CN209233845U

CN209233845U - Divide the quantum key distribution time bit-phase decoding device and corresponding system of polarization difference control

Info

Publication number: CN209233845U
Application number: CN201821752660.5U
Authority: CN
Inventors: 许华醒
Original assignee: China Electronics Technology Group Corp CETC
Current assignee: China Electronics Technology Group Corp CETC; Electronic Science Research Institute of CTEC
Priority date: 2018-10-29
Filing date: 2018-10-29
Publication date: 2019-08-09
Anticipated expiration: 2028-10-29

Abstract

The utility model proposes the quantum key distribution time bit-phase decoding devices and corresponding system of a kind of point of polarization difference control.The decoding apparatus includes: preposition beam splitter, receives input optical pulse through input port and exports the two-way light pulse obtained by input optical pulse beam splitting through two output ports；With the interferometer of one of two output ports of preposition beam splitter optical coupling, including beam splitter, bundling device and by two arms of beam splitter and bundling device optical coupling；Phase-modulator positioned at interferometer front end or in one of two-arm.A polarization difference control device is provided with point in one of two-arm of interferometer comprising polarization beam apparatus, polarization beam combiner and by two strip optical paths of polarization beam apparatus and polarization beam combiner optical coupling.The two-arm of interferometer and optical device thereon are configured so that the phase difference through two-arm transmission in each comfortable interferometer of two orthogonal polarisation states of corresponding light pulse differs the integral multiple of 2 π.The embodiment of the utility model is resistant to polarization induction decline.

Description

Point polarization difference control quantum key distribution time bit-phase decoding device and Corresponding system

Technical field

The utility model relates to optical transport private communication technology field more particularly to the quantum of a kind of point of polarization difference control M- phase decoding method, apparatus and the quantum key distribution system including the device when key is distributed.

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.

Time bit-phase code quantum key distribution uses one group of time base and one group of phase base, and time base uses two The time mode of a different time position encodes, and phase base is encoded using two phase differences of front and back light pulse.Ground amount Quantum key distribution is based primarily upon fibre channel transmission, and optical fiber fabrication there are the non-circular symmetrical, fiber core refractive indexs in section radially not Equal non-idealities are uniformly distributed, and optical fiber is influenced by temperature, strain, bending etc. in the actual environment, can generated random double Refraction effect.It is influenced by optical fiber random birefringence, when light pulse reaches receiving end after long-distance optical fiber transmits, polarization state It can occur to change at random.Time base decoding in time bit-phase code is not influenced by polarization state variation, however phase base When interfering decoding, because of the influence of transmission fiber and encoding and decoding interferometer fiber birefringence, there are problems that polarization induction decline, Cause decoding interference unstable, causes the bit error rate to increase, need to increase 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.For quantum key distribution time bit- Phase encoding scheme, how to carry out to stability and high efficiency phase interference decoding is to carry out quantum secure based on existing optical cable infrastructure The hot spot and problem of communications applications.

Utility model content

The main purpose of the utility model is that proposing the quantum key distribution time bit-of a kind of point of polarization difference control Phase decoding method and apparatus, because partially when solving phase base decoding in time bit-phase code quantum key distribution application Phase decoding caused by vibration induction declines interferes unstable problem.

The utility model provides at least following technical scheme:

1. quantum key distribution time bit-phase decoding device of a kind of point of polarization difference control, for incidence The input optical pulse all the way of random polarization state carries out time bit-phase decoding, which is characterized in that the decoding apparatus includes:

There is input port and two output ports, the input port to be used for for preposition beam splitter, the preposition beam splitter The input optical pulse is received, described two output ports are respectively used to export first obtained by the input optical pulse beam splitting Road light pulse and the second tunnel light pulse；With

It is described with the interferometer of an output port optical coupling in described two output ports of the preposition beam splitter Interferometer includes the first beam splitter, the first bundling device and merges with the first beam splitter optocoupler and the first bundling device light The first arm and the second arm of coupling, first beam splitter are coupled to first bundling device through first arm and the second arm, A point polarization difference control device is provided on wherein at least described first arm, described point of polarization difference control device includes polarization point Beam device, the second bundling device and merge with the polarization beam apparatus optocoupler with two sub-lights of the second bundling device optical coupling Road, the polarization beam apparatus are coupled to second bundling device through the two strips optical path, wherein first arm and the second arm And optical device thereon is configured so as to pass through in each leisure interferometer of two orthogonal polarisation states of the first via light pulse First arm and the phase difference of the second arm transmission differ the integral multiple of 2 π,

Wherein the decoding apparatus also has positioned at the preposition beam splitter front end or is located at the interferometer front end or position Phase-modulator at least one of first arm and the second arm,

Wherein the phase-modulator is used to randomly carry out 0 degree of phase-modulation or 180 degree phase to by its light pulse Position modulation.

2. quantum key distribution time bit-phase decoding device of according to scheme 1 point of polarization difference control, It is characterized in that, first arm and the second arm are polarization maintaining optical fibre optical path, and the optical device on first arm and the second arm is polarization Keep optical device and/or non-birefringent optical device.

3. quantum key distribution time bit-phase decoding device of according to scheme 1 point of polarization difference control, It is characterized in that, the decoding apparatus further include:

Polarization maintaining optical fibre stretcher, the polarization maintaining optical fibre stretcher are located on any arm in first arm and the second arm； And/or

Birefringent phase modulator, the birefringent phase modulator are located at any arm in first arm and the second arm On.

4. quantum key distribution time bit-phase decoding device of according to scheme 1 point of polarization difference control, It is characterized in that, the phase-modulator includes:

Phase-modulator positioned at the interferometer front end；Or

Phase-modulator on second arm；Or

Phase-modulator on the first arm is set before the polarization beam apparatus, or in second bundling device Phase-modulator on the first arm is set later, or two phase-modulations being located in the two strips optical path Device.

5. quantum key distribution time bit-phase decoding device of according to scheme 1 point of polarization difference control, It is characterized in that, at least one sub-light road in the two strips optical path is provided with optical fiber phase shifter or phase-modulator.

6. quantum key distribution time bit-phase decoding device of according to scheme 1 point of polarization difference control, It is characterized in that,

The interferometer uses the structure of unequal arm Mach-Zender interferometer；Or

The interferometer uses the structure of unequal arm Michelson's interferometer, and first bundling device and the first beam splitter are Same device, the interferometer further include:

The first reflecting mirror on first arm, for that will be passed from first beam splitter through first arm Defeated next light pulse is reflected back first bundling device；

The second reflecting mirror on second arm, for that will be passed from first beam splitter through second arm Defeated next light pulse is reflected back first bundling device.

