Abstract
Passive-state-preparation (PSP) continuous-variable quantum key distribution (CVQKD) protocol explores the intrinsic field fluctuations of a thermal source. Compared with traditional Gaussian-modulated coherent-state CVQKD, it does not need active modulations and has promising applications in chip integration and portable free-space quantum key distribution. In this Letter, we propose and experimentally realize a PSP CVQKD scheme with transmitted local oscillator (LO) through fluctuating transmittance free-space channel using an off-the-shelf amplified spontaneous emission source for the first time. By proposing thermal-state polarization multiplexing transmitted LO, synchronized channel transmittance monitoring and fine-grained phase compensation techniques, secure keys within −15 dB transmittance of simulated free-space channel with turbulence are generated, with a final average secure key rate of 1.015 Mbps asymptotically. Equivalent atmospheric turbulence model analysis shows that the free-space PSP CVQKD scheme provides a promising outlook for high-speed and chip-based CVQKD for kilometer-level atmospheric channel networks.
© 2023 Optica Publishing Group
Full Article | PDF ArticleMore Like This
Xue-Tao Zheng, Qi-Fa Zhang, Jing-yu Han, Jie Ling, Guang-can Guo, and Zheng-Fu Han
Opt. Lett. 48(18) 4837-4840 (2023)
Shiyu Wang, Peng Huang, Tao Wang, and Guihua Zeng
Opt. Lett. 45(21) 5921-5924 (2020)
Xiangyu Wang, Ziyang Chen, Zhenghua Li, Dengke Qi, Song Yu, and Hong Guo
Opt. Lett. 48(12) 3327-3330 (2023)