Hardware System Design And Implementation Supporting Multi-Users Quantum Key Distribution

For centuries, cryptography plays an important role in the history of human civilization. As the continuously development of computing technology, computational complexity based classical cryptography is unable to provide information security effectively. Quantum key distribution technology can provide absolute information security via quantum mechanics theory. After30years, quantum cryptography has amazing achievement. It even played an important role in some areas, but there are still many problems to be solved such as limited transmission distance. Efficient and stable quantum key distribution network is the key to the commercialization of this technology. Currently, there have been many domestic quantum key distribution network in the world, but those networks are small-scale and have many defects such as high maintenance costs, upgrades difficulties and poor flexibility. The paper proposes a quantum key distribution supporting node structure aiming at solving the problems above. Meanwhile, we design and realize the related control circuit and conducted a series of experiments in the multi-user quantum key distribution network.This paper make a conclusion of what has done during my master career. Firstly, the paper has studied passive optical components and Faraday-Michelson interferometers. The paper has researched several influential multi-user quantum key distribution network and analyzed the features of each network. Secondly, the paper designed a multi-function quantum key distribution node, aiming at reducing node maintenance complexity and equipment costs, while saving fiber resources and reducing relative delay of two signal. At the same time, it can be regarded as super user node, central node or trusted relay node and applied to a variety of network environment. Finally, the paper improved F-M interferometers based QKD node, including optical system stability and control circuit of multi-user supporting QKD node. This paper has conducted performance test in multi-user QKD network for several days.Point-to-point quantum key distribution and QKD networking is developing rapidly, and make amazing progress in some aspects. But there are still many key technologies needed to be studied and solved. In the final, future development of quantum key distribution are presented.