7. quantum key distribution time bit-phase decoding device of according to scheme 6 point of polarization difference control, It is characterized in that,

Described point of polarization difference control device uses the structure of Mach-Zehnder optical path；Or

Described point of polarization difference control device uses the structure of Michelson optical path, and the polarization beam apparatus and second closes beam Device is same device, and described point of polarization difference control device further includes two reflecting mirrors, wherein one in described two reflecting mirrors In an a strip optical path in the two strips optical path, for will be from the polarization beam apparatus through a sub-light The light pulse that road transmission comes is reflected back second bundling device；Another in described two reflecting mirrors is located at two sub-lights Light arteries and veins in another strip optical path in road, for will come from the polarization beam apparatus through another strip optic path Punching is reflected back second bundling device, wherein the interferometer uses the structure of unequal arm Michelson's interferometer, it is described two One of reflecting mirror is first reflecting mirror.

8. according to quantum key distribution time bit-phase of point polarization difference control any in scheme 1~6 Decoding apparatus, which is characterized in that second bundling device is polarization-maintaining coupler or polarization beam combiner.

9. quantum key distribution time bit-phase decoding device of according to scheme 1 point of polarization difference control, It is characterized in that, the decoding apparatus further includes the second beam splitter, and second beam splitter is optically coupled to the preposition beam splitter Another output mouth in described two output ports.

10. a kind of quantum key distribution system, which is characterized in that the quantum key distribution system includes:

According to quantum key distribution time bit-phase decoding of point polarization difference control any in scheme 1~9 The receiving end of the quantum key distribution system is arranged in device, is used for time bit-phase decoding；And/or

According to quantum key distribution time bit-phase decoding of point polarization difference control any in scheme 1~9 The transmitting terminal of the quantum key distribution system is arranged in device, is used for time bit-phase code.

Using the embodiment of the utility model, it can be achieved that multiple advantages.For time bit-phase code quantum key distribution Using each comfortable unequal arm of two orthogonal polarisation states of the utility model in the decoding of phase base through control input optical pulse is dry The difference of the phase difference transmitted in the two-arm of interferometer realizes that the two orthogonal polarisation states effectively interfere output in output port simultaneously, It is achieved in the immune phase base decoding function of environmental disturbances, makes it possible to realize the immune time ratio of stable environmental disturbances Spy-phase code quantum key distribution solution.In addition, by being carried out to the light pulse of at least arm transmission along interferometer Polarization diversity processing, makes it possible to independently carry out phase controlling to two orthogonal polarisation states of the light pulse, to be easier Realize that the difference of the phase difference transmitted in the two-arm of each comfortable unequal arm interferometer of two orthogonal polarisation states of input optical pulse meets It is required that (that is, being the integral multiple of 2 π).The utility model provides a kind of time bit-for facilitating feasible anti-polarization induction decline Phase code quantum key distribution solution, while avoid the need for complicated correcting device.In addition, the utility model pair The type for the interferometer that decoding apparatus uses does not constrain, and most common unequal arm Mach-Zender interferometer can be used, make Light pulse need to only pass through a phase-modulator in decoding, thus be conducive to the insertion loss, the raising system that reduce receiving end Efficiency.

Detailed description of the invention

Fig. 1 is quantum key distribution time bit-phase of point polarization difference control of one preferred embodiment of the utility model The flow chart of position coding/decoding method；

Fig. 2 is quantum key distribution time bit-phase of point polarization difference control of one preferred embodiment of the utility model The composed structure schematic diagram of position decoding apparatus；

Fig. 3 is the quantum key distribution time bit-of point polarization difference control of another preferred embodiment of the utility model The composed structure schematic diagram of phase decoding device；

Fig. 4 is the quantum key distribution time bit-of point polarization difference control of another preferred embodiment of the utility model The composed structure schematic diagram of phase decoding device；

Fig. 5 is the quantum key distribution time bit-of point polarization difference control of another preferred embodiment of the utility model The composed structure schematic diagram of phase decoding device；

Fig. 6 is the quantum key distribution time bit-of point polarization difference control of another preferred embodiment of the utility model The composed structure schematic diagram of phase decoding device；

Fig. 7 is the quantum key distribution time bit-of point polarization difference control of another preferred embodiment of the utility model The composed structure schematic diagram of phase decoding device；

Fig. 8 is the quantum key distribution time bit-of point polarization difference control of another preferred embodiment of the utility model The composed structure schematic diagram of 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 Point, 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 When the theme of the utility model may be made smudgy, to the detailed specific of the known function and structure of device described herein Illustrate to omit.

A kind of quantum key distribution time bit-phase of point of polarization difference control of one preferred embodiment of the utility model Coding/decoding method is as shown in Figure 1, comprising 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.

Incident input optical pulse is random polarization state, can be linear polarization, circular polarization or elliptical polarization Complete polarized light is also possible to partial poolarized light or non-polarized light.

Step S102: according to quantum key distribution agreement, phase decoding is carried out to the first via light pulse and to described Second tunnel light pulse carries out the decoding of time bit.

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 first via light pulse beam splitting can also equally regard as by with the road light pulse identical two A orthogonal polarisation state composition.

Phase decoding is carried out to the first via light pulse can include: by the first via optical pulse strikes to including beam splitting The interferometer of device and bundling device, using by the beam splitter by the first via light pulse beam splitting as the pulse of first via sub-light and second Way light pulse；The first via sub-light pulse and the second way light are transmitted along the first arm of the interferometer and the second arm respectively Pulse, and it is defeated by beam is closed by the bundling device after the first via sub-light pulse and the second way light pulse progress relative time delay Out.

In the method, phase-modulation is carried out according to quantum key distribution agreement to the input optical pulse before beam splitting, Perhaps to the first via light pulse before beam splitting according to quantum key distribution agreement progress phase-modulation or in the beam splitting To at least one in the first via sub-light pulse and the second way light pulse during device beam splitting to bundling device conjunction beam Way light pulse carries out phase-modulation according to quantum key distribution agreement.

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.

Method according to the present utility model is can obtaining first via light pulse beam splitting, respectively along the first arm and second Any way light pulse in the pulse of first via sub-light and the second way light pulse of arm transmission carries out polarization diversity processing, or Polarization diversity processing is carried out respectively to both the pulse of first via sub-light and the second way light pulse.

For carrying out polarization diversity processing to the first via sub-light pulse transmitted along first arm, for the first via Sub-light pulse: being the mutually orthogonal two-way polariton light pulse of polarization state by the first via sub-light pulse polarization beam splitting, along two Two-way polariton light pulse described in sub- optic path, it is the first via sub-light that beam then is closed in the two-way polariton light pulse Pulse is transmitted to the bundling device along first arm.

Method according to the present utility model, each leisure of two orthogonal polarisation states for controlling the first via light pulse are described dry The phase difference transmitted in interferometer through first arm and the second arm differs the integral multiple of 2 π.

For example, it is assumed that the two orthogonal polarisation states are respectively x-polarisation state and y-polarisation state, by x-polarisation state at described point The phase meter that bundling device described in beam device beam splitting transmits during closing beam through the first arm and the second arm is shown as Δ x, by y-polarisation state The phase meter transmitted during beam is closed in the beam splitter beam splitting to the bundling device through the first arm and the second arm is shown as Δ Y is then closed in each comfortable interferometer of the two of first via light pulse orthogonal polarisation state in the beam splitter beam splitting to the bundling device The integral multiple that the phase difference transmitted during beam through the first arm and the second arm differs 2 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.

