CN103199994A - Active phase compensation method and device of joint scan - Google Patents

Abstract

The invention discloses an active phase compensation method and device of joint scan. A middle ring is added at an Alice end, the middle ring respectively interferes and scans a ring of the Alice end and a ring of a Bob end to respectively obtain the interference curve of the Alice end and the interference curve of the Bob end, so that the phase drift parameter of a phase modulator is obtained, and then active phase compensation is respectively conducted to the Alice end and the Bob end. In the active phase compensation method and device of the joint scan, the Alice end and the Bob end only need to be scanned once, scanning time is shortened, and the safety of a system is improved. The active phase compensation method and device further shortens the time of phase scanning, lowers the complexity of phase scanning, and is used for achieving independent scanning of the Alice end and the Bob end and avoiding phase remapping attack or side channel attack.

Description

Active phase compensating method and the device of associating scanning

Technical field

The present invention relates to the quantum key distribution field, more specifically, relate to a kind of active phase compensating method and device of uniting scanning.

Background technology

Phase drift is the intrinsic problem of quantum key distribution (QKD) system of phase code, is one of key factor that influences QKD system availability energy.Single-phase scanning is the compensation scheme of phase place initiatively: the phase-modulator voltage that loads and the phase place of modulating of supposing the Alice end are linear, thereby only scan the interference curve of Bob end.The voltage that phase-modulator loads in practical devices and the phase place of modulating not are linear, have therefore proposed the active phase compensation scheme of four phasescan methods.But four phasescan methods need scan the interference curve 4 times of Bob end, time and the complexity of phasescan have been increased, and need Bob that scanning result is transferred to Alice by common signal channel, Eve just can obtain the information of phasescan like this, phase place remaps attack or the limit channel attack provides possibility in order to implement, and causes relevant safety issue.

Summary of the invention

In order to overcome the deficiencies in the prior art, the present invention at first proposes a kind of active phase compensating method of uniting scanning, when improving security of system, has shortened sweep time.

To achieve these goals, its technical scheme is:

A kind of active phase compensating method of uniting scanning, add an adapter ring at the Alice end, adapter ring is interfered with the ring of Alice and Bob end respectively, scanning obtains the interference curve of Alice end and Bob end respectively, thereby obtain the phase drift parameter of phase-modulator, again Alice and Bob end are carried out active phase compensation respectively.

Wherein, in the regular hour scope, the phase difference of adapter ring is constant, exchanges the phase drift that Alice and Bob hold relative adapter ring respectively for, and phase drift and the adapter ring of Alice and Bob end are made comparisons, and obtains the phase drift parameter that Alice and Bob hold.This moment, the phasescan of Alice end was to finish in this locality fully, without long-range optical fiber, Eve can not obtain any information about Alice end phasescan or change the quantum state that the Alice end sends, under this condition, the quantum state that the Alice end sends is the quantum state of pairwise orthogonal, and known phase place remaps attack and then can not implement.

Preferably, the scanning process of described Alice end is:

S11. Alice is held the phase modulation voltage of phase-modulator PMA to scan Vmax from Vmin with step-length △ V, Vmin is minimum phase modulation voltage, and Vmax is maximum phase modulation TV university;

S12. wait for N lock-out pulse at each magnitude of voltage Vi place, and the counting of single-photon detector is added up, obtain counting Ci, { { Vi, the curve that Ci} constitutes are the single photon interference curve of Alice end to the data group for Vi, Ci} to obtain one group of data;

S13. obtain the half-wave voltage V of Alice end phase-modulator according to the single photon interference curve of Alice end _{π, a}And load 0, pi/2, π, the voltage V during 3 pi/2 phases _{A, 0},

V _{A, π},

The scanning process of described Bob end is:

S21. Bob is held the phase modulation voltage of phase-modulator PMB to scan V ' max from V ' min with step-length △ V, V ' min is minimum phase modulation voltage, and V ' max is maximum phase modulation TV university;

S22. wait for M lock-out pulse at each magnitude of voltage V ' i place, and the counting of single-photon detector added up, obtain counting C ' i, obtain one group of data V ' i, C ' i}, the data group V ' i, the curve that C ' i} constitutes is the single photon interference curve that Bob holds;

S23. obtain the half-wave voltage V of Bob end phase-modulator according to the single photon interference curve of Bob end _{π, b}And load 0, pi/2, π, the voltage V during 3 pi/2 phases _{B, 0},

V _{B, π},

Preferably, Vmin covers the phase range of 2 π at least among the described step S11 to Vmax; V ' min covers the phase range of 2 π at least among the described step S21 to V ' max.

