CN206790495U - A kind of decoding apparatus for time bit phase coding - Google Patents
A kind of decoding apparatus for time bit phase coding Download PDFInfo
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- CN206790495U CN206790495U CN201720574670.3U CN201720574670U CN206790495U CN 206790495 U CN206790495 U CN 206790495U CN 201720574670 U CN201720574670 U CN 201720574670U CN 206790495 U CN206790495 U CN 206790495U
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Abstract
A kind of decoding apparatus for time bit phase coding is disclosed in the utility model, including：Unequal arm Michelson's interferometer, two photodetectors, decoding unit and circulator；Unequal arm Michelson's interferometer includes beam splitter and two speculums, two speculums connect and compose the long-armed and galianconism of interferometer with beam splitter respectively, and the time interval between time difference corresponding to the arm length difference of unequal arm Michelson's interferometer and 2 temporal mode light pulses of phase basic vector is consistent；Two photodetectors connect two output ports of unequal arm Michelson's interferometer respectively；Decoding unit connects two photodetectors, and the decoding under phase basic vector and/or time basic vector is carried out according to the output of photodetector；Circulator is connected with the input port of decoding apparatus, an output port of unequal arm Michelson's interferometer and a photodetector.Solve the problems, such as that polarization is related present in prior art, Insertion Loss is high, system complex and cost are high.
Description
Technical field
It the utility model is related to Technique on Quantum Communication field, and in particular to a kind of solution for time bit-phase code
Code device.
Background technology
Forward position of the quantum secret communication as contemporary communication technical field, it, which develops, makes rapid progress, and leads to relative to traditional
For letter technology, the absolute safety of communication is ensure that from principle, this is that conventional communication techniques can not be unmatch.Quantum
In secret communication field, most widely used, development most ripe is exactly quantum key distribution direction.Quantum key distribution make use of
The general principles such as quantum in quantum mechanics is not reproducible, use the mode of " one-time pad " to encrypt information, are highly suitable for
The national defence unit higher to confidentiality requirement, government bodies, R＆D institution, financial institution etc..
At present in the encoding scheme of quantum key distribution, relatively conventional is polarization encoder and phase encoding scheme.Polarization
Encoding scheme as the encoding scheme proposed earliest in 1984, have that receiving terminal Insertion Loss is low, cost is low and it is simple in construction the advantages of,
So be main coded system at present, and its inferior position is easily influenceed for polarized systems by optical fiber polarisation disturbance, direct shadow
Ringing needs frequent starting polarization feedback or the fast control bit error rate of module partially of needs under its bit error rate, particularly aerial optical cable environment
Could be into code to normal level.And these factors also result in it is temporal waste so that into code check reduce or it is unstable.
Compared to polarization encoder, the application scenarios of phase code are relatively adapted to the more violent situation of polarization variations, phase
Encoding scheme prepares light pulse by unequal arm interferometer, by the use of the phase difference of front and rear light pulse as information carrier, and optical fiber
Influence of the polarization variations to phase difference it is smaller, therefore polarization variations will not cause the bit error rate to rise, and at most to receive meter
Digit rate declines.This is in long-distance transmissions or has in the environment of strong external interference and would indicate that larger advantage.But its inferior position
It is very big for the receiving terminal Insertion Loss of conventional phase system, than the receiving terminal increase at least 3dB of polarization encoder system.And become in polarization
Change relatively acutely in the case of, receive loss further increase 3dB, cause into code check and farthest into code distance less than polarization be
System, differs and is surely advantageously applied to long range aerial optical cable environment.
Under the premise of herein, there has been proposed the scheme of time bit-phase code.The coding of its transmitting terminal and receiving terminal and
2 groups of targeted basic vectors of decoding design are time basic vector and phase basic vector, are also：Z basic vectors (eigenstate is | t0〉、|t1＞), and
(eigenstate is X (or Y) basic vector(or)).This
In, | t0>、|t1>2 different temporal modes are represented, namely both are complete nonoverlapping patterns from time shaft.Fig. 1
Show the X basic vectors and Z basic vectors in time bit-phase code.
