the port D of phase-modulator 503 to polarization beam apparatus 502 port B, by the port B input polarization beam splitter 502 of polarization beam apparatus 502, and it is defeated by the port A of polarization beam apparatus 502 Out.Time-varying is exported by port A after being reflected by device by the y-polarisation state component of the port A input optical pulse inputted in this way, realizing It is changed to x-polarisation state.Polarized orthogonal rotation is made to two orthogonal polarisation states using half-wave plate 504, so that the x-polarisation of input optical pulse Phase between state and y-polarisation state is identical as the phase holding between the y-polarisation state of output optical pulse and x-polarisation state.
First via light pulse by port D input phase modulator 503 and by port E input phase modulator 503 Two tunnel light pulses are with identical polarization state input phase modulator 503 and are subjected to identical phase-modulation, realize and polarize unrelated phase Position modulation.Two orthogonal polarisation states of input optical pulse reflected by reflection unit each orthogonal polarisation state when exporting be transformed to Its orthogonal polarization state.
Phase-modulator 503 can be birefringent phase modulator or single polarization phase modulator.
The position and the order of connection of phase-modulator 503 and half-wave plate 504 change, and the above results are unaffected.
Phase codec of the invention, such as phase codec described above and back are referring to Fig. 9 description Phase codec can be used as the component part of HVDC Modulation quantum key distribution phase coding and decoding device, it is close to can be used as quantum Key distributes time bit-phase coding and decoding device component part, it is also possible to make HVDC Modulation quantum key distribution time bit- The component part of phase coding and decoding device.
Utilize a kind of HVDC Modulation quantum key based on polarized orthogonal rotary reflection of phase codec of the invention Distribute phase coding and decoding device as shown in fig. 6, include consisting of part: preposition beam splitter 603, optical circulator 604 and 610, Polarization-maintaining beam splitter 605 and 611 and polarized orthogonal rotary reflection device 606,607,612 and 613 (are hereafter also referred to as anti- Injection device 606,607,612 and 613).
605, two reflection units 606 and 607 of polarization-maintaining beam splitter and polarization-maintaining beam splitter 605 and the two reflection units it Between two arms form the first polarization-maintaining unequal arm Michelson's interferometer, i.e., first phase codec according to the present invention.The Two arms of one phase codec are polarization maintaining optical fibre optical path.At least one of reflection unit 606 and 607 includes direct current phase tune Device processed.
Similarly, 611, two reflection units 612 and 613 of polarization-maintaining beam splitter and polarization-maintaining beam splitter 611 are anti-with the two Two arms between injection device form the second polarization-maintaining unequal arm Michelson's interferometer, i.e., second phase according to the present invention compiles solution Code device.Two arms of second phase codec are polarization maintaining optical fibre optical path.At least one of reflection unit 612 and 613 includes straight Flow phase-modulator.
In the following, by the coding and decoding device of Fig. 6 for carrying out example description to it for being decoded.
Input port of one of two ports 601 and 602 of preposition 603 side of beam splitter as device.Optical circulator 604 First port A and second port B be separately connected preposition beam splitter 603 an output port and polarization-maintaining beam splitter 605 one A input port.By an output port 608 of polarization-maintaining beam splitter 605 after the light pulse decoding of input first phase codec Output, or the transmission of another output port (that is, one input port of polarization-maintaining beam splitter 605) through polarization-maintaining beam splitter 605 Second port B to optical circulator 604 and the third port C output from optical circulator 604.The first port A of optical circulator 610 The another output mouth of preposition beam splitter 603 and an input terminal of polarization-maintaining beam splitter 611 are separately connected with second port B Mouthful.It is exported after the light pulse decoding of input second phase codec by an output port 614 of polarization-maintaining beam splitter 611, or Another output port (that is, one input port of polarization-maintaining beam splitter 611) through polarization-maintaining beam splitter 611 is transmitted to ring of light shape The second port B of device 610 is simultaneously exported from the third port C of optical circulator 610.