Preferably, described Alice end active phase compensation mode is:

In the single photon interference curve of Alice end, the point voltage of choosing phase difference and be π is reference voltage V _{Ref, a}, then:

Wherein,

For adapter ring poor by the proper phase that length difference causes,

For Alice holds the proper phase of interference ring poor,

It then is phase drift at random;

The modulation voltage working point of the phase place modulation of Alice end is:

$\{V_{a,0},V_{a,1},V_{a,2},V_{a,3}\}=\{V_{a,0},V_{a,\frac{\mathrm{\π}}{2}},V_{a,\mathrm{\π}},V_{a,\frac{3\mathrm{\π}}{2}}\}$

$=\{V_{\mathrm{ref},a}-V_{\mathrm{\π},a},V_{\mathrm{ref},a}-\frac{1}{2}{V}_{\mathrm{\π},a},V_{\mathrm{ref},a},V_{\mathrm{ref},a}+\frac{1}{2}{V}_{\mathrm{\π},a}\}$

Then the voltage of Alice end phase-modulator loading is V _{A, i}The time, phase difference is:

Described Bob end initiatively phase compensation mode is:

In the single photon interference curve of Bob end, the point voltage of choosing phase difference and be π is reference voltage V _{Ref, b}, then

Wherein,

For adapter ring poor by the proper phase that length difference causes,

For Bob holds the proper phase of interference ring poor,

It then is phase drift at random;

The modulation voltage working point of the phase place modulation of Bob end is:

$\{V_{b,0},V_{b,1},V_{b,2},V_{b,3}\}=\{V_{b,0},V_{b,\frac{\mathrm{\π}}{2}},V_{b,\mathrm{\π}},V_{b,\frac{3\mathrm{\π}}{2}}\}$

$=\{V_{\mathrm{ref},b}-V_{\mathrm{\π},b},V_{\mathrm{ref},b}-\frac{1}{2}{V}_{\mathrm{\π},b},V_{\mathrm{ref},b},V_{\mathrm{ref},b}+\frac{1}{2}{V}_{\mathrm{\π},b})$

Then the voltage of Bob end phase-modulator loading is V _{B, j}The time, phase difference is:

The present invention also proposes a kind of for the compensation arrangement of realizing said method, for realization compensation automatically, reduces time and the complexity of phasescan and also avoids phase place to remap attack or limit channel attack for the independence scanning that realizes Alice and Bob end.

Its specific implementation is as follows:

A kind of device that is applied to the active phase compensating method of associating scanning comprises Alice end and the Bob end that is connected with the Alice end, adds an adapter ring at described Alice end, and described adapter ring is used for interfering with Alice end and Bob end respectively.

Preferably, described active phase compensation device of uniting scanning is based on two MZ systems, and described adapter ring is the MZ interference ring,

Described Alice end comprises first and second laser, phase-modulator PMA, ring retard DL1, isolator ISO1, isolator ISO2, coupler C1-C2, single-photon detector SPD3 and adapter ring; Adapter ring comprises coupler C3, C4, ring retard DL3;

Described first laser meets phase-modulator PMA and ring retard DL1 respectively by coupler C1, phase-modulator PMA and ring retard DL1 are connected in parallel, phase-modulator PMA and ring retard DL1 connect two inputs of coupler C2 respectively, the input of the output termination coupler C3 of coupler C2, the input of another output termination isolator ISO1 of coupler C2, the output of the output termination coupler C3 of isolator ISO1, coupler C3 is connected to coupler C4 by the MZ interference ring, the output order photon detector SPD3 of coupler C4, the output of the input termination isolator ISO2 of coupler C4, second laser connects the input of ISO2;

