CN209218109U - Quantum key distribution time bit-phase decoding device and corresponding system - Google Patents

Abstract

The utility model proposes a kind of quantum key distribution time bit-phase decoding device and corresponding systems.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, by two arms and the direct current phase-modulator in one of two-arm of beam splitter and bundling device optical coupling.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

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 Key distributes time bit-phase decoding method, apparatus 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 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 HVDC Modulation quantum key distribution of a kind of point of polarization difference control Time bit-phase decoding method and apparatus, to solve phase base solution in time bit-phase code quantum key distribution application Phase decoding interferes unstable problem caused by declining when code because of polarization induction.

The utility model provides at least following technical scheme:

1. HVDC Modulation quantum key distribution time bit-phase decoding device of a kind of point of polarization difference control, is used for Time bit-phase decoding is carried out to the input optical pulse all the way of incident random polarization state, which is characterized in that the decoding dress It sets and 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, The interferometer also has the direct current phase-modulator at least one of first arm and the second arm, wherein at least institute It states and is provided with a point polarization difference control device on the first arm, described point of polarization difference control device includes polarization beam apparatus, 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 splitter is coupled to second bundling device through the two strips optical path, wherein first arm and the second arm and light device thereon Part be configured so that in each leisure interferometer of two orthogonal polarisation states of the first via light pulse through first arm and The phase difference of second arm transmission differs the integral multiple of 2 π,

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

2. HVDC Modulation quantum key distribution time bit-phase solution of according to scheme 1 point of polarization difference control Code device, which is characterized in that first arm and the second arm 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.

3. HVDC Modulation quantum key distribution time bit-phase solution of according to scheme 1 point of polarization difference control Code device, which 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. HVDC Modulation quantum key distribution time bit-phase solution of according to scheme 1 point of polarization difference control Code device, which is characterized in that the direct current phase-modulator includes:

Direct current phase-modulator on second arm；And/or

Direct current phase-modulator on the first arm is set before the polarization beam apparatus, or is closed described second Direct current phase-modulator on the first arm is set after beam device, or two be located in the two strips optical path are straight Flow phase-modulator.

5. HVDC Modulation quantum key distribution time bit-phase solution of according to scheme 1 point of polarization difference control Code device, which 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 tune Device processed.

6. HVDC Modulation quantum key distribution time bit-phase solution of according to scheme 1 point of polarization difference control Code device, which is characterized in that

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 first beam splitting will to be come from The light pulse of device come through first arm transmission is reflected back first bundling device；The second reflection on second arm Mirror, for the light pulse come through second arm transmission from first beam splitter to be reflected back first bundling device, And

The decoding apparatus further includes the optical circulator positioned at first beam splitter front end, and the optical circulator has the Single port, second port and third port, the first port is for receiving the first via light pulse, the second port light It is coupled to first beam splitter, the third port is for exporting, wherein the input port and output port of the interferometer One of be same port；Or

The interferometer uses the structure of unequal arm Mach-Zender interferometer.

7. HVDC Modulation quantum key distribution time bit-phase solution of according to scheme 6 point of polarization difference control Code device, which 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 includes two reflecting mirrors, wherein one in described two reflecting mirrors In the strip optical path in the two strips optical path, for will be from the polarization beam apparatus through the strip optical path The light pulse that transmission comes is reflected back second bundling device；Another in described two reflecting mirrors is located at the two strips optical path In another strip optical path on, the light pulse for will come from the polarization beam apparatus through another strip optic path It is reflected back second bundling device, wherein the interferometer uses the structure of unequal arm Michelson's interferometer, it is described two anti- Penetrating one of mirror is first reflecting mirror.

8. according to the HVDC Modulation quantum key distribution time ratio of point polarization difference control any in scheme 1~6 Spy-phase decoding device, which is characterized in that second bundling device is polarization-maintaining coupler or polarization beam combiner.