When work, port 601 or 602 of the light pulse through beam splitter 603 is into beam splitter 603 and by 603 beam splitting of beam splitter For first via light pulse and the second tunnel light pulse.First via light pulse inputs and through the first port A of optical circulator 604 by the ring of light The second port B of shape device 604 is exported to polarization-maintaining beam splitter 605.The first via light pulse beam splitting of input is by polarization-maintaining beam splitter 605 Two-way the first sub-light pulse.All the way the first sub-light pulse through polarization maintaining optical fibre be transmitted to reflection unit 606 and by reflection unit 606 it is anti- It being emitted back towards and, another way the first sub-light pulse is transmitted to reflection unit 607 through polarization maintaining optical fibre and is reflected by reflection unit 607, The direct current phase-modulator in reflection unit 606 and/or 607 carries out direct current phase tune according to quantum key distribution agreement therebetween System.It is exported after polarization-maintaining beam splitter 605 closes beam by port 608 through reflected two-way the first sub-light pulse of relative time delay, Or be output to the second port B of optical circulator 604 and be transmitted to optical circulator 604 third port C it is defeated by port 609 Out.Second tunnel light pulse is inputted through the first port A of optical circulator 610 and is exported by the second port B of optical circulator 610 to guarantor Inclined beam splitter 611.Second tunnel light pulse beam splitting of input is the pulse of the second sub-light of two-way by polarization-maintaining beam splitter 611.All the way second Sub-light pulse is transmitted to reflection unit 612 through polarization maintaining optical fibre and is reflected by reflection unit 612, another way the second sub-light pulse Reflection unit 613 is transmitted to through polarization maintaining optical fibre and is reflected by reflection unit 613, therebetween in reflection unit 612 and/or 613 Direct current phase-modulator according to quantum key distribution agreement carry out direct current phase-modulation.Reflected two through relative time delay Road the second sub-light pulse is exported after polarization-maintaining beam splitter 611 closes beam by port 614, or is output to the of optical circulator 610 The Two-port netwerk B and third port C for being transmitted to optical circulator 610 is exported by port 615.Wherein, in reflection unit 606 and/or 607 Direct current phase-modulator carry out direct current phase-modulation and/or reflection unit 612 and/or 613 according to quantum key distribution agreement In direct current phase-modulator according to quantum key distribution agreement carry out direct current phase-modulation, lead to the first unequal arm Michelson A made direct current phase-modulation in interferometer and the second unequal arm Michelson's interferometer is relative to made by another Direct current phase-modulation differs 90 degree.
Next, by the coding and decoding device of Fig. 6 for carrying out example description to it for being encoded.
The a port 608 of polarization-maintaining beam splitter 605, the third port C of optical circulator 604, one of polarization-maintaining beam splitter 611 Port 614, optical circulator 610 input port of the third port C as device.The first port A of optical circulator 604 and second Port B is separately connected a port of preposition beam splitter 603 and another port of polarization-maintaining beam splitter 605.From optical circulator 604 Third port C input light pulse through optical circulator 604 second port B input first phase codec.From polarization-maintaining point The light pulse that one port 608 of beam device 605, the third port C of optical circulator 604 are inputted is through first phase codec The second port B to optical circulator 604 is exported by polarization-maintaining beam splitter 605 after coding and the first port A by optical circulator 604 is passed Transport to preposition beam splitter 603.The first port A and second port B of optical circulator 610 are separately connected the another of preposition beam splitter 603 Another port of a port and polarization-maintaining beam splitter 611.The light pulse inputted from the third port C of optical circulator 610 is through light The second port B of circulator 610 inputs second phase codec.From one port 614 of polarization-maintaining beam splitter 611, light The light pulse of the third port C input of circulator 610 is exported extremely after second phase codec coding by polarization-maintaining beam splitter 611 The second port B of optical circulator 610 is simultaneously transmitted to preposition beam splitter 603 by the first port A of optical circulator 610.Preposition beam splitting Output port of one of two ports 601 and 602 of 603 side of device (being left side in Fig. 6) as device.By polarization-maintaining beam splitter 605 one port 608, the third port C of optical circulator 604, one port 614 of polarization-maintaining beam splitter 611, light Four kinds of phase codes are realized respectively after the light pulse of the third port C input of circulator 610 is encoded, the light pulse warp after coding Beam splitter 603 is exported after closing beam by port 601 or 602.
