CN206440817U - Quantum radar based on continuous variable - Google Patents
Quantum radar based on continuous variable Download PDFInfo
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- CN206440817U CN206440817U CN201720059389.6U CN201720059389U CN206440817U CN 206440817 U CN206440817 U CN 206440817U CN 201720059389 U CN201720059389 U CN 201720059389U CN 206440817 U CN206440817 U CN 206440817U
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Abstract
The utility model provides a kind of quantum radar based on continuous variable, including detectable signal generating means and echo signal processing equipment, the detectable signal generating means includes pulse generation device, the code device encoded based on continuous variable, the echo signal processing equipment includes monitoring device and imaging device, the code device is used to encode flashlight, and coded signal light passes through detectable signal of the first polarization beam apparatus combining for quantum radar with local oscillator light；The monitoring device is additionally operable to record the quantum state of flashlight in first echo signal and detectable signal, and both are compared, and judges whether detectable signal is disturbed.The utility model overcomes the problem of meeting polarization by reflection changes after photon reflects through actual object.The utility model uses general-purpose device, economical and practical.Whether the utility model energy real-time awareness radar pulse by target acquisition and accordingly sends error signal and detection is interfered.
Description
Technical field
Utility model belongs to a kind of quantum detection and quantum information field, more particularly to the quantum thunder based on continuous variable
Reach.
Background technology
With the development of the theoretical and corresponding experimental technique of quantum information, solved using quantum key distribution mechanism classical logical
The safety problem that letter field is present is increasingly becoming reality, and this will fundamentally solve Communication Security Problem.Quantum information is managed
The development of opinion is not exclusively advantageous for absolutely the communications field, and increasing other field can be solved by using for reference its principle and method
The safety problem that certainly field itself is present, this causes the extension in quantum information field to be expanded constantly.
In military field, the concept of quantum radar is widely paid close attention in recent years.The development of existing quantum radar
Trend mainly has following two：
1. by ingenious borrow quantum key distribution mechanism, to solve the problem of radar is interfered.Here refer mainly to existing
There is the most reluctant active interference problem of radar：The detectable signal of radar intercepts and captures target object or the simultaneously by target object
Tripartite's device launches the interference signal with detectable signal same waveform（From the point of view of classical physics, both signals are can not
Distinguish）, promote radar to object judgement mistake, it is impossible to obtain target real information.
2. the correlation technique detected using quantum, by non-classical light（Such as squeezed light）Or by means of quantum entanglement
To be obviously improved the resolution ratio of radar, the resolution ratio of radar can be lifted to quantum limit by classical limit（Heisenberg pole
Limit）.
It is possible thereby to which the quantum radar of above-mentioned two different directions is referred to as first kind quantum radar and Equations of The Second Kind quantum
Radar.
On first kind radar, earliest theoretical scheme and experimental verification was proposed by Mehul Malik et al. in 2012
And completion, and be published in by topic of Quantum-secured imaging on Applied Physics Letters magazines.
The method that the first kind quantum radar provided in above-mentioned document is just simply provided below.
Scheme is comprised the following steps that（Reference picture 1）：
1st, the laser that He-Ne laser is sent first passes through acousto-optic modulator（AOM）Modulation so as to forming a series of average lights
Subnumber is 1 pulse.
2nd, a half-wave plate (HWPa) being placed in electric rotating platform is passed through in pulse, so that the polarization of pulse is random
It is polarised to following four situation：Horizontal polarization（H）, vertical polarization (V), diagonal polarization (D) and opposition angle polarize (A).This amount of being
Coding in quantum key distribution.
3rd, the light pulse alignment target object emission completed will be encoded.
4th, the ambient noise that environment is come from reflection light pulse is disturbed using interferometric filter (IF) and filtered.
5th, half-wave plate is utilized（HWPb）Light pulse of the polarimeter to receiving is constituted with polarization beam apparatus (PBS)
Measure.When half-wave plate is parallel with vertical polarization, measurement light pulse is in horizontal state of polarization or perpendicular polarisation state.
And when half-wave plate and vertical polarization are into 22.5 ° of angles, measurement light pulse is in diagonal or opposes angle polarization state.
6th, two camera lenses are placed in the both sides of polarization beam apparatus, is respectively used to the imaging of different polarization light pulse.Last profit
It is imaged with electron multiplication CCD (EMCCD).