Fig. 2 shows a kind of decoding end structure based on time bit-PE system of prior art, wherein, pin
Decoding to Z basic vectors is unrelated with polarization, and in terms of X basic vector decodings, then it is in silicon substrate using optical planar circuit technology (PLC)
The fiber waveguide formed on plate by patterning makes asymmetric mach Zeng Deer (MZ) interference systems to perform.As shown in Fig. 2
Light pulse signal caused by coding side first passes around a beam splitter and can be under its effect after being transferred to and reaching decoding end
Into Z basic vectors decoded portion or enter X basic vector decoded portions.In Z basic vector decoded portions, based on the difference of time location come
Realize the decoding to Z basic vectors；In X basic vector decoded portions, system is interfered by the asymmetric mach Zeng Deer formed by PLC technology
System to X basic vectors come to decoding.In this X basic vectors decoded portion, it is extremely complex to reach the unrelated effect needs of polarization
Control process, such as need to carry out high-precision control to parameters such as temperature.In the decoding end structure shown in Fig. 2,
X basic vector decoded portions can also be realized simply by optical fibre device, the part-structure now formed can be equivalent to
MZ interferometers, and this optical fiber MZ interferometer is related to polarization, it is necessary to polarize feedback.In addition, this X basic vectors decoded portion
In, non-interference portion in result of interference be present, and non-interference portion proportion is 50%, this results in this X basic vectors decoding
Intrinsic 3dB decoding losses in part be present.
Fig. 3 shows the decoding end structure based on time bit-PE system of another prior art, and it is used for
Receive the signal pulse of first latter two different polarization states (horizontal and vertical polarization state).In the decoding end structure, two are not
Signal pulse with polarization state successively reaches polarization beam apparatus 22 and being divided into two-way according to the difference of polarization state has difference inclined
The light of polarization state, such as：Orthogonal polarized light is reflected to be exported by port 22C, again through Faraday rotation after the delay of delay line 24
Mirror 25 is changed into horizontal polarization light and is back to polarization beam apparatus along original optical path, is exported through transmiting by port 22B；Horizontal polarization light
It is projected and is exported through port 22D, is changed into orthogonal polarized light by faraday rotation mirror 26 and is back to polarization point along original optical path
Beam device, equally exported after reflection by port 22B.Wherein, there are different polarization states by the setting two-way of delay line 24
Light exported by port 22B after is formed in time it is consistent, then by the wave plate adjustment polarization direction of λ/2 and in polarization beam apparatus 27
Interfere, result of interference is finally measured by photodetector 13 and 14, so as to complete the decoding of X basic vectors.In this solution
In code end structure, the problem of can avoiding loss caused by non-interference portion, but bringing, is needed to this phase system
Polarization is fed back, and (such as aerial optical cable, high ferro circuit) is difficult when carrying out polarization feedback, equally to have non-in the presence of a harsh environment
Interference portion causes to be lost.In addition, transmission channel is also inconsistent to the phase place change of different polarization states under varying environment, phase states
2 pulses between phase it is affected by environment, cause the rate request to phase feedback very high, or change adverse circumstances
Have little time phase feedback at all down, so as to allow phase states bit error rate severe exacerbation.
Therefore, it is related, slotting for polarization existing for the decoding end structure of time bit-phase encoding scheme in the prior art
The problems such as damage is high, system complex and cost are high, turns into current urgent problem to be solved.
Utility model content
In view of this, the utility model embodiment provides a kind of decoding apparatus for time bit-phase code, can
Solve in the prior art for polarization existing for the decoding end structure of time bit-phase encoding scheme to be related, Insertion Loss is high, system
The problems such as complicated and cost is high.
To achieve the above object, the utility model embodiment provides following technical scheme：
A kind of decoding apparatus for time bit-phase code, including：Unequal arm Michelson's interferometer, two light
Electric explorer, decoding unit and circulator；
The unequal arm Michelson's interferometer includes beam splitter and two speculums, described two speculums respectively with institute
Beam splitter connection is stated to form the long-armed and galianconism of the interferometer, the arm length difference of the unequal arm Michelson's interferometer corresponds to
Time difference it is consistent with the time interval between 2 temporal mode light pulses of phase basic vector；
Described two photodetectors connect two output ports of the unequal arm Michelson's interferometer respectively；
The decoding unit connects described two photodetectors, to be carried out according to the output of described two photodetectors
Decoding under the phase basic vector and/or time basic vector；
The circulator and input port, the unequal arm of the decoding apparatus for time bit-phase code
An output port and a photodetector for Michelson's interferometer is connected.
