Practical gigahertz quantum key distribution robust against channel disturbance
Shuang Wang, Wei Chen, Zhen−Qiang Yin, De‐Yong He, Cong Hui, Peng-Lei Hao, Guan‐Jie Fan‐Yuan, Chao Wang, Lijun Zhang, Jie Kuang, Shufeng Liu, Zheng Zhou, Yonggang Wang, Guang‐Can Guo, Zheng‐Fu Han · Optics Letters · 2018
Quantum key distribution (QKD) provides an attractive solution for secure communication. However, channel disturbance severely limits its application when a QKD system is transferred from the laboratory to the field. Here a high-speed Faraday-Sagnac-Michelson QKD system is proposed that can automatically compensate for the channel polarization disturbance, which largely avoids the intermittency limitations of environment mutation. Over a 50 km fiber channel with 30 Hz polarization scrambling, the practicality of this phase-coding QKD system was characterized with an interference fringe visibility of 99.35% over 24 h and a stable secure key rate of 306 k bits/s over seven days without active polarization alignment.