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

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

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

According to the HVDC Modulation quantum key distribution time bit-of point polarization difference control any in scheme 1~9 The transmitting terminal of the quantum key distribution system is arranged in phase decoding 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).In addition, by receiving end by input optical pulse beam splitting be two-way light pulse after respectively to this Two-way light pulse carries out the decoding of time bit and phase decoding, carries out direct current to light pulse in phase decoding and selects keynote system, can It advantageously reduces to decode with phase base and selects the relevant requirement of phase-modulation when base, particularly with avoiding understanding for High Speed System Code selects high-speed phase modulation when base to require.The utility model provides a kind of time for facilitating feasible anti-polarization induction decline Bit-phase code quantum key distribution solution, while avoid the need for complicated correcting device.In addition, this is practical The type of the novel interferometer used to decoding apparatus does not constrain, and can be used most common unequal arm Mach-Zender dry Interferometer makes light pulse only need to thus be conducive to reduce the insertion loss of receiving end, mention by a phase-modulator in decoding High system effectiveness.

Detailed description of the invention

Fig. 1 is the HVDC Modulation quantum key distribution time of point polarization difference control of one preferred embodiment of the utility model Bit-phase decoding method flow chart；

Fig. 2 is the HVDC Modulation quantum key distribution time of point polarization difference control of one preferred embodiment of the utility model Bit-phase decoding device composed structure schematic diagram；

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

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

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

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

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

When Fig. 8 is the HVDC Modulation quantum key distribution of point polarization difference control of another preferred embodiment of the utility model Between bit-phase decoding device composed structure schematic diagram.

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 HVDC Modulation quantum key distribution time of point of polarization difference control of one preferred embodiment of the utility model Bit-phase 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, HVDC Modulation phase decoding is carried out to the first via light pulse And the decoding of time bit is carried out to second tunnel light pulse.

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.

HVDC Modulation phase decoding is carried out to the first via light pulse can include: arrive the first via optical pulse strikes Interferometer including beam splitter and bundling device, using by the beam splitter by the first via light pulse beam splitting as first via sub-light arteries and veins Punching and the second way light pulse；The first via sub-light pulse and the are transmitted along the first arm of the interferometer and the second arm respectively Two way light pulses, and the first via sub-light pulse and the second way light pulse are carried out after relative time delay by the bundling device Close beam output.

In the method, during beam is closed in the beam splitter beam splitting to the bundling device, to the first via sub-light pulse With in the second way light pulse at least all the way sub-light pulse according to quantum key distribution agreement carry out direct current 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.

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 during the bundling device of the beam splitter beam splitting of interferometer to interferometer closes beam to described In the pulse of first via sub-light and the second way light pulse at least all the way sub-light pulse carried out according to quantum key distribution agreement it is straight Flow phase-modulation.Furthermore it is possible to the first via sub-light pulse and second to being transmitted respectively along the first arm of interferometer and the second arm Both way light pulses or either of which carry out polarization diversity processing.To any way light arteries and veins for being subjected to polarization diversity processing Punching --- such as first via sub-light pulse --- carry out direct current phase-modulation can pass through following any realization: polarization beam splitting it It is preceding right to first via sub-light pulse progress direct current phase-modulation, or after carrying out conjunction beam to corresponding two-way polariton light pulse First via sub-light pulse carries out direct current phase-modulation, or carries out conjunction beam to corresponding two-way polariton light pulse in polarization beam splitting During identical direct current phase-modulation is carried out to this two-way polariton light pulse.To the sub-light for not being subjected to polarization diversity processing Pulse --- if any, such as the second way light pulse --- carrying out direct current phase-modulation may include: in interferometer The bundling device of beam splitter beam splitting to interferometer carries out direct current phase-modulation to the second way light pulse during closing beam.Any In the case of, carrying out direct current phase-modulation to corresponding light pulse may include carrying out 0 degree of phase-modulation or 180 degree phase to the light pulse Position modulation.Here, 0 degree of phase-modulation of progress or 180 degree phase-modulation, which refer to, carries out selected from 0 degree of phase-modulation and 180 degree phase One of both modulation phase-modulation.

