title: Measurement-Device-Independent Quantum Key Distribution Over a 404 km Optical Fiber.
abstract: Measurement-device-independent quantum key distribution (MDIQKD) with the decoy-state method negates security threats of both the imperfect single-photon source and detection losses. Lengthening the distance and improving the key rate of quantum key distribution (QKD) are vital issues in practical applications of QKD. Herein, we report the results of MDIQKD over 404 km of ultralow-loss optical fiber and 311 km of a standard optical fiber while employing an optimized four-intensity decoy-state method. This record-breaking implementation of the MDIQKD method not only provides a new distance record for both MDIQKD and all types of QKD systems but also, more significantly, achieves a distance that the traditional Bennett-Brassard 1984 QKD would not be able to achieve with the same detection devices even with ideal single-photon sources. This work represents a significant step toward proving and developing feasible long-distance QKD.
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Hua-Lei
authors.initials: HL
authors.lastname: Yin
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Teng-Yun
authors.initials: TY
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.|Data Communication Science and Technology Research Institute, Beijing 100191, China.
authors.forename: Zong-Wen
authors.initials: ZW
authors.lastname: Yu
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
authors.forename: Li-Xing
authors.initials: LX
authors.lastname: You
authors.affiliation: CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
authors.forename: Yi-Heng
authors.initials: YH
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
authors.forename: Si-Jing
authors.initials: SJ
authors.lastname: Chen
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Yingqiu
authors.initials: Y
authors.lastname: Mao
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Ming-Qi
authors.initials: MQ
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Zhang
authors.affiliation: Corning Incorporated, Corning, New York 14831, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Corning Incorporated, Corning, New York 14831, USA.
authors.forename: Ming Jun
authors.initials: MJ
authors.lastname: Li
authors.affiliation: Corning Incorporated, Corning, New York 14831, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Nolan
authors.affiliation: Jinan Institute of Quantum Technology, Jinan, Shandong 250101, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Zhou
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Jinan Institute of Quantum Technology, Jinan, Shandong 250101, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.|Jinan Institute of Quantum Technology, Jinan, Shandong 250101, China.
authors.forename: Xiang-Bin
authors.initials: XB
authors.lastname: Wang
authors.affiliation: National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Pan