Independent-optical-frequency-comb-powered 546-km field test of twin-field quantum key distribution
Lai Zhou, Jinping Lin, Chendong Ge, Yuanbin Fan, Zhiliang L. Yuan, Hao Dong, Yang Liu, Di Ma, Jiu-Peng Chen, Cong Jiang, Xiang‐Bin Wang, Lixing You, Qiang Zhang, Jian-Wei Pan · Physical Review Applied · 2024
Twin-field quantum key distribution exploits single-photon interference to provide long-haul secure communication. However, real-time phase tracking between optical signals sent from opposite ends of the communication link is necessary to realize this scheme. Here the authors show that it is feasible to apply independent optical frequency combs in a quantum communication field trial, using a coherent dual-band stabilization technique. A practical finite-size-secure-key rate of 0.53 bit/s is recorded over a 546-km link connecting two major cities in China. This study represents a significant setup toward the integration of long-distance fiber links into quantum networks.