Described Bob end comprises phase-modulator PMB, ring retard DL2, coupler C5, C6 and single-photon detector SPD1, SPD2, the output of coupler C5 connects the input of coupler C6, the output order photon detector SPD1 of coupler C6 by phase-modulator PMB; Another output of coupler C5 connects another input of coupler C6, another output order photon detector SPD2 of coupler C6 by ring retard DL2;

Described Alice end is connected with the Bob end by long-range optical fiber; Long-range optical fiber connects the output of isolator ISO1; Described MZ interference ring comprises ring retard DL2 and galianconism optical fiber.

The scanning process of Alice end: the light pulse that first laser sends is by coupler C1, be divided into two pulses, walk short circuit for one and enter coupler C2 through phase-modulator PMA, a walk long distances enters C2 through ring retard DL1, one in front and one in back enter C3 again, through being divided into 4 pulses after the C3, pass through long-armed optical fiber and the galianconism optical fiber of adapter ring respectively.Get ahead in 4 pulses long-armed optical fiber, after walk the pulse of galianconism optical fiber and the galianconism optical fiber that gets ahead, after walk long-armed optical fiber pulse interfere at the C4 place, survey the single photon interference curve by photon detector SPD3.

The scanning process of Bob end: the light pulse that second laser sends is divided into two pulses by coupler C4, by entering C3 after the adapter ring, one in front and one in back enter long-range optical fiber, arrive the Bob end and be divided into 4 through coupler C5, through interfering at coupler C6 place after phase-modulator PMB and the ring retard DL2, photon detector is carried out the detection of key by SPD1 and SPD2 respectively.

Preferably, described active phase compensation device of uniting scanning is based on two FM systems, and described adapter ring is the FM interference ring,

Described Alice end comprises faraday mirror FM1-FM2, first and second laser, phase-modulator PMA, coupler BS1, circulator CIR1-CIR2, ring retard DL1, single-photon detector SPD and adapter ring, and described adapter ring comprises ring retard DL2, coupler BS2 and faraday mirror FM3-FM4;

The laser that first laser sends enters coupler BS1 and is divided into two pulses, walk long-armed and galianconism respectively, entered first port of circulator CIR1 by the other end of faraday mirror FM1 and faraday mirror FM2 reflected back coupler BS1, second port by circulator CIR1 enters adapter ring, through being divided into 4 pulses respectively by faraday mirror FM3 and faraday mirror FM4 reflected back coupler BS2 behind the coupler BS2; Get ahead and walk two long-armed pulses in the interference of coupler BS2 place after walking galianconism and the galianconism that gets ahead after long-armed, detect the single photon interference curve by single-photon detector SPD; Thereby, obtain the phase drift parameter that Alice holds

Described Bob end comprises faraday mirror FM5-FM6, phase-modulator PMB, coupler BS3, ring retard DL3, photon detector SPD1 and circulator CIR3, the laser that second laser sends enters coupler BS2 through circulator CIR2, be divided into two pulses and walk the long-armed and galianconism of coupler BS2 respectively, one in front and one in back entered second port of circulator CIR1 again by faraday mirror FM3 and faraday mirror FM4 reflected back coupler BS2, enter long-range optical fiber through port not; Enter first port that Bob holds circulator CIR3 by long-range optical fiber, enter coupler BS3 through second port and be divided into 4 pulses, faraday mirror FM5 and faraday mirror FM6 reflected back coupler BS3 are arranged respectively; Equally, get ahead to walk after long-armed and walk two long-armed pulses behind galianconism and the galianconism that gets ahead and interfere at coupler BS3 place, obtain the single photon interference curve by SPD1, obtain the phase drift parameter that Bob holds.

Preferably, described circulator is three port open loop circulators, i.e. then second port output of optical routing first port input, then the 3rd port output of second port input; Described not port is the 3rd port.

