title: 25 MHz clock continuous-variable quantum key distribution system over 50 km fiber channel.
abstract: In this paper, a practical continuous-variable quantum key distribution system is developed and it runs in the real-world conditions with 25 MHz clock rate. To reach high-rate, we have employed a homodyne detector with maximal bandwidth to 300 MHz and an optimal high-efficiency error reconciliation algorithm with processing speed up to 25 Mbps. To optimize the stability of the system, several key techniques are developed, which include a novel phase compensation algorithm, a polarization feedback algorithm, and related stability method on the modulators. Practically, our system is tested for more than 12 hours with a final secret key rate of 52 kbps over 50 km transmission distance, which is the highest rate so far in such distance. Our system may pave the road for practical broadband secure quantum communication with continuous variables in the commercial conditions.
authors.affiliation: State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Key Laboratory on Navigation and Location-based Service, and Center of Quantum Information Sensing and Processing, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Key Laboratory on Navigation and Location-based Service, and Center of Quantum Information Sensing and Processing, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Duan
authors.initials: D
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Key Laboratory on Navigation and Location-based Service, and Center of Quantum Information Sensing and Processing, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Key Laboratory on Navigation and Location-based Service, and Center of Quantum Information Sensing and Processing, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Dakai
authors.initials: D
authors.lastname: Lin
authors.affiliation: College of Information Science and Technology, Northwest University, Xi'an 710127, Shanxi, China.
authors.forename: Jinye
authors.initials: J
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Key Laboratory on Navigation and Location-based Service, and Center of Quantum Information Sensing and Processing, Shanghai Jiao Tong University, Shanghai 200240, China.|College of Information Science and Technology, Northwest University, Xi'an 710127, Shanxi, China.
authors.forename: Guihua
authors.initials: G
authors.lastname: Zeng