CN209151179U - HVDC Modulation quantum key distribution phase decoding device and corresponding system based on 90 degree of welding difference control - Google Patents

Abstract

A kind of HVDC Modulation quantum key distribution phase decoding device and corresponding system based on 90 degree of welding difference control.The phase decoding device includes: preposition beam splitter, first phase decoder and second phase decoder, and preposition beam splitter is used to the incident beam splitting of input optical pulse all the way be two-way light pulse.First phase decoder includes the first beam splitter, the first bundling device and two the first sub-light roads, at least one the first sub-light roads include at least one 90 degree of fusion point, second phase decoder includes the second beam splitter, the second bundling device and two the second sub-light roads, at least one the second sub-light roads include at least one 90 degree fusion point, and first phase decoder and/or second phase decoder have for the direct current phase-modulator to the sub-light pulse progress direct current phase-modulation through the sub- optic path where it.The phase decoding device of the utility model can resist polarization induction decline, suitable for there are the high speed quantum key distribution systems of environmental disturbances.

Description

HVDC Modulation quantum key distribution phase decoding dress based on 90 degree of welding difference control It sets and corresponding system

Technical field

The utility model relates to optical transport private communication technology fields, more particularly to a kind of differed based on 90 degree of weldings to control HVDC Modulation quantum key distribution phase decoding device and the quantum key distribution system including the device.

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 demand for security.

Currently, the encoding scheme of quantum key distribution mainly uses polarization encoder and phase code.Ground quantum key point Hair is based primarily upon fibre channel transmission, and there are the non-circular symmetrical, fiber core refractive index in section radially uneven distributions for optical fiber fabrication Equal non-idealities, and optical fiber is influenced by temperature, strain, bending etc. in the actual environment, can generate random birefringence effect. It when using polarization encoder, is influenced by optical fiber random birefringence, the quantum state of polarization encoder reaches after long-distance optical fiber transmits When receiving end, light pulse polarization state can occur to change at random, and the bit error rate is caused to increase, and result in the need for increasing correcting device, increase System complexity and cost, and stable application is difficult to realize for strong jammings situations such as aerial optical cable, road and bridge optical cables.Compared to inclined Vibration coding, the phase difference of phase code light pulse before and after is come encoded information, energy during long-distance optical fiber transmission Enough stablize keeps.However for phase encoding scheme, when interfering decoding, because transmission fiber and encoding and decoding interferometer optical fiber are two-fold There is polarization induction decline, cause decoding interference unstable in the influence penetrated.Equally, if increasing correcting device, although only It needs to rectify a deviation to a kind of polarization state, but also will increase system complexity and cost.For quantum key distribution phase code Scheme, how to carry out to stability and high efficiency interference decoding is that the heat of quantum secret communication application is carried out based on existing optical cable infrastructure Point and problem.

Utility model content

The main purpose of the utility model is that proposing a kind of based on 90 degree of welding difference control (alternatively referred to as " phase differences Control ") HVDC Modulation quantum key distribution phase decoding device and quantum key distribution system, to solve phase code quantum Phase decoding caused by polarization induction declines in key distribution application interferes unstable problem.

The utility model provides at least following technical scheme:

1. a kind of HVDC Modulation quantum key distribution phase decoding device based on 90 degree of welding difference control, feature exist In, the phase decoding device include: preposition beam splitter, with the first phase decoder of the preposition beam splitter optical coupling and the Two phase decoder, wherein

The preposition beam splitter is configured for the beam splitting of input optical pulse all the way of incident random polarization state being first Road light pulse and the second tunnel light pulse；

The first phase decoder is configured for carrying out phase decoding to the first via light pulse；And

The second phase decoder is configured for carrying out phase decoding to second tunnel light pulse,

Wherein, the first phase decoder include the first beam splitter, the first bundling device and with first beam splitter Optical coupling and two the first sub-light roads with the first bundling device optical coupling, wherein

First beam splitter is configured for the first via light pulse beam splitting being the pulse of the first sub-light of two-way；

At least one sub-light road in two first sub-light roads includes at least two sections of polarization maintaining optical fibres, and described two first Sub-light road is configured for transmitting the first sub-light of two-way pulse respectively, and for realizing the first sub-light of two-way pulse Relative time delay；

First bundling device is configured for closing two-way the first sub-light pulse into beam output,

Wherein, comprising by making one section of polarization-maintaining in at least one the first sub-light roads in two first sub-light roads The slow axis of optical fiber is directed at least one 90 degree of fusion point of welding formation with the fast axle of another section of polarization maintaining optical fibre,

Wherein in the first phase decoder, two first sub-light roads and optical device thereon are configured to control A polarization state in two orthogonal polarisation states of the first via light pulse is made during beam splitting to conjunction beam through described two The phase difference of the sub- optic path of item first makes two through the phase difference of two first sub- optic paths with another polarization state A phase difference differs the integral multiple of 2 π；

Wherein, the second phase decoder include the second beam splitter, the second bundling device and with second beam splitter Optical coupling and two the second sub-light roads with the second bundling device optical coupling, wherein

Second beam splitter is configured for the second tunnel light pulse beam splitting being the pulse of the second sub-light of two-way；

At least one sub-light road in two second sub-light roads includes at least two sections of polarization maintaining optical fibres, and described two second Sub-light road is configured for transmitting the second sub-light of two-way pulse respectively, and for realizing the second sub-light of two-way pulse Relative time delay；

Second bundling device is configured for closing two-way the second sub-light pulse into beam output,

Wherein, comprising by making one section of polarization-maintaining in at least one the second sub-light roads in two second sub-light roads The slow axis of optical fiber is directed at least one 90 degree of fusion point of welding formation with the fast axle of another section of polarization maintaining optical fibre,

Wherein in the second phase decoder, two second sub-light roads and optical device thereon are configured to, The polarization state controlled in two orthogonal polarisation states of second tunnel light pulse is described to passing through during closing beam in beam splitting The phase difference of two the second sub- optic paths makes with another polarization state through the phase difference of two second sub- optic paths Two phase differences differ the integral multiple of 2 π,

Wherein the first phase decoder has the direct current phase being located at least one of described two first sub-light roads Position modulator and/or the second phase decoder have the direct current being located at least one of described two second sub-light roads Phase-modulator, the direct current phase-modulator are used for the sub-light pulse through the sub- optic path where it according to quantum key Distribution protocol carries out direct current phase-modulation.

2. the HVDC Modulation quantum key distribution phase decoding dress according to scheme 1 based on 90 degree of welding difference control It sets, which is characterized in that

Two first sub-light roads and optical device thereon are further constructed to, and control one of the polarization maintaining optical fibre What polarization eigen state was transmitted when transmitting on a first sub-light road in two first sub-light roads through polarization maintaining optical fibre fast axle The first distance of distance and the distance through slow axis transmission is poor and the polarization eigen state is another in two first sub-light roads The second range difference of distance and the distance through slow axis transmission that one the first sub-light road is transmitted when transmitting through polarization maintaining optical fibre fast axle, So that the integral multiple of first distance difference and second range difference difference beat length of polarization maintaining optical fiber；And/or

Two second sub-light roads and optical device thereon are further constructed to, and control one of the polarization maintaining optical fibre What polarization eigen state was transmitted when transmitting on a second sub-light road in two second sub-light roads through polarization maintaining optical fibre fast axle The third range difference and the polarization eigen state of distance and the distance through slow axis transmission are another in two second sub-light roads 4th range difference of distance and the distance through slow axis transmission that one article of second sub-light road is transmitted when transmitting through polarization maintaining optical fibre fast axle, So that the integral multiple of third range difference and the 4th range difference difference beat length of polarization maintaining optical fiber.

3. the HVDC Modulation quantum key distribution phase solution based on 90 degree of welding difference control according to scheme 1 or 2 Code device, which is characterized in that

Two first sub-light roads include 90 degree of fusion points, and each fusion point is located at place the first sub-light road Midpoint；And/or

Two second sub-light roads include 90 degree of fusion points, and each fusion point is located at place the second sub-light road Midpoint.

