CN208174698U - A kind of continuous variable quantum key distribution system - Google Patents
A kind of continuous variable quantum key distribution system Download PDFInfo
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- CN208174698U CN208174698U CN201820485873.XU CN201820485873U CN208174698U CN 208174698 U CN208174698 U CN 208174698U CN 201820485873 U CN201820485873 U CN 201820485873U CN 208174698 U CN208174698 U CN 208174698U
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Abstract
The utility model discloses continuous variable quantum key distribution systems, it includes main laser module, for respectively to being set to the first of the end Alice from laser module and be set to the second of the end Bob and provide seed light from laser module, so that generated in a manner of injecting locking from laser module for signal light first from laser pulse and for local local oscillator light second from laser pulse, so that the wavelength between signal light and local local oscillator light has extraordinary consistency, and stable phase reference can be set up, it solves the problems, such as to be difficult to realize stablize coherent detection in existing LLO scheme.
Description
Technical field
The utility model relates to quantum key distribution fields, and in particular to a kind of continuous variable based on injection locking technique
Quantum key distribution system.
Background technique
The detection mode not instead of single photon detection of continuous variable quantum key distribution (CVQKD), coherent detection such as zero
Difference detection and heterodyne detection, so that it uses traditional optical communication technique can be achieved with.Coherent detection needs local oscillator light and signal
Again by balanced detector detection after the interference of light.In the experiment of early stage CVQKD, local oscillator light is generated by coding side (modulation methods) Alice
, after the laser of coding side Alice generates a pulse, by the pulse by being divided into local oscillator light after a polarization-maintaining beam splitter BS
And signal light.In this transmission local oscillator light (TLO) scheme, it is emphasized that local oscillator light and signal light are due to being by same
Laser generates, so their frequency is identical, initial phase is also identical, and after identical path, their phase is still
Keep identical.Even across path it is different, their phase difference be also it is certain, which can be returned.Cause
This, the coherent detection of TLO scheme only needs to consider the line width of laser, and the line width of general distributed feed-back (DFB) laser
Requirement can be reached.But there is also some limitations and deficiencies for this scheme.Firstly, there are security holes for the program, occur
For the various attacks of local oscillator light.Although having corresponding measure for these known attacks, system and device is also increased
Complexity, but also there may be the still not found attacks for local oscillator light, so that there are potential security holes for system.
Secondly as signal light and local oscillator light need to transmit in the same channel, in order to reduce between strong local oscillator light and weak signal light
Coupling, local oscillator light and signal light need in time significant interval open, this to a certain degree on limit mentioning for system repetition rate
It rises.The noise that strong local oscillator light generates simultaneously influence whether signal light to reduce system at code rate.
In order to make up the deficiency of TLO scheme, there is local local oscillator light (LLO) scheme, i.e., local oscillator light is by decoding end (detection
Side) Bob transmission.Due to generally assuming that the experimental provision of Alice and Bob are safe in quantum key distribution, so not passing through
The local oscillator light for going through quantum channel not will receive the attack of Eve.However, local local oscillator light also faces the challenge.Due to signal light and
Local oscillator light is sent by two lasers respectively, and signal light and local oscillator light are visited firstly the need of stable phase reference, such Bob is established
The data measured could be set up with the data of Alice after phase only pupil filter and be associated with, secondly the middle cardiac wave of two lasers
It is long that height is needed unanimously just to be able to achieve interference good enough.
The relative phase that the phase reference between signal light and local oscillator light needs to know local oscillator light and signal light is set up,
It can be realized by sending phase reference light.And send phase reference light mode can be due to the difference of Bob coherent detection mode
It is somewhat different.It is fairly simple for heterodyne detection, a corresponding signal pulse, it is only necessary to send a strong reference light arteries and veins
Punching.For zero-difference detection, because the two quadrature components of the X and P of phase reference light require to be measured simultaneously to calculate phase,
So sender needs to send two identical pulses as phase reference light, such recipient can be to the two pulses point
Not carry out X and P measurement.But, this pulse issued by laser directly modulates the scheme pair of reference light and signal light
The requirement of two lasers is relatively high.Phase drift between the reference light and signal light of laser will lead to phase noise, be
Reduction phase noise, the line width of laser must obtain very narrow, can use outside cavity gas laser (ECL) at this time, bandwidth can reach
To several kHz.In order to reduce the requirement to laser, add all the way wherein again after each pulse beam splitting that laser can be issued
Delay line finally closes beam at the signal light and reference light pulse for being in front and back, as long as the path difference of two-way keeps stabilization, signal light
It is just able to maintain stabilization with the phase difference of reference light, can finally establish the phase reference between signal light and local oscillator light.On however
Stating two schemes always can not solve the problems, such as that two-way laser center wavelength is inconsistent.Laser center wavelength is inconsistent can shadow
The stability of acoustic system leads to biggish noise excessively, influences final safe transmission distance and at code rate.
It in order to realize local local oscillator optical coherent detection, is gone out from signal light point sub-fraction light in classical coherence communication
Injection locking is carried out to local oscillator light, however this method is not suitable for CVQKD, because signal light is too weak in CVQKD, Wu Fajin
Row locking.In addition to LLO scheme, plug-and-play scheme also occur can solve the TLO scheme problem.This side
Case is that each pulse that detection side Bob is generated is divided into local oscillator light and signal light, and signal light re-sends to the end modulation methods Alice
Modulation.After modulation methods Alice is to signal light modulation, signal light carries out coherent detection back to the local oscillator light at the end Bob and the end Bob.