Compared with prior art, beneficial effect of the present invention is: the present invention interferes adapter ring to carry out active phase compensation by increasing by one at the Alice end.The more existing Active Compensation scheme of this scheme has following raising:

1, Alice end and Bob end are interfered with adapter ring respectively, obtain the operating voltage point of key distribution separately, and the phasescan process of Alice end is finished in this locality fully, avoided transmission phasescan result in common signal channel, make Eve can not obtain the information of phasescan, improved the fail safe of system.

2, the phasescan process of Alice end is finished in this locality fully, and photon has avoided Eve to change the quantum state that Alice sends in the phasescan process without long-range optical fiber in the scanning process, and the defence phase place remaps attacks and possible distortion.

3, Alice and Bob only need distinguish run-down, obtain separately interference curve and can draw separately voltage power supply point, have reduced the complexity of scanning, have shortened the time of scanning, and this just means the duty ratio of the information that improved.

4, the prerequisite of a run-down is that the adjustment curve of hypothesis phase-modulator is linear, and in practical devices, adjustment curve is not linear.For the nonlinear problem of phase-modulator adjustment curve, can be divided into two aspects and consider.Be about the nonlinear problem of phase-modulator adjustment curve on the one hand, though adjustment curve can not be accomplished complete linearity in the practical devices, but the linearity of lithium niobate phase modulator commonly used can satisfy the requirement of QKD at present, and is less for the influence of key distribution.Be about the time dependent problem of half-wave voltage of phase modulator on the other hand.Observe by experiment and find, the half-wave voltage of phase-modulator can change after long-time the use, and influence loads the accuracy of phase place.In this scheme, the half-wave voltage of Alice and Bob end phase-modulator all is to obtain by scanning result, has reflected the half-wave voltage of phase-modulator in real time, has therefore well solved the problem that half-wave voltage changes.

Description of drawings

Fig. 1 is applied to the scanning schematic diagram of Alice end in two MZ systems for the present invention.

Fig. 2 is applied to Bob end structure schematic diagram in two MZ systems for the present invention.

Fig. 3 is applied to the Alice end structure schematic diagram of FM system for the present invention.

Fig. 4 is the structural representation of the Bob end of FM system.

Embodiment

The present invention will be further described below in conjunction with accompanying drawing, but embodiments of the present invention are not limited to this.

Embodiment one

The scanning schematic diagram of Alice end when using in two MZ system for the present invention as shown in Figure 1, 2; Add an adapter ring at the Alice end, interfered with the ring of Alice and Bob end respectively by it, draw the phase drift parameter of Alice and Bob end phase-modulator, compensate respectively then.Described Alice end comprises first and second laser, phase-modulator PMA, ring retard DL1, isolator ISO1, isolator ISO2, coupler C1-C2, single-photon detector SPD3 and adapter ring; Adapter ring comprises coupler C3, C4, ring retard DL3;

Described first laser meets phase-modulator PMA and ring retard DL1 respectively by coupler C1, phase-modulator PMA and ring retard DL1 are connected in parallel, phase-modulator PMA and ring retard DL1 connect two inputs of coupler C2 respectively, the input of the output termination coupler C3 of coupler C2, the input of another output termination isolator ISO1 of coupler C2, the output of the output termination coupler C3 of isolator ISO1, coupler C3 is connected to coupler C4 by the MZ interference ring, the output order photon detector SPD3 of coupler C4, the output of the input termination isolator ISO2 of coupler C4, second laser connects the input of ISO2;

Described Bob end comprises phase-modulator PMB, ring retard DL2, coupler C5, C6 and single-photon detector SPD1, SPD2, the output of coupler C5 connects the input of coupler C6, the output order photon detector SPD1 of coupler C6 by phase-modulator PMB; Another output of coupler C5 connects another input of coupler C6, another output order photon detector SPD2 of coupler C6 by ring retard DL2;

Described Alice end is connected with the Bob end by long-range optical fiber; Long-range optical fiber connects the output of isolator ISO1; Described MZ interference ring comprises ring retard DL2 and galianconism optical fiber.