Carrying out direct current phase-modulation to a light pulse can be realized by polarizing unrelated phase-modulator.Polarize unrelated phase Modulator is suitable for carrying out identical phase-modulation to two orthogonal polarisation states of light pulse, so referred to as polarizing unrelated.It lifts For example, polarizing unrelated phase-modulator can be realized by two birefringent phase modulator serial or parallel connections.According to circumstances, may be used To realize direct current phase-modulation by a variety of specific meanss.For example, these means can include: the length of modulation free space optical path It spends the perhaps length of modulation optical fiber or utilizes serial or parallel connection optical waveguide phase-modulator etc..For example, can be by using motor Change the length of free space optical path to realize desired direct current phase-modulation.For another example, the optical fiber using piezoelectric effect can be passed through Stretcher carrys out the length of modulation optical fiber, is achieved in phase-modulation.In addition, phase-modulator can be suitable for it is voltage-controlled its His type, by apply suitable DC voltage to polarize unrelated phase-modulator come two orthogonal polarisation states to light pulse into The identical phase-modulation of row is, it can be achieved that desired direct current phase-modulation.In the case where direct current phase-modulation, apply without converting To the voltage of phase-modulator.

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 HVDC Modulation quantum key distribution time of point of polarization difference control of one preferred embodiment of the utility model Bit-phase decoding device is as shown in Fig. 2, include consisting of part: preposition beam splitter 201, beam splitter 202 and 203, polarization Beam splitter 204, polarization beam combiner 205, direct current 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 direct current phase-modulator 206.For convenience, polarizing inserted with point for interferometer differs The arm of control device is hereinafter also referred to be the first arm, and the arm inserted with direct current phase-modulator 206 of interferometer is hereinafter Also known as the second arm.

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.

Direct current phase-modulator 206 is used for the sub-light pulse through the arm transmission where it according to quantum key distribution agreement Carry out direct current 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.

Direct current phase-modulator 206 can carry out 0 degree of phase-modulation or 180 degree of phase tune to by its sub-light pulse System.

Direct current phase-modulator 206 can be the unrelated phase-modulator of polarization, birefringence-compensated two-fold including having carried out Emitter part (such as being realized by two birefringent phase modulators of serial or parallel connection) or other above-mentioned polarizations are 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 direct current phase-modulator is only arranged on the second arm of interferometer, but it is also possible that only dry Direct current phase-modulator or each setting direct current on both the first arm of interferometer and the second arm are set on the first arm of interferometer Phase-modulator.In the case where setting direct current phase-modulator each on both the first arm of interferometer and the second arm, the first arm On direct current phase-modulator and the second arm on the difference of phase modulated of direct current phase-modulator assisted by quantum key distribution View determines.

The decoding apparatus of Fig. 2 or its 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.

The interferometer uses the structure of unequal arm Michelson's interferometer as described above, and the decoding apparatus further includes Optical circulator, the optical circulator are located at the beam splitter front end of the interferometer, the first via light from preposition beam splitter Pulse is inputted from the first port of the optical circulator and is exported from the second port of the optical circulator to the interferometer The conjunction beam output of beam splitter, the bundling device from the interferometer is input to the second port of the optical circulator and from described The third port of optical circulator exports, wherein one of input port and output port of the interferometer are same port.

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.

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 direct current phase-modulator, for carrying out direct current phase to the light pulse through the arm transmission where it Modulation.

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 direct current phase-modulator, for carrying out identical direct current phase to two-way polariton light pulse Modulation.

