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Nature Photonics

Long-distance free-space quantum key distribution in daylight towards inter-satellite communication

Sheng‐Kai Liao, Hai-Lin Yong, Chang Liu, Guo-Liang Shentu, Dongdong Li, Jin Lin, Hui Dai, Shuang-Qiang Zhao, Bo Li, Jian-Yu Guan, Wei Chen, Yun-Hong Gong, Yang Li, Ze-Hong Lin, Ge-Sheng Pan, Jason S. Pelc, M. M. Fejer, Wenzhuo Zhang, Wei-Yue Liu, Juan Yin, Ji-Gang Ren, Xiang‐Bin Wang, Qiang Zhang, Cheng-Zhi Peng, Jian-Wei Pan

Published Jul 24, 2017• 475 citations
Publisher
DOI
10.1038/nphoton.2017.116

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The future global-scale quantum communication network will require free-space and satellite links able to work in daylight conditions and compatible with the telecom fiber infrastructure. Here we present a full prototype for daylight quantum key distribution at 1550 nm exploiting an integrated silicon-photonics chip as state encoder. We tested our prototype in the urban area of Padua (Italy) over a 145m-long free-space link, obtaining a quantum bit error rate around 0.5% and an averaged secret key rate of 30 kbps. The developed chip represents a cost-effective solution for portable free-space transmitters and a promising resource for future satellite missions.
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