The scheme of the quantum radar system is derived from the BB84 agreements in quantum key distribution.When reflection photon polarization and
When incident compared to 25% error rate is occurred more than, you can judge that target, in interference detection, now corresponds to detection light complete
The complete all interference signals of signal intercepted and captured and returned.In above-mentioned technical article, researcher does not propose directly in itself should
Scheme is quantum radar, while the target object used in confirmatory experiment is mirror.
Be clear that existing technical scheme uses from the introduction of background technology above is weak light-pulse generator（It is flat
Equal number of photons is 1）, polarization encoder and coding are by electric device progress, it is necessary to unusual fine imaging device.This allows for existing
There is technical scheme to there is problem in the following areas：
1st, there are some researches show the polarization of light is via object（Non-specular surface）Significant change can occur after scattering, this is indicated that
There is root problem in original scheme.In the case where not there is any interference, will monitor the polarization of echo impulse has significantly
Error rate.Therefore when detecting actual object, differentiate whether echo-signal is disturbed from principle and can not using the program
OK.
2 use average photon number for 1 weak pulse punching as detectable signal, due to free space kind exist various environment because
Element makes photon equilibrium state more obvious, therefore the detection range of the program will be extremely limited.
3rd, it uses electromechanical device to encode, and code rate will be very low.Electromechanical device is used for a long time simultaneously
Reliability is also a problem.
4th, due to using weak pulse punching, then corresponding echo-signal also can be weaker, it is necessary to unusual fine imaging device.This
Cost is added, the reliability of device is reduced.
Based on above mentioned problem, a kind of quantum radar new departure based on continuous variable is proposed in the utility model, so that
The problem of in the presence of solution existing scheme.
The content of the invention
Technical problem to be solved in the utility model is to provide a kind of quantum radar based on continuous variable.Can be in radar
During detection, whether real-time awareness radar pulse by target acquisition and accordingly sends error signal and detection is interfered.Therefore,
The utility model provides following technical scheme：
Including detectable signal generating means and echo signal processing equipment, the detectable signal generating means is given birth to including pulse
The code device encoded into device, based on continuous variable, the echo signal processing equipment includes monitoring device and imaging device,
The quantum radar also includes beam splitting arrangement, the first fiber delay line and the second fiber delay line, and the beam splitting arrangement includes the
One beam splitter, the second beam splitter, the first polarization beam apparatus；
Light path is connected between the pulse generation device and code device, and the pulse generation device is used to generate light pulse
Signal, the light pulse signal is divided into local oscillator light and flashlight by the first beam splitter, and the code device is used for flashlight
Encoded, coded signal light is combined into the detectable signal of quantum radar with local oscillator light by the first polarization beam apparatus；Local oscillator light
For subsidiary.
Echo-signal after the detectable signal reflects through object is split by the second beam splitter, and is formed after beam splitting
One echo-signal and second echo signal, the monitoring device are connected with beam splitter light path and receive first echo signal, described
Imaging device is connected with beam splitter light path and receives second echo signal；First fiber delay line makes local oscillator light and flashlight
Deviate synchronous；Second fiber delay line makes local oscillator light and flashlight re-synchronization in first echo signal, enters back into monitoring
Device；
That is, if described first fiber delay line is used to postponing the local oscillator light that is divided into of the first beam splitter, corresponding described the
Two fiber delay lines are used to postpone the flashlight in second echo signal, if otherwise the first fiber delay line is used for first point of delay
The flashlight that beam device is divided into, then corresponding second fiber delay line is for postponing the local oscillator light in second echo signal；Cause
Two kinds of optical signals are asynchronous and synchronous when measuring during this detection, measurement is completed.
The monitoring device is additionally operable to record the quantum state of flashlight in first echo signal and detectable signal, and by two
Person is compared, and judges whether detectable signal is disturbed.
The monitoring device is additionally operable to record the quantum state of flashlight in first echo signal and detectable signal, and by two
Person is compared, and judges whether detectable signal is disturbed.
The flashlight after local oscillator light and coding is contained in said apparatus, detectable signal, wherein local oscillator light is used to aid in
Measurement.When flashlight and local oscillator light are all launched, both interval times are very short, therefore phase offset can caused by environment
To be considered identical, new phase difference, direct measurement will not be produced.
On the basis of using above-mentioned technical proposal, the utility model can also be using technical scheme further below：
Further, the monitoring device includes the second polarization beam apparatus, balanced homodyne measurement apparatus/heterodyne measurement dress
Put, the second fiber delay line and data processing equipment, when for balanced homodyne measurement apparatus, in addition to second phase modulator and
Quantum random number generator；
Balanced homodyne measurement apparatus/heterodyne measurement the device is used for the quantum for measuring flashlight in first echo signal
State；The data processing equipment is used for the quantum state for recording flashlight in detectable signal and first echo signal, and both are entered
Row is compared.The data processing equipment can be computer or single-chip microcomputer etc..
