title: Phase-Reference-Free Experiment of Measurement-Device-Independent Quantum Key Distribution.
abstract: Measurement-device-independent quantum key distribution (MDI QKD) is a substantial step toward practical information-theoretic security for key sharing between remote legitimate users (Alice and Bob). As with other standard device-dependent quantum key distribution protocols, such as BB84, MDI QKD assumes that the reference frames have been shared between Alice and Bob. In practice, a nontrivial alignment procedure is often necessary, which requires system resources and may significantly reduce the secure key generation rate. Here, we propose a phase-coding reference-frame-independent MDI QKD scheme that requires no phase alignment between the interferometers of two distant legitimate parties. As a demonstration, a proof-of-principle experiment using Faraday-Michelson interferometers is presented. The experimental system worked at 1 MHz, and an average secure key rate of 8.309 bps was obtained at a fiber length of 20 km between Alice and Bob. The system can maintain a positive key generation rate without phase compensation under normal conditions. The results exhibit the feasibility of our system for use in mature MDI QKD devices and its value for network scenarios.
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Xiao-Tian
authors.initials: XT
authors.lastname: Song
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Zhen-Qiang
authors.initials: ZQ
authors.lastname: Yin
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Guang-Can
authors.initials: GC
authors.lastname: Guo
authors.affiliation: Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Zheng-Fu
authors.initials: ZF
authors.lastname: Han