Utilize a kind of quantum key distribution time based on polarized orthogonal rotary reflection of phase codec of the invention Bit-phase coding and decoding device is as shown in fig. 7, comprises consisting of part: beam splitter 703 and 704, polarization-maintaining beam splitter 707, with And polarized orthogonal rotary reflection device 708 and 709 (being hereafter also referred to as reflection unit 708 and reflection unit 709).
707, two reflection units 708 and 709 of polarization-maintaining beam splitter and polarization-maintaining beam splitter 707 and the two reflection units it Between two arms form polarization-maintaining unequal arm Michelson's interferometer, i.e., phase codec according to the present invention.Described two arms For polarization maintaining optical fibre optical path.At least one of reflection unit 708 and 709 includes phase-modulator.
In the following, by the coding and decoding device of Fig. 7 for carrying out example description to it for being decoded.
Beam splitter 703 is used as preposition beam splitter, input terminal of one of two ports 701 and 702 of one side as device Mouthful.Beam splitter 704 will be exported after the beam splitting of light pulse all the way from beam splitter 703 by port 705 or 706.Input polarization-maintaining differs It is exported after the light pulse of arm Michelson's interferometer is decoded by port 710.
When work, input optical pulse enters beam splitter 703 through the port 701 or 702 of beam splitter 703, and by beam splitter 703 It is divided into two-way light pulse to be transmitted.Light pulse all the way from beam splitter 703 is input to beam splitter 704, and by beam splitter 704 It exports after beam splitting through port 705 or 706 to realize that time bit decodes.Another way light pulse from beam splitter 703 is input to Polarization-maintaining beam splitter 707, and be the pulse of two-way sub-light by 707 beam splitting of polarization-maintaining beam splitter.Sub-light pulse all the way is transmitted through polarization maintaining optical fibre It is reflected to reflection unit 708 and by reflection unit 708, another way sub-light pulse is transmitted to reflection unit through polarization maintaining optical fibre It 709 and is reflected by reflection unit 709, the phase-modulator in reflection unit 708 and/or 709 is according to quantum key therebetween Distribution protocol carries out phase-modulation.Through the reflected two-way sub-light pulse of relative time delay after polarization-maintaining beam splitter 707 closes beam It is exported by port 710.
Here, it should be noted that beam splitter 704 is optional.It is by preposition beam splitter 703 that above-mentioned light pulse all the way is straight It is possible that output, which is connect, for carrying out the decoding of time bit.
Next, by the coding and decoding device of Fig. 7 for carrying out example description to it for being encoded.
The input port of the port 705 and 706 of beam splitter 704 and the port 710 of polarization-maintaining beam splitter 707 as device. Output realizes that time bit is compiled to preposition beam splitter 703 after the light pulse inputted from port 705 and 706 closes beam by beam splitter 704 Code.From port 710 input light pulse through polarization-maintaining unequal arm Michelson's interferometer coding after by polarization-maintaining beam splitter 707 output to Preposition beam splitter 703 realizes two kinds of phase codes by the phase-modulator in modulation reflection unit 708 and/or 709 therebetween. Output port of one of the port 701 and 702 of preposition beam splitter 703 as device.Beam splitter 703 will be exported by beam splitter 704 Light pulse and the light pulse that is exported by polarization-maintaining beam splitter 707 close beam after exported by port 701 or 702.