Further, the code device is discrete codes modulating device, and the discrete codes modulating device includes light path
The phase-modulator and quantum random number generator of connection.
Further, the code device is Gauss code modulation device, and the code device fills for Gauss coded modulation
Put, the Gauss code modulation device includes amplitude modulaor, phase-modulator, variable optical attenuator, the first quantum random number
Generator and the second quantum random number generator, the amplitude modulaor, phase-modulator, variable optical attenuator connect successively
Connect, first quantum random number generator is connected with the amplitude modulaor light path, the first quantum random number generator and institute
State the connection of phase-modulator light path.
The utility model, which further comprises, separately can solve a kind of quantum radar based on continuous variable of constructed problem, bag
Detectable signal generating means and echo signal processing equipment are included, the detectable signal generating means includes pulse generation device, base
The code device encoded in continuous variable, the echo signal processing equipment includes monitoring device and imaging device；The quantum
Radar also includes beam splitting arrangement and fiber delay line；
Light path is connected between the pulse generation device and code device, and the pulse generation device is used to generate light pulse
Signal, the light pulse signal includes reference light, flashlight and local oscillator light.The code device is used to compile flashlight
Code, coded signal light and detectable signal of the reference light as quantum radar, local oscillator light are retained in local be directly entered and monitor dress
Put, for subsidiary.
The detectable signal forms echo-signal after being reflected through object, the echo-signal is divided by beam splitting arrangement
Beam, forms first echo signal and second echo signal after beam splitting, the monitoring device is connected and received with beam splitting arrangement light path
First echo signal, the imaging device is connected with beam splitting arrangement light path and receives second echo signal；The fiber delay line
For the local oscillator light that is delayed so that local oscillator light enters monitoring device with flashlight, with reference to phototiming.
The monitoring device is additionally operable to the echo of measured value amendment first letter according to reference light in the first echo signal
The measured value of flashlight in number, and the quantum state of the measured value of flashlight after amendment and flashlight in the detectable signal of record is entered
Row is compared, and judges whether detectable signal is disturbed.
Further, the monitoring device include balanced homodyne measurement apparatus/heterodyne measurement device, data processing equipment with
And fiber delay line, when for balanced homodyne measurement apparatus, in addition to second phase modulator and quantum random number generator, institute
State the quantum state that balanced homodyne measurement apparatus/heterodyne measurement device is used to measure flashlight and reference light in first echo signal；
The data processing equipment is used for the quantum state for recording coded signal light and reference light in detectable signal, while according to reference light
Measured value amendment first echo signal in flashlight quantum state, the most quantum state of flashlight and in detectable signal at last
The quantum state of flashlight is compared after being corrected in one echo-signal.
Its further apparatus structure is consistent with foregoing device.
Local oscillator light is not sent in said apparatus, i.e. local oscillator light is retained in locally.Now, flashlight is reflected returns to reception dress
Postpone, there is uncertain phase difference between the influence meeting and local oscillator light due to environment.Accordingly, it would be desirable to by reference to the measurement of light
Value calculates the phase difference, recycles the value of the phase difference to carry out the measured value of revise signal light, so just can accurately be believed
The quantum state of number light.Therefore, the detectable signal of the measurement apparatus is to include the flashlight after reference light and coding.
It is not difficult to find out, local oscillator light is operated as the scheme that detectable signal is sent more easy.But in quantum information
The correlative study in field shows that the scheme that local oscillator light is sent has security risk, and enemy is by intercepting and capturing local oscillator light and signal simultaneously
Light may obtain coding information accurately on flashlight.And when local oscillator light is retained in into local, above-mentioned peace can be avoided
Full leak, but need to refer to the auxiliary of light.
Following processing method can be realized using the utility model：
S1. light pulse signal is generated, the light pulse signal includes local oscillator light, flashlight, or including local oscillator light, signal
Light and reference light；
S2., the flashlight of light pulse signal is carried out to the coded modulation of continuous variable, and recorded after coding in detectable signal
The quantum state of flashlight；The coding method includes discrete codes and modulated or Gauss coded modulation, and the continuous variable is continuous
The physical quantity of change；
S3. the light pulse signal for containing coded signal light is used as the detectable signal of quantum radar；
S4. to being reflected through object after echo-signal be split, form first echo signal and second echo signal, the
One echo-signal is measured and compared by monitoring device, and second echo signal carries out imaging by imaging device；
S5. judge whether detectable signal is interfered according to measurement comparison result.
