CN102323826B - Automatic basic vector regulation system and automatic basic vector regulation method for quantum communication system - Google Patents

Abstract

The invention discloses an automatic basic vector regulation system and an automatic basic vector regulation method for a quantum communication system. The system is mainly applied in quantum communication to realize the automatic control of basic vector regulation, and is applicable to various laser communication systems requiring basic vector regulation. A specific orthogonal two-dimensional coordinate system which is called basic vector is introduced into the system as a standard for judging photon polarization state, and moreover, the coordinate system for judging the polarization state of signal light in the whole communication system is consistent. The automatic basic vector regulation system can solve the problem that the polarization direction of the signal light in quantum communication is changed because the direction of a telescope is changed during tracking, thus ensuring that a receiving end can correctly detect the polarization state of the signal light under the specific basic vector standard and that space scale quantum communication can be freely and smoothly carried out.

Description

The basic vector self-checking device and the control method that are used for quantum communication system

Technical field

The present invention relates to the free space Technique on Quantum Communication, be specifically related to a kind of basic vector self-checking device and control method for quantum communication system, it is used for quantum communications are automatically adjusted because of thick change of polarization of following the tracks of the flashlight that causes.

Technical background

Mainly be by having the light quantum transmission information of special polarization state in the space scale quantum communications, the polarization state of judging light quantum need to have unified standard, introduce a kind of specific orthogonal two-dimensional coordinate system that is called basic vector in the native system as the standard of judging the photon polarization state, and be used in the whole communication system judging that the coordinate system of flashlight polarization state is consistent.As the quantum light of standard emission with polarization information, receiving end extracts quantum polarisation of light information after receiving quantum light to transmitting terminal equally take basic vector as standard with basic vector.

In the space scale quantum communications, satellite along track around earth rotation, receiving station's light that transmits earthward ceaselessly, the ground receiving station needs constantly to adjust the telescope attitude so that catch the signal that satellite transmission is come, shown in I among Fig. 2.Telescope mainly contains two kinds of attitudes in the lock-on signal light time to be changed: pitch orientation rotation and horizontal direction rotation.Shown in II among Fig. 2, be as the criterion with earth axes, vertical ground upwards is Z axis, horizontal direction is determined X-axis and Y-axis with the right-hand rule.The angle of regulation pitch orientation rotation is the angle of pitch, and for just, scope be-90 to spend to 90 and spend by-Z-axis direction+Z-direction; The angle of horizontal direction rotation is the position angle, and for axially, dextrorotation is being for just take+Z axis, and scope is-180 to spend to 180 and spend (the actual angle of pitch of telescope and azimuthal scope are smaller).

For being transferred in the rear light path system, processes the flashlight that telescope is captured, need in telescopical pivot arm, reflected light path be installed, as shown in Figure 3, the left side is telescope pivot arm index path, and wherein 6 is that lens cone for telescope, 7 is that telescope pivot arm, 8 is that incident ray, 9 is that horizontal reflection light, 10 is vertical reflection light.As seen from Figure 3, when rotating, telescope can affect the polarization direction of flashlight in the reflected light path.The direction that specified signal light is propagated is Z axis, and the basic vector coordinate is perpendicular to Z axis, and satisfies the right-hand rule, and the represented X-Y axle of A is the basic vector coordinate of incident light 8 among the figure.When the telescopical angle of pitch changes, then can cause the polarization rotation of telescope horizontal reflection light 9; If the lens cone for telescope angle of pitch is a, regulation is along the direction of propagation of flashlight, the dextrorotation of flashlight polarization state is for just, then the angle of the polarization direction of horizontal reflection light 9 rotation is a, shown in B among Fig. 3, wherein dotted line represents the basic vector of whole system, and the X-Y axle represents the Plane Rotation state at the place, polarization direction of flashlight.When pivot arm drives the rotation of telescope horizontal direction, can cause that then pivot arm reflexes to the flashlight generation rotation of rear light path vertically upward, shown among Fig. 3 10; Establishing equally the lens cone for telescope horizontal azimuth is b, defines equally dextrorotation for just, and then the angle of vertical reflection polarisation of light direction rotation is b, shown in C among Fig. 3.