Preferably, the circulator includes：
First, second, and third port, the input port of the decoding apparatus for time bit-phase code is successively
It is connected via the first port and the second port with the unequal arm Michelson's interferometer, the unequal arm Michael
One in the output port of inferior interferometer successively via the second port and the 3rd port and the photodetector
In one be connected.
Preferably, decoding unit is configured to, and two photodetectors are detected within a system cycle first, second
With the output on the 3rd time window, wherein first, second, and third time window is in time successively rearward.
Preferably, the decoding apparatus for time bit-phase code is configured to, according in second time
The photodetector of interference light signal is detected on window to carry out phase basic vector decoding；
Or；
The decoding apparatus for time bit-phase code is configured to, according to described two photodetectors
The position of time window corresponding to output about non-interfering optical signal carries out time basic vector decoding.
Preferably, speculum includes：Faraday rotation mirror；
Also include in the unequal arm Michelson's interferometer：Phase shifter.
A kind of decoding apparatus for time bit-phase code, including：Basic vector alternative pack, phase basic vector lsb decoder
Divide, time basic vector decoded portion and circulator, the basic vector alternative pack are used to be arrived basic vector pulse input according to predetermined probabilities
One in the phase basic vector decoded portion and the time basic vector decoded portion；
The time basic vector decoded portion includes the first photodetector and time basic vector decoding unit section, the time
Basic vector decoding unit section connects first photodetector to carry out the time according to the output of first photodetector
Basic vector decodes；
The phase basic vector decoded portion include unequal arm Michelson's interferometer, second and the 3rd photodetector and
Phase basic vector decoding unit section, the phase basic vector decoding unit section connection described second and the 3rd photodetector, with
According to described second and the 3rd photodetector output carry out phase basic vector decoding；
The interferometer includes beam splitter and two speculums, described two speculums be connected respectively with the beam splitter with
The long-armed and galianconism of the interferometer is formed, at 2 of time difference corresponding to the arm length difference of the interferometer and phase basic vector
Between time interval between pattern light pulse it is consistent；And
Described second and the 3rd photodetector connect two output ports of the interferometer respectively；
The circulator and input port, the unequal arm of the decoding apparatus for time bit-phase code
An output port and a photodetector for Michelson's interferometer is connected.
Preferably, the circulator includes：First, second, and third port, the output port of the basic vector alternative pack
It is connected successively via the first port and the second port with the interferometer, in the output port of the interferometer
One successively via the phase of the second port and the 3rd port with described second and the 3rd in photodetector
Even.
Preferably, the phase basic vector decoding unit section is configured to, and described second is detected within a system cycle
With output of the 3rd photodetector on the second time window；
The time basic vector decoding unit section is configured to, and first photodetection is detected within a system cycle
Output of the device on first and second time window；
First and second time window is in time successively rearward.
Preferably, the phase basic vector decoding unit section is configured to, and is detected according on second time window
Photodetector to interference light signal carries out phase basic vector decoding；
Or the time basic vector decoding unit section is configured to, light is detected according to first photodetector
The position of the time window of signal carries out time basic vector decoding.
Preferably, speculum includes：Faraday rotation mirror；
Also include in the unequal arm Michelson's interferometer：Phase shifter.
Based on above-mentioned technical proposal, disclosed in the utility model embodiment a kind of for time bit-phase code
Decoding apparatus, including：Unequal arm Michelson's interferometer, two photodetectors, decoding unit and circulator；The unequal arm
Michelson's interferometer includes beam splitter and two speculums, and described two speculums are connected with the beam splitter to form respectively
The long-armed and galianconism of the interferometer, time difference corresponding to the arm length difference of the unequal arm Michelson's interferometer and phase base
Time interval between 2 temporal mode light pulses of arrow is consistent；Described two photodetectors connect the unequal arm respectively
Two output ports of Michelson's interferometer；The decoding unit connects described two photodetectors, with according to described two
The output of individual photodetector carries out the decoding under the phase basic vector and/or time basic vector；The circulator is used for described
The input port of the decoding apparatus of time bit-phase code, the unequal arm Michelson's interferometer an output port,
And a photodetector is connected.It can solve the problem that the decoding end knot for being used for time bit-phase encoding scheme in the prior art
The problems such as existing polarization of structure is related, Insertion Loss is high, system complex and cost are high.
