Field Experiment on a “Star Type” Metropolitan Quantum Key Distribution Network

Quantum key distribution (QKD) networks have recently attracted growing attention. The topology of the local QKD network is the basis of the next-generation global secure communication network. In this letter, we report a realization of a wavelength-routing star type QKD network which can span a metropolis using a commercial backbone optical fiber network without trusted relays. The longest and the shortest fiber lengths between two geographically separated nodes are 42.6 and 32 km, respectively, and the maximum average quantum bit-error rate is below 8%. A novel analysis model with experimental validation is also proposed to evaluate the user's performance in this network under the condition of maximum multiuser crosstalk.