Through the first arm and the second arm in each leisure interferometer of two orthogonal polarisation states to realize first via light pulse The phase difference of transmission differs the integral multiple of 2 π, can be using any or any combination thereof in following means:

It is inclined to the pulse of sub-light all the way for being subjected to polarization diversity processing in the pulse of first via sub-light and the second way light pulse At least one of the two-way polariton light pulse that vibration beam splitting obtains carries out phase controlling.To first transmitted along first arm For way light pulse carries out polarization diversity processing, in this case: can be along described in the two strips optic path the To at least one of this two-way polariton light pulse during the two-way polariton light pulse that sub-light pulse polarization beam splitting obtains all the way Carry out phase controlling.For example, carrying out phase controlling at least one of this two-way polariton light pulse can include: adjust this two-way The phase of any road polariton light pulse in polariton light pulse, or to adjust the road this two-way polariton light pulse Zhong Mei inclined The phase of oscillator light pulse.For example, as needed, can match on the sub-light road for transmitting one of this two-way polariton light pulse Optical fiber phase shifter or phase-modulator are set, or in the every of transmission this two-way polariton light pulse Zhong Mei road polariton light pulse Optical fiber phase shifter or phase-modulator are configured in strip optical path, respectively to adjust phase by the optical fiber phase shifter or phase-modulator Answer the transmission phase of polariton light pulse.Optical fiber phase shifter is suitable for being adjusted the length of the optical path where it and thus adjusting The transmission phase of the light pulse of optic path where it, is particularly suitable for the length adjustment of polarization maintaining optical fibre optical path.

First arm and the second arm include that there are birefringent optical paths for described two orthogonal polarisation states, and/or On first arm and the second arm have for described two orthogonal polarisation states, there are birefringent optical devices, in the case such as Under control in each leisure interferometer of two orthogonal polarisation states of the first via light pulse describedly through first arm and The difference of the phase difference of second arm transmission: it is kept in each leisure interferometer of the two orthogonal polarisation states respectively along first arm It is constant with polarization state when the transmission of the second arm；And adjustment is there are the length of birefringent optical path and/or there are birefringent smooth devices The birefringent size of part, so that being transmitted in each leisure interferometer of the two orthogonal polarisation states through first arm and the second arm Phase difference differ 2 π integral multiple.Optionally, this can pass through following any realization: i) match first arm and the second arm It is set to polarization maintaining optical fibre optical path, configures non-birefringent optical device and/or polarization for the optical device on first arm and the second arm Keep optical device；Ii free space optical path) is configured by first arm and the second arm, it will be on first arm and the second arm Optical device is configured to polarization and keeps optical device.It, can be at least one arm in first arm and the second arm in the case where i) Upper configuration polarization maintaining optical fibre stretcher and/or birefringent phase modulator.Polarization maintaining optical fibre stretcher is suitable for adjusting the optical path where it Polarization maintaining optical fibre length.Birefringent phase modulator is suitable for applying different adjustable phases to by its two orthogonal polarisation states Position modulation, thus can be provided to influence and adjust in each comfortable interferometer of two orthogonal polarisation states of first via light pulse through institute State the difference of the phase difference of the first arm and the transmission of the second arm.For example, birefringent phase modulator can be lithium niobate phase modulator, It is applied to the voltage of lithium columbate crystal by controlling, can respectively be passed through to by two orthogonal polarisation states of the phase-modulator The phase-modulation received is controlled and is adjusted.Birefringent phase modulator can be used for influencing and adjusting first via light pulse as a result, Each comfortable interferometer of two orthogonal polarisation states in the difference of phase difference transmitted through first arm and the second arm.

Free space optical path is configured by first arm and the second arm, by the light device on first arm and the second arm Part is configured to non-birefringent optical device.In this case, each comfortable institute of two orthogonal polarisation states of the first via light pulse It is constant to state polarization state when transmitting in interferometer along first arm and the second arm, and described in each leisure of the two orthogonal polarisation states It can be identical along the phase difference that first arm and the second arm transmit in interferometer.

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." non-birefringent optical device ", which refers to, has identical folding for different polarization states (for example, two orthogonal polarisation states) Penetrate the optical device of rate.In addition, polarization keeps optical device to be alternatively referred to as polarization-maintaining optical device.

It as described above, can be optionally during the bundling device of the beam splitter beam splitting of interferometer to interferometer closes beam To in the first via sub-light pulse and the second way light pulse at least all the way sub-light pulse according to quantum key distribution agreement Carry out phase-modulation.Furthermore it is possible to the first via sub-light pulse transmitted respectively along the first arm of interferometer and the second arm and the Both two way light pulses or either of which carry out polarization diversity processing.To any way light for being subjected to polarization diversity processing Pulse --- such as first via sub-light pulse ---, which carries out phase-modulation, to pass through following any realization: before polarization beam splitting Phase-modulation is carried out to first via sub-light pulse, or to the first via after carrying out conjunction beam to corresponding two-way polariton light pulse Sub-light pulse carries out phase-modulation, or in polarization beam splitting to right during carrying out conjunction beam to corresponding two-way polariton light pulse This two-way polariton light pulse carries out identical phase-modulation.Sub-light pulse to polarization diversity processing is not subjected to --- if there is If, such as the second way light pulse --- carrying out phase-modulation may include: the beam splitter beam splitting in interferometer to interferometer Bundling device close beam during to the second way light pulse carry out phase-modulation.In any case, to corresponding light pulse into Row phase-modulation may include that 0 degree of phase-modulation or 180 degree phase-modulation are randomly carried out to the light pulse.Here, randomly Carry out 0 degree phase-modulation or 180 degree phase-modulation refer to randomly carry out being selected from 0 degree of phase-modulation and 180 degree phase-modulation this Phase-modulation in the two.

Carrying out phase-modulation to a light pulse can be realized by polarizing unrelated phase-modulator.Polarize unrelated phase-modulation Device is suitable for carrying out identical phase-modulation to two orthogonal polarisation states of light pulse, so referred to as polarizing unrelated.Citing and Speech, polarizing unrelated phase-modulator can be realized by two birefringent phase modulator serial or parallel connections.According to circumstances, Ke Yitong A variety of specific meanss are crossed to realize phase-modulation.For example, these means can include: the length of modulation free space optical path, or The length of modulation optical fiber, or utilize serial or parallel connection optical waveguide phase-modulator etc..For example, can be by being changed freely with motor The length of space optical path realizes desired phase-modulation.For another example, it can be modulated by the fiber stretcher using piezoelectric effect The length of optical fiber, is achieved in phase-modulation.In addition, phase-modulator can be suitable for voltage-controlled other types, pass through Apply suitable voltage to polarizing unrelated phase-modulator to carry out identical phase tune to two orthogonal polarisation states of light pulse System is, it can be achieved that desired phase-modulation.

The decoding of time bit is carried out to second tunnel light pulse can include: second tunnel light pulse is directly exported into use In detection；Or output after the second tunnel light pulse beam splitting is used to detect.