4. the HVDC Modulation quantum key distribution phase decoding dress according to scheme 1 based on 90 degree of welding difference control It sets, which is characterized in that the phase decoding device further include:

First polarization maintaining optical fibre stretcher of any first sub-light road in two first sub-light roads, and/or First birefringent phase modulator of any first sub-light road in two first sub-light roads, first polarization-maintaining Fiber stretcher is used to adjust the polarization maintaining optical fibre length of the optical path where it, and the first birefringent phase modulator is used for logical Two orthogonal polarisation states for crossing its light pulse apply different adjustable phase-modulations；And/or

Second polarization maintaining optical fibre stretcher of any second sub-light road in two second sub-light roads, and/or Second birefringent phase modulator of any second sub-light road in two second sub-light roads, second polarization-maintaining Fiber stretcher is used to adjust the polarization maintaining optical fibre length of the optical path where it, and the second birefringent phase modulator is used for logical Two orthogonal polarisation states for crossing its light pulse apply different adjustable phase-modulations.

5. the HVDC Modulation quantum key distribution phase decoding dress according to scheme 1 based on 90 degree of welding difference control It sets, which is characterized in that the direct current phase-modulator fiber stretcher or length-adjustable free space optical path or polarization nothing Phase-modulator is closed to realize；The direct current phase-modulator is configured for so that in the first phase decoder and the second phase Made phase-modulation is relative in the first phase decoder and the second phase in a phase decoder in the decoder of position Made phase-modulation differs 90 degree in another phase decoder in the decoder of position.

6. the HVDC Modulation quantum key distribution phase decoding dress according to scheme 1 based on 90 degree of welding difference control It sets, which is characterized in that

The first phase decoder use unequal arm Michelson's interferometer structure, first bundling device with it is described First beam splitter is same device, the first phase decoder further include:

Two the first reflecting mirrors, described two first reflecting mirrors are located at two the first sub-lights road, use respectively In the two-way the first sub-light pulse-echo that will come from first beam splitter through two first sub- optic paths Return first bundling device；With

First optical circulator, first optical circulator are located at first beam splitter front end, the first via light pulse It is input to the first port of first optical circulator and exports from the second port of first optical circulator to described first Beam splitter, the light pulse after the conjunction beam from first bundling device are input to the second port of first optical circulator simultaneously It is exported from the third port of first optical circulator；And/or

The second phase decoder use unequal arm Michelson's interferometer structure, second bundling device with it is described Second beam splitter is same device, the second phase decoder further include:

Two the second reflecting mirrors, described two second reflecting mirrors are located at two the second sub-lights road, use respectively In the two-way the second sub-light pulse-echo that will come from second beam splitter through two second sub- optic paths Return second bundling device；With

Second optical circulator, second optical circulator are located at second beam splitter front end, second tunnel light pulse It is input to the first port of second optical circulator and exports from the second port of second optical circulator to described second Beam splitter, the light pulse after the conjunction beam from second bundling device are input to the second port of second optical circulator simultaneously It is exported from the third port of second optical circulator,

Wherein one of output port of the unequal arm Michelson's interferometer and input port are same port.

7. the HVDC Modulation quantum key distribution phase decoding dress according to scheme 1 based on 90 degree of welding difference control It sets, which is characterized in that first beam splitter, first bundling device and first beam splitter and first bundling device Between optical device in optical path be that polarization keeps optical device；And/or second beam splitter, second bundling device and institute It states the optical device between the second beam splitter and second bundling device in optical path and keeps optical device for polarization.

8. the HVDC Modulation quantum key distribution phase decoding dress according to scheme 1 based on 90 degree of welding difference control It sets, which is characterized in that the first phase decoder and second phase decoder are using unequal arm Mach-Zender interferometer Light channel structure.

9. a kind of quantum key distribution system characterized by comprising

HVDC Modulation quantum key distribution based on 90 degree of welding difference control according to any one of scheme 1~8 The receiving end of the quantum key distribution system is arranged in for phase decoding in phase decoding device；And/or

HVDC Modulation quantum key distribution based on 90 degree of welding difference control according to any one of scheme 1~8 The transmitting terminal of the quantum key distribution system is arranged in for phase code in phase decoding device.

10. quantum key distribution system according to scheme 9, which is characterized in that the quantum key distribution system is also Including single-photon source, quantum channel, single-photon detector, the single-photon source is optically coupled to compiling for phase positioned at transmitting terminal The phase decoding device of code, the single-photon detector are coupled to the phase for phase decoding positioned at receiving end Decoding apparatus.

Using the embodiment of the utility model, it can be achieved that multiple advantages.For example, the utility model passes through control light pulse two The difference of the phase difference of each comfortable polarization-maintaining decoding interferometer two-arm transmission of orthogonal polarisation state, realizes random polarization state input optical pulse Stablize decoding interference, and by the 90 degree of weldings of interferometer two-arm polarization maintaining optical fibre, is easy to realize by the control of fiber lengths steady The phase difference requirement of definite decoding solves polarization induction decline in phase code quantum key distribution system and causes system that can not stablize The problem of work.In addition, by receiving end by input optical pulse beam splitting be two-way light pulse after respectively to this two-way light pulse Phase decoding is carried out, direct current is carried out to every road light pulse during phase decoding and selects keynote system, it may be advantageous to reduce and solve Code selects the relevant requirement of phase-modulation when base, particularly with the high-speed phase tune avoided when base is selected in decoding for High Speed System System requires.The quantum key distribution decoding scheme of the utility model can resist polarization induction decline, can be highly suitable for existing The high speed quantum key distribution application scenarios of environmental disturbances.

Detailed description of the invention

Fig. 1 is the HVDC Modulation quantum key distribution phase solution based on 90 degree of welding difference control for the utility model The flow chart of the phase decoding method of code device；

Fig. 2 is the HVDC Modulation quantum key based on 90 degree of welding difference control of one preferred embodiment of the utility model Distribute the composed structure schematic diagram of phase decoding device；

Fig. 3 is that the HVDC Modulation quantum based on 90 degree of welding difference controls of another preferred embodiment of the utility model is close The composed structure schematic diagram of key distribution phase decoding device；

Fig. 4 is that the HVDC Modulation quantum based on 90 degree of welding difference controls of another preferred embodiment of the utility model is close The composed structure schematic diagram of key distribution phase decoding device.

Specific embodiment

Specifically describe the preferred embodiment of the utility model with reference to the accompanying drawing, wherein attached drawing constitutes the application one Part, and be used to illustrate the principles of the present invention together with the embodiments of the present invention.For purpose of clarity and simplification, When it may make the theme of the utility model smudgy, to the detailed of the known function and structure of device described herein Illustrating will omit.

Fig. 1 is the HVDC Modulation quantum key distribution phase solution based on 90 degree of welding difference control for the utility model The flow chart of the phase decoding method of code device, specifically includes the following steps:

Step S101: being first via light pulse and the second tunnel by the beam splitting of input optical pulse all the way of incident random polarization state Light pulse.

Specifically, incident input optical pulse is random polarization state, it is can be linear polarization, circular polarization or oval The complete polarized light of polarization is also possible to partial poolarized light or non-polarized light.

It preferably, is two-way light pulse by 50:50 beam splitting by incident input optical pulse all the way.

Step S102: according to quantum key distribution agreement to the first via light pulse and the second tunnel light pulse after beam splitting Phase decoding output is carried out respectively.

As skilled in the art will understand, it can regard as per light pulse all the way and be made of two orthogonal polarisation states.From So, the two-way sub-light pulse obtained by light pulse beam splitting all the way can also be regarded as equally by two identical with the road light pulse Orthogonal polarisation state composition.