Further, in step S1, flashlight, local oscillator light and reference light are generated by same pulse generation device, or
Person, a pulse generation device generation flashlight and reference light, another pulse generation device generation local oscillator light.The local oscillator light
For subsidiary.
Further, in step S2, coded modulation is modulated for discrete codes：It is right under quantum random number generator control
The phase of flashlight is modulated, and makes its random coded to two discrete quantum states that 0 or π is differed with local oscillator light phase.
Further, in step S2, coded modulation is Gauss coded modulation：Generated using two quantum random number generators
The random number of two groups of following Gaussian Profiles of satisfaction, average is 0, and variance is VAN0, according to the value modulated signal light quantity of two groups of random numbers
X and p in sub- state.Last Regulate signal luminous intensity, makes its variance consistent with the Gaussian Profile.
Further, in step S3, when the detectable signal includes flashlight and local oscillator light, this need to only be generated in step S1
Light in two.
Further, in step S3, it is considered to be retained in local oscillator light locally, when the detectable signal does not include local oscillator light,
In step S1 while flashlight and local oscillator light is generated, also need to generate reference light.Now reference light and flashlight synthesize spy
Signal is surveyed, and local oscillator light is retained in locally and is directly entered monitoring modular subsidiary.
Further, in step S5, believed by comparing in first echo signal in the quantum state and detectable signal of flashlight
The quantum state of number light, judges whether detectable signal is disturbed.
Further, if the measured value that detectable signal includes reference light in reference light, the first echo signal is used for
Correct the measured value of flashlight in first echo signal.
Further, light pulse signal pulse is split device and is divided into strong and weak clearly demarcated two-beam, wherein strong light is this
Shake light, enters a part of light in monitoring device, dim light through flashlight weaker in ovennodulation formation intensity through optical fiber
It is unmodulated to be used as reference light.
This kind of measurement apparatus is that local oscillator light is not being sent locally, that is, when being retained in local, flashlight is through being transferred back into
After reception device, due to environment influence can and local oscillator light there is uncertain phase difference.Come by reference to the measured value of light
The phase difference is calculated, recycles the value of phase difference to carry out the measured value of revise signal light, so can just obtain accurate flashlight
Quantum state.Therefore, the detectable signal of the device includes the flashlight after reference light and coding.
Theoretically simple analysis is of the invention once below.For laser pulse, according to the knowledge of quantum optices, Ke Yiyong
Coherent state | α>To be described.α is a plural number, can be expressed as α=| α | eiϴ.Wherein | α | represent pulse amplitude and
Represent the phase of pulse.Above-mentioned phase and Modulation and Amplitude Modulation, are the change to the two values in theory.While α=x+ip, phase
Modulation of the modulation also with x and p with amplitude is corresponding.And x and p and well known position and momentum are corresponding in coherent state, are all
The physical quantity of consecutive variations.The modulation that pair coherent state enters line phase and amplitude is also equal to and does corresponding modulation to x and p.This hair
The bright physical quantity to above-mentioned consecutive variations is modulated to realize coding, therefore the present invention is a kind of amount based on continuous variable
Sub- radar.
Two different coherent states of α values are simultaneously non-orthogonal.| α | bigger, the orthogonality between coherent state is better.In order to avoid upper
State situation, it is necessary to encoded from weaker light.Due between state and non-orthogonal, quantum non-clone principle is set up, for
A series of such pulse signals, enemy would be impossible to definitely know its quantum state and can not possibly accurately replicate.Therefore enemy without
Method is sent in coding identical interference signal in quantum mechanics meaning.Its interference signal sent is inevitable and primary signal is in the presence of poor
Not, i.e., some quantum states can change（Error）.By the error situation for monitoring echo-signal quantum state, you can find echo
It whether there is enemy's interference signal in signal.
When in the absence of any active interference, due to each factor in environment（Such as cloud）And instrument oneself factor（Optics device
The inherent shortcoming of part itself）Influence, the quantum state of flashlight is there is also certain error rate in echo-signal, and these factors are all
It can sum up in the point that among signal to noise ratio, and can be quantified by early stage.Active interference, from view of theory, greatly
Signal to noise ratio is reduced, the quantum state of echo-signal has the lifting of manifest error rate.
In actual applications, it is necessary to monitor the error rate of quantum state in real time.If signal is all disturbed, then will go out
Existing very high error rate, this is very readily detected.And when only fraction signal is disturbed, in real-time monitoring some
Occur that error rate becomes big situation suddenly in period.