Suppose that in the regular hour scope phase difference of adapter ring is that constant Alice so and Bob only needs to do phasescan with adapter ring respectively.Determine the parameter of phase drift separately, the phase difference when interfering so, then the phase difference that is loaded by Alice and Bob end phase-modulator determines.The phasescan process of Alice end is then finished in this locality fully like this, without long-range optical fiber, Eve can not obtain any information about Alice end phasescan or change the quantum state that the Alice end sends, under this condition, the quantum state that the Alice end sends is the quantum state of pairwise orthogonal, and known phase place remaps attack and then can not implement.

The scanning process of Alice and Bob was carried out in the very near at interval time in the scheme of present embodiment, and the result that this scheme obtains is not the phase drift of per two rings, but the working point of key distribution, the result that obtains of scanning and the phase drift of the 3rd ring have nothing to do so.

Be example with the MZ system below, specifically describe its scanning and the process that compensates.

One, Sao Miao process

The scanning process of Alice end is as follows:

1, Alice is held the phase modulation voltage of phase-modulator PMA scan Vmax from Vmin with step delta V, Vmin will cover the phase range of 2 π at least to Vmax.

2, wait for N lock-out pulse at each magnitude of voltage Vi place, and the counting of single-photon detector added up that obtain counting Ci, { this curve is the single photon interference curve for Vi, Ci} to obtain one group of data.

3, can obtain the half-wave voltage V of Alice end phase-modulator according to curve _{π, a}And load 0, pi/2, π, the voltage V during 3 pi/2 phases _{A, 0},

Va, π,

Scanning process and the Alice end of Bob end are similar, when different is Bob scanning, are the light that sends from the laser2 laser that Alice holds, and enter long-range optical fiber after the process adapter ring, and then interfere to the Bob end.Obtain afterwards the interference curve of Bob end equally through above-mentioned 1,2,3 step, and obtain the half-wave voltage V of Bob end phase-modulator _{π, b}And load 0, pi/2, π, the voltage V during 3 pi/2 phases _{B, 0},

V _{B, π},

Two, phase drift compensation

1, the active phase compensation of Alice end

Twice scanning process all can obtain the interference curve of single photon, and the scanning of holding with Alice is example.In the single photon interference curve, the voltage of counting maximum point correspondence is with the difference of the voltage of the counting smallest point half-wave voltage V for compensation back Alice end phase-modulator _{π, a}, the point voltage of choosing phase difference and be π is reference voltage V _{Ref, a}, then have following formula to set up:

Wherein,

For adapter ring poor by the proper phase that length difference causes,

For Alice holds the proper phase of interference ring poor, It then is phase drift at random.

The modulation voltage working point of the phase place modulation of Alice end is:

$\{V_{a,0},V_{a,1},V_{a,2},V_{a,3}\}=\{V_{a,0},V_{a,\frac{\mathrm{\π}}{2}},V_{a,\mathrm{\π}},V_{a,\frac{3\mathrm{\π}}{2}}\}$

$=\{V_{\mathrm{ref},a}-V_{\mathrm{\π},a},V_{\mathrm{ref},a}-\frac{1}{2}{V}_{\mathrm{\π},a},V_{\mathrm{ref},a},V_{\mathrm{ref},a}+\frac{1}{2}{V}_{\mathrm{\π},a}\}$

Then the voltage of Alice end phase-modulator loading is V _{A, i}The time, phase difference is:

2, the active phase compensation of Bob end

The point voltage of choosing phase difference equally and be π is reference voltage V _{Ref, b}, then

In like manner we can derive the modulation voltage working point of the phase-modulator of Bob end:

$\{V_{b,0},V_{b,1},V_{b,2},V_{b,3}\}=\{V_{b,0},V_{b,\frac{\mathrm{\π}}{2}},V_{b,\mathrm{\π}},V_{b,\frac{3\mathrm{\π}}{2}}\}$

$=\{V_{\mathrm{ref},b}-V_{\mathrm{\π},b},V_{\mathrm{ref},b}-\frac{1}{2}{V}_{\mathrm{\π},b},V_{\mathrm{ref},b},V_{\mathrm{ref},b}+\frac{1}{2}{V}_{\mathrm{\π},b})$

Then the voltage of Bob end phase-modulator loading is V _{B, j}The time, phase difference is:

When hypothesis in the regular hour scope, the proper phase difference of adapter ring remains unchanged, and the intrinsic phase difference of Alice and Bob end interference ring is when equating, phase drift is compensated.