Step S103: the first via light pulse and the second tunnel light pulse are carried out according to quantum key distribution agreement respectively Phase decoding can include:

For in the first via light pulse and the second tunnel light pulse per light pulse all the way,

It is the pulse of two-way sub-light by the road light pulse beam splitting；And

The two-way sub-light pulse is transmitted in two strip optical paths respectively, and relative time delay is made into the two-way sub-light pulse Beam output is closed afterwards, at least one sub-light road in the two strips optical path includes at least two sections of polarization maintaining optical fibres,

It wherein, include at least one 90 degree of fusion point at least one sub-light road in the two strips optical path, 90 degree of fusion points are formed in the following manner: by the opposite rotation of two sections of polarization maintaining optical fibres at least one sub-light road It turn 90 degrees, so that the slow axis of one section of polarization maintaining optical fibre is directed at welding with the fast axle of another section of polarization maintaining optical fibre, and

Wherein, a polarization state in two orthogonal polarisation states of the road light pulse is controlled in beam splitting to during closing beam Phase difference and another polarization state through the two strips optic path make two through the phase difference of the two strips optic path A phase difference differs the integral multiple of 2 π.

Step S104: respectively to the first via light pulse and the second tunnel light pulse according to quantum key distribution agreement into Phase-modulation is carried out during row phase decoding as described below: during beam splitting to conjunction beam, to the first via light arteries and veins It rushes at least one of two-way sub-light pulse that beam splitting obtains and carries out direct current phase-modulation according to quantum key distribution agreement, and/or At least one of two-way sub-light pulse obtained to the second tunnel light pulse beam splitting carries out straight according to quantum key distribution agreement Flow phase-modulation.

Here, relative time delay and phase-modulation are carried out according to the requirement and regulation of quantum key distribution agreement, are not made herein It is described in detail.

For step S103, passed through during each comfortable beam splitting to conjunction beam of two orthogonal polarisation states about light pulse all the way The phase difference of corresponding two strips optic path differs the integral multiple of 2 π, for example, it is assumed that the two orthogonal polarisation states difference For x-polarisation state and y-polarisation state, x-polarisation state is indicated in beam splitting to phase difference during closing beam through two strip optic paths For Δ x, y-polarisation state is shown as Δ y in beam splitting to the phase meter through two strip optic paths during closing beam, then accordingly A polarization state in two orthogonal polarisation states of input optical pulse is during beam splitting to conjunction beam through the two strips optical path The phase difference of transmission differs the integral multiple of 2 π with another polarization state through the phase difference of the two strips optic path, in other words should Phase difference difference 2 through two strip optic paths during each comfortable beam splitting to conjunction beam of two orthogonal polarisation states of road light pulse The integral multiple of π can indicate are as follows:

Δ x-Δ y=2 π * m,

Wherein m is integer, can be positive integer, negative integer or zero.

It is advantageous, control a strip optical path of the polarization eigen state of the polarization maintaining optical fibre in the two strips optical path The difference of the distance and the distance through slow axis transmission transmitted when upper transmission through polarization maintaining optical fibre fast axle and the polarization eigen state are described The distance transmitted when being transmitted in another strip optical path in two strip optical paths through polarization maintaining optical fibre fast axle and the distance transmitted through slow axis Difference so that two apart from its difference difference beat length of polarization maintaining optical fiber integral multiple, enable to two of corresponding input optical pulse A polarization state in orthogonal polarisation state is in beam splitting to phase difference during closing beam through the two strips optic path and another One polarization state differs the integral multiple of 2 π through the phase difference of the two strips optic path, in other words, so that corresponding input light Phase difference difference 2 through the two strips optic path during each comfortable beam splitting to conjunction beam of two orthogonal polarisation states of pulse The integral multiple of π.

Specifically, it is assumed that an optical path of a certain polarization eigen state of polarization maintaining optical fibre in two optical paths is along polarization maintaining optical fibre The distance of fast axle transmission is L1, is L2 along the distance that slow axis transmits, and is along the distance that polarization maintaining optical fibre fast axle is transmitted in another optical path L3, along slow axis transmission distance be L4, then

(L1-L2)-(L3-L4)=n β, in other words

(L1-L3)-(L2-L4)=n β

Wherein n is positive integer, negative integer or zero, and β is beat length of polarization maintaining optical fiber.

" beat length of polarization maintaining optical fiber " is concept well known in the art, refers to two polarization eigen states of polarization maintaining optical fibre along polarization-maintaining light Fibre transmission generates polarization maintaining optical fibre length corresponding to 2 π phase differences.

Advantageous, a polarization state in two orthogonal polarisation states for controlling the road light pulse is in beam splitting to conjunction beam Phase difference and phase difference of another polarization state through the two strips optic path in the process through the two strips optic path So that two phase differences differ the integral multiple of 2 π, comprising: the two strips optical path includes 90 degree of fusion points, and each molten Contact is located at the midpoint on place sub-light road.

In a kind of possible embodiment, for every light all the way in the first via light pulse and the second tunnel light pulse Pulse: the two strip optical paths for being used for transmission the two-way sub-light pulse that the road light pulse beam splitting obtains include for the road light pulse There are birefringent optical paths for two orthogonal polarisation states, and/or with two for the road light pulse in this two strips optical path There are birefringent optical devices for orthogonal polarisation state.In this case, it controls in two orthogonal polarisation states of the road light pulse Phase difference and another polarization state of one polarization state during beam splitting to conjunction beam through the two strips optic path are through institute State the integral multiple that the phase difference of two strip optic paths makes two phase differences differ 2 π, comprising: keep the two orthogonal respectively When transmitting in the two strips optical path, polarization state is constant during each comfortable beam splitting to conjunction beam of polarization state；And adjustment is deposited Length in birefringent optical path and/or the birefringent size there are birefringent optical device, so that the two orthogonal polarisation states In a polarization state in beam splitting to phase difference through two strips optic path during closing beam and another polarization state Phase difference through the two strips optic path makes the integral multiple of two 2 π of phase differences difference, in other words, so that the two are just The phase difference through the two strips optic path differs the integral multiple of 2 π during handing over each comfortable beam splitting of polarization state extremely to close beam.It can Selection of land, this can pass through following any realization: i) polarization maintaining optical fibre optical path be configured by the two strips optical path, by the polarization-maintaining light Optical device in fine optical path is configured to non-birefringent optical device and/or polarization-maintaining optical device；Ii) one of described two strips optical path is matched It is set to free space optical path, configures non-birefringent optical device and/or polarization-maintaining optical device for the optical device in two optical paths. Herein, " polarization maintaining optical fibre optical path ", which refers to, connects the light to be formed using the optical path or polarization maintaining optical fibre of polarization maintaining optical fibre transmission light pulse Road." non-birefringent optical device ", which refers to, has identical refractive index for different polarization states (for example, two orthogonal polarisation states) Optical device.In addition, polarization keeps optical device to be alternatively referred to as polarization-maintaining optical device.

A polarization state in two orthogonal polarisation states for controlling the road light pulse is in beam splitting to during closing beam Phase difference and another polarization state through the two strips optic path make two through the phase difference of the two strips optic path A phase difference differs the integral multiple of 2 π, comprising:

A polarization eigen state of the polarization maintaining optical fibre is controlled to transmit in the strip optical path in the two strips optical path When the distance transmitted through polarization maintaining optical fibre fast axle and the distance through slow axis transmission difference and the polarization eigen state in two strip The difference of the distance and the distance through slow axis transmission transmitted when transmitting in another strip optical path in optical path through polarization maintaining optical fibre fast axle, makes Two integral multiples apart from its difference difference beat length of polarization maintaining optical fiber are obtained, so that in two orthogonal polarisation states of the road light pulse Phase difference and another polarization state of one polarization state during beam splitting to conjunction beam through the two strips optic path are through institute The phase difference for stating two strip optic paths differs the integral multiple of 2 π, in other words, so that each comfortable beam splitting of the two orthogonal polarisation states To the integral multiple for closing phase difference through the two strips optic path during beam and differing 2 π.

