阅读说明：本技术 一种经典信道和量子信道的波分复用系统及方法 (Classical channel and quantum channel wavelength division multiplexing system and method ) 是由 陈柳平 万相奎 李杨 于 2019-11-01 设计创作，主要内容包括：本发明公开了一种经典信道和量子信道的波分复用系统及方法。系统包括发送端，接收端。发送端包括第一激光器，其发出占空比小于等于30％窄脉冲的经典光；第二激光器，发出同步光；量子密钥编码单元，进行量子密钥编码并以量子光形式发出；波分复用器，对量子光、经典光、同步光进行波分复用。接收端经典光探测器，用于对经典光进行探测；同步光探测器，用于对同步光进行探测；量子密钥探测单元，用于对量子密钥进行探测。方法包括波分复用方法以及量子密钥分发方法。本发明可以有效降低经典光的拉曼散射效应，从而降低经典光对量子光的干扰和影响，从而很大程度上提高量子密钥传输距离以及成码率。(The invention discloses a wavelength division multiplexing system and method of a classical channel and a quantum channel. The system comprises a sending end and a receiving end. The transmitting end comprises a first laser which emits classical light with a duty ratio of less than or equal to 30% of narrow pulses; a second laser for emitting a synchronous light; the quantum key coding unit is used for carrying out quantum key coding and emitting the quantum key in a quantum light form; the wavelength division multiplexer is used for carrying out wavelength division multiplexing on the quantum light, the classical light and the synchronous light. The receiving end classical light detector is used for detecting the classical light; the synchronous light detector is used for detecting synchronous light; and the quantum key detection unit is used for detecting the quantum key. The method comprises a wavelength division multiplexing method and a quantum key distribution method. The invention can effectively reduce the Raman scattering effect of classical light, thereby reducing the interference and influence of the classical light on quantum light, and improving the transmission distance and the code rate of quantum keys to a great extent.)

1. A method of wavelength division multiplexing classical and quantum channels, comprising:

receiving classical light of a classical signal from a first laser, wherein the classical light is a narrow pulse with a duty cycle of less than or equal to 30%;

receiving quantum light of a quantum signal from a quantum key encoding unit; and

at a wavelength division multiplexer, classical light of the classical channel is multiplexed with quantum light wavelength division of the quantum channel.

2. The method of claim 1, wherein the classical light is a narrow pulse with a duty cycle of 20% or less or 10%.

3. The method of claim 1, wherein the first laser is a pulse width tunable laser.

4. The method of claim 1, further comprising: attenuating the classical light and/or the quantum light.

5. The method of claim 1, further comprising: receiving the synchronization light from the second laser; and wavelength division multiplexing the synchronization light with the classical light and/or the quantum light.

6. The method of claim 5, further comprising: attenuating the synchronous light.

7. A transmitting end of a wavelength division multiplexing system of classical channels and quantum channels, comprising:

a first laser configured to emit a narrow pulse of classical light with a duty cycle of 30% or less;

a quantum key encoding unit configured to encode with a probabilistically random quantum key and emit the encoded result as quantum light; and

a first wavelength division multiplexer configured to wavelength division multiplex the classical light with the quantum light.

8. The transmit end of claim 7, further comprising: a second laser configured to emit a synchronization light.

9. The transmit end of claim 8, wherein the first wavelength division multiplexer is configured to multiplex the synchronous light with the classical light and quantum light wavelengths.

10. The transmit end of claim 8, further comprising: a second wavelength division multiplexer configured to wavelength division multiplex the isochronous light with the classical light or the quantum light.

11. The transmitting end according to claim 10, wherein the first wavelength division multiplexer is configured to multiplex two of the classical light, the quantum light, and the synchronous light, and the second wavelength division multiplexer is configured to multiplex signal light emitted from the first wavelength division multiplexer with another wavelength division.

12. The transmitting end according to claim 8, further comprising a first attenuator, and/or a second attenuator, and/or a third attenuator; wherein the first attenuator is configured to precisely adjust the intensity of the classical light according to system requirements; the second attenuator is configured to accurately adjust the light intensity of the synchronous light according to system requirements; a third attenuator is configured to attenuate the quantum light to a single photon level.

13. The transmitting end according to any one of claims 7-12, further comprising a third wavelength division multiplexer, a first classical optical detector, and the third wavelength division multiplexer is configured to demultiplex the classical light emitted from the receiving end of the present invention from the optical path and transmit the classical light to the first classical optical detector, so as to establish a communication link between the transmitting end and the receiving end of the present invention.

14. The transmitting end according to any one of claims 7 to 12, further comprising a first optical transmission unit, a first detection unit; the first optical transmission unit comprises three optical interfaces, wherein an optical signal input by the first interface is output from the second interface, and an optical signal input by the second interface is output from the third interface; the first optical transmission unit is configured with a first interface to receive the quantum light, a second interface is directly connected with the wavelength division multiplexer, and a third interface is connected with the first detection unit; the first detection unit is a light intensity detection device that receives the light pulse transmitted by the first optical transmission unit and detects the light intensity of the light pulse.

15. The transmitting end according to any one of claims 7 to 12, further comprising a second optical transmission unit, a second detection unit; the second optical transmission unit is configured to receive the quantum light, divide the quantum light into two quantum light outputs according to any proportion of 1:99 to 50:50, input one of the two quantum light outputs to the second detection unit and perform light intensity detection.

16. The transmitting end according to any one of claims 7 to 12, further comprising a third optical transmission unit, a first filtering unit; the third optical transmission unit comprises three optical interfaces, wherein the optical signal input by the first interface is output from the second interface, and the optical signal input by the second interface is output from the third interface; the first filtering unit is configured to receive the quantum light transmitted by the third optical transmission unit and filter spontaneous emission noise of the quantum light before being output by the third optical transmission unit.