Embodiment two

As Fig. 3,4, the Alice end comprises faraday mirror FM1-FM2, first and second laser, phase-modulator PMA, coupler BS1-BS2, circulator CIR1-CIR2, ring retard DL1, single-photon detector SPD and adapter ring, and described adapter ring comprises ring retard DL2 and faraday mirror FM3-FM4; The laser that first laser sends enters coupler BS1 and is divided into two pulses, walk long-armed and galianconism respectively, entered first port of circulator CIR1 by the other end of faraday mirror FM1 and faraday mirror FM2 reflected back coupler BS1, second port by circulator CIR1 enters adapter ring, through being divided into 4 pulses respectively by faraday mirror FM3 and faraday mirror FM4 reflected back coupler BS2 behind the coupler BS2; Get ahead and walk two long-armed pulses in the interference of coupler BS2 place after walking galianconism and the galianconism that gets ahead after long-armed, detect the single photon interference curve by single-photon detector SPD; Thereby, obtain the phase drift parameter that Alice holds

Described Bob end comprises faraday mirror FM5FM6, phase-modulator PMB, coupler BS3, ring retard DL3, photon detector SPD1, SPD2 and circulator CIR3, the laser that second laser sends enters coupler BS2 through circulator CIR2, be divided into two pulses and walk the long-armed and galianconism of coupler BS2 respectively, one in front and one in back entered second port of circulator CIR1 again by faraday mirror FM3 and faraday mirror FM4 reflected back coupler BS2, enter long-range optical fiber through port not; Enter first port that Bob holds circulator CIR3 by long-range optical fiber, enter coupler BS3 through second port and be divided into 4 pulses, faraday mirror FM5 and faraday mirror FM6 reflected back coupler BS3 are arranged respectively; Equally, get ahead to walk after long-armed and walk two long-armed pulses behind galianconism and the galianconism that gets ahead and interfere at coupler BS3 place, obtain the single photon interference curve by SPD1 or SPD2, obtain the phase drift parameter that Bob holds.

In the present embodiment, circulator is three port open loop circulators, i.e. then second port output of optical routing first port input, then the 3rd port output of second port input; Described not port is the 3rd port.

The scanning of the present invention in the FM system and process and the MZ systems compliant of compensation.

The scanning active phase compensation scheme of uniting of the present invention has following advantage:

1, Alice and Bob only need carry out single pass respectively, namely can obtain the phase drift parameter, shorten sweep time, reduce the complexity of scanning, have improved the information duty ratio of system.

2, in single-phase and four phasescan methods, Bob all needs the result of phasescan is informed Alice by classical channel, therefrom obtains the possibility of phase information so just for Eve, causes it to have an opportunity to influence or change the result of phase compensation.The scanning result of Alice and Bob is fully by obtaining respectively separately in this scheme, classical information transmission between them can not relate to the result of phasescan, Eve then can't obtain the relevant information of phasescan from common signal channel, thus the fail safe that has improved system.

3, the scanning of Alice end is finished in this locality fully, and the listener-in can not obtain any information about Alice end phasescan or change the quantum state that Alice sends.4 quantum states sending of Alice end must be pairwise orthogonal each other like this, the standard that meets the BB84 agreement fully, known phase place remap attack and possible distortion has just lost its physical basis, and institute is in order to can not implement, therefore, improved the fail safe of system.

Above-described embodiments of the present invention do not constitute the restriction to protection range of the present invention.Any modification of within spiritual principles of the present invention, having done, be equal to and replace and improvement etc., all should be included within the claim protection range of the present invention.

Claims (8)

1. active phase compensating method of uniting scanning, it is characterized in that, add an adapter ring at the Alice end, adapter ring is interfered with the ring of Alice and Bob end respectively, scanning obtains the interference curve of Alice end and Bob end respectively, thereby obtain the phase drift parameter of phase-modulator, again Alice and Bob end are carried out active phase compensation respectively.