Due to using the technical solution of the utility model, the beneficial effects of the utility model are：Instant invention overcomes original
In scheme, because reflecting the problem of rear polarizer changes through actual object using the light pulse present in polarization encoder.
The device that the utility model is used all is ripe and general optics and communication device, compares and more passes through with original scheme
Practical and precision and stability help more preferably..For example, homodyne detection has had highly developed device now, this and former scheme
Pulse is counted and compared, and is implemented efficiently and accurately a lot.
Signal pulse of the present utility model does not require single photon, and its average photon number is significantly larger than 1.If environment is identical,
The distance detected in the utility model will be apparently higher than original scheme, and this improves the practicality of quantum radar.Original scheme by
It is 1 in the average photon number of transmitting pulse signal, 1 will be less than by making the average photon number of its echo pulse signal, it is therefore desirable to non-
Often fine imaging system.And this programme is stronger due to pulse, thus only need to common CCD i.e. can obtain more clearly scheme
Picture.
The utility model simultaneously being capable of the measurement signal situation partly being disturbed and disturbed.
Brief description of the drawings
Fig. 1 is the method schematic diagram for the first kind quantum radar pointed out in background technology.
The embodiment for the quantum radar based on continuous variable that Fig. 2 provides for the utility model（Local oscillator light and flashlight are same
When the scheme launched）.
The embodiment for the quantum radar based on continuous variable that Fig. 3 provides for the utility model（The side that local oscillator light is not launched
Case）.
The embodiment for the quantum radar based on continuous variable that Fig. 4 provides for the utility model（The side that local oscillator light is not launched
Case）.
Fig. 5-1 is the concrete structure of discrete codes modulation code device.
Fig. 5-2 is the concrete structure of Gauss code modulation device.
Fig. 6 is the concrete structure of balanced homodyne measurement apparatus.
Fig. 7 is the concrete structure of heterodyne measurement device.
Embodiment
Embodiment 1：
As shown in Fig. 2 LASER Light Source launches continuous laser, continuous laser forms a series of after being modulated through impulse regulator
Light pulse signal.Preferably LASER Light Source is RIO companies of U.S. model PLANEX slab guide outside cavity gas lasers（Its noise water
It is flat low to be easy to accurate measurement）, wavelength is 1064nm, with a width of 1.5kHz.
Using amplitude modulaor AM by the continuous light modulation of output into 1MHz clock light pulse signal.The present embodiment passes through
Continuous laser source adds amplitude modulaor to obtain laser pulse, can also directly use pulse laser.
Light pulse signal is via 1:99 the first beam splitter BS1 is divided into two clearly demarcated light of power.It is strong for local oscillator light, and
It is not encoded, its main function will aid in homodyne detection below.Weak light is flashlight, that is, needs coding
Light.According to quantum-mechanical theory, the intensity of coherent state is lower（Laser pulse is described with coherent state）, the orthogonality between its state
It is poorer.The security of all quantum key distribution mechanism all originates from quantum non-clone principle, and can not cloning theorem premise
It is the nonorthogonality between state.Therefore it must be encoded from weaker light.
For flashlight, it will perform the encoding operation.Coded system mainly has following two（See Fig. 5）.
The first：Discrete codes are modulated.Only need to use phase-modulator PM.Phase-modulation will be by a quantum random number
Generator（QRNG）Control.Quantum random number generator will generate 0 and 1 at random, and corresponding phase-modulator is by flashlight
Phase-modulation is to 0 or π（Relative to the phase of local oscillator light）, so as to complete cataloged procedure.Now the quantum state of flashlight will be with
Machine | α>Or |-α>( |x+ip>Or |-x-ip>), and both and it is non-orthogonal.Therefore target can not have full knowledge that the quantum of flashlight
State, any interference, which is retransmitted, can all cause the quantum state of mistake to occur.With the 0 of computer recording random number, 1 sequence, so also
It has recorded the quantum state of flashlight.
Second：Gauss coded modulation.Amplitude modulator AM is needed, phase regulator PM and variable optical attenuator come
（VOA）.Specifically modulation system is：Utilize two quantum random number generators（QRNG1 and QRNG2）Generate two groups and meet Gauss point
(average is 0 to cloth, and variance is VAN0, wherein N0For shot noise limit) random number xAAnd pA, and pass through phase and Modulation and Amplitude Modulation
The modulation of device makes flashlight become following coherent state | xA+ipA>.The letter after ovennodulation is then adjusted by variable optical attenuator
Number light, the variance for making its light intensity is VAN0.In order to precisely control variance, can also Jia one again behind variable optical attenuator
Individual amplitude modulaor.With every group of x of computer recordingAAnd pAValue, so also just have recorded the quantum state of flashlight.