The deficiency of this scheme is that one is susceptible to Trojan horse attack, second is that backscattering noise is very big, limits CVQKD
Safe transmission distance.
Summary of the invention
For the above-mentioned problems in the prior art, the utility model proposes a kind of continuous variable quantum key distributions
System may include main laser module 11, first from laser module 12, second from laser module 21, and relevant spy
Survey module 24.In the dissemination system of the utility model, described first be can be set from laser module at the end Alice, described
Second is arranged from laser module at the end Bob；The main laser pulse of the main laser module output passes through the first beam splitting mould
Block 13 is divided into the first main laser segment pulse and the second main laser segment pulse.Wherein, the first main laser pulse
Part is used as the described first seed light from laser module, so that described first locks from laser module to inject
Mode generate first and be used to form signal light from laser pulse from laser pulse, described first；Second main laser
Device segment pulse is used as the described second seed light from laser module so that described second from laser module to infuse
The mode for entering locking generates second and is used to form local local oscillator light from laser pulse from laser pulse, described second；It is described
Coherent detection module 24 is used to detect the result of interference of the signal light and the local local oscillator light.
Preferably, the width that the main laser segment pulse is less than from the width of one of laser pulse or both
Degree；Also, when injecting locking, the main laser segment pulse and the relative time delay between laser pulse make
The stable part of intermediate amplitude for corresponding to the main laser pulse from the phase of laser pulse.
In the continuous variable key distribution system of the first aspect of the utility model, the main laser module 11 and institute
Stating the first beam splitting module 13 can be set at the end Alice.
In the first aspect, the end Alice may include：Signal optical modulator module 15, be used for described first from
Laser pulse is modulated to form the signal light；First optical transmission module 14 is used to make first main laser
Device segment pulse is transmitted towards described first from laser module 12, and is made described first from laser pulse towards the letter
Number optical modulator module 15 transmits；And beam module 16 is closed, it is used for the signal light and the second main laser pulse portion
It point carries out closing beam and obtains combined beam light.
Preferably, the signal optical modulator module 15 may include intensity modulated module 151 and first phase modulation module
152。
Preferably, the signal optical modulator module 15 can also include modulation variance detection module 153 and/or adjustable damping
Device 154.
Preferably, the first beam splitting module 13 may include that polarization-maintaining beam splitting element and/or first optics pass
Defeated module 14 may include circulator and/or the conjunction beam module 16 may include polarization-maintaining polarization coupling element.
In the dissemination system of the first aspect of the utility model, the end Bob may include：Second beam splitting module 23,
For the signal light and the second main laser segment pulse in the combined beam light to be separated；And second optical delivery
Module 22 for transmitting the second main laser segment pulse towards described second from laser module 21, and makes institute
Second is stated to transmit from laser pulse towards the coherent detection module 24.
Preferably, the end Bob can also include：Seed light intensity detection module 27 is used to detect injection described second
It requires, and produces from whether the intensity of the second main laser segment pulse of laser module 21 is sufficient for injection locking
The clock signal at the raw end Bob；And/or second phase modulation module 25, it is used to carry out 0 at random to the local local oscillator light
Or pi/2 phase modulation.
Preferably, the second beam splitting module 23 may include polarization-maintaining polarization beam splitting element and/or second light
Transmission module 22 may include circulator and/or the coherent detection module 24 may include zero-difference detection device.
Preferably, the end Bob can also include Polarization Control Module 26, for carrying out polarization control to the combined beam light
System.
In the continuous variable key distribution system of the second aspect of the utility model, the main laser module 11 and institute
Stating the first beam splitting module 13 can be set at the end Bob.
In the dissemination system of the second aspect of the utility model, the end Alice may include：Signal optical modulator module
15, it is used to be modulated to described first from laser pulse to form the signal light；Second beam splitting module 23, is used for
It transmits the first main laser segment pulse towards described first from laser module 12, and makes the signal light direction
The end the Bob transmission；And first optical transmission module 14, it is used to make the first main laser segment pulse described in
First transmits from laser module 12, and makes described first to pass from laser pulse towards the signal optical modulator module 15
It is defeated.
Preferably, the signal optical modulator module 15 may include intensity modulated module 151 and first phase modulation module
152。
Preferably, the signal optical modulator module 15 can also include modulation variance detection module 153 and/or adjustable damping
Device 154.
Preferably, the end Alice can also include seed light intensity detection module 27, be used to detect injection described first
It is wanted from whether the stability of the intensity of the first main laser segment pulse of laser module 12 is sufficient for injection locking
It asks, and generates the clock signal at the end Alice.
Preferably, the second beam splitting module 23 may include polarization-maintaining polarization beam splitting element and/or first light
Learning transmission module 14 may include circulator.
It is highly preferred that the end Alice can also include Polarization Control Module 26, for main to described first received
The polarization state of laser pulse part is controlled.
In the dissemination system of the second aspect of the utility model, the end Bob may include：Beam module 16 is closed, is used for
It transmits the first main laser segment pulse towards the end Alice, and makes the signal light towards the relevant spy
Module 24 is surveyed to transmit；And second optical transmission module 22, for making the second main laser segment pulse towards described
Two transmit from laser module 21, and make described second to transmit from laser pulse towards the coherent detection module 24.
Preferably, the end Bob can also include second phase modulation module 25, be used for the local local oscillator light with
Machine carries out 0 or pi/2 phase modulation.