When the HVDC Modulation quantum key distribution of a kind of point of polarization difference control of another preferred embodiment of the utility model Between bit-phase decoding device 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, direct current 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 direct current phase-modulator 311 are inserted into the two-arm of Mach-Zender interferometer respectively.Polarization-maintaining light Fine phase shifter 309 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For convenience, Mach-Zehnder is dry Interferometer is also known as the first arm, the insertion of Mach-Zender interferometer inserted with a point arm for polarization difference control device below There is the arm of direct current phase-modulator 311 to be 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 Pulse is transmitted to polarization-maintaining bundling device 312 after direct current phase-modulator 311 modulates 0 degree of phase or 180 degree phase.It is transmitted to polarization-maintaining 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 by Port 313 or 314 exports.Polarization beam splitting is being carried out to during closing beam to first via sub-light pulse, polarization maintaining optical fibre phase shift can be passed through 309 pairs of polariton light pulses through the sub- optic path where polarization maintaining optical fibre phase shifter 309 of device carry out phase adjustment.

Direct current phase-modulator 311 is to polarize unrelated device, including carried out birefringence-compensated birefringent device (such as Realized by two birefringent phase modulators of serial or parallel connection) 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 direct current phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, by This realizes the phase-modulation function of direct current phase-modulator 311；I.e., it is possible to omit direct current phase-modulator 311.

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

When the HVDC Modulation quantum key distribution of a kind of point of polarization difference control of another preferred embodiment of the utility model Between bit-phase decoding device as shown in figure 4, include consisting of part: beam splitter 403, polarization-maintaining beam splitter 405, polarization point Beam device 406, polarization maintaining optical fibre phase shifter 407, polarization beam combiner 408, direct current 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 direct current phase-modulator 409 are inserted into the two-arm of Mach-Zender interferometer respectively.Polarization-maintaining light Fine phase shifter 407 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For convenience, Mach-Zehnder is dry Interferometer is also known as the first arm, the insertion of Mach-Zender interferometer inserted with a point arm for polarization difference control device below There is the arm of direct current phase-modulator 409 to be 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 Pulse is transmitted to polarization-maintaining bundling device 410 after direct current phase-modulator 409 modulates 0 degree of phase or 180 degree phase.It is transmitted to polarization-maintaining 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 by Port 411 or 412 exports.Polarization beam splitting is being carried out to during closing beam to first via sub-light pulse, polarization maintaining optical fibre phase shift can be passed through 407 pairs of polariton light pulses through the sub- optic path where polarization maintaining optical fibre phase shifter 407 of device carry out phase adjustment.

Direct current phase-modulator 409 is to polarize unrelated device, including carried out birefringence-compensated birefringent device (such as Realized by two birefringent phase modulators of serial or parallel connection) 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 direct current phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, by This realizes the phase-modulation function of direct current phase-modulator 409；I.e., it is possible to omit direct current phase-modulator 409.

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

When the HVDC Modulation quantum key distribution of a kind of point of polarization difference control of another preferred embodiment of the utility model Between bit-phase decoding device as shown in figure 5, include consisting of part: beam splitter 503 and 504, optical circulator 507, protect Inclined beam splitter 508, polarization beam apparatus 509, polarization maintaining optical fibre phase shifter 510, polarization beam combiner 511, direct current phase-modulator 513, And reflecting mirror 512 and 514.