A kind of quantum key distribution time bit-phase of point of polarization difference control of one preferred embodiment of the utility model Decoding apparatus is as shown in Fig. 2, include consisting of part: preposition beam splitter 201, beam splitter 202 and 203, polarization beam apparatus 204, polarization beam combiner 205, phase-modulator 206 and bundling device 207.

Beam splitter 203, bundling device 207 and the two-arm between them constitute an interferometer.Polarization beam apparatus 204, polarization Bundling device 205 and two strip optical paths between them totally can be described as a point polarization difference control device.Divide polarization difference control dress Set the two-arm for being inserted into interferometer respectively with phase-modulator 206.For convenience, differing inserted with a point polarization for interferometer controls The arm of device is hereinafter also referred to the first arm, and the arm inserted with phase-modulator 206 of interferometer is hereinafter also referred to the Two arms.

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.

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

Beam splitter 202 and preposition 201 optical coupling of beam splitter, for receiving the another way light arteries and veins in above-mentioned two-way light pulse Punching, and output after the another way light pulse beam splitting is used to carry out time bit decoding.Here, it should be noted that beam splitter 202 be optional.The another way light pulse is directly exported by preposition beam splitter 201 and is used to carry out time bit to decode to be possible 's.

Beam splitter 203 for will from the first via light pulse beam splitting of preposition beam splitter 201 be the pulse of first via sub-light and Second way light pulse.

First arm and the second arm are used for real for transmitting the first via sub-light pulse and the second way light pulse respectively The relative time delay of the existing first via sub-light pulse and the second way light pulse.

Bundling device 207 is used to the first via sub-light pulse through relative time delay and the second way light pulse closing beam defeated Out.

Phase-modulator 206 is used to carry out the sub-light pulse through the arm transmission where it according to quantum key distribution agreement Phase-modulation.

Polarization beam apparatus 204 is used to be that the mutually orthogonal two-way of polarization state is inclined by the first via sub-light pulse polarization beam splitting Oscillator light pulse.

The two strips optical path for transmitting the two-way polariton light pulse respectively.

The two-way polariton light pulse of the polarization beam combiner 205 for that will come through the two strips optic path, which polarizes, closes Beam is transmitted to bundling device 207 along first arm for the first via sub-light pulse.

For the decoding apparatus of Fig. 2, the first arm and the second arm of interferometer and optical device thereon are constructed such that, enter It is incident upon in each leisure interferometer of two orthogonal polarisation states of the first via light pulse of the interferometer through first arm and The phase difference of two arms transmission differs the integral multiple of 2 π.

It can be long by adjusting optical path physics any in the first arm and the second arm between beam splitter 203 and bundling device 207 Spend the relative time delay to realize two-way sub-light pulse.

Phase-modulator 206 can randomly carry out 0 degree of phase-modulation or 180 degree of phases to by its sub-light pulse Modulation.

Phase-modulator 206 can be the unrelated phase-modulator of polarization, including having carried out birefringence-compensated doublet refractor Part (such as being realized by two birefringent phase modulators of serial or parallel connection) or above-mentioned other polarize unrelated phase Modulator.

A point polarization difference control device is provided on only the first arm of interferometer although showing in Fig. 2, but it is also possible that It is provided on only the second arm of interferometer each on both the first arm and second arms of point polarization difference control device or interferometer It is provided with a point polarization difference control device.

Although point polarization difference control device in Fig. 2 has used polarization beam combiner 205, however it is possible that with polarization-maintaining coupling Clutch replaces polarization beam combiner 205 to carry out conjunction beam to the light pulse of two-way polariton.

Although the interferometer in Fig. 2 is the structure of unequal arm Mach-Zender interferometer, which can be using not The structure of equiarm Michelson's interferometer.

In addition, although point polarization difference control device in Fig. 2 is the structure of Mach-Zehnder optical path, this point polarization It is possible that control device, which is differed, using the structure of Michelson optical path.

Although Fig. 2 shows phase-modulator only is arranged on the second arm of interferometer, but it is also possible that only in interferometer The first arm on phase-modulator or one phase-modulator of each setting on both the first arm of interferometer and the second arm are set. In the case where one phase-modulator of each setting on both the first arm of interferometer and the second arm, two phase-modulators are modulated The difference of phase determined by quantum key distribution agreement.In addition, instead of in one of the first arm of interferometer and the second arm or two Phase-modulator is set on person, phase-modulator can be set in 203 front end of beam splitter, i.e., to the first via before beam splitting Light pulse carries out phase-modulation according to quantum key distribution agreement.Furthermore, it is also possible that being set before preposition beam splitter 201 Phase-modulator is set, i.e., phase-modulation is carried out to incident input optical pulse.

For the decoding apparatus of Fig. 2, interferometer can optionally have any or any combination thereof in following setting:

The first arm and the second arm of the interferometer are polarization maintaining optical fibre optical path, the light device on first arm and the second arm Part is that polarization keeps optical device and/or non-birefringent optical device.

The interferometer further include: polarization maintaining optical fibre stretcher, the polarization maintaining optical fibre stretcher be located at first arm and On any arm in second arm, for adjusting the polarization maintaining optical fibre length of the arm where it；And/or birefringent phase modulator, institute It states on any arm that birefringent phase modulator is located in first arm and the second arm, for the sub-light pulse by it Two orthogonal polarisation states apply different adjustable phase-modulations.

At least one sub-light road in the two strip optical paths for being divided to polarization difference control device of insertion is provided with optical fiber Phase shifter or phase-modulator, the optical fiber phase shifter or phase-modulator are for adjusting through the inclined of the sub- optic path where it The transmission phase of oscillator light pulse.

The interferometer uses the structure of unequal arm Michelson's interferometer, the beam splitter and bundling device of the interferometer For same device, the interferometer further include: the first reflecting mirror on first arm, for the interferometer will to be come from Beam splitter through first arm transmission come the first via sub-light pulse-echo return the interferometer bundling device；It is located at The second reflecting mirror on second arm, for the institute of coming will to be transmitted through second arm from the beam splitter of the interferometer State the bundling device that the second way light pulse is reflected back the interferometer.

Point polarization difference control device of insertion uses the structure of Michelson optical path, the polarization beam apparatus and polarization Bundling device is same device, and described point of polarization difference control device further includes two reflecting mirrors, wherein in described two reflecting mirrors A strip optical path being located in the two strips optical path on, for will be from the polarization beam apparatus through described one The polariton light pulse that sub- optic path is come is reflected back the polarization beam combiner；Another in described two reflecting mirrors is located at institute It states in another strip optical path in two strip optical paths, for that will be passed from the polarization beam apparatus through another strip optical path Defeated next polariton light pulse is reflected back the polarization beam combiner, wherein the interferometer uses unequal arm Michael as described above The structure of inferior interferometer, the first reflecting mirror are one of described two reflecting mirrors of described point of polarization difference control device.