Preferably, the first beam splitting module 13 may include polarization-maintaining beam splitting element and/or the conjunction beam module 16
It may include polarization-maintaining polarization coupling element and/or second optical transmission module 22 may include circulator.
Preferably, the end Bob can also include Postponement module 28, for making based on the same main laser pulse beam splitting
Obtained the first main laser segment pulse and the second main laser segment pulse is respectively to inject lock mode shape
At the signal light and the local local oscillator light reach coherent detection module 24 simultaneously, so that effect is interfered, so as to right
The result of interference carries out zero-difference detection.
Preferably, the Postponement module may include faraday rotation mirror, and further can also include delay line and
Polarization-maintaining polarization beam splitting element.
Detailed description of the invention
Utility model will be further described in detail below with reference to the attached drawings and specific embodiments.
It is first exemplary to schematically show continuous variable quantum key distribution system according to the present utility model by Fig. 1
Embodiment；And
Second Fig. 2 schematically shows continuous variable quantum key distribution system according to the present utility model is exemplary
Embodiment.
Specific embodiment
Hereinafter, the exemplary embodiment of the utility model is with reference to the accompanying drawings to detailed description.The following examples with
Example way provides, sufficiently to convey the spirit of the utility model to give the utility model those skilled in the art.Cause
This, the utility model is not limited to embodiment disclosed herein.
In order to overcome defect existing in the prior art, existing LLO scheme is compared, in the continuous variable of the utility model
Main laser module is provided in quantum key distribution system, for respectively to be set to coding side Alice (that is, transmitting terminal or
Person's modulation methods) first from laser module and be set to the second of decoding end Bob (that is, receiving end or detection side) from sharp
Light device module provides seed light, so that first is generated in a manner of injecting locking for believing from laser module based on the seed light
The first of number light is generated in a manner of injecting locking based on the seed light for this from laser pulse, second from laser module
The second of ground local oscillator light is from laser pulse.In this way, so that the wavelength between signal light and local oscillator light has very
Good consistency, and stable phase reference can be set up, so as to solve to be difficult to realize stablize in existing LLO scheme
The problem of coherent detection.
It is first exemplary to schematically show continuous variable quantum key distribution system according to the present utility model by Fig. 1
Embodiment.The dissemination system may include coding side Alice and decoding end Bob.Coding side Alice and decoding end Bob pass through light
Learn channel connection.Preferably, which can realize by optical fiber.
As shown, coding side Alice may include main laser module 11 and first from laser module 12, decoding end
Bob may include second from laser module 21, wherein first will be used to provide signal light from laser module 12, second from
Laser module 21 will be used to provide local local oscillator light.Principle according to the present utility model, the master that main laser module 11 exports
Laser pulse will be divided into the first main laser segment pulse and the second main laser segment pulse through the first beam splitting module 13, with
First is used separately as from laser module 12 and second from the seed light of laser module 21.Preferably, the first beam splitting module 13
It may include polarization-maintaining beam splitting element, such as polarization-maintaining beam splitter (BS).
According to the utility model, the first main laser segment pulse is for injecting first from laser module 12, as kind
Sub-light makes first from laser module 12 to export first in a manner of injecting locking from laser pulse, this is first from laser arteries and veins
Punching will be used to be modulated to form signal light.Second main laser segment pulse is for being injected into second from laser module
21, make second to export second from laser pulse in a manner of injecting locking from laser module 21 as seed light, this second
Local local oscillator light will be used to form from laser pulse.
Preferably, it can be selected to the laser arteries and veins less than main laser module from the laser pulse width of laser module
Rush width.Therefore, can for example by adjusting main laser segment pulse and accordingly from the relative time delay between laser pulse,
So that output pulse width is relatively narrow in a manner of injecting locking under excitation of the laser module in main laser segment pulse accordingly
Slave laser pulse, and from the phase of laser pulse correspond to the wider main laser segment pulse of pulsewidth intermediate amplitude
Stable part, thus obtain phase and polarize and line width consistent with main laser segment pulse it is narrower from laser pulse.
It can also include coherent detection module 24 in decoding end Bob to realize decoding, for signal light and this
The result of interference of ground local oscillator light is detected.Preferably, coherent detection module 24 may include zero-difference detection device.
In order to form signal light, coding side Alice can also include signal optical modulator module 15, for first from laser
Device pulse is modulated to form signal light.As shown, the signal optical modulator module 15 may include first phase modulation element
Part 152 and intensity modulation elements 151.Optionally, first phase modulation element 152 may include phase-modulator (PM)；Intensity
Modulation element 151 may include intensity modulator (AM).
Coding side Alice can also include the first optical transmission module 14.First optical transmission module 14 may include
Three ports, and be configured to：First port and second of the first main laser segment pulse through the first optical transmission module 14
Port injection first from laser module 12, and the first second port from laser pulse through the first optical transmission module 14 and
Third port is transmitted to signal optical modulator module 15.Preferably, the first optical transmission module 14 may include circulator or beam splitting
Element.
Coding side Alice can also include closing beam module 16, for that will modulate the letter formed through signal optical modulator module 15
Number light and the second main laser segment pulse carry out conjunction beam, to export combined beam light.The combined beam light will be defeated outward from coding side Alice
Out, such as through optical fiber it is transmitted to decoding end Bob.Preferably, closing beam module 16 may include polarization-maintaining polarization coupling element, such as protect
Inclined polarization beam combiner (PBC).