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 508, two two arms between reflecting mirror 512 and 514 and polarization-maintaining beam splitter 508 and the two reflecting mirrors Constitute a polarization-maintaining Michelson's interferometer.Optical circulator 507 is arranged in Michelson's interferometer front end, optical circulator 507 First port A and second port B are optically coupled to beam splitter 503 and polarization-maintaining beam splitter 508 respectively.By the port A of optical circulator 507 The light pulse of input is exported by the port B of optical circulator 507, and the light pulse inputted by the port B of optical circulator 507 is by ring of light shape The third port C of device 507 is exported.Polarization beam apparatus 509, polarization beam combiner 511 and two strip optical paths between them totally may be used Referred to as divide polarization difference control device.This point polarization difference control device and direct current phase-modulator 513 are inserted into Michael respectively The two-arm of inferior interferometer.Polarization maintaining optical fibre phase shifter 510 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 direct current phase-modulator 513 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 inputs from the port A of optical circulator 507 and from optical circulator 507 port B is exported to polarization-maintaining beam splitter 508, and is the pulse of first via sub-light and the second way by 508 beam splitting of polarization-maintaining beam splitter Light pulse.The pulse of first via sub-light is the light pulse of two-way polariton by 509 polarization beam splitting of polarization beam apparatus；This two-way polarizes sub-light Pulse is transmitted to polarization beam combiner 511 through two the first sub-light roads respectively, and is the first via by 511 polarization coupling of polarization beam combiner Sub-light pulse is transmitted to reflecting mirror 512 along the first arm and is reflected by reflecting mirror 512.Second way light pulse is through direct current phase Modulator 513 is transmitted to reflecting mirror 514 after modulating 0 degree of phase or 180 degree phase and is reflected by reflecting mirror 514.It is reflected back Come through the first via sub-light pulse of relative time delay and the second way light pulse after polarization-maintaining beam splitter 508 closes beam by port 516 Output, or port 515 is transmitted to by the port C of optical circulator 507 after the port B of optical circulator 507 input and is exported.To It, can be by 510 pairs of polarization maintaining optical fibre phase shifter through polarization maintaining optical fibre phase shifter during sub-light pulse carries out polarization beam splitting extremely conjunction beam all the way The polariton light pulse of sub- optic path where 510 carries out phase adjustment.

Direct current phase-modulator 513 is to polarize unrelated device, including carried out birefringence-compensated birefringent device (such as Realized by two birefringent phase modulators of serial or parallel connection) 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 direct current phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, by This realizes the phase-modulation function of direct current phase-modulator 513；I.e., it is possible to omit direct current phase-modulator 513.

In addition, Michelson's interferometer can be inserted in this point polarization difference control device and direct current phase-modulator 513 Same arm, and the above-mentioned course of work is unaffected.

When the HVDC Modulation quantum key distribution of a kind of point of polarization difference control of another preferred embodiment of the utility model Between bit-phase decoding device as shown in fig. 6, include consisting of part: beam splitter 603 and 604, optical circulator 607, protect Inclined beam splitter 608, polarization beam apparatus 609, polarization maintaining optical fibre phase shifter 610, direct current phase-modulator 613 and reflecting mirror 611, 612 and 614.

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 608 between polarization-maintaining beam splitter 608, polarization-maintaining beam splitter 608 and two reflecting mirrors 611 and 612 and anti- Another arm and reflecting mirror 611,612,614 penetrated between mirror 614 constitute a polarization-maintaining Michelson's interferometer.Optical circulator 607 are arranged in Michelson's interferometer front end, and the first port A and second port B of optical circulator 607 are optically coupled to beam splitting respectively Device 603 and polarization-maintaining beam splitter 608.The light pulse inputted by the port A of optical circulator 607 is defeated by the port B of optical circulator 607 Out, the light pulse inputted by the port B of optical circulator 607 is exported by the third port C of optical circulator 607.Polarization beam apparatus 609, two strip optical paths between polarization beam apparatus 609 and two reflecting mirrors 611 and 612 and the two reflecting mirrors can totally claim For a point polarization difference control device.This point polarization difference control device and direct current phase-modulator 613 are inserted into Michelson respectively The two-arm of interferometer.Polarization maintaining optical fibre phase shifter 610 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 inserted with a point arm for polarization difference control device below, and Michelson is dry The arm inserted with direct current phase-modulator 613 of interferometer 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 inputs from the port A of optical circulator 607 and from optical circulator 607 port B is exported to polarization-maintaining beam splitter 608, and is the pulse of first via sub-light and the second way by 608 beam splitting of polarization-maintaining beam splitter Light pulse.The pulse of first via sub-light is the light pulse of two-way polariton by 609 polarization beam splitting of polarization beam apparatus；This two-way polarizes sub-light Pulse is transmitted separately to reflecting mirror 611,612 through two the first sub-light roads respectively and is reflected back partially by reflecting mirror 611,612 respectively Shake beam splitter 609, and is transmitted to polarization-maintaining beam splitter along the first arm for the pulse of first via sub-light by 609 polarization coupling of polarization beam apparatus 608.Second way light pulse is transmitted to reflecting mirror 614 after direct current phase-modulator 613 modulates 0 degree of phase or 180 degree phase And it is reflected by reflecting mirror 614.The reflected first via sub-light pulse through relative time delay and the second way light pulse warp Polarization-maintaining beam splitter 608 is exported after closing beam by port 616, or by optical circulator 607 after the port B of optical circulator 607 input Port C is transmitted to the output of port 615.Polarization beam splitting is being carried out to during closing beam to first via sub-light pulse, polarization-maintaining light can be passed through The 610 pairs of polariton light pulses through the sub- optic path where polarization maintaining optical fibre phase shifter 610 of fine phase shifter carry out phase adjustment.