Can draw according to above analysis: angle of pitch a can cause the 9 polarization dextrorotation of lens barrel horizontal reflection light, and position angle b causes pivot arm vertical reflection light 10 polarization right avertence.Because the lens barrel angle of pitch and azimuthal stack, the polarization direction of the vertical emergent ray of pivot arm is a+b with respect to the basic vector direction deflection angle of incident ray.So when polarization angle is after the flashlight of α enters telescope, can converge to through the concave mirror of lens cone for telescope bottom on the catoptron in the middle of the lens barrel, through the lens barrel catoptron light level be reflexed to reflected light path in the pivot arm.If this moment, the angle of pitch a of lens barrel was non-vanishing, horizontal reflection light polarization angle and the angle of the X-axis of basic vector will be changed to α+a.When entering reflected light path, light at first needs by a slice convex lens light to be become directional light, and then light path after arriving through the three dimensions mirror reflects.During light path, if this moment, telescopical horizontal azimuth b was non-vanishing, the X-axis angle of the polarization direction of flashlight and basic vector will become α+a+b so, shown in D among Fig. 3 after flashlight reflexes to vertically upward through last piece plane mirror.

Quantum receiving end in Fig. 1 quantum communication system 5 is fixed in the rear light path, its polarization state must be rotated to the polarization state that receiving end can correctly detect with the basic vector standard before flashlight detects, and this just need to increase the optically-active element in rear light path.Adopt half-wave plate that the flashlight polarization is rotated in the native system, when half-wave plate quick shaft direction and basic vector X-axis angle were θ (counter clockwise direction for just), its Jones matrix was:

$\left[\begin{array}{c}\cos 2\mathrm{\θ},\sin 2\mathrm{\θ}\\ \sin 2\mathrm{\θ},-\cos 2\mathrm{\θ}\end{array}\right]$

When light vector became the α angle with the basic vector X-axis, its Jones matrix was:

$E_{\mathrm{\α}}=\left[\begin{array}{c}\cos \mathrm{\α}\\ \sin \mathrm{\α}\end{array}\right]$

When this light vector transmission half-wave plate, the Jones matrix of emergent ray is:

$E_{\mathrm{out}}=\left[\begin{array}{c}\cos 2\mathrm{\θ},\sin 2\mathrm{\θ}\\ \sin 2\mathrm{\θ},-\cos 2\mathrm{\θ}\end{array}\right]\left[\begin{array}{c}\cos \mathrm{\α}\\ \sin \mathrm{\α}\end{array}\right]=\left[\begin{array}{c}\cos (2\mathrm{\θ}-\mathrm{\α})\\ \sin (2\mathrm{\θ}-\mathrm{\α})\end{array}\right]$

Be changed to 2 θ-α so see through the polarization angle of the emergent ray of half-wave plate by α.

According to front surface analysis, if incoming signal light polarization direction and X-direction angle are α among Fig. 3, then because the impact of telescope rotation, reflect the angle that the polarization direction of the flashlight of light path backward has been rotated counterclockwise (a+b) through pivot arm, namely this moment, flashlight and horizontal direction angle were α+(a+b).If the angle of the quick shaft direction of half-wave plate and basic vector X-direction is set to

As shown in Figure 4, wherein angle 12 is half-wave plate and basic vector X-axis angle, and angle 13 is flashlight polarization deflection angle.According to half-wave plate revolve the ripple principle, the flashlight polarization angle that half-wave plate is crossed in transmission is:

$2\left(\frac{a+b}{2}\right)-[\mathrm{\α}+(a+b)]=-\mathrm{\α}$

The polarization angle that is flashlight finally is changed to-α by α, only needs the negate of detected polarization angle just can correctly be obtained the signal polarized state of light at the quantum detection end like this.