Brief description of the drawings
, below will be to embodiment in order to illustrate more clearly of the utility model embodiment or technical scheme of the prior art
Or the required accompanying drawing used is briefly described in description of the prior art, it should be apparent that, drawings in the following description are only
It is embodiment of the present utility model, for those of ordinary skill in the art, on the premise of not paying creative work, also
Other accompanying drawings can be obtained according to the accompanying drawing of offer.
Fig. 1 is the X basic vectors and Z basic vector schematic diagrames in the time bit-phase code provided in the prior art；
Fig. 2 is a kind of decoding end structural representation based on time bit-PE system of prior art；
Fig. 3 is the decoding end structural representation based on time bit-PE system of another prior art；
Fig. 4 is the decoding apparatus knot for time bit-phase code of the first exemplary embodiment of the present utility model
Structure schematic diagram；
Fig. 5 shows the decoding principle schematic diagram of Fig. 4 decoding apparatus for time bit-phase code；
Fig. 6 shows another decoding apparatus structural representation for being used for time bit-phase code of the present utility model；
Fig. 7 shows that Fig. 6 another kind is used for the time basic vector decoding principle of the decoding apparatus of time bit-phase code
Schematic diagram；
Fig. 8 shows that Fig. 6 another kind is used for the phase basic vector decoding principle of the decoding apparatus of time bit-phase code
Schematic diagram.
Embodiment
Hereinafter, exemplary embodiment of the present utility model is with reference to the accompanying drawings to be described in detail.The following examples with
Way of example provides, fully to pass on spirit of the present utility model to the utility model those skilled in the art.Cause
This, the utility model is not limited to embodiment disclosed herein.
For being deposited in the decoding apparatus using the trick state BB84 systems of time bit-phase encoding scheme of prior art
High Insertion Loss, polarization is related, system complex and cost are high the problems such as, the utility model proposes it is a kind of it is new particularly suitable for when
Between bit-phase encoding scheme decoding apparatus, it can not only realize the measurement unrelated with polarizing, and can effectively reduce
Decoding loss, realizes the lifting of decoding efficiency.
Fig. 4 schematically illustrates the decoding apparatus of the first exemplary embodiment of the present utility model, for illustrating this reality
With new decoding principle.As shown in figure 4, the decoding apparatus can include circulator 1, unequal arm Michelson's interferometer, light
Electric explorer 4-1 and 4-2 and decoding unit (not shown).Unequal arm Michelson's interferometer can include beam splitter (BS) 2
With two speculums 3-1,3-2, the wherein port 2B and speculum 3-1 of beam splitter 2 forms the long-armed of interferometer, beam splitter 2
Port 2C and speculum 3-2 forms the galianconism of interferometer, and the long-armed arm length difference between galianconism can be configured to and X basic vectors
Time interval between 2 temporal mode light pulses is consistent.The port 2A of the port 1B connections beam splitter 2 of circulator 1, ring
The port 1C connection photodetector D4-1 of shape device 1, the port 2D connection detectors D4-2 of beam splitter 2.Decoding unit and photoelectricity
Detector D4-1 is connected with D4-2 to receive the output signal from photodetector, so as to carry out the solution of Z basic vectors and X basic vectors
Code.
Fig. 5 illustrates that Fig. 4 decoding apparatus carries out the principle of X basic vectors and Z basic vectors.
