Experimental Study On The Optical Fiber Based Quantum Key Distribution Network

Quantum Key Distribution (QKD) provides unconditional security for communication, so the development of quantum network plays an important role in aerospace and civilian in the future. Recently, the study from point-point QKD system to QKD network develops quickly. There are many solutions using optical passive devices for quantum network. Considering that these solutions have obvious disadvantages such as inferior flexibility and more materials using affecting the performance of quantum network, we proposed a novel quantum network system structure, which is more flexible, economical and efficient for quantum network in the near future. Our team did a series of experiments to study the quantum key distribution network structure.Works in this paper are summarized as follows.(1) This paper is based on extensive study on quantum key distribution and the experimental system for the optical fiber based quantum key distribution network.(2) The quantum key distribution system between two users based on the Faraday-Michelson (FM) structure was finished, including the optical circuit, hardware and software. Using this system, we verified the switch node’s function.(3) The new user node is made up of MUX/DEMUX, CIR, FM and so on, using which, a kind of experimental QKD network structure based on switch node was set up. The structure combines the quantum signal, the synchronizing controlling signal and the classical optical signal into one optical fiber based on the quantum switching node using CIR and CWDM. A series of experiments have been conducted to prove advantages of the structure. Despite of the progress achieved in the quantum communication field, there are still some problems to solve, this paper prospects the future of the quantum communication.