In a kind of possible realization, for every light arteries and veins all the way in the first via light pulse and the second tunnel light pulse Punching: at least one son in the two strip optical paths that the two-way sub-light pulse for obtaining to the road light pulse beam splitting is transmitted Polarization maintaining optical fibre stretcher and/or birefringent phase modulator are configured in optical path.Polarization maintaining optical fibre stretcher is suitable for adjusting where it The polarization maintaining optical fibre length of optical path.Birefringent phase modulator is suitable for applying two orthogonal polarisation states by it different adjustable Phase-modulation, thus each comfortable beam splitting of two orthogonal polarisation states that can be provided to influence and adjust the road light pulse is to closing beam During the phase difference through the two strips optic path difference.For example, birefringent phase modulator can be lithium niobate phase Position modulator is applied to the voltage of lithium columbate crystal by controlling, can to by two of the lithium niobate phase modulator just The phase-modulation for handing over polarization state to be respectively subjected to is controlled and is adjusted.As a result, birefringent phase modulator can be used for influence and Each comfortable beam splitting of two orthogonal polarisation states of the road light pulse is adjusted to closing during beam through the two strips optic path The difference of phase difference.

Carrying out direct current phase-modulation to a light pulse can be realized by multiple means, these means can include: modulation is certainly By the length perhaps length of modulation optical fiber or the unrelated phase-modulator of modulating polarization etc. of space optical path.For example, can pass through Change the length of free space optical path with motor to realize desired direct current phase-modulation.It for another example, can be by utilizing piezoelectric effect Fiber stretcher carry out the length of modulation optical fiber, be achieved in phase-modulation.In addition, phase-modulator can be suitable for voltage control The other types of system, it is orthogonal partially come two to light pulse to unrelated phase-modulator is polarized by applying suitable DC voltage Polarization state carries out identical phase-modulation, it can be achieved that desired direct current phase-modulation.In the case where direct current phase-modulation, without becoming Change the voltage for being applied to phase-modulator.

In a preferred embodiment, to the light pulse all the way in the first via light pulse and the second tunnel light pulse point Phase-modulation made by least one of two-way sub-light pulse that beam obtains with to the first via light pulse and the second road Guang Mai Phase-modulation made by least one of two-way sub-light pulse that another way light pulse beam splitting in punching obtains differs 90 degree.

A kind of HVDC Modulation quantum key based on 90 degree of welding difference control of one preferred embodiment of the utility model Distribute phase decoding device as shown in Fig. 2, including consisting of part: preposition beam splitter 201；First beam splitter 202, first closes Beam device 204 and two the first sub-light roads between them；And second beam splitter 205, the second bundling device 207 and they between Two the second sub-light roads.Be provided with first phase modulator 203 on one of two first sub-light roads, two the second sub-light roads it Second phase modulator 206 is provided on one.It may be provided at least one the one 90 degree of welding on one of two article of first sub-light road 208 are put, may be provided at least one the 2nd 90 degree of fusion point 209 on one of two article of second sub-light road.The one 90 degree of welding Point 208 or the 2nd 90 degree of fusion point 209 are formed in the following manner: by two sections in one of described two article of first sub-light road 90 degree of polarization maintaining optical fibre relative rotation, or by two sections of polarization maintaining optical fibre relative rotation 90 in one of described two second sub-light roads Degree, so that the slow axis of one section of polarization maintaining optical fibre is directed at welding with the fast axle of another section of polarization maintaining optical fibre.First beam splitter 202, first closes Beam device 204 and two the first sub-light roads between them totally can be described as first phase decoder, the second beam splitter 205, second Bundling device 207 and two the second sub-light roads between them totally can be described as second phase decoder.First phase modulator 203 It can be direct current phase-modulator with second phase modulator 206.

Preposition beam splitter 201 is used to the beam splitting of input optical pulse all the way of incident random polarization state be two-way light pulse.

First phase decoder and preposition 201 optical coupling of beam splitter, for receiving the light all the way in above-mentioned two-way light pulse Pulse simultaneously carries out phase decoding to it.For convenience, this all the way light pulse be hereinafter also referred to be first via light pulse.

Second phase decoder and preposition 201 optical coupling of beam splitter, for receiving the another way in above-mentioned two-way light pulse Light pulse simultaneously carries out phase decoding to it.For convenience, which is hereinafter also referred to be the second tunnel light pulse.

First beam splitter 202 is used to first via light pulse beam splitting be the pulse of the first sub-light of two-way, respectively through two articles the One sub- optic path simultaneously is made to close beam output by the first bundling device 204 after relative time delay by this two the first sub-light roads.First phase Modulator 203 is used for the first sub-light pulse transmitted through one of two the first sub-light roads where it according to quantum key distribution Agreement carries out direct current phase-modulation.Specifically, two the first sub-light roads are used in combination for transmitting this two-way the first sub-light pulse respectively In the relative time delay for realizing this two-way the first sub-light pulse.It can be by adjusting between the first beam splitter 202 and the first bundling device 204 Two the first sub-light roads in any optical path physical length realize the relative time delay of two-way the first sub-light pulse.First closes beam Beam output is closed in this two-way the first sub-light pulse of device 204 for that will come through two the first sub- optic paths.

Second beam splitter 205 is used to the second tunnel light pulse beam splitting be the pulse of the second sub-light of two-way, respectively through two articles the Two sub- optic paths simultaneously are made to close beam output by the second bundling device 207 after relative time delay by this two the second sub-light roads.Second phase Modulator 206 is used for the second sub-light pulse transmitted through one of two the second sub-light roads where it according to quantum key distribution Agreement carries out direct current phase-modulation.Specifically, two the second sub-light roads are used in combination for transmitting this two-way the second sub-light pulse respectively In the relative time delay for realizing this two-way the second sub-light pulse.It can be by adjusting between the second beam splitter 205 and the second bundling device 207 Two the second sub-light roads in any optical path physical length realize the relative time delay of two-way the second sub-light pulse.Second closes beam Beam output is closed in this two-way the second sub-light pulse of device 207 for that will come through two the second sub- optic paths.

Although all having direct current phase-modulator Fig. 2 shows first phase decoder and second phase decoder, first It is possible that only one in phase decoder and second phase decoder, which has direct current phase-modulator,.In any case, Preferably, available direct current phase-modulator leads to a phase solution in first phase decoder and second phase decoder Made phase-modulation is relative to another phase decoding in first phase decoder and second phase decoder in code device Made phase-modulation differs 90 degree in device.

According to the utility model, in each phase decoder in the first and second phase decoders, two strip optical paths And optical device thereon is configured so that each comfortable beam splitting of two orthogonal polarisation states of corresponding light pulse all the way to the process for closing beam The middle phase difference through two strip optic paths differs the integral multiple of 2 π.

Preferably, as above-mentioned illustrated by method embodiment, two first sub-light roads and light thereon Device can be further constructed to, and control a polarization eigen state of the polarization maintaining optical fibre in two first sub-light roads First sub-light road distance for being transmitted through polarization maintaining optical fibre fast axle and the distance through slow axis transmission when transmitting first distance The poor and polarization eigen state on another the first sub-light road in two first sub-light roads when transmitting through polarization maintaining optical fibre The second range difference of the distance of fast axle transmission and the distance through slow axis transmission, so that first distance difference and second range difference difference are protected Polarisation fibre claps long integral multiple, so that one in two orthogonal polarisation states of the first via light pulse of the input polarizes Phase difference and another polarization state of the state during beam splitting to conjunction beam through two first sub- optic paths are through described two The phase difference of the sub- optic path of item first differs the integral multiple of 2 π, in other words, so that the two of the first via light pulse of the input The phase difference through two first sub- optic paths differs 2 π's during each comfortable beam splitting to conjunction beam of a orthogonal polarisation state Integral multiple.And/or two second sub-light roads and optical device thereon can be further constructed to, and control the polarization-maintaining One polarization eigen state of optical fiber on a second sub-light road in two second sub-light roads when transmitting through polarization maintaining optical fibre The third range difference and the polarization eigen state of the distance of fast axle transmission and the distance through slow axis transmission are in two second sons The distance transmitted through polarization maintaining optical fibre fast axle and the distance through slow axis transmission when another the second sub-light road in optical path is transmitted 4th range difference, so that the integral multiple of third range difference and the 4th range difference difference beat length of polarization maintaining optical fiber, so that described defeated A polarization state in two orthogonal polarisation states of the second tunnel light pulse entered is during beam splitting to conjunction beam through described two The phase difference of second sub- optic path differs 2 π's through the phase difference of two second sub- optic paths with another polarization state Integral multiple, in other words, so that mistake of each comfortable beam splitting of two orthogonal polarisation states of the first via light pulse of the input to conjunction beam The phase difference of two the second sub- optic paths described in Cheng Zhongjing differs the integral multiple of 2 π.

