title: Decoy-state quantum key distribution with polarized photons over 200 km.
abstract: We report an implementation of decoy-state quantum key distribution (QKD) over 200 km optical fiber cable through photon polarization encoding. This is achieved by constructing the whole QKD system operating at 320 MHz repetition rate, and developing high-speed transmitter and receiver modules. A novel and economic way of synchronization method is designed and incorporated into the system, which allows to work at a low frequency of 40kHz and removes the use of highly precise clock. A final key rate of 15 Hz is distributed within the experimental time of 3089 seconds, by using super-conducting single photon detectors. This is longest decoy-state QKD yet demonstrated up to date. It helps to make a significant step towards practical secure communication in long-distance scope.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Teng-Yun
authors.initials: TY
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Wen-Qi
authors.initials: WQ
authors.lastname: Cai
authors.forename: Xu
authors.initials: X
authors.lastname: Wan
authors.forename: Luo-Kan
authors.initials: LK
authors.lastname: Chen
authors.forename: Jin-Hong
authors.initials: JH
authors.lastname: Wang
authors.forename: Shu-Bin
authors.initials: SB
authors.lastname: Liu
authors.forename: Hao
authors.initials: H
authors.lastname: Liang
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Cheng-Zhi
authors.initials: CZ
authors.lastname: Peng
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.forename: Zeng-Bing
authors.initials: ZB
authors.lastname: Chen
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Pan