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

Abstract

A signal detection method and device for a continuous variable quantum key distribution system. The method includes: splitting the received quantum light into a first split beam and a second split beam; combining the first split beam and the second split beam to generate a first combined beam; according to a preset polarization value, calibrate the polarization of the first combined beam; split the first combined beam into the first probe light and the second probe light; according to the preset phase value, modulate the phase of the local oscillator light; split the local oscillator light into the third probe light and the fourth probe light with orthogonal polarizations; perform homodyne detection on the first probe light and the third probe light, and perform homodyne detection on the second probe light and the fourth probe light to obtain the detection result; Detect the result and obtain the quantum state of the quantum light. Since this application introduces the strong light of local local oscillator light, even if the reference light is attenuated due to the long transmission process, the local local oscillator light can be supplemented, so as to prevent the detection efficiency of the receiver from becoming low, thereby improving the cost of the system. code rate.

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 day by day, and quantum communication with high security is getting 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, the weak pulse contains the encoded information in the quantu...

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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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