Beam splitter 704 is optionally, directly using the port of beam splitter 703 connecting with beam splitter 704 as input port It is possible for carrying out time bits of encoded.
Utilize a kind of HVDC Modulation quantum key based on polarized orthogonal rotary reflection of phase codec of the invention Distribute time bit-phase coding and decoding device as shown in figure 8, including consisting of part: beam splitter 803 and 804, optical circulator 807, polarization-maintaining beam splitter 808 and polarized orthogonal rotary reflection device 809 and polarized orthogonal rotary reflection device 810 be (hereafter also It is referred to as reflection unit 809 and reflection unit 810).
808, two reflection units 809 and 810 of polarization-maintaining beam splitter and polarization-maintaining beam splitter 808 and the two reflection units it Between two arms form polarization-maintaining unequal arm Michelson's interferometer, i.e., phase codec according to the present invention.Described two arms For polarization maintaining optical fibre optical path.At least one of reflection unit 809 and 810 includes direct current phase-modulator.
In the following, by the coding and decoding device of Fig. 8 for carrying out example description to it for being decoded.
Beam splitter 803 is used as preposition beam splitter, input terminal of one of two ports 801 and 802 of one side as device Mouthful.Beam splitter 804 will be exported after the beam splitting of light pulse all the way from beam splitter 803 by port 805 or 806.From optical circulator 807 First port A input light pulse by optical circulator 807 second port B export, from the second port B of optical circulator 807 The light pulse of input is exported by the third port C of optical circulator 807.Input the light pulse of polarization-maintaining unequal arm Michelson's interferometer It is exported after decoded by port 811, or another output port through polarization-maintaining beam splitter 808 is transmitted to the of optical circulator 807 Two-port netwerk B is simultaneously exported after the third port C of optical circulator 807 output by port 812.
When work, input optical pulse enters beam splitter 803 through the port 801 or 802 of beam splitter 803, and by beam splitter 803 Two-way light pulse is beamed into be transmitted.Light pulse all the way from beam splitter 803 is input to beam splitter 804, and by beam splitter It is exported by port 805 or 806 for carrying out time bit decoding after 804 beam splitting.Another way light pulse warp from beam splitter 803 The first port A of optical circulator 807 is inputted and is exported from the second port B of optical circulator 807 to polarization-maintaining beam splitter 808.Polarization-maintaining The another way light pulse beam splitting is the pulse of two-way sub-light by beam splitter 808.Sub-light pulse is transmitted to reflection through polarization maintaining optical fibre all the way Device 809 is simultaneously reflected by reflection unit 809, the pulse of another way sub-light through polarization maintaining optical fibre be transmitted to reflection unit 810 and by Reflection unit 810 reflects, and the direct current phase-modulator in reflection unit 809 and/or 810 is according to quantum key distribution therebetween Agreement carries out direct current phase-modulation.It is reflected through the two-way sub-light pulse of relative time delay through polarization-maintaining beam splitter 808 close beam after It is exported by port 811, or is transferred to the second port B of optical circulator 807 and defeated by the third port C of optical circulator 807 It is exported after out by port 812.
Here, it should be noted that beam splitter 804 is optional.It is by preposition beam splitter 803 that above-mentioned light pulse all the way is straight It is possible that output, which is connect, for carrying out the decoding of time bit.
Next, by the coding and decoding device of Fig. 8 for carrying out example description to it for being encoded.
