阅读说明：本技术 一种量子通信时间相位编码装置、方法及密钥分发系统 (Quantum communication time phase coding device and method and key distribution system ) 是由 陈柳平 李杨 万相奎 于 2019-09-23 设计创作，主要内容包括：本发明公开了一种用于量子通信的时间相位编码装置、编码方法及密钥分发系统。时间相位编码装置,包括：第一干涉仪,其经配置以接收光信号,并生成具有时间差的第一信号和第二光信号；以及第二干涉仪,其经配置以基于第一信号生成沿第一光路传输的第三光信号和沿第二光路传输的第四光信号；基于第二信号生成沿第一光路传输的第五光信号和沿第二光路传输的第六光信号；其中,第一光路的第一相位调制器和第二光路中的第二相位调制器分别对第三光信号和第四光信号中的一者增加或减少π相位；或者对第五光信号和第六光信号中的一者增加或减少π相位；以及其中,第一光路的第一相位调制器和第二光路中的第二相位调制器分别对第三光信号和第四光信号中的两者增加或减少π相位；或者对第五光信号和第六光信号中的两者增加或减少π相位。本发明通过增加π相位来实现时间相位编码,编码方法简便,相位调制精度高、成码率高。(The invention discloses a time phase coding device, a coding method and a key distribution system for quantum communication. A temporal phase encoding device comprising: a first interferometer configured to receive an optical signal and generate a first signal and a second optical signal having a time difference; and a second interferometer configured to generate a third optical signal transmitted along the first optical path and a fourth optical signal transmitted along the second optical path based on the first signal; generating a fifth optical signal transmitted along the first optical path and a sixth optical signal transmitted along the second optical path based on the second signal; the first phase modulator in the first optical path and the second phase modulator in the second optical path respectively increase or decrease the pi phase for one of the third optical signal and the fourth optical signal; or increasing or decreasing the pi phase for one of the fifth optical signal and the sixth optical signal; and wherein the first phase modulator in the first optical path and the second phase modulator in the second optical path increase or decrease the pi phase to both of the third optical signal and the fourth optical signal, respectively; or increasing or decreasing the pi phase for both of the fifth optical signal and the sixth optical signal. The invention realizes time phase coding by increasing the pi phase, and has the advantages of simple coding method, high phase modulation precision and high code rate.)

1. A time-phase encoding apparatus for quantum communication, comprising:

a first interferometer configured to receive an optical signal and generate a first signal and a second optical signal having a time difference; and

a second interferometer configured to generate a third optical signal transmitted along the first optical path and a fourth optical signal transmitted along the second optical path based on the first signal; generating a fifth optical signal transmitted along the first optical path and a sixth optical signal transmitted along the second optical path based on the second signal;

the first phase modulator in the first optical path and the second phase modulator in the second optical path respectively increase or decrease the pi phase for one of the third optical signal and the fourth optical signal; or increasing or decreasing the pi phase for one of the fifth optical signal and the sixth optical signal; and

the first phase modulator in the first optical path and the second phase modulator in the second optical path respectively increase or decrease the pi phase for two of the third optical signal and the fourth optical signal; or increasing or decreasing the pi phase for both of the fifth optical signal and the sixth optical signal.

2. A time phase encoding apparatus according to claim 1, wherein the first phase modulator in the first optical path and the second phase modulator in the second optical path respectively increase or decrease a phase to one of the third optical signal and the fourth optical signal or increase or decrease a phase to one of the fifth optical signal and the sixth optical signal, outputting one of the two optical signals with a time difference.

3. The time phase encoding apparatus according to claim 1, wherein the first phase modulator in the first optical path and the second phase modulator in the second optical path respectively increase or decrease a phase by pi to both of the third optical signal and the fourth optical signal or increase or decrease a phase by pi to both of the fifth optical signal and the sixth optical signal, outputting one of two sets of optical signals having a phase difference of 0 or a phase by pi.

4. The time phase encoding apparatus according to claim 1, wherein the phases of the fifth optical signal and the sixth optical signal are kept unchanged while the first phase modulator of the first optical path and the second phase modulator of the second optical path respectively increase or decrease the pi phase to one or both of the third optical signal and the fourth optical signal; or increasing or decreasing the pi phase to one or both of the fifth optical signal and the sixth optical signal, the third optical signal and the fourth optical signal are kept unchanged in phase.

5. A time phase encoding device according to claim 1, wherein the second interferometer comprises a first output optical path and a second output optical path.

6. The time phase encoding apparatus of claim 1, wherein the second interferometer comprises first and second beam splitting units and first and second optical paths before the first and second beam splitting units.

7. The temporal phase encoding device of claim 1, wherein the second interferometer is a Sagnac interferometer; the first optical path and the second optical path are two opposite optical paths of a loop optical path of the Sagnac interferometer.

8. The temporal phase encoding device of claim 7, wherein the first phase modulator and the second phase modulator are both phase modulators in a loop path of the Sagnac interferometer, and the distance between both sides of the phase modulators and an optical entrance of the Sagnac interferometer is different.

9. The time phase encoding device of claim 1, further comprising an optical isolator disposed between the first interferometer and the second interferometer.

10. The temporal phase encoding device of claim 1, further comprising a circulator disposed between the first interferometer and the second interferometer.

11. The time phase encoding apparatus of claim 1, wherein the circulator comprises a first interface, a second interface, and a third interface; wherein the optical signal entered from the first interface is output from the second interface, and the optical signal entered from the second interface is output from the third interface; the first interface of the circulator is connected with the output of the first interferometer; the second interface of the circulator is connected with the output of the second interferometer; the third interface of the circulator is used as the output of the time phase coding device.

12. The time phase encoding apparatus of claim 1, wherein the first phase modulator or the second phase modulator has only an operating voltage that adjusts pi phase.

13. A time phase encoding apparatus according to claim 1, wherein the first phase modulator or the second phase modulator operates only in an operating state in which a phase is adjusted to 0 or pi.

14. The temporal phase encoding device of claim 1, wherein the first interferometer is an unequal arm interferometer.

15. The time-phase encoding apparatus of claim 1, wherein the first interferometer is a mach-zehnder interferometer or a michelson interferometer.

16. A method of time-phase encoding for quantum communication, comprising:

receiving the optical signal and generating a first optical signal and a second optical signal having a time difference using a first interferometer;

generating a third optical signal and a fourth optical signal which propagate along the loop optical path in a mutual-facing way based on the first optical signal by using a Sagnac interferometer;

generating a fifth optical signal and a sixth optical signal which propagate along the loop optical path in a mutual direction based on the second optical signal by using a Sagnac interferometer; and

increasing or decreasing the pi phase to one of the third optical signal and the fourth optical signal with a phase modulator in the loop optical path; or, increasing or decreasing the pi phase to one of the fifth optical signal and the sixth optical signal, and outputting one of the two optical signals with a time difference; and

increasing or decreasing the pi phase for both of the third optical signal and the fourth optical signal with a phase modulator in the loop optical path; alternatively, the phase of pi is added or subtracted to both of the fifth optical signal and the sixth optical signal, and one of the two sets of optical signals whose phases are different by 0 or pi is output.

17. A quantum key distribution system comprising the time phase encoding apparatus of any one of claims 1 to 15 or employing the time phase encoding method of claim 16.