Within a system cycle, when former and later two continuous time pattern light pulses of X basic vectors enter decoding apparatus, by
The port 1A of circulator enters and exported from port 1B to beam splitter 2, enters respectively from port 2B and 2C after the beam splitting of beam splitter 2
The long-armed and galianconism of interferometer, and return to port 2B and 2C after speculum 3-1 and 3-2 reflection respectively.Because unequal arm is interfered
The time interval that the long-armed arm length difference between galianconism of instrument is configured between 2 temporal mode light pulses of X basic vectors is protected
Hold it is consistent, therefore for reflecting continuous two light pulses returned through speculum on long-armed and galianconism, the previous light on galianconism
Pulse the very first time reach beam splitter 2, the latter light pulse the second time reach beam splitter 2, it is long-armed on previous light
Pulse reaches beam splitter 2 in the second time, and the latter light pulse reaches beam splitter 2, the wherein very first time in the 3rd time<Second
Time<3rd time.As can be seen here, will occur two on the second time within a system cycle, on beam splitter 2 to be concerned with
Light pulse, and the two coherent optical pulses correspond to former and later two continuous time pattern light pulses of X basic vectors, exist between them
The phase difference relation related to coding.Therefore, when the phase difference between former and later two continuous light pulses of X basic vectors be 0 when (such as
Represent coding 0), result of interference will be exported at the 2A of port on the second time, correspondingly, photodetector D4-1 corresponding to
A stronger interference light signal is received on the second time window t01 of second time, photodetector D4-2 is in time window
Optical signal is not received on mouth t01；, will be defeated at the 2D of port on the second time when phase difference is π (such as representing coding 1)
Go out result of interference, i.e. photodetector D4-2 receives a stronger optical signal, photodetection on the second time window t01
Device D4-1 does not receive optical signal on the second time window t01.In addition, in the very first time window corresponding to the very first time
On t00, photodetector D4-1 and D4-2 are likely to be received what previous light pulse on galianconism exported after the beam splitting of beam splitter 2
Optical signal；On the 3rd time window t02 corresponding to the 3rd time, photodetector D4-1 and D4-2 are likely to be received length
The optical signal that the latter light pulse exports after beam splitter beam splitting on arm.As can be seen here, in the decoding apparatus shown in Fig. 4, when
When carrying out the decoding of X basic vectors, within a system cycle, one in photodetector D4-1 and D4-2 will be in t00, t01 and t02
Optical signal is likely to be received on three time windows, the wherein optical signal on t01 time windows is interference signal, t01 and t02
Optical signal on time window is non-interfering signal.Result of detection of the photodetector on t01 time windows, corresponding to X bases
Encoded radio under arrow.For example, when photodetector D4-1 is detecting interference signal on t01 time windows, X bases can be represented
The coding 0 of arrow；Vice versa.
Within a system cycle, when a light pulse under Z basic vectors enters decoding apparatus, by the port 1A of circulator
Export to beam splitter 2 into and from port 1B, after the beam splitting of beam splitter 2 respectively from port 2B and 2C enter the long-armed of interferometer and
Galianconism, and return to port 2B and 2C after speculum 3-1 and 3-2 reflection respectively.Because the arm length difference of unequal arm interferometer is set,
If the time location of the light pulse of the Z basic vectors preceding (such as representing time encoding 0), galianconism and it is long-armed on light pulse will
Beam splitter 2 is reached in the very first time and the second time respectively, correspondingly, detector D4-1 or D4-2 will respectively have half probability the
Optical signal is detected on one time window t00 and the second time window t01.Very first time window t00 is non-interfering window, is Z
Basic vector detection window.If the time location of the light pulse of the Z basic vectors is in rear (such as representing time encoding 1), galianconism and length
Light pulse on arm will reach beam splitter 2 in the second time and the 3rd time respectively, and correspondingly, detector D4-1 or D4-2 will be each
There is half probability to detect optical signal on the second time window t01 and the 3rd time window t02, the 3rd time window t02 is
Non-interfering window, also it is Z basic vector detection windows.As can be seen here, in the decoding apparatus shown in Fig. 4, when progress Z basic vector decodings
When, within a system cycle, one of two photodetectors have in non-interfering time window namely Z basic vector detection windows
The position t00 and t02 of two time windows of detection, the encoded radio corresponded respectively under Z basic vectors.For example, photodetector D4-
1 or D4-2 has detection in very first time window t00, then it represents that the coding 0 of Z basic vectors；During photodetector D4-1 or D4-2 the 3rd
Between have detection on window t02, then it represents that the coding 1 of Z basic vectors.