Direct current phase-modulator 613 is to polarize unrelated device, including carried out birefringence-compensated birefringent device (such as Realized by two birefringent phase modulators of serial or parallel connection) 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 direct current phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, by This realizes the phase-modulation function of direct current phase-modulator 613；I.e., it is possible to omit direct current phase-modulator 613.

In addition, Michelson's interferometer can be inserted in this point polarization difference control device and direct current phase-modulator 613 Same arm, and the above-mentioned course of work is unaffected.

When the HVDC Modulation quantum key distribution of a kind of point of polarization difference control of another preferred embodiment of the utility model Between bit-phase decoding device as shown in fig. 7, comprises consisting of part: beam splitter 703, optical circulator 705, polarization-maintaining beam splitting Device 706, polarization beam apparatus 707, polarization maintaining optical fibre phase shifter 708, polarization beam combiner 709, direct current phase-modulator 711, and it is anti- Penetrate mirror 710 and 712.

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 706, two two arms between reflecting mirror 710 and 712 and polarization-maintaining beam splitter 706 and the two reflecting mirrors Constitute a polarization-maintaining Michelson's interferometer.Optical circulator 705 is arranged in Michelson's interferometer front end, optical circulator 705 First port A and second port B are optically coupled to beam splitter 703 and polarization-maintaining beam splitter 706 respectively.By the port A of optical circulator 705 The light pulse of input is exported by the port B of optical circulator 705, and the light pulse inputted by the port B of optical circulator 705 is by ring of light shape The third port C of device 705 is exported.Polarization beam apparatus 707, polarization beam combiner 709 and two strip optical paths between them totally may be used Referred to as divide polarization difference control device.This point polarization difference control device and direct current phase-modulator 711 are inserted into Michael respectively The two-arm of inferior interferometer.Polarization maintaining optical fibre phase shifter 708 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 direct current phase-modulator 711 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 inputs from the port A of optical circulator 705 and from optical circulator 705 port B is exported to polarization-maintaining beam splitter 706, and is the pulse of first via sub-light and the second way by 706 beam splitting of polarization-maintaining beam splitter Light pulse.The pulse of first via sub-light is the light pulse of two-way polariton by 707 polarization beam splitting of polarization beam apparatus；This two-way polarizes sub-light Pulse is transmitted to polarization beam combiner 709 through two the first sub-light roads respectively, and is the first via by 709 polarization coupling of polarization beam combiner Sub-light pulse is transmitted to reflecting mirror 710 along the first arm and is reflected by reflecting mirror 710.Second way light pulse is through direct current phase Modulator 711 is transmitted to reflecting mirror 712 after modulating 0 degree of phase or 180 degree phase and is reflected by reflecting mirror 712.It is reflected back Come through the first via sub-light pulse of relative time delay and the second way light pulse after polarization-maintaining beam splitter 706 closes beam by port 714 Output, or port 713 is transmitted to by the port C of optical circulator 705 after the port B of optical circulator 705 input and is exported.To It, can be by 708 pairs of polarization maintaining optical fibre phase shifter through polarization maintaining optical fibre phase shifter during sub-light pulse carries out polarization beam splitting extremely conjunction beam all the way The polariton light pulse of sub- optic path where 708 carries out phase adjustment.

