Experimental Demonstration of High-Rate Measurement-Device-Independent Quantum Key Distribution over Asymmetric Channels

Hui Liu; Wenyuan Wang; Kejin Wei; Xiao-Tian Fang; Li Li; Nai-Le Liu; Hao Liang; Si-Jie Zhang; Weijun Zhang; Hao Li; Lixing You; Zhen Wang; Hoi-Kwong Lo; Teng-Yun Chen; Feihu Xu; Jian-Wei Pan

doi:10.1103/PhysRevLett.122.160501

Experimental Demonstration of High-Rate Measurement-Device-Independent Quantum Key Distribution over Asymmetric Channels

Phys Rev Lett. 2019 Apr 26;122(16):160501. doi: 10.1103/PhysRevLett.122.160501.

Authors

Hui Liu^{1

2}, Wenyuan Wang³, Kejin Wei^{1

2}, Xiao-Tian Fang^{1

2}, Li Li^{1

2}, Nai-Le Liu^{1

2}, Hao Liang^{1

2}, Si-Jie Zhang^{1

2}, Weijun Zhang⁴, Hao Li⁴, Lixing You⁴, Zhen Wang⁴, Hoi-Kwong Lo³, Teng-Yun Chen^{1

2}, Feihu Xu^{1

2}, Jian-Wei Pan^{1

2}

Affiliations

¹ Shanghai Branch, Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China.
² CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China.
³ Centre for Quantum Information and Quantum Control (CQIQC), Department of Electrical & Computer Engineering and Department of Physics, University of Toronto, Toronto, Ontario M5S 3G4, Canada.
⁴ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.

PMID: 31075015
DOI: 10.1103/PhysRevLett.122.160501

Abstract

Measurement-device-independent quantum key distribution (MDI-QKD) can eliminate all detector side channels and it is practical with current technology. Previous implementations of MDI-QKD all used two symmetric channels with similar losses. However, the secret key rate is severely limited when different channels have different losses. Here we report the results of the first high-rate MDI-QKD experiment over asymmetric channels. By using the recent 7-intensity optimization approach, we demonstrate>10×higher key rate than the previous best-known protocols for MDI-QKD in the situation of large channel asymmetry, and extend the secure transmission distance by more than 20-50 km in standard telecom fiber. The results have moved MDI-QKD towards widespread applications in practical network settings, where the channel losses are asymmetric and user nodes could be dynamically added or deleted.