Based on above-mentioned decoding principle, in Fig. 4 decoding apparatus, decoding unit can be configured to, a system week
Detections of two photodetector D4-1 and D4-2 on first, second, and third time window t00, t01 and t02 is received in phase
As a result, wherein：For X basic vectors, decoded according to the photodetector that interference light signal is detected on the second time window；It is right
In Z basic vectors, solved according to the position for occurring continuous two time windows of non-interfering signal on two photodetectors simultaneously
Code.
In this exemplary decoding apparatus of the present utility model, employ by beam splitter (non-polarizing beamsplitter) with it is anti-
The Michelson unequal arm interferometer that mirror is built is penetrated, realizes with polarizing completely irrelevant measurement, greatly simplify solution
Code structure, reduces cost；By the decoding principle of novelty, point based on the result of detection on specific three time windows
Analysis, Z basic vectors and X only can be realized by the combination of unequal arm interferometer and two photodetectors simultaneously by same optical texture
The decoding of basic vector, the structure of simple knowledge code device, while non-interfering signal section is applied in decoding, realize lossless
Decoding, so as to improve system into code check, into code distance so that decoding apparatus can better adapt to long range aerial optical cable ring
Border.
Fig. 6 schematically illustrates the decoding apparatus of the second exemplary embodiment of the present utility model, its structure with Fig. 4
Compare, increase is provided with a basic vector alternative pack 5 and photodetector D4-0.Wherein, circulator 1, unequal arm interferometer, light
Electric explorer D4-1, D4-2 and corresponding decoding cell mesh are used as X basic vector decoded portions, photodetector D4-0 and corresponding solution
Code cell mesh is used as Z basic vector decoded portions, and basic vector alternative pack 5 is used for according to predetermined probabilities that light pulse to be decoded is defeated
Enter into X basic vectors decoded portion or Z basic vector decoded portions to be decoded under corresponding basic vector.
Fig. 7 schematically illustrates the decoding process and principle of Z basic vector decoded portions.As shown in fig. 7, a system week
In phase, when two temporal mode light pulses under basic vector alternative pack 5 allows X basic vectors enter Z basic vector decoded portions, no matter this two
Phase difference between individual light pulse is 0 or π (i.e. X basic vectors are encoded to 0 or 1), and photodetector D4-0 is possible to first
Optical signal is received on time window t00 or the second time window t01, it means that Z basic vectors decoded portion can not realize X basic vectors
Decoding.When a temporal mode light pulse under basic vector alternative pack 5 allows Z basic vectors enters Z basic vector decoded portions, if should
The time location of the light pulse of Z basic vectors will be only in very first time window in preceding (such as representing time encoding 0), then detector D4-0
T00 detects optical signal；If the time location of light pulse, rear (such as representing time encoding 1), detector D4-0 will only
Optical signal is detected on the second time window t01.In other words, within a system cycle, photodetector D4-0 is detected
The time window position of light, corresponding to the encoded radio under Z basic vectors.For example, optical signal is detected on very first time window t00,
Then represent the coding 0 of Z basic vectors；Optical signal is detected on the second time window t01, then it represents that the coding 1 of Z basic vectors.
Fig. 8 correspond to X basic vector decoded portions decoding process and principle it is similar with embodiment illustrated in fig. 4, therefore herein not
Repeat again.Need herein it is especially mentioned that, because X basic vectors decoded portion is only used for decoding under X basic vectors herein, therefore, only
Detector position by detecting interference signal on the second time window t01 can embody the difference of X basic vectors coding, for example,
Detector D4-1 detects interference signal on the second time window t01, you can to represent X basic vectors coding 0；Detector D4-2 exists
Interference signal is detected on second time window t01, you can to represent X basic vectors coding 1.
Therefore, in Fig. 6 decoding apparatus, decoding unit can be configured to, and three are received within a system cycle
The result of detection of photodetector D4-0, D4-1 and D4-2 on the first and second time window t00 and t01, wherein：For X
Basic vector, decoded according to the photodetector that interference light signal is detected on t01 time windows；For Z basic vectors, according to photoelectricity
Detector D4-0 detects the time window position of optical signal to decode.