Can also include the second beam splitting module 23 in decoding end Bob, for by the combined beam light received signal light and
Second main laser segment pulse separates, and transmits it along different light paths respectively.As previously discussed, signal light will
Be transferred to coherent detection module 24, the second main laser segment pulse will act as second from the seed light of laser module 21 with
It is set to export second from laser pulse, to be used to form local local oscillator light in a manner of injecting locking.Preferably, the second beam splitting
Module 23 may include polarization-maintaining polarization beam splitting element, such as polarization-maintaining polarization beam apparatus (PBS).
Similarly, decoding end Bob also may include having the second optical transmission module 22.Second optical transmission module 22 can be with
Including three ports, and it is configured to：First port of the second main laser segment pulse through the second optical transmission module 22 and
Second port injection second is from laser module 21, and the second second end from laser pulse through the second optical transmission module 22
Mouth and third port are exported towards coherent detection module 24.Preferably, the second optical transmission module 22 may include circulator or
Beam splitting element.
Further, decoding end Bob can also include second phase modulation element 25, for carrying out 0 to local local oscillator light
Or pi/2 phase modulation, X or P measurement is carried out to randomly choose.Preferably, second phase modulation element 25 may include phase
Position modulator (PM).
Further, in coding side Alice, signal optical modulator module 15 can also include modulation variance detection module
153, for detecting the modulation variance in signal light.As an example, modulation variance detection module 153 may include third point
Beam module and the first detector module, wherein third beam splitting module is used to separate signal light sub-fraction light so that first visits
It surveys the detection of device module to use, to know the modulation covariance information in signal light.Preferably, third beam splitting module may include protecting
Inclined beam splitting element, such as polarization-maintaining beam splitter (BS).
Further, in coding side Alice, signal optical modulator module 15 can also include adjustable attenuator (VOA)
154。
Further, in decoding end Bob, it is also provided with seed light intensity detection module 27, is injected into for detecting
Whether second can reach the requirement of injection locking from the intensity of the second main laser segment pulse of laser module 21, and
Generate the clock signal at the end Bob.As an example, seed light intensity detection module 27 may include the 4th beam splitting module and second
Detector module, wherein the 4th beam splitting module is used to separate the second main laser segment pulse a part of light so that second visits
The detection of device module is surveyed to use.Preferably, the 4th beam splitting module may include polarization-maintaining beam splitting element, such as polarization-maintaining beam splitter (BS).
It preferably, can also include Polarization Control Module 26 in decoding end Bob, for entering second point in combined beam light
The polarization state of signal light therein and the second main laser segment pulse is respectively controlled before beam module 23, so as to for example
The polarization variations that may be introduced in optical transmission process can be eliminated.Preferably, Polarization Control Module 26 may include Polarization Control
Device (PC).
The working principle of quantum key distribution system shown in Fig. 1 is further illustrated below in conjunction with a preferable example.
In the preferable example, the first beam splitting module 13 includes polarization-maintaining beam splitter BS；First optical transmission module 14 includes circulator；It closes
Beam module 16 includes polarization-maintaining polarization beam combiner PBC；Third beam splitting module includes polarization-maintaining beam splitter；Coherent detection module 24 is single
Zero-difference detection device；Second beam splitting module 23 includes polarization-maintaining polarization beam apparatus PBS；Second optical transmission module 22 includes circulator；
And the 4th beam splitting module includes polarization-maintaining beam splitter.
In this example, the main laser module 11 in coding side Alice exports main laser pulse, the main laser arteries and veins
Punching is divided into the first main laser segment pulse and the second main laser segment pulse through polarization-maintaining beam splitter 13.First main laser arteries and veins
First port and second port of the punching part through circulator 14 are injected into first from laser module 12.
Due to first from the laser pulse width of laser module 12 be less than main laser module laser pulse width, because
This, can be by adjusting the first main laser segment pulse and first from the relative time delay between laser pulse, so that first
Output pulse width is relatively narrow in a manner of injecting locking under excitation of the laser module in the first main laser segment pulse first
From laser pulse, and first corresponds in the wider first main laser segment pulse of pulsewidth from the phase of laser pulse
Between the stable part of amplitude, to obtain phase and polarization consistent with the first main laser segment pulse and narrower line width first
From laser pulse.
First adjusts in signal optical modulator module 15 through amplitude modulator 151 and phase-modulator 152 from laser pulse
After system, the corresponding two quadrature components X and P of coherent state is in Gaussian Profile, to form the signal light for having modulation intelligence.
Preferably, in signal optical modulator module 15, the modulation methods in signal light can also be detected using modulation variance detection module 153
Poor information, and/or intensity adjustment is carried out to signal light using adjustable attenuator 154.
At polarization-maintaining polarization beam combiner 16, signal light and the second main laser segment pulse close beam and mutually hang down at front and back polarization
Two straight pulses, such as the second main laser segment pulse is preceding, are vertical polarization, and signal light is horizontal polarization rear, from
And the end Alice is exported as combined beam light.
At decoding end Bob, due to realizing the light splitting to combined beam light using polarization-maintaining polarization beam apparatus 23, in order to
Eliminate transmission process in may introduce polarization variations and ensure spectrophotometric result, can use Polarization Controller 26 make signal light and
Second main laser segment pulse is in desired polarization state, such as signal light can be made to revert to level in the preferable example
Polarization, and the second main laser segment pulse is made to revert to vertical polarization.Therefore, the second main laser pulse of vertical polarization
Part will be reflected at polarization-maintaining polarization beam apparatus 23, and the signal light of horizontal polarization will be saturating at polarization-maintaining polarization beam apparatus 23
It penetrates.