Direct current phase-modulator 711 is to polarize unrelated device, including carried out birefringence-compensated birefringent device (such as Realized by two birefringent phase modulators of serial or parallel connection) 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 direct current phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, by This realizes the phase-modulation function of direct current phase-modulator 711；I.e., it is possible to omit direct current phase-modulator 711.

In addition, Michelson's interferometer can be inserted in this point polarization difference control device and direct current phase-modulator 711 Same arm, and the above-mentioned course of work is unaffected.

A kind of HVDC Modulation quantum key distribution time ratio of point of polarization difference control of another embodiment of the utility model Spy-phase decoding device is as shown in figure 8, include consisting of part: beam splitter 803, optical circulator 805, polarization-maintaining beam splitter 806, polarization beam apparatus 807, polarization maintaining optical fibre phase shifter 808, direct current phase-modulator 811 and reflecting mirror 809,810 and 812.

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 806 between polarization-maintaining beam splitter 806, polarization-maintaining beam splitter 806 and two reflecting mirrors 809 and 810 and anti- Another arm and reflecting mirror 809,810,812 penetrated between mirror 812 constitute a polarization-maintaining Michelson's interferometer.Optical circulator 805 are arranged in Michelson's interferometer front end, and the first port A and second port B of optical circulator 805 are optically coupled to beam splitting respectively Device 803 and polarization-maintaining beam splitter 806.The light pulse inputted by the port A of optical circulator 805 is defeated by the port B of optical circulator 805 Out, the light pulse inputted by the port B of optical circulator 805 is exported by the third port C of optical circulator 805.Polarization beam apparatus 807, two strip optical paths between two reflecting mirrors 809 and 810 and polarization beam apparatus 807 and the two reflecting mirrors totally may be used Referred to as divide polarization difference control device.This point polarization difference control device and direct current phase-modulator 811 are inserted into Michael respectively The two-arm of inferior interferometer.Polarization maintaining optical fibre phase shifter 808 is inserted into any in the two strip optical paths for being divided to polarization difference control device.For side Just for the sake of, 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 direct current phase-modulator 811 of inferior 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 inputs from the port A of optical circulator 805 and from optical circulator 805 port B is exported to polarization-maintaining beam splitter 806, and is the pulse of first via sub-light and the second way by 806 beam splitting of polarization-maintaining beam splitter Light pulse.The pulse of first via sub-light is the light pulse of two-way polariton by 807 polarization beam splitting of polarization beam apparatus；This two-way polarizes sub-light Pulse is transmitted separately to reflecting mirror 809,810 through two the first sub-light roads respectively and is reflected back partially by reflecting mirror 809,810 respectively Shake beam splitter 807, and is transmitted to polarization-maintaining beam splitter along the first arm for the pulse of first via sub-light by 807 polarization coupling of polarization beam apparatus 806.Second way light pulse is transmitted to reflecting mirror 812 after direct current phase-modulator 811 modulates 0 degree of phase or 180 degree phase And it is reflected by reflecting mirror 812.The reflected first via sub-light pulse through relative time delay and the second way light pulse warp Polarization-maintaining beam splitter 806 is exported after closing beam by port 814, or by optical circulator 805 after the port B of optical circulator 805 input Port C is transmitted to the output of port 813.Polarization beam splitting is being carried out to during closing beam to first via sub-light pulse, polarization-maintaining light can be passed through The 808 pairs of polariton light pulses through the sub- optic path where polarization maintaining optical fibre phase shifter 808 of fine phase shifter carry out phase adjustment.

Direct current phase-modulator 811 is to polarize unrelated device, including carried out birefringence-compensated birefringent device (such as Realized by two birefringent phase modulators of serial or parallel connection) 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 direct current phase-modulation is carried out to two-way polariton light pulse by two optical fiber phase shifters in this two strips optical path, by This realizes the phase-modulation function of direct current phase-modulator 811；I.e., it is possible to omit direct current phase-modulator 811.