Preferably, two first sub-light roads include 90 degree of fusion points, and each fusion point is located at place The midpoint of optical path, so that mistake of each comfortable beam splitting of two orthogonal polarisation states of corresponding input optical pulse easy to accomplish to conjunction beam The difference of the phase difference of two the first sub- optic paths described in Cheng Zhongjing is the integral multiple of 2 π.The two second sub-light roads and/or It include 90 degree of fusion points, and each fusion point is located at the midpoint on place sub-light road, so that easy to accomplish corresponding defeated The phase through two second sub- optic paths during beam is extremely closed in each comfortable beam splitting of two orthogonal polarisation states for entering light pulse The difference of potential difference is the integral multiple of 2 π.

One sub- optical path there may be birefringent or there is no birefringent, depends on the sub-light for two orthogonal polarisation states The type on road.For example, free space optical path for input optical pulse all the way two orthogonal polarisation states there is no birefringent, and protect Inclined optic fibre light path differs greatly each other for two orthogonal polarisation states usually presence of input optical pulse all the way birefringent.Separately Outside, for an optical device in optical path for two orthogonal polarisation states there may be birefringent or there is no birefringent, depending on should The type of optical device.For example, two orthogonal polarisation states of input optical pulse all the way are not present in a non-birefringent optical device It is birefringent, and a polarization-maintaining optical device differs greatly each other for two orthogonal polarisation states usually presence of input optical pulse all the way It is birefringent.

For each of the first and second phase decoders phase decoder, can optionally there be following setting:

● one of two strip optical paths between the beam splitter and bundling device in phase decoder are free space optical path, this two Optical device in strip optical path, including direct current phase-modulator --- it is non-birefringent optical device and/or polarization-maintaining if any Optical device.For the setting, in the case where there is polarization-maintaining optical device, polarization-maintaining optical device itself causes to be input to the phase decoder Light pulse each comfortable beam splitting of two orthogonal polarisation states to closing the phase difference difference 2 through two strip optic paths during beam The integral multiple of π.

● two strip optical paths between the beam splitter and bundling device in phase decoder are polarization maintaining optical fibre optical path, this two strip Optical device in optical path, including direct current phase-modulator --- it is polarization-maintaining optical device and/or non-birefringent smooth device if any Part.

● phase decoder may also include fiber stretcher and/or birefringent phase modulator.Fiber stretcher can be located at Any sub-light road in two strip optical paths between the beam splitter and bundling device of phase decoder, where can be used for adjusting it The polarization maintaining optical fibre length on sub-light road.By adjusting polarization maintaining optical fibre length by means of fiber stretcher, it may be advantageous to be easily achieved defeated Enter during extremely closing beam to each comfortable beam splitting of two orthogonal polarisation states of the light pulse of the phase decoder through two strip optical paths The phase difference of transmission differs the integral multiple of 2 π.In addition, fiber stretcher also is used as the use of direct current phase-modulator.Birefringent phase Position modulator can be located at any sub-light road in the two strips optical path, can be used for by its two of light pulse it is orthogonal Polarization state applies different phase-modulations.It is orthogonal by two of its light pulse by controlling the birefringent phase modulator The difference for the phase-modulation that polarization state is respectively subjected to is adjustable.In this way, by utilizing birefringent phase modulator, it is convenient to shadow Through institute during each comfortable beam splitting to conjunction beam of two orthogonal polarisation states of the light pulse that sound and adjustment are input to phase decoder State the difference of the phase difference of two strip optic paths, it is easy to accomplish the integral multiple that the difference is 2 π.The birefringent phase modulator can Think previously described lithium niobate phase modulator.

● phase decoder uses the structure of unequal arm Mach-Zender interferometer, and the optical path of interferometer two-arm is (that is, phase Two strip optical paths between the beam splitter and bundling device of position decoder) use polarization maintaining optical fibre, it is assumed that and the two-arm of interferometer is wrapped respectively Containing 90 degree of fusion points, it is assumed that the distance of 90 degree fusion point of the beam splitter into an arm is L1,90 degree of weldings in an arm The distance of point to bundling device is L2, and the distance of 90 degree fusion point of the beam splitter into another arm is L3,90 degree in another arm The distance of fusion point to bundling device is L4, and length relation meets (L1-L2)-(L3-L4)=n β, and wherein n is positive integer, bears Integer or zero, β are beat length of polarization maintaining optical fiber.In a preferred embodiment, two 90 degree of fusion points can be located at two-arm Midpoint, that is to say L1=L2 and L3=L4, length relation meets (L1-L2)-(L3-L4)=0.

● phase decoder uses the structure of unequal arm Michelson's interferometer.At this point, the bundling device of phase decoder with Beam splitter is same device.In the case, phase decoder further includes two reflecting mirrors, the two reflecting mirrors are located at use In in two strip optical paths of the two-way sub-light pulse that the beam splitter beam splitting of transmission phase decoder obtains, it is respectively used to that phase will be come from The two-way sub-light pulse-echo of the beam splitter of position decoder come through the two strips optic path is gone back so as to by phase decoding Device closes beam output with beam splitter for the bundling device of same device.The beam splitter and described two reflecting mirrors are constituted described dry Two arms of interferometer separately include 90 degree of fusion points, it is assumed that the distance of 90 degree fusion point of the beam splitter into an arm be L1, The distance of a reflecting mirror of 90 degree of fusion points into two reflecting mirrors in one arm be L2, beam splitter into another arm 90 The distance for spending fusion point is L3, the distance of another reflecting mirror of the 90 degree of fusion points in another arm into two reflecting mirrors is L4, it is contemplated that along two-arm round-trip transmission, the distance that polarization maintaining optical fibre slow axis or fast axle transmission are passed through in transmission process is for light pulse 2 times of corresponding polarization maintaining optical fibre length, length relation meets 2 (L1-L2) -2 (L3-L4)=n β, and wherein n is positive integer, bears Integer or zero, β are beat length of polarization maintaining optical fiber.In a preferred embodiment, two 90 degree of fusion points can be located at two-arm Midpoint, that is to say L1=L2 and L3=L4, length relation meets 2 (L1-L2) -2 (L3-L4)=0.In addition, unequal arm One of output port of Michelson's interferometer and input port can be that (in other words, one of output port is defeated to same port Inbound port), and phase decoder further includes optical circulator.The optical circulator can be located at the beam splitter front end of phase decoder. Corresponding light pulse all the way from preposition beam splitter 201 can input from the first port of optical circulator and from the second of optical circulator Port exports the bundling device to the beam splitter of phase decoder, from phase decoder, and (beam splitter with phase decoder is same One device) conjunction beam output can be input to optical circulator second port and from the third port of optical circulator export.

" beat length of polarization maintaining optical fiber " is concept well known in the art, refers to two polarization eigen states of polarization maintaining optical fibre along polarization maintaining optical fibre Transmission generates polarization maintaining optical fibre length corresponding to the phase difference of 2 π.

For the embodiment of Fig. 2, the first beam splitter and the second beam splitter preferably use polarization-maintaining beam splitter, the first bundling device Polarization-maintaining bundling device is preferably used with the second bundling device.

A kind of HVDC Modulation quantum based on 90 degree of welding difference controls of another preferred embodiment of the utility model is close Key distribute phase decoding device as shown in figure 3, wherein phase decoder use unequal arm Mach-Zender interferometer structure, Including consisting of part: preposition beam splitter 303, polarization-maintaining beam splitter 304 and 312, polarization maintaining optical fibre stretcher 306 and 314, straight Flow phase-modulator 308 and 316, polarization-maintaining bundling device 309 and 317 and 90 degree fusion point 305,307,313 and 315.