By the second main laser segment pulse that reflex is separated from combined beam light will continue towards second from swash
Light device module 21 is transmitted；Zero-difference detection device 24 will be transferred to by the signal light that transmission effect separates.
Preferably, seed light intensity detection module 27 can also be set before laser module 21 second to detect second
Whether the light intensity of main laser segment pulse sufficiently achieves the requirement of injection locking, while generating the clock of decoding end Bob.
As shown in Figure 1, at decoding end Bob, the second main laser segment pulse via circulator 22 first port and
Second port is injected into second from laser pulse module 21.Similarly, it again may be by adjusting the second main laser pulse
Part and second from the relative time delay between laser pulse so that second from laser module 21 in the second main laser pulse
Output pulse width is relatively narrow in a manner of injecting locking under partial excitation second is from laser pulse, and second from laser pulse
Phase correspond to the wider second main laser segment pulse of pulsewidth the stable part of intermediate amplitude, thus obtain wavelength,
Phase and polarization are consistent with the second main laser segment pulse, and line width it is narrower second from laser pulse, as local
Local oscillator light uses.
Second transmits via the second port and third port of circulator 22 towards zero-difference detection device 24 from laser pulse.
In this example, second phase modulator 25 is arranged between the third port of circulator 22 and zero-difference detection device 24, so as to right
Second carries out the phase-modulation of 0 or pi/2 from laser pulse, carries out X or P measurement to randomly choose.
Then, local oscillator light and signal light reach simultaneously interferes at zero-difference detection device, and by zero-difference detection device to dry
Result is related to be detected.
In this embodiment, by being arranged main laser in coding side Alice, make it possible to obtain TLO scheme simultaneously
The advantages of with LLO scheme, LLO scheme is only slightly inferior in safety.Compared with TLO scheme, it is equivalent at decoding end Bob
Provided with this vibrating light amplifier.Originally because shot noise limits, the local oscillator light needs of transmission are very strong, after passing through channel in this way,
Shot noise could be much larger than electrical noise.And in this embodiment, second for injecting locking for being sent to decoding end Bob is main
The light intensity of laser pulse part can be less than the light intensity of local local oscillator light, and small multiple is equivalent to times of this vibrating light amplifier
Number.Simultaneously as local oscillator light is without quantum channel, listener-in Eve can not be attacked directly against local oscillator light, so the reality
The dissemination system for applying example is better than TLO scheme in safety.
Second Fig. 2 schematically shows continuous variable quantum key distribution system according to the present utility model is exemplary
Embodiment.The dissemination system equally includes coding side Alice and decoding end Bob.Coding side Alice and decoding end Bob pass through light
Learn channel connection.Preferably, which can realize by optical fiber.
As shown, coding side Alice may include first from laser module 12, decoding end Bob may include main sharp
Light device module 11 and second is from laser module 21, wherein first will be used to provide signal light from laser module 12, second from
Laser module 21 will be used to provide local local oscillator light.Principle according to the present utility model, the master that main laser module 11 exports
Laser pulse will be divided into the first main laser segment pulse and the second main laser segment pulse through the first beam splitting module 13, with
First is used separately as from laser module 12 and second from the seed light of laser module 21.Preferably, the first beam splitting module 13
It may include polarization-maintaining beam splitting element, such as polarization-maintaining beam splitter (BS).
Specifically, the first main laser segment pulse is used to make as seed light injection first from laser module 12
It exports first from laser pulse in a manner of injecting locking, this first will be used to be modulated with shape from laser pulse
At signal light.Second main laser segment pulse is used to be injected into second from laser module 21 as seed light, makes it with note
The mode for entering locking exports second from laser pulse, this second will be used to form local local oscillator light from laser pulse.
Preferably, it can be selected to the laser arteries and veins less than main laser module from the laser pulse width of laser module
Rush width.Therefore, can for example by adjusting main laser segment pulse and accordingly from the relative time delay between laser pulse,
So that output pulse width is relatively narrow in a manner of injecting locking under excitation of the laser module in main laser segment pulse accordingly
Slave laser pulse, and from the phase of laser pulse correspond to the wider main laser segment pulse of pulsewidth intermediate amplitude
Stable part, thus obtain phase and polarize and line width consistent with main laser segment pulse it is narrower from laser pulse.
Further include having coherent detection module 24 in decoding end Bob to realize decoding, for signal light and it is local this
The result of interference of vibration light is detected.Preferably, which may include zero-difference detection device.
Decoding end Bob can also include closing beam module 16, for making the first main laser segment pulse towards coding side
Alice transmission, and the signal light that coding side Alice is sent is transmitted towards coherent detection module 24.Preferably, Shu Mo is closed
Block 16 may include three ports, and be configured to：First main laser segment pulse through its first port and second port to
The transmission of the end Alice, and the signal light that sends of the end Alice through its second port and third port towards coherent detection module transfer.
Optionally, closing beam module 16 may include circulator or conjunction beam element, such as polarization-maintaining polarization coupling element PBC.
Decoding end Bob can also include the second optical transmission module 22, for making the second main laser segment pulse direction
Second transmits from laser module 21, and makes second to transmit from laser pulse towards coherent detection module 24.Preferably,
Two optical transmission modules 22 may include three ports, and be configured to：Second main laser segment pulse is through its first port
With second port towards second from laser module 21 transmit, and second from laser pulse through its second port and third port
It is transmitted towards coherent detection module 24.Optionally, the second optical transmission module 22 may include circulator or beam splitting element.
