Experimental Demonstration of Fully Passive Quantum Key Distribution

Feng-Yu Lu; Ze-Hao Wang; Víctor Zapatero; Jia-Lin Chen; Shuang Wang; Zhen-Qiang Yin; Marcos Curty; De-Yong He; Rong Wang; Wei Chen; Guan-Jie Fan-Yuan; Guang-Can Guo; Zheng-Fu Han

doi:10.1103/PhysRevLett.131.110802

Experimental Demonstration of Fully Passive Quantum Key Distribution

Phys Rev Lett. 2023 Sep 15;131(11):110802. doi: 10.1103/PhysRevLett.131.110802.

Authors

Feng-Yu Lu^{1

2}, Ze-Hao Wang^{1

2}, Víctor Zapatero^{3

4

5}, Jia-Lin Chen^{1

2}, Shuang Wang^{1

2

6}, Zhen-Qiang Yin^{1

2

6}, Marcos Curty^{3

4

5}, De-Yong He^{1

2

6}, Rong Wang⁷, Wei Chen^{1

2

6}, Guan-Jie Fan-Yuan^{1

2}, Guang-Can Guo^{1

2

6}, Zheng-Fu Han^{1

2

6}

Affiliations

¹ CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
² CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
³ Vigo Quantum Communication Center, University of Vigo, Vigo E-36310, Spain.
⁴ Escuela de Ingeniería de Telecomunicación, Department of Signal Theory and Communications, University of Vigo, Vigo E-36310, Spain.
⁵ AtlanTTic Research Center, University of Vigo, Vigo E-36310, Spain.
⁶ Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, People's Republic of China.
⁷ Department of Physics, University of Hong Kong, Hong Kong SAR, People's Republic of China.

PMID: 37774301
DOI: 10.1103/PhysRevLett.131.110802

Abstract

The passive approach to quantum key distribution (QKD) consists of removing all active modulation from the users' devices, a highly desirable countermeasure to get rid of modulator side channels. Nevertheless, active modulation has not been completely removed in QKD systems so far, due to both theoretical and practical limitations. In this Letter, we present a fully passive time-bin encoding QKD system and report on the successful implementation of a modulator-free QKD link. According to the latest theoretical analysis, our prototype is capable of delivering competitive secret key rates in the finite key regime.