The interferometer uses the structure of unequal arm Michelson's interferometer, the input terminal of the interferometer as described above Mouth and output port are same port, and the interferometer further includes optical circulator, and the optical circulator is located at the interferometer Beam splitter front end, the first via light pulse from preposition beam splitter input from the first port of the optical circulator and from institutes The second port for stating optical circulator exports the conjunction beam output of the bundling device to the beam splitter of the interferometer, from the interferometer It is input to the second port of the optical circulator and is exported from the third port of the optical circulator.

It, can be optionally in the case where being provided with polarization maintaining optical fibre stretcher on the first arm of interferometer and/or the second arm Polarization maintaining optical fibre stretcher is used as phase-modulator, for carrying out phase-modulation to the light pulse through the arm transmission where it.

For interferometer inserted with a point arm for polarization difference control device, such as fiber-draw of polarization maintaining optical fibre stretcher Device can be set on the arm before or after this point polarizes difference control device.

It, can be in the case where being each provided with optical fiber phase shifter in the two strips optical path for being divided to polarization difference control device Optical fiber phase shifter is optionally used as phase-modulator, for carrying out identical phase-modulation to two-way polariton light pulse.

A kind of quantum key distribution time bit-phase of point of polarization difference control of another preferred embodiment of the utility model Position decoding apparatus is as shown in figure 3, include consisting of part: beam splitter 303 and 304, polarization-maintaining beam splitter 307, polarization beam apparatus 308, polarization maintaining optical fibre phase shifter 309, polarization beam combiner 310, phase-modulator 311, polarization-maintaining bundling device 312.

Beam splitter 303 is used as preposition beam splitter, input terminal of one of two ports 301 and 302 of one side as device. Polarization-maintaining beam splitter 307, polarization-maintaining bundling device 312 and two arms between them constitute a polarization-maintaining Mach-Zender interferometer.Partially Vibration beam splitter 308, polarization beam combiner 310 and two strip optical paths between them totally can be described as a point polarization difference control device. This point polarization difference control device and phase-modulator 311 are inserted into the two-arm of Mach-Zender interferometer respectively.Polarization maintaining optical fibre moves Phase device 309 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For convenience, Mach-Zender interferometer Inserted with point polarization difference control device an arm below be also known as the first arm, Mach-Zender interferometer inserted with phase The arm of position modulator 311 is also known as the second arm below.

When work, incident input optical pulse through preposition beam splitter 303 port 301 or 302 enter beam splitter 303, by Beam splitter 303, which is divided into two-way light pulse, to be transmitted.

Light pulse all the way from preposition beam splitter 303 is input to beam splitter 304, and by after 304 beam splitting of beam splitter through holding Mouth 305 or the output of port 306 are for carrying out time bit decoding.

Another way light pulse from preposition beam splitter 303 is input to polarization-maintaining beam splitter 307, and by polarization-maintaining beam splitter 307 Beam splitting is the pulse of first via sub-light and the second way light pulse.The pulse of first via sub-light is by 308 polarization beam splitting of polarization beam apparatus Two-way polariton light pulse；This two-way polariton light pulse is transmitted to polarization beam combiner 310 through two the first sub-light roads respectively, and Polarization-maintaining bundling device 312 is transmitted to along the first arm by 310 polarization coupling of polarization beam combiner for the pulse of first via sub-light.Second way light Polarization-maintaining bundling device 312 is transmitted to after pulse 0 degree of phase of phase modulated 311 Stochastic Modulation of device or 180 degree phase.It is transmitted to guarantor Inclined bundling device 312 through the first via sub-light pulse of relative time delay and the second way light pulse after polarization-maintaining bundling device 312 closes beam It is exported by port 313.Polarization beam splitting is being carried out to during closing beam to first via sub-light pulse, polarization maintaining optical fibre phase shifter can be passed through 309 pairs of polariton light pulses through the sub- optic path where polarization maintaining optical fibre phase shifter 309 carry out phase adjustment.

Phase-modulator 311 is to polarize unrelated device, (such as logical including having carried out birefringence-compensated birefringent device Two birefringent phase modulators for crossing serial or parallel connection are realized) or other above-mentioned unrelated phase-modulators of polarization.

An optical fiber phase shifter can be respectively inserted by being divided to two strip optical paths of polarization difference control device.In this case, it is possible to Identical phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, it is thus real The phase-modulation function of existing phase-modulator 311；I.e., it is possible to omit phase-modulator 311.

In addition, the same of Mach-Zender interferometer can be inserted in this point polarization difference control device and phase-modulator 311 One arm, and the above-mentioned course of work is unaffected.

A kind of quantum key distribution time bit-phase of point of polarization difference control of another preferred embodiment of the utility model Position decoding apparatus is as shown in figure 4, include consisting of part: beam splitter 403, polarization beam apparatus 406, is protected polarization-maintaining beam splitter 405 Polarisation fibre phase shifter 407, polarization beam combiner 408, phase-modulator 409, polarization-maintaining bundling device 410.

Beam splitter 403 is used as preposition beam splitter, input terminal of one of two ports 401 and 402 of one side as device. Polarization-maintaining beam splitter 405, polarization-maintaining bundling device 410 and two arms between them constitute a polarization-maintaining Mach-Zender interferometer.Partially Vibration beam splitter 406, polarization beam combiner 408 and two strip optical paths between them totally can be described as a point polarization difference control device. This point polarization difference control device and phase-modulator 409 are inserted into the two-arm of Mach-Zender interferometer respectively.Polarization maintaining optical fibre moves Phase device 407 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For convenience, Mach-Zender interferometer Inserted with point polarization difference control device an arm below be also known as the first arm, Mach-Zender interferometer inserted with phase The arm of position modulator 409 is also known as the second arm below.

When work, incident input optical pulse through preposition beam splitter 403 port 401 or 402 enter beam splitter 403, by Beam splitter 403, which is divided into two-way light pulse, to be transmitted.

Light pulse all the way from preposition beam splitter 403 is either directly output for carrying out time bit decoding.

Another way light pulse from preposition beam splitter 403 is input to polarization-maintaining beam splitter 405, and by polarization-maintaining beam splitter 405 Beam splitting is the pulse of first via sub-light and the second way light pulse.The pulse of first via sub-light is by 406 polarization beam splitting of polarization beam apparatus Two-way polariton light pulse；This two-way polariton light pulse is transmitted to polarization beam combiner 408 through two the first sub-light roads respectively, and Polarization-maintaining bundling device 410 is transmitted to along the first arm by 408 polarization coupling of polarization beam combiner for the pulse of first via sub-light.Second way light Polarization-maintaining bundling device 410 is transmitted to after pulse 0 degree of phase of phase modulated 409 Stochastic Modulation of device or 180 degree phase.It is transmitted to guarantor Inclined bundling device 410 through the first via sub-light pulse of relative time delay and the second way light pulse after polarization-maintaining bundling device 410 closes beam It is exported by port 411.Polarization beam splitting is being carried out to during closing beam to first via sub-light pulse, polarization maintaining optical fibre phase shifter can be passed through 407 pairs of polariton light pulses through the sub- optic path where polarization maintaining optical fibre phase shifter 407 carry out phase adjustment.