Coding side Alice may include signal optical modulator module 15, for first from laser pulse be modulated with
Form signal light.As shown, signal optical modulator module 15 may include first phase modulation element 152 and intensity modulation elements
151.Optionally, first phase modulation element 152 may include phase-modulator (PM)；Intensity modulation elements 151 may include
Intensity modulator (AM).
Coding side Alice can also include the second beam splitting module 23, the first main laser pulse for sending the end Bob
It is partially toward first to transmit from laser module 12, and signal light is sent towards decoding end Bob.Preferably, the second beam splitting
Module 23 may include three ports, and be configured to：First main laser segment pulse is through its first port and second port
It is transmitted to first from laser module 12, signal light is transmitted through its third port and first port towards the end Bob.Optionally,
Two beam splitting modules 23 may include circulator or beam splitting element, such as polarization-maintaining polarization beam splitting element PBS.
Coding side Alice can also include the first optical transmission module 14, for export the second beam splitting module 23
First main laser segment pulse is transmitted to first from laser module 12, and by first from laser pulse to signal light tune
Molding block 15 transmits.Preferably, the first optical transmission module 14 may include three ports, and be configured to：First main laser
Device segment pulse is transmitted through its first port and second port to first from laser module 12, first from laser pulse through it
Second port and third port are transmitted towards signal optical modulator module 15.Optionally, the first optical transmission module 14 may include
Circulator or beam splitting element.
It preferably, can also include modulation variance detection module 153 in signal optical modulator module 15, for detecting signal light
In modulation variance.As an example, modulation variance detection module 153 may include the second beam splitting module and the first detector
Module, wherein the second beam splitting module is used to separate signal light sub-fraction light and uses so that the first detector module detects, from
And know the modulation covariance information in signal light.Preferably, the second beam splitting module may include polarization-maintaining beam splitting element, such as polarization-maintaining
Beam splitter.
It preferably, can also include adjustable attenuator (VOA) 154 in signal optical modulator module 15.
Preferably, it is also provided with seed light intensity detection module 27 in coding side Alice, is injected into first for detecting
Whether can reach the requirement of injection locking from the intensity of the first main laser segment pulse of laser module 12, and generate
The clock signal at the end Alice.As an example, seed light intensity detection module 27 may include that third beam splitting module and second are visited
Survey device module, wherein third beam splitting module is used to separate the first main laser segment pulse a part of light for the second detection
The detection of device module uses.Preferably, third beam splitting module may include polarization-maintaining beam splitting element, such as polarization-maintaining beam splitter.
Further, decoding end Bob can also include second phase modulation element 25, for signal light or local local oscillator
Light carries out 0 or pi/2 phase modulation, carries out X or P measurement to randomly choose.Preferably, second phase modulation element 25 can
To include phase-modulator.
Similarly, the working principle of dissemination system shown in Fig. 2 is further illustrated below in conjunction with a preferable example.
In the preferable example, the first beam splitting module 13 include polarization-maintaining beam splitter, close beam module 16 include polarization-maintaining polarization beam combiner, second
Optical transmission module 22 includes circulator, and the second beam splitting module 23 includes polarization-maintaining polarization beam apparatus, the first optical transmission module 14
Including circulator, the second beam splitting module includes polarization-maintaining beam splitter, and third beam splitting module includes polarization-maintaining beam splitter.
In this example, the main laser module 11 in decoding end Bob exports main laser pulse, through polarization-maintaining beam splitter
13 are divided into the first main laser segment pulse and the second main laser segment pulse.
As shown in Fig. 2, being optionally also provided with Postponement module 28 in decoding end Bob in the preferable example, being used for
Make the first main laser segment pulse and the second main laser segment pulse obtained based on the same main laser pulse beam splitting
The signal light that is formed and local local oscillator light while coherent detection module 24 is reached in a manner of injecting locking respectively, to occur to do
Effect is related to, to carry out zero-difference detection to the result of interference.Preferably, which may include faraday rotation mirror
It (FM), and preferably can also include delay line and polarization-maintaining polarization beam splitting element PBS.
Second main laser pulse injects second from laser module via the first port and second port of circulator 22
21.By adjusting the second main laser segment pulse and second from the relative time delay between laser pulse, so that second from swashing
Light device module 21 under the excitation of the second main laser segment pulse by inject locking in a manner of output pulse width it is relatively narrow second from
Laser pulse, and the second centre from the phase of laser pulse corresponding to the wider second main laser segment pulse of pulsewidth
The stable part of amplitude, so that it is consistent with the second main laser segment pulse to obtain wavelength, phase and polarization, and line width is narrower
Second, from laser pulse, uses as local local oscillator light.
Second transmits via the second port and third port of circulator 22 towards zero-difference detection device 24 from laser pulse.
In this example, second phase modulator 25 is arranged between the third port of circulator 22 and zero-difference detection device 24, so as to right
Second carries out the phase-modulation of 0 or pi/2 from laser pulse, carries out X or P measurement to randomly choose.
For the first main laser segment pulse separated, sent out after the reflection of polarization-maintaining polarization beam combiner 16 to the end Alice
It send.
At the end Alice, the second main laser pulse of vertical polarization is reflected at polarization-maintaining polarization beam apparatus 23.It is preferred that
Ground, the end Alice are additionally provided with Polarization Controller 26, control for the polarization state to the first main laser segment pulse.Example
Such as, Polarization Controller 26 can be used for reverting to the polarization state for being sent to the first main laser segment pulse at the end Alice vertical
Straight polarization, to eliminate possible polarization variations in transmission process.