Input terminal of one of two ports 301 and 302 of side of preposition beam splitter 303 as phase decoding device.It protects Inclined beam splitter 304 and polarization-maintaining bundling device 309 constitute the component part of the first Mach-Zender interferometer, 304 He of polarization-maintaining beam splitter Two the first sub-light roads (that is, two-arm of the first Mach-Zender interferometer) between polarization-maintaining bundling device 309 are polarization maintaining optical fibre light Road, polarization maintaining optical fibre stretcher 306 and direct current phase-modulator 308 can be inserted into the first Mach-Zender interferometer same arm or Person is inserted into two arms of the first Mach-Zender interferometer respectively.First Mach-Zender interferometer two-arm includes at least one 90 degree of fusion points, such as 90 degree of fusion points 305 and 307 can be separately included.Input optical pulse is dry through the first Mach-Zehnder It is exported after interferometer decoding by port 310 or 311.

Polarization-maintaining beam splitter 312 and polarization-maintaining bundling device 317 constitute the component part of the second Mach-Zender interferometer, polarization-maintaining Two the second sub-light roads (that is, two-arm of the second Mach-Zender interferometer) between beam splitter 312 and polarization-maintaining bundling device 317 For polarization maintaining optical fibre optical path, polarization maintaining optical fibre stretcher 314 and direct current phase-modulator 316 can be inserted into the second Mach Zehnder interference The same arm of instrument or two arms for being inserted into second Mach of-Zeng Deer interferometer respectively.Second Mach-Zender interferometer two Arm includes at least one 90 degree of fusion point, such as can separately include 90 degree of fusion points 313 and 315.Input optical pulse is through It is exported after the decoding of two Mach-Zender interferometers by port 318 or 319.

When work, port 301 or 302 of the light pulse through beam splitter 303 is beamed into two-way light pulse into beam splitter 303 and passes It is defeated, wherein light pulse input 304 beam splitting of polarization-maintaining beam splitter is the pulse of two-way sub-light all the way, the way in the two-way sub-light pulse Light pulse modulates (wherein 90 degree of fusion points 305 and polarization maintaining optical fibre through 90 degree of transmission of fusion point 305 and polarization maintaining optical fibre stretcher 306 The setting sequence of stretcher 306 is convertible, or referred to as " sequence is unrelated "), the pulse of another way sub-light is through 90 degree of fusion points 307 It transmits and is modulated 0 degree of phase (sequence is unrelated) through direct current phase-modulator 308, closed after two-way sub-light pulse relative time delay through polarization-maintaining Beam device 309 is exported after closing beam by port 310 or 311.The another way light pulse exported from beam splitter 303 inputs polarization-maintaining beam splitter 312 beam splitting are the pulse of two-way sub-light, and sub-light pulse is modulated through 90 degree of transmission of fusion point 313 and polarization maintaining optical fibre stretcher 314 all the way (sequence is unrelated), the pulse of another way sub-light are transmitted through 90 degree of fusion points 315 and modulate 90 degree of phases through direct current phase-modulator 316 (sequence unrelated) is exported after polarization-maintaining bundling device 317 closes beam by port 318 or 319 after two-way sub-light pulse relative time delay.

Assuming that length is L1 between polarization-maintaining beam splitter 304 and 90 degree fusion point 305,90 degree of fusion points 305 and polarization-maintaining close beam Length is L2 between device 309, length is L3,90 degree of fusion points 307 and protects between polarization-maintaining beam splitter 304 and 90 degree fusion point 307 Length is L4 between inclined bundling device 309, modulates polarization maintaining optical fibre stretcher 306, so that length relation meets:

(L1-L3)-(L2-L4)=n β, in other words

(L1-L2)-(L3-L4)=n β,

Wherein β is beat length of polarization maintaining optical fiber, n is integer；So that two orthogonal polarisation states of input optical pulse each comfortable The integral multiple that the difference of the phase difference of one Mach-Zender interferometer two-arm transmission is 2 π.

Assuming that length is L5 between polarization-maintaining beam splitter 312 and 90 degree fusion point 313,90 degree of fusion points 313 and polarization-maintaining close beam Length is L6 between device 317, length is L7,90 degree of fusion points 315 and protects between polarization-maintaining beam splitter 312 and 90 degree fusion point 315 Length is L8 between inclined bundling device 317, modulates polarization maintaining optical fibre stretcher 314, so that length relation meets:

(L5-L7)-(L6-L8)=m β, in other words

(L5-L6)-(L7-L8)=m β,

Wherein β is beat length of polarization maintaining optical fiber, m is integer；

So that each comfortable second Mach-Zender interferometer two-arm transmission of two orthogonal polarisation states of input optical pulse The difference of phase difference is the integral multiple of 2 π.

Direct current phase-modulator 308 and 316 is to polarize unrelated optical device.Direct current phase-modulator 308 modulates 90 degree of phases, Direct current phase-modulator 316 modulates 0 degree of phase, and the above results are unaffected.If device does not include direct current phase-modulator 308 And/or 316, realize that direct current phase-modulation function, the above results are unaffected by polarization maintaining optical fibre stretcher 306 and/or 314.

A kind of HVDC Modulation quantum based on 90 degree of welding difference controls of another preferred embodiment of the utility model is close Key distribute phase decoding device as shown in figure 4, wherein phase decoder use unequal arm Michelson's interferometer structure, including Consisting of part: preposition beam splitter 403, optical circulator 404 and 414, polarization-maintaining beam splitter 405 and 415, polarization maintaining optical fibre stretcher 407 and 417, direct current phase-modulator 410 and 420,90 degree of fusion points 406,409,416 and 419 and reflecting mirror 408, 411,418 and 421.

Input terminal of one of two ports 401 and 402 of side of preposition beam splitter 403 as phase decoding device.Light Circulator 404 receives input from port A and can then export via port B, and receiving input from port B can then export via port C.It protects Inclined beam splitter 405 and reflecting mirror 408,411 form the first Michelson's interferometer, polarization maintaining optical fibre stretcher 407 and direct current phase Modulator 410 can be inserted into the same arm of the first Michelson's interferometer or be inserted into two of the first Michelson's interferometer respectively Arm.An at least arm includes at least one 90 degree of fusion point in first Michelson's interferometer two-arm, such as two-arm may include respectively One 90 degree of fusion point 406 and 90 degree of fusion points 409.Input optical pulse is after the decoding of the first Michelson's interferometer by holding Mouth 413 exports or is transmitted to port C through 404 port B of optical circulator and exported by port 412.

Optical circulator 414 receives input from port D and can then export via port E, and receiving input from port E then can be via end Mouth F output.Polarization-maintaining beam splitter 415 and reflecting mirror 418,421 form the second Michelson's interferometer, polarization maintaining optical fibre stretcher 417 It can be inserted into the same arm of the second Michelson's interferometer with direct current phase-modulator 420 or be inserted into the second Michelson respectively and do Two arms of interferometer.An at least arm includes at least one 90 degree of fusion point, such as two-arm in second Michelson's interferometer two-arm 90 degree of fusion points 416 and 90 degree of fusion points 419 can be separately included.Input optical pulse is through the second Michelson interference It is exported by port 423 after instrument decoding or is transmitted to port F through 414 port E of optical circulator and exported by port 422.

When work, port 401 or 402 of the light pulse through beam splitter 403 is beamed into two-way light pulse into beam splitter 403 and passes Defeated, light pulse is input to 404 port A of optical circulator and exports through 404 port B of optical circulator to polarization-maintaining beam splitter 405 and divides all the way Beam is the sub- optical pulse propagation of two-way, and sub-light pulse is modulated through 90 degree of transmission of fusion point 406 and polarization maintaining optical fibre stretcher 407 all the way It is reflected after (sequence is unrelated) by reflecting mirror 408, the pulse of another way sub-light is transmitted through 90 degree of fusion points 409 and through direct current phase Position modulator 410 reflects after modulating 0 degree phase (sequentially unrelated) by reflecting mirror 411, reflected through relative time delay The pulse of two-way sub-light is exported after polarization-maintaining beam splitter 405 closes beam by port 413 or after 404 port B of optical circulator input by holding Mouth C is transmitted to the output of port 412.The another way light pulse exported from beam splitter 403 is input to 414 port D of optical circulator and passes through It is the sub- optical pulse propagation of two-way that 414 port E of optical circulator, which is exported to 415 beam splitting of polarization-maintaining beam splitter, and sub-light pulse is through 90 degree all the way It is reflected after the transmission of fusion point 416 and the modulation of polarization maintaining optical fibre stretcher 417 (sequence is unrelated) by reflecting mirror 418, another way Light pulse is transmitted through 90 degree of fusion points 419 and after direct current phase-modulator 420 modulates 90 degree of phases (sequence is unrelated) by reflecting Mirror 421 reflects, it is reflected through the two-way sub-light pulse of relative time delay through polarization-maintaining beam splitter 415 close beam after by port 423 outputs are transmitted to port 422 by port F and export after 414 port E of optical circulator input.

