Free-Space and Fiber-Integrated Measurement-Device-Independent Quantum Key Distribution under High Background Noise
Yu-Huai Li, Shuang-Lin Li, Xiao‐Long Hu, Cong Jiang, Zong‐Wen Yu, Wei Li, Wei-Yue Liu, Sheng‐Kai Liao, Ji-Gang Ren, Hao Li, Lixing You, Zhen Wang, Juan Yin, Feihu Xu, Qiang Zhang, Xiang‐Bin Wang, Yuan Cao, Cheng-Zhi Peng, Jian-Wei Pan
Abstract
Measurement-device-independent quantum key distribution (MDI QKD) provides immunity against all attacks targeting measurement devices. It is essential to implement MDI QKD in the future global-scale quantum communication network. Toward this goal, we demonstrate a robust MDI QKD fully covering daytime, overcoming the high background noise that prevents BB84 protocol even when using a perfect single-photon source. Based on this, we establish a hybrid quantum communication network that integrates free-space and fiber channels through Hong-Ou-Mandle (HOM) interference. Additionally, we investigate the feasibility of implementing HOM interference with moving satellites. Our results serve as a significant cornerstone for future integrated space-ground quantum communication networks that incorporate measurement-device-independent security.