Experimental research on continuous variable quantum key distribution in fiber channel

The use of quantum key distribution for encryption to realize the secure transmission of information is a research hotspot in the field of secure communication. In theory, it has a high degree of security with quantum mechanics as a guarantee. In particular, continuous variable quantum key distribution has the advantages of simple quantum state preparation, relatively high key rate and low detector cost, so it has attracted wide attention from all over the world. However, the continuous variable quantum key distribution will be affected by factors such as fiber type and fiber attenuation when it is transmitted in the fiber channel. Therefore, a large number of experimental tests must be carried out in the fiber channel before the quantum key distribution device is connected to the optical network. Therefore, this paper conducted continuous quantum key distribution experiments in different lengths of terrestrial optical fiber G.652D and submarine optical fiber G.654D. Among them, the quantum key generation rate reaches an average of 10kbit/s, and the quantum error rate is within 10%. As the distance increases, the variance of the transmission coefficient and the shot noise becomes smaller and the amplitude of the excess noise fluctuation becomes larger. The negotiation efficiency is above 92.44%. The experimental results show that continuous quantum key distribution has good compatibility in both G.652D and G.654D fibers. The experimental data provides a large amount of data support for subsequent research on the access of quantum key distribution equipment to optical networks.