2. active phase compensating method of uniting scanning according to claim 1 is characterized in that,

The scanning process of described Alice end is:

S11. Alice is held the phase modulation voltage of phase-modulator PMA to scan Vmax from Vmin with step-length △ V, Vmin is minimum phase modulation voltage, and Vmax is maximum phase modulation TV university;

S12. wait for N lock-out pulse at each magnitude of voltage Vi place, and the counting of single-photon detector is added up, obtain counting Ci, { { Vi, the curve that Ci} constitutes are the single photon interference curve of Alice end to the data group for Vi, Ci} to obtain one group of data;

S13. obtain the half-wave voltage V of Alice end phase-modulator according to the single photon interference curve of Alice end _{π, a}And load 0, pi/2, π, the voltage V during 3 pi/2 phases _{A, 0},

V _{A, π},

The scanning process of described Bob end is:

S21. Bob is held the phase modulation voltage of phase-modulator PMB to scan V ' max from V ' min with step-length △ V, V ' min is minimum phase modulation voltage, and V ' max is maximum phase modulation TV university;

S22. wait for M lock-out pulse at each magnitude of voltage V ' i place, and the counting of single-photon detector added up, obtain counting C ' i, obtain one group of data V ' i, C ' i}, the data group V ' i, the curve that C ' i} constitutes is the single photon interference curve that Bob holds;

S23. obtain the half-wave voltage V of Bob end phase-modulator according to the single photon interference curve of Bob end _{π, b}And load 0, pi/2, π, the voltage V during 3 pi/2 phases _{B, 0},

V _{B, π},

3. active phase compensating method of uniting scanning according to claim 1 is characterized in that, Vmin covers the phase range of 2 π at least among the described step S11 to Vmax; V ' min covers the phase range of 2 π at least among the described step S21 to V ' max.

4. active phase compensating method of uniting scanning according to claim 1 is characterized in that,

Described Alice end initiatively phase compensation mode is:

In the single photon interference curve of Alice end, the point voltage of choosing phase difference and be π is reference voltage V _{Ref, a}, then:

Wherein, For adapter ring poor by the proper phase that length difference causes, For Alice holds the proper phase of interference ring poor,

It then is phase drift at random;

The modulation voltage working point of the phase place modulation of Alice end is:

$\{V_{a,0},V_{a,1},V_{a,2},V_{a,3}\}=\{V_{a,0},V_{a,\frac{\mathrm{\π}}{2}},V_{a,\mathrm{\π}},V_{a,\frac{3\mathrm{\π}}{2}}\}$

$=\{V_{\mathrm{ref},a}-V_{\mathrm{\π},a},V_{\mathrm{ref},a}-\frac{1}{2}{V}_{\mathrm{\π},a},V_{\mathrm{ref},a},V_{\mathrm{ref},a}+\frac{1}{2}{V}_{\mathrm{\π},a}\}$

Then the voltage of Alice end phase-modulator loading is V _{A, i}The time, phase difference is:

Described Bob end initiatively phase compensation mode is:

In the single photon interference curve of Bob end, the point voltage of choosing phase difference and be π is reference voltage V _{Ref, b}, then

Wherein,

For adapter ring poor by the proper phase that length difference causes,

For Bob holds the proper phase of interference ring poor,

It then is phase drift at random;

The modulation voltage working point of the phase place modulation of Bob end is:

$\{V_{b,0},V_{b,1},V_{b,2},V_{b,3}\}=\{V_{b,0},V_{b,\frac{\mathrm{\π}}{2}},V_{b,\mathrm{\π}},V_{b,\frac{3\mathrm{\π}}{2}}\}$

$=\{V_{\mathrm{ref},b}-V_{\mathrm{\π},b},V_{\mathrm{ref},b}-\frac{1}{2}{V}_{\mathrm{\π},b},V_{\mathrm{ref},b},V_{\mathrm{ref},b}+\frac{1}{2}{V}_{\mathrm{\π},b})$

Then the voltage of Bob end phase-modulator loading is V _{B, j}The time, phase difference is:

5. one kind is applied to described device of uniting the active phase compensating method of scanning, comprise Alice end and the Bob end that is connected with the Alice end, it is characterized in that, add an adapter ring at described Alice end, described adapter ring is used for interfering with Alice end and Bob end respectively.