Phase-modulator 409 is to polarize unrelated device, (such as logical including having carried out birefringence-compensated birefringent device Two birefringent phase modulators for crossing serial or parallel connection are realized) or other above-mentioned unrelated phase-modulators of polarization.

An optical fiber phase shifter can be respectively inserted by being divided to two strip optical paths of polarization difference control device.In this case, it is possible to Identical phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, it is thus real The phase-modulation function of existing phase-modulator 409；I.e., it is possible to omit phase-modulator 409.

In addition, the same of Mach-Zender interferometer can be inserted in this point polarization difference control device and phase-modulator 409 One arm, and the above-mentioned course of work is unaffected.

A kind of quantum key distribution time bit-phase of point of polarization difference control of another preferred embodiment of the utility model Position decoding apparatus is as shown in figure 5, include consisting of part: beam splitter 503 and 504, polarization-maintaining beam splitter 507, polarization beam apparatus 508, polarization maintaining optical fibre phase shifter 509, polarization beam combiner 510, phase-modulator 512 and reflecting mirror 511 and 513.

Beam splitter 503 is used as preposition beam splitter, input terminal of one of two ports 501 and 502 of one side as device. Polarization-maintaining beam splitter 507, two two arms between reflecting mirror 511 and 513 and polarization-maintaining beam splitter 507 and the two reflecting mirrors Constitute a polarization-maintaining Michelson's interferometer.Polarization beam apparatus 508, polarization beam combiner 510 and two strip optical paths between them It totally can be described as a point polarization difference control device.This point polarization difference control device and phase-modulator 512 are inserted into mikey respectively The two-arm of your inferior interferometer.Polarization maintaining optical fibre phase shifter 509 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For For the sake of convenient, Michelson's interferometer is also known as the first arm, Michael inserted with a point arm for polarization difference control device below The arm inserted with phase-modulator 512 of inferior interferometer is also known as the second arm below.

When work, incident input optical pulse through preposition beam splitter 503 port 501 or 502 enter beam splitter 503, by Beam splitter 503, which is divided into two-way light pulse, to be transmitted.

Light pulse all the way from preposition beam splitter 503 is input to beam splitter 504, and by after 504 beam splitting of beam splitter through holding Mouth 505 or the output of port 506 are for carrying out time bit decoding.

Another way light pulse from preposition beam splitter 503 is input to polarization-maintaining beam splitter 507, and by polarization-maintaining beam splitter 507 Beam splitting is the pulse of first via sub-light and the second way light pulse.The pulse of first via sub-light is by 508 polarization beam splitting of polarization beam apparatus Two-way polariton light pulse；This two-way polariton light pulse is transmitted to polarization beam combiner 510 through two the first sub-light roads respectively, and By 510 polarization coupling of polarization beam combiner be the pulse of first via sub-light along the first arm be transmitted to reflecting mirror 511 and by reflecting mirror 511 it is anti- It is emitted back towards and.Reflecting mirror is transmitted to after second way light pulse, 0 degree of phase of phase modulated 512 Stochastic Modulation of device or 180 degree phase It 513 and is reflected by reflecting mirror 513.The reflected first via sub-light pulse through relative time delay and the second way light arteries and veins Punching is exported after polarization-maintaining beam splitter 507 closes beam by port 514.Polarization beam splitting is being carried out to the conjunction beam phase to first via sub-light pulse Between, 509 pairs of polarization sub-light arteries and veins through the sub- optic path where polarization maintaining optical fibre phase shifter 509 of polarization maintaining optical fibre phase shifter can be passed through Rush in horizontal phasing control.

Phase-modulator 512 is to polarize unrelated device, (such as logical including having carried out birefringence-compensated birefringent device Two birefringent phase modulators for crossing serial or parallel connection are realized) or other above-mentioned unrelated phase-modulators of polarization.

An optical fiber phase shifter can be respectively inserted by being divided to two strip optical paths of polarization difference control device.In this case, it is possible to Identical phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, it is thus real The phase-modulation function of existing phase-modulator 512；I.e., it is possible to omit phase-modulator 512.

In addition, the same of Michelson's interferometer can be inserted in this point polarization difference control device and phase-modulator 512 Arm, and the above-mentioned course of work is unaffected.

A kind of quantum key distribution time bit-phase of point of polarization difference control of another preferred embodiment of the utility model Position decoding apparatus is as shown in fig. 6, include consisting of part: beam splitter 603 and 604, polarization-maintaining beam splitter 607, polarization beam apparatus 608, polarization maintaining optical fibre phase shifter 609, phase-modulator 612 and reflecting mirror 610,611 and 613.

Beam splitter 603 is used as preposition beam splitter, input terminal of one of two ports 601 and 602 of one side as device. An arm, polarization-maintaining beam splitter 607 between polarization-maintaining beam splitter 607, polarization-maintaining beam splitter 607 and two reflecting mirrors 610 and 611 and anti- Another arm and reflecting mirror 610,611,613 penetrated between mirror 613 constitute a polarization-maintaining Michelson's interferometer.Polarization beam splitting Two strip optical paths and the two reflecting mirrors between device 608, polarization beam apparatus 608 and two reflecting mirrors 610 and 611 totally may be used Referred to as divide polarization difference control device.It is dry that this point polarization difference control device and phase-modulator 612 are inserted into Michelson respectively The two-arm of interferometer.Polarization maintaining optical fibre phase shifter 609 is inserted into any in the two strip optical paths for being divided to polarization difference control device.It rises for convenience See, Michelson's interferometer is also known as the first arm, Michelson interference inserted with a point arm for polarization difference control device below The arm inserted with phase-modulator 612 of instrument is also known as the second arm below.

When work, incident input optical pulse through preposition beam splitter 603 port 601 or 602 enter beam splitter 603, by Beam splitter 603, which is divided into two-way light pulse, to be transmitted.

Light pulse all the way from preposition beam splitter 603 is input to beam splitter 604, and by after 604 beam splitting of beam splitter through holding Mouth 605 or the output of port 606 are for carrying out time bit decoding.

Another way light pulse from preposition beam splitter 603 is input to polarization-maintaining beam splitter 607, and by polarization-maintaining beam splitter 607 Beam splitting is the pulse of first via sub-light and the second way light pulse.The pulse of first via sub-light is by 608 polarization beam splitting of polarization beam apparatus Two-way polariton light pulse；This two-way polariton light pulse respectively through two the first sub-light roads be transmitted separately to reflecting mirror 610, 611 and polarization beam apparatus 608 is reflected back by reflecting mirror 610,611 respectively, and is the first via by 608 polarization coupling of polarization beam apparatus Sub-light pulse is transmitted to polarization-maintaining beam splitter 607 along the first arm.Phase modulated 0 degree of 612 Stochastic Modulation of device of second way light pulse It is transmitted to reflecting mirror 613 after phase or 180 degree phase and is reflected by reflecting mirror 613.It is reflected through relative time delay The pulse of first via sub-light and the second way light pulse are exported after polarization-maintaining beam splitter 607 closes beam by port 614.To the first way It, can be by 609 pairs of polarization maintaining optical fibre phase shifter through where polarization maintaining optical fibre phase shifter 609 during light pulse carries out polarization beam splitting extremely conjunction beam Sub- optic path polariton light pulse carry out phase adjustment.

