Simple Multiuser Twin-Field Quantum Key Distribution Network
Xiaoqing Zhong, Wenyuan Wang, Reem Mandil, Hoi‐Kwong Lo, Li Qian
Abstract
Meet Alice, Bob, and David. Establishing secure encryption keys between any two of these users is important for a long-range communication network, but with dubious Charlie also around, it becomes tricky. Twin-field quantum key distribution (TFQKD), while promising for this application, has been limited so far to two users, because of its requirement for phase stability of optical signals. In this work, the authors demonstrate a TFQKD network by connecting three users in a Sagnac fiber ring, a configuration with inherent phase stability. This experiment suggests that the Sagnac TFQKD system is an effective, practical approach to implementing a long-range secure communication network.