Multi-user QKD network system based on Sagnac ring, and secret key distribution method thereof

Abstract

The invention discloses a multi-user QKD network system based on a Sagnac ring, and a secret key distribution method thereof. The system comprises an Alice control end, a multiuser Bob client and a Sagnac annular pulse transmission link. The multiuser Bob client comprises a multi-wavelength pulse laser generation device, a photon interference signal detection device, a multiuser multiplexing module and a coupler; the Sagnac annular pulse transmission link comprises a CW link and a CCW link; and pulses generated by the multi-wavelength pulse laser generation device, after penetrating into the CW link and the CCW link through the coupler according to a proportion of 50:50, are merged and output from the coupler and then are transmitted to the photon interference signal detection device for detection. According to the invention, multiple users are multiplexed into the system through a wavelength division multiplexer / demultiplexer in a wavelength addressing mode, a phase coding mode is employed, the optical pulses are respectively modulated for loading information at the Alice end and the Bob end, the pulses are interfered at the coupler, the overall structure is simple, the photon utilization rate and the code rate are high, the transmission stability is good, and one-to-N multiuser transmission is realized.

Description

technical field [0001] The invention relates to the technical field of quantum information and optical fiber communication, in particular to a Sagnac ring-based multi-user QKD network system and a key distribution method thereof. Background technique [0002] Quantum cryptography is an emerging interdisciplinary subject combining information science, quantum mechanics and cryptography. It is the application of quantum mechanics and information science in cryptography. It mainly involves quantum physics, information science and computer science. Potential application value and great scientific significance. Quantum communication refers to a new type of communication method that uses quantum effects to transmit information. The quantum uncertainty theorem and the non-cloning theorem guarantee the absolute security of quantum cryptography in principle. [0003] In quantum communication technology, the point-to-point two-party quantum key distribution technology has matured, bu...

AI Technical Summary

Problems solved by technology

[0005] As mentioned above, both solutions largely limit the increase of users, and user expansion leads to problems such as a decrease in the key generation rate.

Although the number of users has been increased in the schemes that have been proposed successively, problems such as crosstalk between users and increased bit error rate have occurred, and its feasibility needs to be verified by actual experiments.

Images