Signal detection method and device for continuous variable quantum key distribution system

Abstract

The invention discloses a signal detection method and device for a continuous variable quantum key distribution system. The method comprises the following steps: splitting received quantum light into first split light and second split light; combining the first split light and the second split light to generate first combined light; calibrating the polarization of the first combined beam according to a preset polarization value; splitting the first combined beam into first detection light and second detection light; modulating the phase of the local oscillation light according to a preset phase value; splitting the local oscillation light into third detection light and fourth detection light which are polarized and orthogonal; carrying out the homodyne detection on the first detection light and the third detection light, carrying out the homodyne detection on the second detection light and the fourth detection light, and obtaining a detection result; and obtaining the quantum state of the quantum light according to the detection result. According to the invention, because the strong light of the local local oscillation light is introduced, even if the transmission process is too long and the reference light is attenuated, the local local oscillation light can also complement the reference light, so that the detection efficiency of a receiver is prevented from being reduced, and the code rate of the system is further improved.

Description

technical field [0001] The embodiments of the present application relate to the technical field of quantum communication, and in particular to a signal detection method and device for a continuous variable quantum key distribution system. Background technique [0002] With the development of global informatization, the requirements of information technology for information security are increasing, and quantum communication with high security has attracted more and more attention. In the field of quantum communication, Continuous Variable Quantum Key Distribution (CV-QKD) technology is one of the core technologies. [0003] For CV-QKD, the receiver structure in the related art is usually as follows figure 1 shown. The optical signal received by the receiver includes two types of pulses: one is a strong pulse, that is, a reference pulse, and the other is a weak pulse, that is, a signal pulse. Among them, weak pulses contain encoded information in the quantum key distributio...

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Problems solved by technology

[0005] This application provides a signal detection method and device for a continuous variable quantum key distribution system, which can be used to solve the problem that in the prior art, strong pulses will attenuate along the path during transmission, resulting in low detection efficiency of the QKD system, and Too low detection efficiency will reduce the coding rate index of the overall system

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