In addition, Michelson's interferometer can be inserted in this point polarization difference control device and direct current phase-modulator 811 Same 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 direct current tune that can be controlled in point polarization difference that the receiving end of quantum key distribution system configures the utility model Quantum key distribution time bit-phase decoding device processed is used for time bit-phase decoding.Alternatively, it is also possible to close in quantum The transmitting terminal of key dissemination system configures the HVDC Modulation quantum key distribution time ratio of point polarization difference control of the utility model Spy-phase decoding device is used 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 (10)

1. HVDC Modulation quantum key distribution time bit-phase decoding device of a kind of point of polarization difference control, for entering The input optical pulse all the way for the random polarization state penetrated carries out time bit-phase decoding, which is characterized in that the decoding apparatus packet It 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, described Interferometer also has a direct current phase-modulator at least one of first arm and the second arm, and wherein at least described A point polarization difference control device is provided on one arm, described point of polarization difference control device includes polarization beam apparatus, the second conjunction beam Device and merge with the polarization beam apparatus optocoupler with two strip optical paths of the second bundling device optical coupling, the polarization beam splitting Device is coupled to second bundling device through the two strips optical path, wherein first arm and the second arm and optical device structure thereon It causes so that through first arm and second in each leisure interferometer of two orthogonal polarisation states of the first via light pulse The phase difference of arm transmission differs the integral multiple of 2 π,

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

2. HVDC Modulation quantum key distribution time bit-phase solution of according to claim 1 point of polarization difference control Code device, which is characterized in that first arm and the second arm 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.

3. HVDC Modulation quantum key distribution time bit-phase solution of according to claim 1 point of polarization difference control Code device, which 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. HVDC Modulation quantum key distribution time bit-phase solution of according to claim 1 point of polarization difference control Code device, which is characterized in that the direct current phase-modulator includes:

Direct current phase-modulator on second arm；And/or

Direct current phase-modulator on the first arm is set before the polarization beam apparatus, or in second bundling device Direct current phase-modulator on the first arm is set later, or two direct current phases being located in the two strips optical path Position modulator.

5. HVDC Modulation quantum key distribution time bit-phase solution of according to claim 1 point of polarization difference control Code device, which 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 tune Device processed.

6. HVDC Modulation quantum key distribution time bit-phase solution of according to claim 1 point of polarization difference control Code device, which is characterized in that

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 will be from first beam splitter The light pulse come through first arm transmission is reflected back first bundling device；The second reflecting mirror on second arm, For the light pulse come through second arm transmission from first beam splitter to be reflected back first bundling device, and

The decoding apparatus further includes the optical circulator positioned at first beam splitter front end, and the optical circulator has first end Mouth, second port and third port, the first port is for receiving the first via light pulse, the second port optical coupling To first beam splitter, the third port is for exporting, wherein one of the input port and output port of the interferometer For same port；Or

The interferometer uses the structure of unequal arm Mach-Zender interferometer.

7. HVDC Modulation quantum key distribution time bit-phase solution of according to claim 6 point of polarization difference control Code device, which 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 the second bundling device are Same device, described point of polarization difference control device includes two reflecting mirrors, wherein one in described two reflecting mirrors is located at In a strip optical path in the two strips optical path, for will be from the polarization beam apparatus through the strip optic path The light pulse come is reflected back second bundling device；Another in described two reflecting mirrors is located in the two strips optical path In another strip optical path, for that will be reflected from the light pulse of the polarization beam apparatus come through another strip optic path Second bundling device is returned, wherein the interferometer uses the structure of unequal arm Michelson's interferometer, described two reflecting mirrors One of be first reflecting mirror.

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

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

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

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

The HVDC Modulation quantum key distribution time ratio of point polarization difference control described according to claim 1~any one of 9 Spy-phase decoding device, is arranged in the transmitting terminal of the quantum key distribution system, is used for time bit-phase code.