Assuming that length is L1,90 degree of fusion points 406 and reflecting mirror between polarization-maintaining beam splitter 405 and 90 degree fusion point 406 Between 408 length be L2, between polarization-maintaining beam splitter 405 and 90 degree fusion point 409 length be L3,90 degree of fusion points 409 and reflection Length is L4 between mirror 411, modulates polarization maintaining optical fibre stretcher 407, so that length relation meets:

2 (L1-L3) -2 (L2-L4)=n β, or

2 (L1-L2) -2 (L3-L4)=n β

Wherein β is beat length of polarization maintaining optical fiber, n is integer；

So that the phase of each comfortable first Michelson's interferometer two-arm transmission of two orthogonal polarisation states of input optical pulse The difference of potential difference is the integral multiple of 2 π.

Assuming that length is L5,90 degree of fusion points 416 and reflecting mirror between polarization-maintaining beam splitter 415 and 90 degree fusion point 416 Between 418 length be L6, between polarization-maintaining beam splitter 415 and 90 degree fusion point 419 length be L7,90 degree of fusion points 419 and reflection Length is L8 between mirror 421, modulates polarization maintaining optical fibre stretcher 417, so that length relation meets:

2 (L5-L7) -2 (L6-L8)=m β, or

2 (L5-L6) -2 (L7-L8)=m β

Wherein β is beat length of polarization maintaining optical fiber, m is integer；

So that the phase of each comfortable second Michelson's interferometer two-arm transmission of two orthogonal polarisation states of input optical pulse The difference of potential difference is the integral multiple of 2 π.

Direct current phase-modulator 410 and 420 is to polarize unrelated device.Direct current phase-modulator 410 modulates 90 degree of phases, Direct current phase-modulator 420 modulates 0 degree of phase, and the above results are unaffected.If device does not include direct current phase-modulator 410 And/or 420, realize that direct current phase-modulation function, the above results are unaffected by polarization maintaining optical fibre stretcher 407 and/or 417.

Herein, term " beam splitter " and " bundling device " are used interchangeably, and beam splitter is also referred to as and as bundling device, instead ?.

In another aspect, the utility model also provides a kind of quantum key distribution system, the quantum key distribution system packet It includes and the receiving end of the quantum key distribution system is set is controlled for the above-mentioned of phase decoding based on 90 degree weldings differences HVDC Modulation quantum key distribution phase decoding device, and/or the transmitting terminal including the quantum key distribution system is arranged in The above-mentioned HVDC Modulation quantum key distribution phase decoding device based on 90 degree of welding difference control for phase code.

Preferably, the quantum key distribution system can also include single-photon source, quantum channel, single-photon detector, The single-photon source is optically coupled to the phase decoding device for phase code positioned at transmitting terminal and (now functions as " phase " the phase decoding device for phase code " can be known as " phase code device " below by code device "), the list Photon detector is coupled to the phase decoding device for phase decoding positioned at receiving end.

Single-photon source is for generating single-photon optical pulse.Phase code device is used for the monochromatic light sub-light generated to single-photon source Pulse carries out phase code according to quantum key distribution agreement.Quantum channel is used for transmission single-photon optical pulse.Particularly, quantum Single-photon optical pulse through phase code is transmitted to phase decoding device by channel.The phase decoding device is used for according to quantum Key distribution protocol carries out phase decoding to the single-photon optical pulse come through quantum channel transmission.Single-photon detector is used for phase The single-photon optical pulse of position decoding apparatus output is detected, and according to testing result and the quantum key distribution agreement amount of progress Quantum key distribution.When work, single-photon source emits a single-photon optical pulse and enters phase code device, phase code device pair Single-photon optical pulse carries out phase code, and the light pulse after phase code is transmitted to phase decoding device, phase through quantum channel Decoding apparatus carries out phase decoding, the light pulses that phase decoding device exports to single-photon detecting to incident single photon pulses Survey device.Phase code device and phase decoding device according to quantum key distribution agreement respectively to light pulse carry out phase code and Phase decoding, and key distribution is carried out according to quantum key distribution agreement.

Specifically, phase code device can be used it is following any one: unequal arm Mach-Zender interferometer, unequal arm Michelson's interferometer, above-described phase decoding device.

Quantum channel can be optical waveguide, optical fiber, free space, discrete optical element, planar waveguide optical element, fiber Optical element or among the above any two combination of the above at light propagation channel.

In general, environmental disturbances cause communicating pair transmission fiber and the generation of encoding and decoding interferometer optical fiber birefringent, lead to light Pulse polarization state when reaching receiving end decoding interference changes at random, so that decoding interference has polarization induction decline, influence amount Sub- secret signalling job stability.The utility model can be realized two orthogonal polarisation states of light pulse simultaneously in output end Mouth effectively interference output, is equivalent to and carries out polarization diversity processing to two orthogonal polarisation states, can effectively solve to polarize induction decline Caused interference decodes instability problem, the immune stable phase angle decoding of environmental disturbances is realized, without using polarization beam apparatus Two polarization states are decoded respectively with two interferometers, in addition also eliminate the needs to correction.In addition, the utility model By the 90 degree of weldings of interferometer two-arm polarization maintaining optical fibre, it is easy to stablize decoded phase difference by the control realization of fiber lengths and wants Ask, solve the problems, such as in phase code quantum key distribution system polarization induction decline cause system can not steady operation, furthermore By being that two-way light pulse carries out phase decoding respectively by input optical pulse beam splitting, direct current is carried out to every road light pulse and selects keynote System avoids High Speed System decoding and high-speed phase modulation when base is selected to require.

It should be able to be the technology hand reaching predetermined purpose and being taken to the utility model by the explanation of specific embodiment Section and effect have more deeply and it is specific understand, however appended diagram is only to provide reference and description and is used, and is not used to pair The utility model limits.

Although being described in detail by example embodiment, preceding description be all in all respects it is illustrative rather than It is restrictive.It should be appreciated that can be designed that range of a number of other remodeling with variant without departing from example embodiment, these Both fall within the protection scope of the utility model.Therefore, the protection scope of the utility model should be determined by the appended claims.

Claims (10)

1. a kind of HVDC Modulation quantum key distribution phase decoding device based on 90 degree of welding difference control, which is characterized in that The phase decoding device includes: preposition beam splitter, the first phase decoder and second with the preposition beam splitter optical coupling Phase decoder, wherein

The preposition beam splitter is configured for the beam splitting of input optical pulse all the way of incident random polarization state being first via light Pulse and the second tunnel light pulse；

The first phase decoder is configured for carrying out phase decoding to the first via light pulse；And

The second phase decoder is configured for carrying out phase decoding to second tunnel light pulse,

Wherein, the first phase decoder include the first beam splitter, the first bundling device and with the first beam splitter optocoupler Merging and two the first sub-light roads with the first bundling device optical coupling, wherein

First beam splitter is configured for the first via light pulse beam splitting being the pulse of the first sub-light of two-way；

At least one sub-light road in two first sub-light roads includes at least two sections of polarization maintaining optical fibres, two first sub-lights Road is configured for transmitting the first sub-light of two-way pulse respectively, and for realizing the opposite of the first sub-light of two-way pulse Delay；

First bundling device is configured for closing two-way the first sub-light pulse into beam output,

Wherein, comprising by making one section of polarization maintaining optical fibre in at least one the first sub-light roads in two first sub-light roads Slow axis be aligned with the fast axle of another section of polarization maintaining optical fibre welding formation at least one 90 degree of fusion point,