For local oscillator light, make signal pulse relative to local oscillator optical pulse delay using 20m the first fiber delay line 1
100ns。
Polarized orthogonal part in local oscillator light and flashlight is coupled with the first polarization beam apparatus PBS1, in order to most
After measure when separated.Light pulse after local oscillator light and flashlight are coupled is exactly the detection light needed for quantum radar
The detectable signal in source, i.e. quantum radar.Detectable signal is transmitted into progress target spy in free space by an optical telescope
Survey.
Identical optical telescope is used for the reception of echo-signal.Point of signal transmitting and receiving is realized using circulator simultaneously
From.
Echo-signal is by entering echo signal processing equipment after circulator.Signal entered an interferometric filter first
（IF）.The centre wavelength of interferometric filter is identical with optical maser wavelength, and a width of 10nm of half-peak.Done to filter off the noise in echo
Disturb signal.
Echo-signal is divided into two-way by subsequent second beam splitter BS2.Its splitting ratio is 10：90,90% is used to be imaged, and 10% uses
In measurement, preferably polarization-maintaining beam splitter.This two-way echo-signal will respectively enter monitoring device and imaging device.
For being imaged that all the way, it is imaged by imaging device.Echo-signal is allowed to be directly over imaging len, and in imaging lens
Place imaging device behind head to be imaged, the imaging device can be CCD devices.
For monitoring this all the way, light pulse is first separated into flashlight and local oscillator light again with the second polarization beam apparatus PBS2
Two-way.
For local oscillator light, it is first allowed to pass through a phase-modulator PM2.Phase-modulator PM2 phase is by a quantum
Randomizer（QRNG）Control, random changes between the two in pi/2 and 0, so as in follow-up random measurement signal
X or p in light quantum state.Synchronous signal light by 20m the second fiber delay line 2 delay make its in time with local oscillator light
It is synchronous to enter balanced homodyne measurement apparatus（BHD）.
Flashlight and local oscillator phototiming enter BHD（It is specifically shown in Fig. 6）, BHD measures signal light quantum in echo-signal at random
X or p value in state.Measurement result is input to computer, passes through corresponding point with flashlight quantum state in correspondence detectable signal
Amount contrast, differentiates whether quantum state changes.
The utility model can also replace BHD from heterodyne measurement device.When using heterodyne measurement device, local oscillator light
Random phase modulation need not be first passed through, but enters heterodyne measurement device simultaneously with flashlight after delay.Heterodyne measurement
Device can be measured simultaneously obtains x and p value in flashlight quantum state.Then the quantum of flashlight in same and correspondence detectable signal
State is contrasted to differentiate whether quantum state changes.
Embodiment 2：
Above-described embodiment launches local oscillator light and flashlight simultaneously, can also be retained in local oscillator light locally, without hair
Penetrate, as shown in figure 3, relative embodiment 1 has following distinguishing characteristics and same characteristic features：
1st, while the modulation of pulse generation device 1 generation flashlight, reference light is also generated.And the preferably intensity of reference light
A magnitude higher than flashlight, but it is still weaker than local oscillator light a lot.
2nd, code device will be encoded only to flashlight.Coded system and embodiment 1 are identical.
3rd, in monitoring device, the generation local oscillator light of pulse generation device 2, and embodiment 1 is identical, local oscillator light first to carry out π/
2 and 0 random phase modulation, then passes through fiber delay line to ensure itself and echo-signal while entering BHD.
4th, embodiment 2 carries out the coupling of local oscillator light and flashlight to form detectable signal without polarization beam apparatus.
By the measurement result of the further revise signal light of measurement result according to reference light when the 5th, being measured using BHD.
Remaining step is identical with the photoemissive embodiment of local oscillator, is no longer described in detail.
Embodiment 3：
Two pulse generation devices in embodiment 2 are reduced to a pulse generation device, as shown in Figure 4.
Specific implementation step is：
1st, pulse generation device generation flash.
2nd, it is 10 that splitting ratio was entered in pulse：90 beam splitter（BS1）It is divided into strong and weak clearly demarcated two-beam.Wherein strong light is this
Shake light, enters monitoring device through optical fiber.
3rd, a part of light in dim light passes through Modulation and Amplitude Modulation（AM2）Modulation form flashlight weaker in intensity and not
Modulated light is used as reference light.