Phase-modulator 612 is to polarize unrelated device, (such as logical including having carried out birefringence-compensated birefringent device Two birefringent phase modulators for crossing serial or parallel connection are realized) or other above-mentioned unrelated phase-modulators of polarization.

An optical fiber phase shifter can be respectively inserted by being divided to two strip optical paths of polarization difference control device.In this case, it is possible to Identical phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, it is thus real The phase-modulation function of existing phase-modulator 612；I.e., it is possible to omit phase-modulator 612.

In addition, the same of Michelson's interferometer can be inserted in this point polarization difference control device and phase-modulator 612 Arm, and the above-mentioned course of work is unaffected.

A kind of quantum key distribution time bit-phase of point of polarization difference control of another preferred embodiment of the utility model Position decoding apparatus is as shown in fig. 7, comprises consisting of part: beam splitter 703, polarization beam apparatus 706, is protected polarization-maintaining beam splitter 705 Polarisation fibre phase shifter 707, polarization beam combiner 708, phase-modulator 710 and reflecting mirror 709 and 711.

Beam splitter 703 is used as preposition beam splitter, input terminal of one of two ports 701 and 702 of one side as device. Polarization-maintaining beam splitter 705, two two arms between reflecting mirror 709 and 711 and polarization-maintaining beam splitter 705 and the two reflecting mirrors Constitute a polarization-maintaining Michelson's interferometer.Polarization beam apparatus 706, polarization beam combiner 708 and two strip optical paths between them It totally can be described as a point polarization difference control device.This point polarization difference control device and phase-modulator 710 are inserted into mikey respectively The two-arm of your inferior interferometer.Polarization maintaining optical fibre phase shifter 707 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For For the sake of convenient, Michelson's interferometer is also known as the first arm, mikey inserted with a point arm for polarization difference control device below The arm inserted with phase-modulator 710 of your inferior interferometer is also known as the second arm below.

When work, incident input optical pulse through preposition beam splitter 703 port 701 or 702 enter beam splitter 703, by Beam splitter 703, which is divided into two-way light pulse, to be transmitted.

Light pulse all the way from preposition beam splitter 703 is either directly output for carrying out time bit decoding.

Another way light pulse from preposition beam splitter 703 is input to polarization-maintaining beam splitter 705, and by polarization-maintaining beam splitter 705 Beam splitting is the pulse of first via sub-light and the second way light pulse.The pulse of first via sub-light is by 706 polarization beam splitting of polarization beam apparatus Two-way polariton light pulse；This two-way polariton light pulse is transmitted to polarization beam combiner 708 through two the first sub-light roads respectively, and By 708 polarization coupling of polarization beam combiner be the pulse of first via sub-light along the first arm be transmitted to reflecting mirror 709 and by reflecting mirror 709 it is anti- It is emitted back towards and.Reflecting mirror is transmitted to after second way light pulse, 0 degree of phase of phase modulated 710 Stochastic Modulation of device or 180 degree phase It 711 and is reflected by reflecting mirror 711.The reflected first via sub-light pulse through relative time delay and the second way light arteries and veins Punching is exported after polarization-maintaining beam splitter 705 closes beam by port 712.Polarization beam splitting is being carried out to the conjunction beam phase to first via sub-light pulse Between, 707 pairs of polarization sub-light arteries and veins through the sub- optic path where polarization maintaining optical fibre phase shifter 707 of polarization maintaining optical fibre phase shifter can be passed through Rush in horizontal phasing control.

Phase-modulator 710 is to polarize unrelated device, (such as logical including having carried out birefringence-compensated birefringent device Two birefringent phase modulators for crossing serial or parallel connection are realized) or other above-mentioned unrelated phase-modulators of polarization.

An optical fiber phase shifter can be respectively inserted by being divided to two strip optical paths of polarization difference control device.In this case, it is possible to Identical phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, it is thus real The phase-modulation function of existing phase-modulator 710；I.e., it is possible to omit phase-modulator 710.

In addition, the same of Michelson's interferometer can be inserted in this point polarization difference control device and phase-modulator 710 Arm, and the above-mentioned course of work is unaffected.

A kind of quantum key distribution time bit-phase of point of polarization difference control of another preferred embodiment of the utility model Position decoding apparatus is as shown in figure 8, include consisting of part: beam splitter 803, polarization beam apparatus 806, is protected polarization-maintaining beam splitter 805 Polarisation fibre phase shifter 807, phase-modulator 810 and reflecting mirror 808,809 and 811.

Beam splitter 803 is used as preposition beam splitter, input terminal of one of two ports 801 and 802 of one side as device. An arm, polarization-maintaining beam splitter 805 between polarization-maintaining beam splitter 805, polarization-maintaining beam splitter 805 and two reflecting mirrors 808 and 809 and anti- Another arm and reflecting mirror 808,809,811 penetrated between mirror 811 constitute a polarization-maintaining Michelson's interferometer.Polarization beam splitting Device 806, two two strip optical paths between reflecting mirror 808 and 809 and polarization beam apparatus 806 and the two reflecting mirrors are overall It can be described as a point polarization difference control device.This point polarization difference control device and phase-modulator 810 are inserted into Michelson respectively The two-arm of interferometer.Polarization maintaining optical fibre phase shifter 807 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For convenience For the sake of, Michelson's interferometer is also known as the first arm, Michelson inserted with a point arm for polarization difference control device below The arm inserted with phase-modulator 810 of interferometer is also known as the second arm below.

When work, incident input optical pulse through preposition beam splitter 803 port 801 or 802 enter beam splitter 803, by Beam splitter 803, which is divided into two-way light pulse, to be transmitted.

Light pulse all the way from preposition beam splitter 803 is either directly output for carrying out time bit decoding.

Another way light pulse from preposition beam splitter 803 is input to polarization-maintaining beam splitter 805, and by polarization-maintaining beam splitter 805 Beam splitting is the pulse of first via sub-light and the second way light pulse.The pulse of first via sub-light is by 806 polarization beam splitting of polarization beam apparatus Two-way polariton light pulse；This two-way polariton light pulse respectively through two the first sub-light roads be transmitted separately to reflecting mirror 808, 809 and polarization beam apparatus 806 is reflected back by reflecting mirror 808,809 respectively, and is the first via by 806 polarization coupling of polarization beam apparatus Sub-light pulse is transmitted to polarization-maintaining beam splitter 805 along the first arm.Phase modulated 0 degree of 810 Stochastic Modulation of device of second way light pulse It is transmitted to reflecting mirror 811 after phase or 180 degree phase and is reflected by reflecting mirror 811.It is reflected through relative time delay The pulse of first via sub-light and the second way light pulse are exported after polarization-maintaining beam splitter 805 closes beam by port 812.To the first way It, can be by 807 pairs of polarization maintaining optical fibre phase shifter through where polarization maintaining optical fibre phase shifter 807 during light pulse carries out polarization beam splitting extremely conjunction beam Sub- optic path polariton light pulse carry out phase adjustment.