The flashlight of tracking satellite emission because telescope needs real-time adjustment attitude in communication, so the basic vector regulating system also needs to adjust automatically in real time the flashlight polarization state that reflexes to rear light path, this just needs to introduce automatic control system.

Summary of the invention

The present invention is directed between star ground in the quantum communication, lens cone for telescope is because tracking satellite and the ceaselessly flashlight rotation that causes of transformation space angle, thereby make signal receiving end can't correctly detect the problem of revolving the light vector information after the change with fixing basic vector, a kind of effective basic vector self-checking device and control method are provided.This device rotates the light vector that changes the polarization direction according to the data of rotary transformer in real time by controlled half-wave plate, by a series of conversion, and can be by correct the detecting of quantum receiving end when making light vector arrive communication terminal.Solved between star ground in the quantum communication and caused that the rotation of flashlight polarization direction changes in the reflex circuit because the telescope Space Angle changes, caused receiving end can't correctly detect the problem of quantum light polarization state.

Set a kind of certain orthogonal two-dimensional coordinate system of basic vector that is called in the invention as the standard of judging the photon polarization state; Transmitting terminal has the quantum light of certain polarization state take basic vector as standard emission, receiving end is take basic vector as standard detection signal polarized state of light.Use this system, quantum light transmitting terminal and receiving end can use unified basic vector as the criterion of light vector.Flashlight enters telescope pivot arm reflected light path, polarization state can change, before arriving the quantum receiving end, quantum polarisation of light direction rotation is arrived the negative direction of initial polarization direction by half-wave plate, just can utilize predetermined basic vector to detect the signal polarized state of light at receiving end like this, and not worry the variation of the flashlight polarization direction of being caused by the telescope tracking satellite.

The present invention utilizes the wave property of revolving of half-wave plate, and the flashlight that changes polarization state is rotated to appropriate angle, and then by a series of conversion, thus make the quantum receiving end can by with the unified basic vector of quantum transmitting terminal with correct the detecting of flashlight.As shown in Figure 1: electric rotating machine assembly 1 can record the position of rotation of half-wave plate 2 by photoelectric encoder; Rotary transformer 5-1 is installed in the telescope pitch axis of quantum communication system 5 with on the transverse axis, can record respectively the telescopical angle of pitch and horizontal azimuth; Utilize real-time controller 4 to read in real time telescopical position by rotary transformer 5-1; Calculate the angle of flashlight deflection and the angle of half-wave plate needs rotation according to algorithm noted earlier again; Then generate control signal and send to electric machine controller; Electric machine controller 3 is received half-wave plate 2 positions that record according to photoelectric encoder after the control signal, and the control motor rotates to the appropriate location with half-wave plate 2; Thereby flashlight is rotated to appropriate polarization state, so that the quantum receiving end can correctly detect quantum polarisation of light information by basic vector.

The structure of quantum communications basic vector self-checking device of the present invention as shown in Figure 1, its structure comprises: the rotary transformer 5-1 in electric rotating machine assembly 1, half-wave plate 2, electric machine controller 3, real-time controller 4 and the quantum communication system 5.Wherein:

1. electric rotating machine assembly 1 is comprised of electric rotating machine, photoelectric encoder and half-wave plate mounting base, and half-wave plate 2 is fixed on the half-wave plate pedestal, and the half-wave plate mounting base is connected with electric rotating machine by the endless screw-worm gear transmission; Photoelectric encoder is installed on the electric rotating machine, the main position of rotation of being responsible for measuring the electric rotating machine assembly, and its accuracy requirement reaches 0.1 degree; Electric rotating machine adopts controlled direct current generator or stepper motor, and reaction velocity is in 0.3s, and electric rotating machine drives the rotation of half-wave plate mounting base by the endless screw-worm gear transmission, and the running accuracy of half-wave plate mounting base is 0.1 degree;

