Source monitoring twin-field quantum key distribution assisted with Hong-Ou-Mandel interference
Ming-Shuo Sun, Wenlin Wang, Xingyu Zhou, Chunhui Zhang, Qin Wang · Physical Review Research · 2023
Twin-field quantum key distribution (TF-QKD) can change the channel-loss dependence of key rates from $O(\ensuremath{\eta})$ to $O(\sqrt{\ensuremath{\eta}})$ and thus significantly increase the secure key rate compared with other existing quantum key distribution protocols. However, it does not take the source security into account in most present TF-QKD protocols. Here, we propose to employ the Hong-Ou-Mandel interference to characterize the source security, i.e., to use the interference visibility to quantify the information leakage from detectable side channels of sources. Furthermore, we establish a corresponding theoretical model and calculate the final key rate, by using the three-intensity decoy-state method and taking finite-data-size effects into account. Consequently, by employing our present scheme, the secure transmission distance can be longer than 100 km under current experimental conditions, significantly surpassing present device-independent QKD systems.