Quantum key distribution system and method based on time-slot mixed active polarization compensation

Abstract

The invention discloses a quantum key distribution system and method based on time-slot mixed active polarization compensation. The quantum key distribution system comprises a transmitting terminal, an optical signal generation module, a polarization modulator, a synchronous signal generator, a wavelength division multiplexing module, a wavelength division multiplexing solution module, a synchronous signal receiver, a polarization demodulator, a signal detection module and a receiving terminal. According to the quantum key distribution system and method, adopted reference light pulse signals and quantum pulse signals have the same wavelength, the magnitude of single pulse energy of the reference light pulse signals is far larger than the magnitude of single pulse energy of the quantum pulse signals, and the magnitude can be detected through a photoelectric detector. The reference light pulses do not need to be accumulated repeatedly to calculate sums when the detection is carried out, and the polarization compensation rate can be greatly promoted. After the active polarization compensation, and different polarization codes are detected based on a unified polarization detection device, so the quantity of SPAD can be reduced. An optical switch is utilized to carry out switchover on a detection light path, the phenomenon that the strong reference light pulse signals directly impact the SPAD, and therefore communication quality of quantum signals can be guaranteed.

Description

technical field [0001] The present invention relates to a polarization coding quantum key distribution system and method, in particular to a quantum key distribution system and method based on time slot interleaving active polarization compensation capable of realizing real-time communication, and belongs to the technical fields of quantum secret communication, information security, etc. . Background technique [0002] Quantum key distribution technology (QKD) can provide legitimate users with unconditional and secure key exchange, and has a wide range of applications in communication information security and other fields. When the quantum communication signal is transmitted on the traditional single-mode fiber, due to the birefringence effect on the fiber, the polarization state of the quantum signal will be significantly changed, which will interfere with the communication effect. Therefore, Active Polarization Compensation (APC) must be used to keep the quantum communica...

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Problems solved by technology

However, this method requires the intensity of the reference signal to be at the single-photon level, so as to avoid the reference signal directly bombarding the SPAD, resulting in a sharp increase in the dark count rate; and, in the polarization compensation process, a large amount of accumulation and summation of the reference light signal is required, It will reduce the communication speed, making it difficult to realize high-speed real-time communication

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