title: High-rate quantum key distribution over 100 km using ultra-low-noise, 2-GHz sinusoidally gated InGaAs/InP avalanche photodiodes.
abstract: We have demonstrated quantum key distribution (QKD) over 100 km using single-photon detectors based on InGaAs/InP avalanche photodiodes (APDs). We implemented the differential phase shift QKD (DPS-QKD) protocol with electrically cooled and 2-GHz sinusoidally gated APDs. The single-photon detector has a dark count probability of 2.8 × 10(-8) (55 counts per second) with a detection efficiency of 6 %, which enabled us to achieve 24 kbit/s secure key rate over 100 km of optical fiber. The DPS-QKD system offers better performances in a practical way than those achieved using superconducting single-photon detectors. Moreover, the distance that secure keys against the general individual attacks can be distributed has been extended to 160 km.
authors.affiliation: Institute of Quantum Science, Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308, Japan. nnao@phys.cst.nihon-u.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Namekata
authors.forename: H
authors.initials: H
authors.lastname: Takesue
authors.forename: T
authors.initials: T
authors.lastname: Honjo
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura
authors.forename: S
authors.initials: S
authors.lastname: Inoue