The third of the port 805 and 806 of beam splitter 804, the port 811 of polarization-maintaining beam splitter 808 and optical circulator 807 Input port of the port C as device.The light pulse inputted from the third port C of optical circulator 807 is by the of optical circulator 807 Two-port netwerk B output, the light pulse inputted from the second port B of optical circulator 807 are exported by the first port A of optical circulator 807. Output realizes that time bit is compiled to preposition beam splitter 803 after the light pulse inputted from port 805 and 806 closes beam by beam splitter 804 Code.Light pulse from the input of port 811 and the third port C by optical circulator 807 are inputted and by the second of optical circulator 807 Port B is exported to the light pulse of polarization-maintaining beam splitter 808, by polarization-maintaining beam splitter after polarization-maintaining unequal arm Michelson's interferometer coding 808 output the second port B to optical circulator 807 and the first port A through optical circulator 807 be transmitted to preposition beam splitter 803. Two are realized respectively after the light pulse inputted by the third port C of the port 811 of polarization-maintaining beam splitter 808, optical circulator 807 is encoded Kind phase code.Output port of one of the port 801 and 802 of beam splitter 803 as device.Beam splitter 803 will be by beam splitter 804 output light pulses and from the first port A of optical circulator 807 export light pulse close beam after it is defeated by port 801 or 802 Out.
Beam splitter 804 is optionally, directly using the port of beam splitter 803 connecting with beam splitter 804 as input port It is possible for carrying out time bits of encoded.
A kind of phase codec of one embodiment of the present invention is as shown in figure 9, include consisting of part: polarization-maintaining point Beam device 903, polarized orthogonal rotary reflection device 904 and polarized orthogonal rotary reflection device 905 (are hereafter also referred to as reflection dress Set 904 and reflection unit 905).
Input port of one of two ports 901 and 902 of 903 side of polarization-maintaining beam splitter as phase codec.It protects Inclined beam splitter 903 constitutes unequal arm Michelson's interferometer with reflection unit 904 and 905, and two arms therebetween are polarization maintaining optical fibre Optical path.At least one of reflection unit 904 and reflection unit 905 include phase-modulator, such as can be for using above-mentioned construction 4 Polarized orthogonal rotary reflection device.The port 901 or 902 of polarization-maintaining beam splitter 903 can be used as the output end of phase codec Mouthful.
When work, light pulse enters polarization-maintaining beam splitter 903 through the port 901 or 902 of polarization-maintaining beam splitter 903 and is divided by polarization-maintaining Beam device 903 is divided into two-way light pulse.Light pulse all the way in this two-way light pulse is transmitted to reflection unit 904 simultaneously through polarization maintaining optical fibre It is reflected by reflection unit 904, another way light pulse through polarization maintaining optical fibre is transmitted to reflection unit 905 and by reflection unit 905 It reflects, the phase-modulator in reflection unit 904 and/or 905 carries out phase tune according to quantum key distribution agreement therebetween System.It is exported after polarization-maintaining beam splitter 903 closes beam by port 901 or 902 through the reflected two-way light pulse of relative time delay.
In the case where one of the input port of polarization-maintaining beam splitter 903 and output port are same port, phase encoding and decoding Device can also include optical circulator.The optical circulator can be located at 903 front end of polarization-maintaining beam splitter.The one of incident random polarization state Road input optical pulse can be inputted from the first port of optical circulator and be exported from the second port of optical circulator to polarization-maintaining beam splitter 903, the conjunction beam output from polarization-maintaining beam splitter 903 is input to the second port of optical circulator and the third end from optical circulator Mouth output.
Herein, term " beam splitter " and " bundling device " are used interchangeably, and beam splitter is also referred to as and as bundling device, instead .Herein, " polarization maintaining optical fibre optical path " refers to the optical path or polarization maintaining optical fibre connection shape using polarization maintaining optical fibre transmission light pulse At optical path.
As described above of the invention can be configured in the receiving end of quantum key distribution system to revolve based on polarized orthogonal The phase codec or corresponding coding and decoding device for turning reflection, for decoding.Alternatively, it is also possible in quantum key distribution system Phase codec of as described above of the invention of transmitting terminal configuration based on polarized orthogonal rotary reflection or corresponding compile Decoding apparatus, for encoding.