Phase-modulator 810 is to polarize unrelated device, (such as logical including having carried out birefringence-compensated birefringent device Two birefringent phase modulators for crossing serial or parallel connection are realized) or other above-mentioned unrelated phase-modulators of polarization.

An optical fiber phase shifter can be respectively inserted by being divided to two strip optical paths of polarization difference control device.In this case, it is possible to Identical phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, it is thus real The phase-modulation function of existing phase-modulator 810；I.e., it is possible to omit phase-modulator 810.

In addition, the same of Michelson's interferometer can be inserted in this point polarization difference control device and phase-modulator 810 Arm, and the above-mentioned course of work is unaffected.

The decoding apparatus of the utility model, as Fig. 3 into Fig. 8 it is any shown in decoding apparatus, the two-arm of interferometer and Optical device in the two-arm is constructed such that two orthogonal polarisation states for being incident to the first via light pulse of the interferometer are each The phase difference transmitted in the comfortable interferometer through this two-arm differs the integral multiple of 2 π.In addition, at least one of described two-arm The light pulse of upper transmission carries out polarization diversity processing, is thus divided to the biography of two orthogonal polarisation states of Polarization Control first via light pulse Defeated phase makes it easy to the difference for realizing above-mentioned phase difference.

Herein, term " beam splitter " and " bundling device " are used interchangeably, and beam splitter is also referred to as and as bundling device, instead ?.Term " polarization beam apparatus " and " polarization beam combiner " are used interchangeably, and polarization beam apparatus is also referred to as and as polarization Bundling device, vice versa

The quantum that can be controlled in point polarization difference that the receiving end of quantum key distribution system configures the utility model is close Key distributes time bit-phase decoding device, is used for time bit-phase decoding.Alternatively, it is also possible in quantum key distribution system The transmitting terminal of system configures quantum key distribution time bit-phase decoding device of point polarization difference control of the utility model, For time bit-phase code.

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.

Claims

1. quantum key distribution time bit-phase decoding device of a kind of point of polarization difference control, for any of incidence The input optical pulse all the way of polarization state carries out time bit-phase decoding, which is characterized in that the decoding apparatus includes:

Preposition beam splitter, the preposition beam splitter have input port and two output ports, and the input port is for receiving The input optical pulse, described two output ports are respectively used to export the first via light obtained by the input optical pulse beam splitting Pulse and the second tunnel light pulse；With

With the interferometer of an output port optical coupling in described two output ports of the preposition beam splitter, the interference Instrument includes the first beam splitter, the first bundling device and merges with the first beam splitter optocoupler and the first bundling device optical coupling The first arm and the second arm, first beam splitter is coupled to first bundling device through first arm and the second arm, wherein A point polarization difference control device is provided at least described first arm, described point of polarization difference control device includes polarization beam splitting Device, the second bundling device and merge with the polarization beam apparatus optocoupler with two strip optical paths of the second bundling device optical coupling, The polarization beam apparatus is coupled to second bundling device through the two strips optical path, wherein first arm and the second arm and its On optical device be configured so that in each leisure interferometer of two orthogonal polarisation states of the first via light pulse through described First arm and the phase difference of the second arm transmission differ the integral multiple of 2 π,

Wherein the decoding apparatus also has positioned at the preposition beam splitter front end or is located at the interferometer front end or is located at institute The phase-modulator at least one of the first arm and the second arm is stated,

Wherein the phase-modulator is used to randomly carry out 0 degree of phase-modulation or 180 degree phase tune to by its light pulse System.

2. quantum key distribution time bit-phase decoding device of according to claim 1 point of polarization difference control, It is characterized in that, first arm and the second arm are polarization maintaining optical fibre optical path, and the optical device on first arm and the second arm is polarization Keep optical device and/or non-birefringent optical device.

3. quantum key distribution time bit-phase decoding device of according to claim 1 point of polarization difference control, It is characterized in that, the decoding apparatus further include:

Polarization maintaining optical fibre stretcher, the polarization maintaining optical fibre stretcher are located on any arm in first arm and the second arm；And/or

Birefringent phase modulator, the birefringent phase modulator are located on any arm in first arm and the second arm.

4. quantum key distribution time bit-phase decoding device of according to claim 1 point of polarization difference control, It is characterized in that, the phase-modulator includes:

Phase-modulator positioned at the interferometer front end；Or

Phase-modulator on second arm；Or

Phase-modulator on the first arm is set before the polarization beam apparatus, or after second bundling device Phase-modulator on the first arm is set, or two phase-modulators being located in the two strips optical path.

5. quantum key distribution time bit-phase decoding device of according to claim 1 point of polarization difference control, It is characterized in that, at least one sub-light road in the two strips optical path is provided with optical fiber phase shifter or phase-modulator.

6. quantum key distribution time bit-phase decoding device of according to claim 1 point of polarization difference control, It is characterized in that,

The first reflecting mirror on first arm, for that will transmit through first arm from first beam splitter Light pulse be reflected back first bundling device；

The second reflecting mirror on second arm, for that will transmit through second arm from first beam splitter Light pulse be reflected back first bundling device.

7. quantum key distribution time bit-phase decoding device of according to claim 6 point of polarization difference control, It is characterized in that,

Described point of polarization difference control device uses the structure of Michelson optical path, and the polarization beam apparatus and the second bundling device are Same device, described point of polarization difference control device further includes two reflecting mirrors, wherein a position in described two reflecting mirrors In a strip optical path in the two strips optical path, for that will be passed from the polarization beam apparatus through the strip optical path Defeated next light pulse is reflected back second bundling device；Another in described two reflecting mirrors is located in the two strips optical path Another strip optical path on, the light pulse for that will come from the polarization beam apparatus through another strip optic path is anti- It is emitted back towards second bundling device, wherein the interferometer uses the structure of unequal arm Michelson's interferometer, described two reflections One of mirror is first reflecting mirror.

8. quantum key distribution time bit-phase of point polarization difference control described according to claim 1~any one of 6 Decoding apparatus, which is characterized in that second bundling device is polarization-maintaining coupler or polarization beam combiner.

9. quantum key distribution time bit-phase decoding device of according to claim 1 point of polarization difference control, It is characterized in that, the decoding apparatus further includes the second beam splitter, and second beam splitter is optically coupled to the preposition beam splitter Another output mouth in described two output ports.

Quantum key distribution time bit-phase solution of point polarization difference control described according to claim 1~any one of 9 Code device, is arranged in the receiving end of the quantum key distribution system, is used for time bit-phase decoding；And/or

Quantum key distribution time bit-phase solution of point polarization difference control described according to claim 1~any one of 9 Code device, is arranged in the transmitting terminal of the quantum key distribution system, is used for time bit-phase code.