This programme remaining step is identical with embodiment 2, will not be described in detail herein.It is identical with described in embodiment 1, can also
BHD is substituted with heterodyne measurement device in scheme 2,3, it is identical described in required change and embodiment 1.
Determining interference of the present utility model is as follows：
The probability that quantum state changes（Or say error rate）The ultimate criterion that will whether there is as judge interference.Need
The situation of change of error rate is monitored in real time.Situation about being disturbed in the event of all or most signal, then overall signal
Error rate will be significantly increased, and will be easy to detect.But if only sub-fraction signal is disturbed, then overall error rate
May not have and obviously fluctuate, but the curve of error rate will have obvious fluctuation in real time.
For Gauss coding, in addition to strictly comparing quantum state, it would however also be possible to employ following alignments：According to measuring
The data arrived, to calculate the average and variance of data.If in the absence of interference, the distribution of data and original Gaussian Profile are bases
What this coincide；And when the generation for having intercepting and capturing and retransmission case, then receiving the distribution of data can deviate, and the deviation can be showed
For the deviation of average and variance.Equally, by monitoring average and variance in real time, situation about can be trapped with monitor portion signal.
Balanced homodyne measurement apparatus BHD structures are shown in Fig. 6.It is main to balance beam splitter by one（Score ratio 50：50）With two
Individual identical high-performance optical electric explorer（D1 and D2 is constituted）.And export is then difference between the obtained photoelectric current of two-way detection
Value.By the phase-modulation to local oscillator light, the x or p value in flashlight quantum state can be determined by difference current.
Heterodyne measurement device concrete structure is shown in Fig. 7.It is main to balance beam splitters and 4 identical high-performance photoelectricity by 4
Detector is constituted.Heterodyne measurement device can simply be interpreted as two BHD combination, and two BHD input light is all logical
Cross and are balanced by beam splitting and is obtained for incident flashlight and local oscillator light.In wherein one BHD, incident local oscillator light is carried out π/
2 phase tone pitch, the p value for obtaining flashlight quantum state can be so measured in the apparatus simultaneously.And another BHD device does not have
There is phase-modulation, measurement is obtained into x values in flashlight quantum state.Therefore heterodyne measurement device can measure the x of flashlight simultaneously
And p value.
Disclosed above is only specific embodiment of the utility model, but the utility model is not limited to this, ability
The technical staff in domain can carry out various changes and modification without departing from spirit and scope of the present utility model to the utility model.
Obviously these are changed and modification all should belong in the protection domain protection of the utility model requirement.Although in addition, in this specification
Some specific terms have been used, but these terms are merely for convenience of description, and it is any special the utility model not to be constituted
Limitation.
Claims (8)
1. the quantum radar based on continuous variable, it is characterised in that
Including detectable signal generating means and echo signal processing equipment, the detectable signal generating means includes pulse and generates dress
The code device put, encoded based on continuous variable, the echo signal processing equipment includes monitoring device and imaging device, described
Quantum radar also includes beam splitting arrangement, the first fiber delay line and the second fiber delay line, and the beam splitting arrangement includes first point
Beam device, the second beam splitter, the first polarization beam apparatus；
Light path is connected between the pulse generation device and code device, and the pulse generation device is used to generate light pulse letter
Number, the light pulse signal is divided into local oscillator light and flashlight by the first beam splitter, and the code device is used to enter flashlight
Row coding, coded signal light is combined into the detectable signal of quantum radar with local oscillator light by the first polarization beam apparatus；The local oscillator
Light is used for subsidiary；
Echo-signal after the detectable signal reflects through object is split by the second beam splitter, is formed first time after beam splitting
Ripple signal and second echo signal, the monitoring device are connected with beam splitter light path and receive first echo signal, the imaging
Device is connected with beam splitter light path and receives second echo signal；First fiber delay line deviates local oscillator light and flashlight
It is synchronous；Second fiber delay line makes local oscillator light and flashlight re-synchronization in first echo signal, enters back into monitoring device；
The monitoring device is additionally operable to record the quantum state of flashlight in first echo signal and detectable signal, and both are entered
Row is compared, and judges whether detectable signal is disturbed.
2. the quantum radar based on continuous variable as claimed in claim 1, it is characterised in that, the monitoring device includes the
Two polarization beam apparatus, balanced homodyne measurement apparatus/heterodyne measurement device, the second fiber delay line and data processing equipment, when for
During balanced homodyne measurement apparatus, in addition to second phase modulator and quantum random number generator；
Balanced homodyne measurement apparatus/heterodyne measurement the device is used for the quantum state for measuring flashlight in first echo signal；Institute
The quantum state that data processing equipment is used to record flashlight in detectable signal and first echo signal is stated, and both are compared
It is right.