6. active phase compensation device of uniting scanning according to claim 5 is characterized in that, described active phase compensation device of uniting scanning is based on two MZ systems, and described adapter ring is the MZ interference ring,

Described Alice end comprises first and second laser, phase-modulator PMA, ring retard DL1, isolator ISO1, isolator ISO2, coupler C1-C2, single-photon detector SPD3 and adapter ring; Adapter ring comprises coupler C3, C4, ring retard DL3;

Described first laser meets phase-modulator PMA and ring retard DL1 respectively by coupler C1, phase-modulator PMA and ring retard DL1 are connected in parallel, phase-modulator PMA and ring retard DL1 connect two inputs of coupler C2 respectively, the input of the output termination coupler C3 of coupler C2, the input of another output termination isolator ISO1 of coupler C2, the output of the output termination coupler C3 of isolator ISO1, coupler C3 is connected to coupler C4 by the MZ interference ring, the output order photon detector SPD3 of coupler C4, the output of the input termination isolator ISO2 of coupler C4, second laser connects the input of ISO2;

Described Bob end comprises phase-modulator PMB, ring retard DL2, coupler C5, C6 and single-photon detector SPD1, SPD2, the output of coupler C5 connects the input of coupler C6, the output order photon detector SPD1 of coupler C6 by phase-modulator PMB; Another output of coupler C5 connects another input of coupler C6, another output order photon detector SPD2 of coupler C6 by ring retard DL2;

Described Alice end is connected with the Bob end by long-range optical fiber; Long-range optical fiber connects the output of isolator ISO1; Described MZ interference ring comprises ring retard DL2 and galianconism optical fiber.

7. active phase compensation device of uniting scanning according to claim 5 is characterized in that, described active phase compensation device of uniting scanning is based on two FM systems, and described adapter ring is the FM interference ring,

Described Alice end comprises faraday mirror FM1-FM2, first and second laser, phase-modulator PMA, coupler BS1, circulator CIR1-CIR2, ring retard DL1, single-photon detector SPD and adapter ring, and described adapter ring comprises ring retard DL2, coupler BS2 and faraday mirror FM3FM4;

The laser that described first laser sends enters coupler BS1 and is divided into two pulses, walk long-armed and galianconism respectively, entered first port of circulator CIR1 by the other end of faraday mirror FM1 and faraday mirror FM2 reflected back coupler BS1, second port by circulator CIR1 enters adapter ring, through being divided into 4 pulses respectively by faraday mirror FM3 and faraday mirror FM4 reflected back coupler BS2 behind the coupler BS2; Get ahead and walk two long-armed pulses in the interference of coupler BS2 place after walking galianconism and the galianconism that gets ahead after long-armed, detect the single photon interference curve by single-photon detector SPD;

Described Bob end comprises faraday mirror FM5-FM6, phase-modulator PMB, coupler BS3, ring retard DL3, photon detector SPD1 and circulator CIR3, the laser that second laser sends enters coupler BS2 through circulator CIR2, be divided into two pulses and walk the long-armed and galianconism of coupler BS2 respectively, one in front and one in back entered second port of circulator CIR1 again by faraday mirror FM3 and faraday mirror FM4 reflected back coupler BS2, enter long-range optical fiber through port not; Enter first port that Bob holds circulator CIR3 by long-range optical fiber, enter coupler BS3 through second port and be divided into 4 pulses, faraday mirror FM5 and faraday mirror FM6 reflected back coupler BS3 are arranged respectively; Equally, get ahead and walk two long-armed pulses in the interference of coupler BS3 place after walking galianconism and the galianconism that gets ahead after long-armed, obtain the single photon interference curve by SPD1.

8. active phase compensation device of uniting scanning according to claim 7 is characterized in that, described circulator is three port open loop circulators, i.e. then second port output of optical routing first port input, then the 3rd port output of second port input; Described not port is the 3rd port.

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