At this time preferably, it can use seed light detection module 27 to detect the first main laser segment pulse, with
It determines whether its light stability reaches the requirement of injection locking, while also generating the clock for being used for coding side Alice.
Further, first port and second port of the first main laser segment pulse through circulator 14 are injected into first
From laser module 12.Being prolonged by adjusting the first main laser segment pulse and first from opposite between laser pulse
When, so that first exports arteries and veins in a manner of injecting locking under excitation of the laser module 12 in the first main laser segment pulse
Wide relatively narrow first from laser pulse, and first corresponds to wider first main laser of pulsewidth from the phase of laser pulse
The stable part of the intermediate amplitude of segment pulse, to obtain phase and polarize and line consistent with the first main laser segment pulse
Wide narrower first from laser pulse.
First second port and third port from laser pulse part through circulator 14 is to signal optical modulator module 15
Transmission.In signal optical modulator module 15, first is modulated from laser pulse through amplitude modulator 151 and phase-modulator 152
Afterwards, the corresponding two quadrature components X and P of coherent state is in Gaussian Profile, to form signal light.
Preferably, it can use modulation variance detection module 153 at this time to detect the modulation variance in signal light, with
And further modulation is made to signal light using adjustable attenuator 154.
Then, signal light transmits output at polarization-maintaining polarization beam apparatus 23, is transmitted with horizontal state of polarization to decoding end Bob.
At decoding end Bob, the signal light of horizontal polarization will transmit at polarization-maintaining polarization beam combiner 16, and direction zero
Gap detector 24 transmits.
In this embodiment, by being arranged main laser in decoding end Bob, so that can not only eliminate for local oscillator light
The possibility of attack, and the Trojan horse attack of Eve can be prevented.Because injection locking light has got around Alice modulator, because
This can add isolator after modulator, and after the optical injection-locked of main laser, and the light pulse sent from laser is only
Its phase, wavelength and polarization information are retained, Eve can not be attacked using these information without being found.In addition, this
Embodiment can also substantially reduce backscattering noise, because injection locking light can be weaker than the signal light directly transmitted, light intensity
Weaker, backscattering noise is with regard to smaller, and the presence of polarization-maintaining polarization beam apparatus has directly filtered the noise of vertical polarization.
Although above in conjunction with attached drawing by specific embodiment to the continuous variable quantum key distribution system of the utility model
It is illustrated, still, it will be readily appreciated by those skilled in the art that above-described embodiment is only exemplary, for illustrating this
The principle of utility model can't cause to limit to the scope of the utility model, and those skilled in the art can be to above-mentioned reality
It applies example and carries out various combinations, modification and equivalent replacement, without departing from the spirit and scope of the utility model.
Claims (22)
1. a kind of continuous variable quantum key distribution system comprising main laser module (11), first are from laser module
(12), second from laser module (21) and coherent detection module (24), it is characterised in that：
Described first is arranged from laser module at the end Alice；
Described second is arranged from laser module at the end Bob；
The main laser pulse of the main laser module output is divided into the first main laser arteries and veins by the first beam splitting module (13)
Punching part and the second main laser segment pulse；
Wherein, the first main laser segment pulse is used as the described first seed light from laser module, so that described
First generates first from laser module in a manner of injecting locking is used for from laser pulse, described first from laser pulse
Form signal light；And
The second main laser segment pulse is used as the described second seed light from laser module so that described second from
Laser module generates second in a manner of injecting locking and is used to form this from laser pulse from laser pulse, described second
Ground local oscillator light；
The coherent detection module (24) is used to detect the result of interference of the signal light and the local local oscillator light.
2. continuous variable quantum key distribution system as described in claim 1, wherein the main laser module (11) and institute
The first beam splitting module (13) is stated to be arranged at the end Alice.
3. continuous variable quantum key distribution system as claimed in claim 2, it is characterised in that the end Alice includes：
Signal optical modulator module (15), for being modulated to described first from laser pulse to form the signal light；
First optical transmission module (14), for making the first main laser segment pulse towards described first from laser die
Block (12) transmission, and make described first to transmit from laser pulse towards the signal optical modulator module (15)；And
It closes beam module (16), obtains closing beam for the signal light and the second main laser segment pulse to be carried out conjunction beam
Light.
4. continuous variable quantum key distribution system as claimed in claim 3, wherein signal optical modulator module (15) packet
Include intensity modulated module (151) and first phase modulation module (152).
5. continuous variable quantum key distribution system as claimed in claim 4, wherein the signal optical modulator module (15) is also
Including modulation variance detection module (153) and/or adjustable attenuator (154).
6. continuous variable quantum key distribution system as claimed in claim 3, wherein the first beam splitting module (13) includes
Polarization-maintaining beam splitting element and/or first optical transmission module (14) include circulator and/or the conjunction Shu Mo
Block (16) includes polarization-maintaining polarization coupling element.
7. continuous variable quantum key distribution system as claimed in claim 3, it is characterised in that the end Bob includes：
Second beam splitting module (23), for by the signal light and the second main laser segment pulse in the combined beam light
It separates；And
Second optical transmission module (22), for making the second main laser segment pulse towards described second from laser die
Block (21) transmission, and make described second to transmit from laser pulse towards the coherent detection module (24).