2. half-wave plate 2 is chosen quantum communication system 5 needs the corresponding λ of signal light wavelength/2 half-wave plates;

3. electric machine controller 3 is used for reading photoelectric encoder data and control electric rotating machine, and has the function of control able to programme;

4. real-time controller 4 programming device that adopts computers or have the floating-point operation function is used for reading in real time the rotary transformer data, and calculating half-wave plate needs the anglec of rotation, the control electric machine controller;

5. rotary transformer 5-1 is two rotary transformers, is installed in respectively on the telescopical pitch axis of optic terminal and the transverse axis, is responsible for reading telescope horizontal azimuth and pitch angle data, and its measuring accuracy is 0.1 degree.

Electric rotating machine assembly 1 is installed in behind the telescope of quantum communication system 5 in the light path; Half-wave plate 2 is fixed in the half-wave plate mounting base on the electric rotating machine assembly 1, and flashlight needs could arrive the quantum signal receiving end by half-wave plate first; Electric machine controller 3 is connected on the electric rotating machine assembly so that read photoelectric encoder data and control electric rotating machine by data line; Real-time controller 4 connects rotary transformer 5-1 by a data lines and reads telescope Space Angle data, connects electric machine controller 3 by an other data lines and transmits control signal to electric machine controller; Rotary transformer 5-1 be installed in respectively on the telescope feathering axis and the pitching turning axle on, respectively measuring telescope horizontal azimuth and pitch angle data, and send data to real-time controller 4 by data line.

Electric rotating machine assembly 1 records the position of rotation of half-wave plate 2 by photoelectric encoder, and rotary transformer 5-1 records telescopical position of rotation, utilizes real-time controller 4 to read in real time telescopical position by rotary transformer; Calculate the angle of flashlight deflection and the angle of half-wave plate needs rotation according to algorithm again, generate control signal and send to electric machine controller 3, electric machine controller 3 is received the half-wave plate position that records according to photoelectric encoder after the control signal, the control motor rotates to the appropriate location with half-wave plate 2, quantum communication system 5 flashlight rotated to appropriate polarization state, so that can correctly detect quantum polarisation of light information by basic vector.

It is as follows that basic vector is regulated concrete steps automatically:

1. set the control time interval t of real-time controller 4 according to the variation maximal rate that detects quantum polarization state and lens cone for telescope Space Angle, per interval t real-time controller will send an instruction to rotary transformer 5-1, reads the data of rotary transformer 5-1;

2. the pivot arm motor is by adjusting in real time signal acquisition light of telescope, when polarization angle is that the angle is after the flashlight of α enters telescope, if telescopical angle of pitch a and feathering angle b are non-vanishing, reflex to the flashlight polarization direction of rear light path and the X-axis angle of basic vector and will become α+a+b, telescopical angle of pitch a and feathering angle b can feed back to real-time controller 4 by rotary transformer 5-1;

3. real-time controller 4 reads respectively telescopical angle of pitch a and telescopical horizontal azimuth b by rotary transformer 5-1, calculating the flashlight polarization angle by flashlight polarization angle rotation superposition principle is α+a+b, and goes out the angle of half-wave plate needs rotation according to half-wave plate optically-active property calculation Thereby the generation control signal, and control signal sent to electric machine controller 3;

4. electric machine controller 3 receives control signal, starts the electric rotating machine rotation half-wave plate 2 in the electric rotating machine assembly 1, and constantly measures the angle of half-wave plate by photoelectric encoder, when half-wave plate rotates to quick shaft direction and basic vector X-axis angle is

In time, just stop the rotation, and waits for next bar instruction of real-time controller 4;

5. the flashlight polarization angle that reflexes to rear light path is α+a+b, and flashlight can first transmission be crossed half-wave plate 2 before arriving the quantum receiver, because the optically-active characteristic of half-wave plate, the polarization angle of flashlight can become-α;

6. the quantum receiver receives flashlight, go out quantum polarisation of light angle take default basic vector as standard detection and be-α, and this angle negate is just obtained the polarization angle α of incident light, automatically regulate with this basic vector of just having finished quantum communication system, make the altered flashlight of polarization state can be finally by correct detecting.