3. the quantum radar as claimed in claim 1 based on continuous variable, it is characterised in that the code device is compiled to be discrete
Code modulating device, the discrete codes modulating device includes the phase-modulator and quantum random number generator that light path is connected.
4. the quantum radar as claimed in claim 1 based on continuous variable, it is characterised in that the code device is compiled for Gauss
Code modulating device, the Gauss code modulation device includes amplitude modulaor, phase-modulator, variable optical attenuator, the first amount
Sub- randomizer and the second quantum random number generator, the amplitude modulaor, phase-modulator, variable optical attenuator
It is sequentially connected, first quantum random number generator is connected with the amplitude modulaor light path, the first quantum random number occurs
Device is connected with the phase-modulator light path.
5. the quantum radar based on continuous variable, it is characterised in that filled including detectable signal generating means and echo signal processing
Put, the detectable signal generating means includes pulse generation device, the code device encoded based on continuous variable, the echo letter
Number processing unit includes monitoring device and imaging device；The quantum radar also includes beam splitting arrangement and fiber delay line；
Light path is connected between the pulse generation device and code device, and the pulse generation device is used to generate light pulse letter
Number, the light pulse signal includes reference light, flashlight and local oscillator light, and the code device is used for the letter in light pulse signal
Number light is encoded, and coded signal light is directly entered prison with detectable signal of the reference light as quantum radar, the local oscillator light
Surveying device is used for subsidiary；
The detectable signal forms echo-signal after being reflected through object, the echo-signal is split by beam splitting arrangement, point
First echo signal and second echo signal are formed after beam, the monitoring device is connected with beam splitting arrangement light path and received first time
Ripple signal, the imaging device is connected with beam splitting arrangement light path and receives second echo signal；The fiber delay line is used to prolong
Shi Benzhen light so that local oscillator light enters monitoring device with flashlight, with reference to phototiming；
The monitoring device is additionally operable in the measured value amendment first echo signal according to reference light in the first echo signal
The measured value of flashlight, and the quantum state of the measured value of flashlight after amendment and flashlight in the detectable signal of record is compared
It is right, judge whether detectable signal is disturbed.
6. the quantum radar as claimed in claim 5 based on continuous variable, it is characterised in that the monitoring device includes balance
Homodyne detection device/heterodyne measurement device, data processing equipment and fiber delay line, when for balanced homodyne measurement apparatus,
Also include second phase modulator and quantum random number generator, the balanced homodyne measurement apparatus/heterodyne measurement device is used for
Measure the quantum state of flashlight and reference light in first echo signal；The data processing equipment, which is used to record in detectable signal, to be compiled
The quantum state of flashlight and reference light after code, while flashlight in the measured value amendment first echo signal of reference light
Quantum state, the quantum state of flashlight is carried out after most being corrected at last in detectable signal in the quantum state and first echo signal of flashlight
Compare.
7. the quantum radar as claimed in claim 5 based on continuous variable, it is characterised in that the code device is compiled to be discrete
Code modulating device, the discrete codes modulating device includes the phase-modulator and quantum random number generator that light path is connected.
8. the quantum radar as claimed in claim 5 based on continuous variable, it is characterised in that the code device is compiled for Gauss
Code modulating device, the Gauss code modulation device includes amplitude modulaor, phase-modulator, variable optical attenuator, the first amount
Sub- randomizer and the second quantum random number generator, the amplitude modulaor, phase-modulator, variable optical attenuator
It is sequentially connected, first quantum random number generator is connected with the amplitude modulaor light path, second quantum random number
Generator is connected with the phase-modulator light path.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106707263A (en) * | 2017-01-18 | 2017-05-24 | 浙江神州量子网络科技有限公司 | Quantum radar based on continuous variable and treatment method thereof |
| CN114938662A (en) * | 2021-10-13 | 2022-08-23 | 深圳市速腾聚创科技有限公司 | Laser radar and control method of laser radar |
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2017
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106707263A (en) * | 2017-01-18 | 2017-05-24 | 浙江神州量子网络科技有限公司 | Quantum radar based on continuous variable and treatment method thereof |
| CN114938662A (en) * | 2021-10-13 | 2022-08-23 | 深圳市速腾聚创科技有限公司 | Laser radar and control method of laser radar |
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