By the explanation of specific embodiment, the present invention can should be reached technological means that predetermined purpose is taken and Effect, which has, more deeply and specifically to be understood, however appended diagram is only to provide reference and description and is used, and is not used to this hair It is bright to limit.

Claims (10)

1. a kind of quantum key distribution phase codec, comprising: beam splitter, respectively through two arms and the beam splitter optical coupling Two polarized orthogonal rotary reflection devices, wherein one of described two polarized orthogonal rotary reflection devices or it is each it is described partially The orthogonal rotary reflection device that shakes includes having first port, second port, third port and the polarization beam apparatus of the 4th port, four / mono- wave plate reflecting mirror and phase-modulator, and the first port through the polarization beam apparatus is coupled in described two arms Respective arms, the second port of the polarization beam apparatus and the 4th port pass through the first transmission optical path optical coupling, the phase tune In the first transmission optical path, the third port of the polarization beam apparatus is coupled to institute by the second transmission optical path for device setting processed State quarter-wave plate reflecting mirror, the quarter-wave plate reflecting mirror includes quarter-wave plate and in the quarter-wave The reflecting mirror that piece rear end and the quarter-wave plate are integrally formed, wherein input the light pulse of the quarter-wave plate The angle of the fast axle or slow axis of polarization direction and the quarter-wave plate is 45 degree.
2. phase codec according to claim 1, wherein described two polarized orthogonal rotary reflection devices are identical The polarized orthogonal rotary reflection device of construction, or the polarized orthogonal rotary reflection device for different configuration.
3. phase codec according to claim 1, wherein the first transmission optical path and/or second transmission Optical path is that polarization keeps optical path.
4. phase codec according to claim 1, wherein the beam splitter is polarization-maintaining beam splitter.
5. phase codec according to claim 1, wherein described two arms are respectively to polarize to keep optical path, described two Optical device on a arm is that polarization keeps optical device and/or non-birefringent optical device.
6. a kind of HVDC Modulation quantum key distribution phase coding and decoding device, including preposition beam splitter and two are according to claim Phase codec described in any one of 1-5, two phase codecs are optically coupled to institute through two strip optical paths respectively Preposition beam splitter is stated, wherein be not coupled to the phase codec described two of the beam splitter of each phase codec One of the port of a arm is optically coupled to the corresponding sub-light road in the two strips optical path, and every sub-light road is provided with one Optical circulator, wherein the phase-modulator is direct current phase-modulator.
7. a kind of quantum key distribution time bit-phase coding and decoding device, including preposition beam splitter and one want according to right Phase codec described in any one of 1-5 is sought, the phase codec is optically coupled to described preposition through a strip optical path Beam splitter, wherein one of the port for not being coupled to described two arms of the beam splitter of the phase codec be optically coupled to it is described One strip optical path.
8. a kind of HVDC Modulation quantum key distribution time bit-phase coding and decoding device, including preposition beam splitter and a root According to phase codec of any of claims 1-5, the phase codec is optically coupled to through a strip optical path The preposition beam splitter, wherein one of port for not being coupled to described two arms of beam splitter of phase codec optocoupler It is bonded to the strip optical path, wherein being provided with an optical circulator in the strip optical path, the phase-modulator is straight Flow phase-modulator.
9. coding and decoding device according to claim 7 or 8 further includes being coupled to the preposition beam splitting through another strip optical path The beam splitter of device.
10. a kind of quantum key distribution system, comprising:
Phase codec according to any one of claims 1 to 5 or according to any one of claim 6~9 Coding and decoding device, the receiving end of the quantum key distribution system is set, for decoding;And/or
Phase codec according to any one of claims 1 to 5 or according to any one of claim 6~9 Coding and decoding device, the transmitting terminal of the quantum key distribution system is set, for encoding.
CN201910176940.9A 2019-03-08 2019-03-08 Quantum key distribution phase codec, corresponding codec device and system Active CN110460428B (en)

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