Beneficial effect of the present invention is: adopt the basic vector controlled system with self-regulation can effectively solve the polarization variations that the telescope dimensional orientation changes the flashlight in the light path that causes in the quantum communication system, effective polarization direction rotation with flashlight arrives appropriate angle in real time, thereby what make that the quantum receiving end can be correct detects the flashlight polarization state, has guaranteed that quantum communications carry out smoothly.

Description of drawings

Fig. 1 is the structural drawing of basic vector self-checking device, among the figure:

1. electric rotating machine assembly 2. half-wave plates 3. electric machine controllers

4. real-time controller 5. quantum communication system 5-1. rotary transformers.

Fig. 2 is telescope space angle explanation diagram: among the figure:

I represents the space synoptic diagram of telescope tracking satellite;

II represents telescope space angle coordinate diagram.

Fig. 3 is that the reflected light path flashlight that the telescope rotation causes rotates the diagram that changes, among the figure:

6. telescope 7. pivot arms 8. incident raies

9. horizontal reflection light 10. vertical reflection light

A. the incident ray basic vector coordinate B. horizontal reflection light polarization anglec of rotation

C. the total anglec of rotation of vertical reflection light polarization anglec of rotation D. reflected light path polarization.

Fig. 4 is half-wave plate placement location synoptic diagram.

Fig. 5 is basic vector Automatic adjustment method program flow diagram.

Embodiment

The whole instance system that can be used for quantum communications basic vector varitrol is as shown in Figure 1: the electric rotating machine assembly PRM1-Z7 that electric rotating machine assembly 1 adopts THORLABS company to produce, and its apparent size 68mm, its half-wave plate pedestal internal diameter is 27mm; It is the direct current generator that 0.1 photoelectric encoder of spending and reaction velocity are 0.2 second that this electric rotating machine assembly comprises precision, direct current generator adopts threaded rod to be connected on the half-wave plate pedestal of rotary components, half-wave plate is fixed on the half-wave plate pedestal of electric rotating machine assembly, by the direct current generator driven rotary; The APT direct current generator servo controller TDC001 that the THORLABS company that electric machine controller 3 adopts and the electric rotating machine assembly is supporting produces, this electric machine controller can carry out programming Control by the APT series control program that THORLABS company provides; Adopt the laser of 850nm as flashlight in this instance system, so half-wave plate adopts the half-wave plate of 800 to 900nm wave bands, it is polished into the circle that diameter is 26mm, is fixed on the electric rotating machine assembly PRM1-Z7, and be installed in the rear light path of quantum communication system 5; Rotary transformer 5-1 adopts the rotary transformer of customization, and measuring accuracy can reach 0.01 degree, can reach 0.1 degree so the basic vector of this instance system is regulated static precision; Real-time controller 4 adopts computer to realize, logical middle control circuit obtains the rotary transformer data, connects electric machine controller by serial port, writes on computers Console program and carries out in real time obtaining of data, calculate, and the transmission of motor instruction.

Electric machine controller TDC001 in this instance system can carry out programming Control by the APT series control program that THORLABS company provides.Mainly use the ActiveX control of two APT softwares: MG17Motor and MG17Logger, wherein the MG17Motor control is the Electric Machine Control control, and MG17Logger is motor instruction daily record control.Can realize the control of motor operation and the position of reading the rotary components rotation by the function that calls in the MG17Motor control, and the MG17Logger major function is to show the instruction that APT direct current generator servo controller is sent.