In this exemplary decoding apparatus of the present utility model, with first embodiment identical be equally realize with
Completely irrelevant measurement is polarized, its difference is：, will be by within a system cycle in decoding structure shown in Fig. 4
First to the 3rd the result of detection on totally three time windows realize the decoding of X basic vectors and Z basic vectors, and in the solution of the present embodiment
In code device, only needed within a system cycle by first and second result of detection on totally two time windows realize
The decoding of X basic vectors and Z basic vectors, due to decoding need time window quantity reduce, it is therefore desirable to decoding periods shorten, detect
Time efficiency can be higher.However, compared to first embodiment, the relatively short detection cycle of the present embodiment, reach
Higher detection time efficiency, and inherent loss is not present in Z basic vectors decoded portion, losslessly encoding, but X basic vectors can be provided
Intrinsic 3dB loss be present in decoding, on the other hand, in order to reduce decoding inherent loss, can by by the Z basic vectors of basic vector alternative pack and
The likelihood ratio of X basic vectors improves, and so as to reduce the loss in efficiency that X basic vector decoded portions are brought, improves the whole efficiency of decoding apparatus.
Alternatively, basic vector alternative pack can be beam splitter.
Preferably, in the utility model (such as decoding apparatus shown in Fig. 4 or Fig. 6), can also by speculum 3-1 and
3-2 is arranged to faraday rotation mirror, the random change of the polarization state caused by birefringence effect when using single-mode fiber to eliminate
Change, so as to ensure the interference contrast in the decoding of X basic vectors.
Preferably, in the utility model (such as decoding apparatus shown in Fig. 4 or Fig. 6), can also interfere in unequal arm
Phase shifter is set in instrument, to provide compensation to possible phase drift.
Each embodiment is described by the way of progressive in the utility model, what each embodiment stressed be and its
The difference of his embodiment, between each embodiment identical similar portion mutually referring to.
It is described above, only it is preferred embodiment of the present utility model, not the utility model is made any formal
Limitation.Although the utility model is disclosed above with preferred embodiment, but it is not limited to the utility model.It is any ripe
Those skilled in the art is known, in the case where not departing from technical solutions of the utility model ambit, all using the side of the disclosure above
Method and technology contents make many possible changes and modifications to technical solutions of the utility model, or be revised as equivalent variations etc.
Imitate embodiment.Therefore, every content without departing from technical solutions of the utility model, according to the technical essence of the utility model to
Any simple modifications, equivalents, and modifications that upper embodiment is done, still fall within the model of technical solutions of the utility model protection
In enclosing.
Claims (10)
- A kind of 1. decoding apparatus for time bit-phase code, it is characterised in that including：Unequal arm Michelson interference Instrument, two photodetectors, decoding unit and circulator；The unequal arm Michelson's interferometer includes beam splitter and two speculums, described two speculums respectively with described point The connection of beam device is to form the long-armed and galianconism of the interferometer, when corresponding to the arm length difference of the unequal arm Michelson's interferometer Between time interval between difference and 2 temporal mode light pulses of phase basic vector it is consistent；Described two photodetectors connect two output ports of the unequal arm Michelson's interferometer respectively；The decoding unit connects described two photodetectors, described in being carried out according to the output of described two photodetectors Decoding under phase basic vector and/or time basic vector；The circulator and the input port of the decoding apparatus for time bit-phase code, the unequal arm mikey An output port and a photodetector for your inferior interferometer is connected.
- 2. it is used for the decoding apparatus of time bit-phase code as claimed in claim 1, it is characterised in that the circulator Including：First, second, and third port, the input port of the decoding apparatus for time bit-phase code successively via The first port and the second port are connected with the unequal arm Michelson's interferometer, and the unequal arm Michelson is done One in the output port of interferometer successively via the second port and the 3rd port with the photodetector One is connected.
- 3. it is used for the decoding apparatus of time bit-phase code as claimed in claim 1 or 2, it is characterised in that decoding unit It is configured to, output of two photodetectors on first, second, and third time window is detected within a system cycle, Wherein described first, second, and third time window is in time successively rearward.
- 4. as claimed in claim 3 be used for time bit-phase code decoding apparatus, it is characterised in that it is described be used for when Between the decoding apparatus of bit-phase code be configured to, detect interference light signal according on second time window Photodetector carries out phase basic vector decoding；Or；Entered according to the position of the time window corresponding to the output of the relevant non-interfering optical signal of described two photodetectors Row time basic vector decodes.