17. The transmitting end according to any one of claims 7-12, further comprising a decoy state preparation unit configured to receive the quantum light and perform probabilistic random decoy state preparation.

18. A receiving end of a wavelength division multiplexing system of classical channels and quantum channels, comprising:

a third laser configured to emit classical light that is received and detected by the first classical light detector to establish a communication link between a receiving end and a transmitting end; and

the fourth wavelength division multiplexer is configured to receive the signal light emitted by the sending end, demultiplex the signal light, obtain quantum light, transmit the quantum light to the quantum key detection unit, obtain classical light and synchronous light, and transmit the classical light and the synchronous light to the fifth wavelength division multiplexer;

the fifth wavelength division multiplexer is configured to receive the classical light and the synchronous light transmitted by the fourth wavelength division multiplexer, demultiplex the classical light to obtain classical light, transmit the classical light to the sixth wavelength division multiplexer, and transmit the synchronous light to the synchronous light detection unit;

a sixth wavelength division multiplexer configured to receive classical light transmitted by the fifth wavelength division multiplexer and demultiplex transmission to a classical light detection unit;

a classical light detection unit configured to receive and detect classical light transmitted from the sixth wavelength division multiplexer;

a synchronous light detection unit configured to receive the synchronous light transmitted by the fifth wavelength division multiplexer and parse the synchronous information to establish system synchronization between the transmitting end and the receiving end;

a quantum key detection unit configured to receive quantum light transmitted by the fourth wavelength division multiplexer and detect a quantum key encoding.

19. The receiving end of claim 18, further comprising a fourth optical transmission unit, a second filtering unit; the fourth optical transmission unit comprises three optical interfaces, wherein the optical signal input by the first interface is output from the second interface, and the optical signal input by the second interface is output from the third interface; the second filtering unit is configured to receive the quantum light transmitted by the fourth optical transmission unit, filter noise generated by the quantum light in communication link transmission, and output the filtered quantum light through the fourth optical transmission unit.

20. The receiving end according to claim 18 or 19, wherein the quantum key detection unit further comprises a fifth optical transmission unit, a phase coding detection unit, a time coding detection unit; the fifth optical transmission unit is configured to receive the quantum light and split the quantum light into two beams, wherein one beam is transmitted to the phase-coded detection unit, and the other beam is transmitted to the time-coded detection unit; the phase encode detection unit is configured to detect an X-basis vector phase encode or a Y-basis vector phase encode; the time encoding unit is configured to detect a Z-basis vector time encoding.

21. The receiving end of claim 20, wherein the time code detection unit further comprises a sixth optical transmission unit, a first time code detector, a second time code detector; the sixth optical transmission unit is configured to receive the quantum light transmitted by the fifth optical transmission unit, and divide the quantum light into two beams to be transmitted to the first time-coded detector and the second time-coded detector respectively; the first temporal encoding detector is configured to detect a 0 encoding in a Z-basis vector temporal encoding, and the second temporal encoding detector is configured to detect a 1 encoding in the Z-basis vector temporal encoding.

22. The receiving end of claim 20, wherein the phase-coding detection unit further comprises a seventh optical transmission unit, an eighth optical transmission unit, a first faraday mirror, a second faraday mirror, a phase modulator, a first phase-coding detection unit, a second phase-coding detection unit; the seventh optical transmission unit comprises three optical interfaces, wherein the optical signal input by the first interface is output from the second interface, and the optical signal input by the second interface is output from the third interface; the first Faraday reflector and the second Faraday reflector are both 90-degree Faraday reflectors, and the polarization of an optical signal is rotated by 90 degrees after the optical signal is reflected by the first Faraday reflector and the second Faraday reflector, so that the influence generated by the birefringence effect of the optical fiber can be eliminated; the phase modulator is configured to compensate for optical signal phase variations to achieve stable interference; the eighth optical transmission unit is configured to receive the quantum light transmitted by the fifth optical transmission unit, transmit the quantum light to the phase modulator, the first faraday reflector and the second faraday reflector, and transmit the quantum light to the first phase-encoding detector and the second phase-encoding detector respectively after eliminating the influence of the optical fiber birefringence effect through phase compensation and polarization rotation; the first phase-coded detector is configured to detect a 0-coding of an X-basis vector or a Y-basis vector, and the second phase-coded detector is configured to detect a 1-coding of the X-basis vector or the Y-basis vector.

23. A quantum key distribution method of a wavelength division multiplexing system of classical channels and quantum channels comprises the following steps:

the quantum key coding unit of the sending terminal carries out quantum key coding and sends out quantum light;

the sending end filters and attenuates the quantum light to obtain the quantum light of a single photon level;

carrying out wavelength division multiplexing on the quantum light, the classical light and the synchronous light of the single photon level by a wavelength division multiplexer of a sending end to obtain signal light after wavelength division multiplexing;

the transmitting end transmits the signal light after wavelength division multiplexing and transmits the signal light in the same optical fiber through a channel;

the receiving end receives the signal light and carries out demultiplexing to obtain quantum light, classical light and synchronous light;

the quantum coding detection unit, the classical light detection unit and the synchronous light detection unit of the receiving end respectively detect the quantum light, the classical light and the synchronous light. The quantum coding detection unit can detect the phase coding of the X basis vector or the Y basis vector and the time coding of the Z basis vector.

24. A wavelength division multiplexing system of classical channels and quantum channels, comprising the transmitting end of any one of claims 7 to 17 or the receiving end of any one of claims 18 to 22 or employing the wavelength division multiplexing method of any one of claims 1 to 6 or employing the quantum key distribution method of claim 23.