Electric rotating machine assembly PRM1-Z7 carries vernier dial, and the vernier dial precision is 0.1 degree.The method that its photoelectric encoder adopts the contact to make zero, dump and restart photoelectric encoder reading are zero.So making the photoelectric encoder reading is the absolute position, in the time of must starting motor is definitely made zero at every turn.This basic vector varitrol example software adopts the C++ programming, need to add the MG17Motor control during programming, at first the hardware sequence number in the control property to be changed into the hardware sequence number of DC motor controller TDC001, come the starter motor controller by control instruction startctrl () during start-up routine.Adopt the programming mode of two-wire journey in the example, main thread mainly is responsible for reading in real time the rotary transformer data, and carries out data and calculate conversion, then sends instruction to DC motor controller.Can trigger a sub-thread after starting TDC, this sub-thread mainly is responsible for constantly reading the absolute position of half-wave plate and showing to the electric rotating machine assembly.Program flow diagram as shown in Figure 5.

Further set forth the present invention below in conjunction with Fig. 1 and can carry out the implementation step that basic vector is regulated automatically:

1. the accuracy requirement that detects the quantum polarization state is ± 0.5 degree, and the pace of change of lens cone for telescope Space Angle is 0.2 degree/second to the maximum in this example approach, so can be on computers control time of control desk be set to 1s, because can ignore time-delay in 0.2 second of rotary components during in real time control, basic vector regulating system precision of real time control can reach 0.3 degree.Console program can send an instruction to rotary transformer 5-1 every 1s, reads the data of rotary transformer 5-1;

In this experiment we adopt wavelength be the 45 degree polarized lights of 850nm as flashlight, during experiment constantly the pitch axis rotary transformer to record the telescopical angle of pitch be 8.93 degree, the horizontal rotational shaft transformer is surveyed

3. Console program reads respectively the telescopical angle of pitch 8.93 degree and telescopical position angle 12.46 degree by rotary transformer 5-1, calculating the angle that half-wave plate need to rotate is 10.695 degree, thereby the generation control signal, and control signal sent to electric machine controller 3 (APT direct current generator servo controller TDC001);

4. electric machine controller 3 receives control signal, start the motor 1 rotation half-wave plate 2 among the electric rotating machine assembly PRM1-Z7, and constantly measure the angle of half-wave plates by photoelectric encoder 4, be 10.695 just to stop operating when spending when half-wave plate rotates to its quick shaft direction and basic vector X-axis angle, wait for next bar instruction of real-time controller 4;

5. after half-wave plate was crossed in the flashlight transmission that has changed the polarization direction, on the quantum receiver, take default basic vector as standard, can detect polarization angle was the flashlight of 135 degree.This has illustrated that polarization angle is to pass through half-wave plate after the rotation variation of 45 flashlights of spending through reflected light path again, and its polarization angle has become-45 degree, and namely 135 degree, have just obtained 45 and spent polarized lights the polarized light negate that records at the quantum receiving end.Automatically regulate with this basic vector of just having finished quantum communication system, make the altered flashlight of polarization state can be finally by correct detecting.

Claims (3)

1. basic vector self-checking device that is used for quantum communication system, it comprises the rotary transformer (5-1) in electric rotating machine assembly (1), half-wave plate (2), electric machine controller (3), real-time controller (4) and the quantum communication system (5), it is characterized in that:

Described electric rotating machine assembly (1) is comprised of electric rotating machine, photoelectric encoder and half-wave plate mounting base, the half-wave plate mounting base is connected with electric rotating machine by worm screw-worm-gear drive pair, the photoelectric encoder of being responsible for measurement electric rotating machine assembly position of rotation is installed on the electric rotating machine, the measuring accuracy of photoelectric encoder reaches 0.1 degree, electric rotating machine adopts controlled direct current generator or stepper motor, reaction velocity is better than 0.3 second, electric rotating machine drives the rotation of half-wave plate mounting base by worm screw-worm-gear drive pair, and the running accuracy of half-wave plate mounting base is 0.1 degree;

