Namekata N, Takesue H, Honjo T, Tokura Y, Inoue S
Institute of Quantum Science, Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308, Japan.
Opt Express. 2011 May 23;19(11):10632-9. doi: 10.1364/OE.19.010632.
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.
我们已经基于InGaAs/InP雪崩光电二极管（APD）的单光子探测器，实现了超过100公里的量子密钥分发（QKD）。我们采用电制冷且2千兆赫兹正弦门控的APD实现了差分相移QKD（DPS-QKD）协议。该单光子探测器的暗计数概率为2.8×10^(-8)（每秒55次计数），探测效率为6%，这使我们能够在100公里长的光纤上实现24千比特/秒的安全密钥率。与使用超导单光子探测器所取得的成果相比，DPS-QKD系统以更实用的方式展现出更好的性能。此外，针对一般个体攻击可分发安全密钥的距离已扩展至160公里。