- 5. it is used for the decoding apparatus of time bit-phase code as claimed in claim 4, it is characterised in that speculum includes： Faraday rotation mirror；Also include in the unequal arm Michelson's interferometer：Phase shifter.
- A kind of 6. decoding apparatus for time bit-phase code, it is characterised in that including：Basic vector alternative pack, phase base Swear decoded portion, time basic vector decoded portion and circulator, the basic vector alternative pack is used for basic vector arteries and veins according to predetermined probabilities Punching is input to one in the phase basic vector decoded portion and the time basic vector decoded portion；The time basic vector decoded portion includes the first photodetector and time basic vector decoding unit section, the time basic vector Decoding unit section connects first photodetector to carry out time basic vector according to the output of first photodetector Decoding；The phase basic vector decoded portion includes the photodetector of unequal arm Michelson's interferometer, second and the 3rd and phase Basic vector decoding unit section, the phase basic vector decoding unit section connection described second and the 3rd photodetector, with basis Described second and the 3rd photodetector output carry out phase basic vector decoding；The interferometer includes beam splitter and two speculums, and described two speculums are connected with the beam splitter to form respectively The long-armed and galianconism of the interferometer, 2 time moulds of time difference corresponding to the arm length difference of the interferometer and phase basic vector Time interval between formula light pulse is consistent；AndDescribed second and the 3rd photodetector connect two output ports of the interferometer respectively；The circulator and the input port of the decoding apparatus for time bit-phase code, the unequal arm mikey An output port and a photodetector for your inferior interferometer is connected.
- 7. it is used for the decoding apparatus of time bit-phase code as claimed in claim 6, it is characterised in that the circulator Including：First, second, and third port, the output port of the basic vector alternative pack is successively via the first port and described Second port is connected with the interferometer, and one in the output port of the interferometer is successively via the second port One with described second and the 3rd in photodetector is connected with the 3rd port.
- 8. the decoding apparatus for time bit-phase code as claimed in claims 6 or 7, it is characterised in thatThe phase basic vector decoding unit section is configured to, detected within a system cycle described second and the 3rd photoelectricity visit Survey output of the device on the second time window；The time basic vector decoding unit section is configured to, and first photodetector is detected within a system cycle and is existed Output on first and second time window；First and second time window is in time successively rearward.
- 9. it is used for the decoding apparatus of time bit-phase code as claimed in claim 8, it is characterised in that the phase base Arrow decoding unit section is configured to, and is entered according to the photodetector that interference light signal is detected on second time window Row phase basic vector decodes；Or；The time basic vector decoding unit section is configured to, and the time of optical signal is detected according to first photodetector The position of window carries out time basic vector decoding.
- 10. it is used for the decoding apparatus of time bit-phase code as claimed in claim 9, it is characterised in that speculum bag Include：Faraday rotation mirror；Also include in the unequal arm Michelson's interferometer：Phase shifter.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108964778A (en) * | 2017-05-22 | 2018-12-07 | 中国科学技术大学 | It is a kind of for time bit-phase code decoding apparatus |
| CN109039625A (en) * | 2018-10-29 | 2018-12-18 | 中国电子科技集团公司电子科学研究院 | Quantum key distribution time bit-phase decoding method, apparatus and system based on polarized orthogonal rotation |
| WO2023207573A1 (en) * | 2022-04-24 | 2023-11-02 | 科大国盾量子技术股份有限公司 | Miniaturized time phase decoder and qkd receiver |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108964778A (en) * | 2017-05-22 | 2018-12-07 | 中国科学技术大学 | It is a kind of for time bit-phase code decoding apparatus |
| CN109039625A (en) * | 2018-10-29 | 2018-12-18 | 中国电子科技集团公司电子科学研究院 | Quantum key distribution time bit-phase decoding method, apparatus and system based on polarized orthogonal rotation |
| CN109039625B (en) * | 2018-10-29 | 2023-05-26 | 中国电子科技集团公司电子科学研究院 | Quantum key distribution time bit-phase decoding method, device and system |
| WO2023207573A1 (en) * | 2022-04-24 | 2023-11-02 | 科大国盾量子技术股份有限公司 | Miniaturized time phase decoder and qkd receiver |
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