8. continuous variable quantum key distribution system as claimed in claim 7, it is characterised in that the end Bob further includes：
Seed light intensity detection module (27) is used to detect injection described second and swashs from second master of laser module (21)
Whether the intensity of light device segment pulse, which is sufficient for injection locking, requires, and generates the clock signal at the end Bob；And/or
Second phase modulation module (25) is used to carry out 0 or pi/2 phase modulation at random to the local local oscillator light.
9. continuous variable quantum key distribution system as claimed in claim 7, wherein the second beam splitting module (23) includes
Polarization-maintaining polarization beam splitting element and/or second optical transmission module (22) include circulator and/or the phase
Dry detecting module (24) includes zero-difference detection device.
10. continuous variable quantum key distribution system as claimed in claim 9, wherein the end Bob further includes Polarization Control
Module (26), for carrying out Polarization Control to the combined beam light.
11. continuous variable quantum key distribution system as described in claim 1, wherein the main laser module (11) and
The first beam splitting module (13) is arranged at the end Bob.
12. continuous variable quantum key distribution system as claimed in claim 11, it is characterised in that the end Alice includes：
Signal optical modulator module (15), for being modulated to described first from laser pulse to form the signal light；
Second beam splitting module (23), for making the first main laser segment pulse towards described first from laser module
(12) it transmits, and transmits the signal light towards the end Bob；And
First optical transmission module (14), for making the first main laser segment pulse towards described first from laser die
Block (12) transmission, and make described first to transmit from laser pulse towards the signal optical modulator module (15).
13. continuous variable quantum key distribution system as claimed in claim 12, wherein the signal optical modulator module (15)
Including intensity modulated module (151) and first phase modulation module (152).
14. continuous variable quantum key distribution system as claimed in claim 12, wherein the signal optical modulator module (15)
It further include modulation variance detection module (153) and/or adjustable attenuator (154).
15. continuous variable quantum key distribution system as claimed in claim 12, wherein the end Alice further includes seed
Light intensity detection module (27) is used to detect described first the first main laser pulse from laser module (12) of injection
Whether partial intensity, which is sufficient for injection locking, requires, and generates the clock signal at the end Alice.
16. continuous variable quantum key distribution system as claimed in claim 12, wherein the second beam splitting module (23) packet
Including polarization-maintaining polarization beam splitting element and/or first optical transmission module (14) includes circulator.
17. continuous variable quantum key distribution system as claimed in claim 16, wherein the end Alice further includes polarization
Control module (26) is controlled for the polarization state to the first main laser segment pulse received.
18. continuous variable quantum key distribution system as claimed in claim 12, it is characterised in that the end Bob includes：
It closes beam module (16), for transmit the first main laser segment pulse towards the end Alice, and described in making
Signal light is transmitted towards the coherent detection module (24)；And
Second optical transmission module (22), for making the second main laser segment pulse towards described second from laser die
Block (21) transmission, and make described second to transmit from laser pulse towards the coherent detection module (24).
19. continuous variable quantum key distribution system as claimed in claim 18, wherein the end Bob further includes the second phase
Position modulation module (25) is used to carry out 0 or pi/2 phase modulation at random to the local local oscillator light.
20. continuous variable quantum key distribution system as claimed in claim 18, wherein the first beam splitting module (13) packet
It includes polarization-maintaining beam splitting element and/or the conjunction beam module (16) includes polarization-maintaining polarization coupling element and/or described
Two optical transmission modules (22) include circulator.
21. continuous variable quantum key distribution system as claimed in claim 20, wherein the end Bob further includes delay mould
Block (28), for making the first main laser segment pulse obtained based on the same main laser pulse beam splitting and described
Two main laser segment pulses are respectively to inject the signal light of lock mode formation and the local local oscillator light while reach
The coherent detection module (24).
22. continuous variable quantum key distribution system as claimed in claim 21, wherein the Postponement module includes faraday
Revolving mirror.
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|---|---|---|---|
| CN201820485873.XU CN208174698U (en) | 2018-04-08 | 2018-04-08 | A kind of continuous variable quantum key distribution system |
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| CN201820485873.XU CN208174698U (en) | 2018-04-08 | 2018-04-08 | A kind of continuous variable quantum key distribution system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109682467A (en) * | 2019-01-23 | 2019-04-26 | 广东朗研科技有限公司 | Infrared single photon frequency upooaversion detection system based on the inclined lock-out pulse pumping of all risk insurance |
| CN110351075A (en) * | 2018-04-08 | 2019-10-18 | 中国科学技术大学 | A kind of continuous variable quantum key distribution system |
| CN111077614A (en) * | 2019-12-31 | 2020-04-28 | 山东国迅量子芯科技有限公司 | Micro-optical integrated light emitting module and application thereof |
-
2018
- 2018-04-08 CN CN201820485873.XU patent/CN208174698U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110351075A (en) * | 2018-04-08 | 2019-10-18 | 中国科学技术大学 | A kind of continuous variable quantum key distribution system |
| CN110351075B (en) * | 2018-04-08 | 2024-05-17 | 中国科学技术大学 | Continuous variable quantum key distribution system |
| CN109682467A (en) * | 2019-01-23 | 2019-04-26 | 广东朗研科技有限公司 | Infrared single photon frequency upooaversion detection system based on the inclined lock-out pulse pumping of all risk insurance |
| CN111077614A (en) * | 2019-12-31 | 2020-04-28 | 山东国迅量子芯科技有限公司 | Micro-optical integrated light emitting module and application thereof |
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