Wherein in the first phase decoder, two first sub-light roads and optical device thereon are configured to control institute State a polarization state in two orthogonal polarisation states of first via light pulse beam splitting to during closing beam through described two articles the The phase difference of one sub- optic path makes two phases through the phase difference of two first sub- optic paths with another polarization state Potential difference differs the integral multiple of 2 π；

Wherein, the second phase decoder include the second beam splitter, the second bundling device and with the second beam splitter optocoupler Merging and two the second sub-light roads with the second bundling device optical coupling, wherein

Second beam splitter is configured for the second tunnel light pulse beam splitting being the pulse of the second sub-light of two-way；

At least one sub-light road in two second sub-light roads includes at least two sections of polarization maintaining optical fibres, two second sub-lights Road is configured for transmitting the second sub-light of two-way pulse respectively, and for realizing the opposite of the second sub-light of two-way pulse Delay；

Second bundling device is configured for closing two-way the second sub-light pulse into beam output,

Wherein, comprising by making one section of polarization maintaining optical fibre in at least one the second sub-light roads in two second sub-light roads Slow axis be aligned with the fast axle of another section of polarization maintaining optical fibre welding formation at least one 90 degree of fusion point,

Wherein in the second phase decoder, two second sub-light roads and optical device thereon are configured to, and are controlled A polarization state in two orthogonal polarisation states of second tunnel light pulse is during beam splitting to conjunction beam through described two The phase difference of second sub- optic path makes two through the phase difference of two second sub- optic paths with another polarization state Phase difference differs the integral multiple of 2 π,

Wherein the first phase decoder has the direct current phase tune being located at least one of described two first sub-light roads Device processed and/or the second phase decoder have the direct current phase being located at least one of described two second sub-light roads Modulator, the direct current phase-modulator are used for the sub-light pulse through the sub- optic path where it according to quantum key distribution Agreement carries out direct current phase-modulation.

2. the HVDC Modulation quantum key distribution phase decoding dress according to claim 1 based on 90 degree of welding difference control It sets, which is characterized in that

Two first sub-light roads and optical device thereon are further constructed to, and one for controlling the polarization maintaining optical fibre is intrinsic The distance that polarization state is transmitted when transmitting on a first sub-light road in two first sub-light roads through polarization maintaining optical fibre fast axle With the first distance for the distance transmitted through slow axis is poor and another in two first sub-light roads of the polarization eigen state The second range difference of distance and the distance through slow axis transmission that first sub-light road is transmitted when transmitting through polarization maintaining optical fibre fast axle, so that The integral multiple of first distance difference and second range difference difference beat length of polarization maintaining optical fiber；And/or

Two second sub-light roads and optical device thereon are further constructed to, and one for controlling the polarization maintaining optical fibre is intrinsic The distance that polarization state is transmitted when transmitting on a second sub-light road in two second sub-light roads through polarization maintaining optical fibre fast axle With another of the third range difference and the polarization eigen state of the distance transmitted through slow axis in two second sub-light roads 4th range difference of distance and the distance through slow axis transmission that the second sub-light road is transmitted when transmitting through polarization maintaining optical fibre fast axle, so that The integral multiple of third range difference and the 4th range difference difference beat length of polarization maintaining optical fiber.

3. the HVDC Modulation quantum key distribution phase solution according to claim 1 or 2 based on 90 degree of welding difference control Code device, which is characterized in that

Two first sub-light roads include 90 degree of fusion points, and each fusion point is located in the first sub-light road of place Point；And/or

Two second sub-light roads include 90 degree of fusion points, and each fusion point is located in the second sub-light road of place Point.

4. the HVDC Modulation quantum key distribution phase decoding dress according to claim 1 based on 90 degree of welding difference control It sets, which is characterized in that the phase decoding device further include:

First polarization maintaining optical fibre stretcher of any first sub-light road in two first sub-light roads, and/or be located at First birefringent phase modulator of any first sub-light road in two first sub-light roads, first polarization maintaining optical fibre Stretcher is used to adjust the polarization maintaining optical fibre length of optical path where it, and the first birefringent phase modulator is used for passing through it Two orthogonal polarisation states of light pulse apply different adjustable phase-modulations；And/or

Second polarization maintaining optical fibre stretcher of any second sub-light road in two second sub-light roads, and/or be located at Second birefringent phase modulator of any second sub-light road in two second sub-light roads, second polarization maintaining optical fibre Stretcher is used to adjust the polarization maintaining optical fibre length of optical path where it, and the second birefringent phase modulator is used for passing through it Two orthogonal polarisation states of light pulse apply different adjustable phase-modulations.

5. the HVDC Modulation quantum key distribution phase decoding dress according to claim 1 based on 90 degree of welding difference control It sets, which is characterized in that the direct current phase-modulator fiber stretcher or length-adjustable free space optical path or polarization nothing Phase-modulator is closed to realize；The direct current phase-modulator is configured for so that in the first phase decoder and the second phase Made phase-modulation is relative in the first phase decoder and the second phase in a phase decoder in the decoder of position Made phase-modulation differs 90 degree in another phase decoder in the decoder of position.

6. the HVDC Modulation quantum key distribution phase decoding dress according to claim 1 based on 90 degree of welding difference control It sets, which is characterized in that

The first phase decoder uses the structure of unequal arm Michelson's interferometer, first bundling device and described first Beam splitter is same device, the first phase decoder further include:

Two the first reflecting mirrors, described two first reflecting mirrors are located at two first sub-lights road, be respectively used to by Institute is gone back in the two-way the first sub-light pulse-echo come through two first sub- optic paths from first beam splitter State the first bundling device；With

First optical circulator, first optical circulator are located at first beam splitter front end, the first via light pulse input To first optical circulator first port and export from the second port of first optical circulator to first beam splitting Device, the light pulse after the conjunction beam from first bundling device are input to the second port of first optical circulator and from institutes State the third port output of the first optical circulator；And/or

The second phase decoder uses the structure of unequal arm Michelson's interferometer, second bundling device and described second Beam splitter is same device, the second phase decoder further include:

Two the second reflecting mirrors, described two second reflecting mirrors are located at two second sub-lights road, be respectively used to by Institute is gone back in the two-way the second sub-light pulse-echo come through two second sub- optic paths from second beam splitter State the second bundling device；With

Second optical circulator, second optical circulator are located at second beam splitter front end, second tunnel light pulse input To second optical circulator first port and export from the second port of second optical circulator to second beam splitting Device, the light pulse after the conjunction beam from second bundling device are input to the second port of second optical circulator and from institutes The third port output of the second optical circulator is stated,

Wherein one of output port of the unequal arm Michelson's interferometer and input port are same port.

7. the HVDC Modulation quantum key distribution phase decoding dress according to claim 1 based on 90 degree of welding difference control It sets, which is characterized in that first beam splitter, first bundling device and first beam splitter and first bundling device Between optical device in optical path be that polarization keeps optical device；And/or second beam splitter, second bundling device and institute It states the optical device between the second beam splitter and second bundling device in optical path and keeps optical device for polarization.

8. the HVDC Modulation quantum key distribution phase decoding dress according to claim 1 based on 90 degree of welding difference control It sets, which is characterized in that the first phase decoder and second phase decoder are using unequal arm Mach-Zender interferometer Light channel structure.

9. a kind of quantum key distribution system characterized by comprising

HVDC Modulation quantum key distribution based on 90 degree of welding difference control described according to claim 1~any one of 8 The receiving end of the quantum key distribution system is arranged in for phase decoding in phase decoding device；And/or

HVDC Modulation quantum key distribution based on 90 degree of welding difference control described according to claim 1~any one of 8 The transmitting terminal of the quantum key distribution system is arranged in for phase code in phase decoding device.

10. quantum key distribution system according to claim 9, which is characterized in that the quantum key distribution system is also Including single-photon source, quantum channel and single-photon detector, the single-photon source is optically coupled to positioned at transmitting terminal for phase The phase decoding device of coding, the single-photon detector are coupled to the phase for phase decoding positioned at receiving end Position decoding apparatus.