Described rotary transformer (5-1) is two rotary transformers, be installed in respectively in the quantum communication system (5) on the telescopical pitch axis and transverse axis, be used for reading telescope horizontal azimuth and pitch angle data, the data reading precision of rotary transformer is 0.1 degree;

Electric rotating machine assembly (1) is installed in the quantum communication system (5) in the telescopical rear light path, half-wave plate (2) is installed on the half-wave plate mounting base in the electric rotating machine assembly (1), electric machine controller (3) is connected on the electric rotating machine assembly so that read photoelectric encoder data and control electric rotating machine by data line, real-time controller (4) connects rotary transformer (5-1) by a data lines and reads telescope Space Angle data, connects electric machine controller (3) by an other data lines and transmits control signal to electric machine controller;

Real-time controller (4) reads telescopical position in real time by rotary transformer (5-1); Calculate the angle of flashlight deflection and the angle of half-wave plate needs rotation according to algorithm again, generate control signal and send to electric machine controller (3), electric rotating machine assembly (1) records the position of rotation of half-wave plate (2) by photoelectric encoder, electric machine controller (3) is received the half-wave plate position that records according to photoelectric encoder after the control signal, the control motor rotates to the appropriate location with half-wave plate (2), quantum communication system (5) flashlight rotated to appropriate polarization state, so that can correctly detect quantum polarisation of light information by basic vector.

2. a kind of basic vector self-checking device for quantum communication system according to claim 1 is characterized in that: the programming device that described real-time controller (4) adopts computer or has the floating-point operation function.

3. basic vector Automatic adjustment method based on the quantum communication system of the described a kind of basic vector self-checking device for quantum communication system of claim 1 is characterized in that may further comprise the steps:

1) sets the control time interval t of real-time controller (4) according to the variation maximal rate that detects quantum polarization state and lens cone for telescope Space Angle, per interval t real-time controller will send an instruction to rotary transformer (5-1), reads the data of rotary transformer (5-1);

2) be positioned at electric rotating machine on telescope pitch axis and the transverse axis by adjusting in real time signal acquisition light of telescope, when polarization angle is after the flashlight of α enters telescope, if telescopical angle of pitch a and horizontal azimuth b are non-vanishing, reflex to the flashlight polarization direction of rear light path and the X-axis angle of basic vector and will become α+a+b, telescopical angle of pitch a and horizontal azimuth b can feed back to real-time controller (4) by rotary transformer (5-1);

3) real-time controller (4) reads respectively telescopical angle of pitch a and telescopical horizontal azimuth b by rotary transformer (5-1), calculating the flashlight polarization angle by flashlight polarization angle rotation superposition principle is α+a+b, and goes out the angle of half-wave plate needs rotation according to half-wave plate optically-active property calculation

Thereby the generation control signal, and control signal sent to electric machine controller (3);

4) electric machine controller (3) receives control signal, starts the electric rotating machine rotation half-wave plate (2) in the electric rotating machine assembly (1), and constantly measures the angle of half-wave plate by photoelectric encoder, when half-wave plate rotates to quick shaft direction and basic vector X-axis angle is

In time, just stop the rotation, and waits for next bar instruction of real-time controller (4);

5) the flashlight polarization angle that reflexes to rear light path is α+a+b, and flashlight can first transmission be crossed half-wave plate (2) before arriving the quantum receiver, because the optically-active characteristic of half-wave plate, the polarization angle of flashlight can become-α;

6) the quantum receiver receives flashlight, go out quantum polarisation of light angle take default basic vector as standard detection and be-α, and this angle negate is just obtained the polarization angle α of incident light, automatically regulate with this basic vector of just having finished quantum communication system, make the altered flashlight of polarization state can be finally by correct detecting.

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