Advanced Photonics, Volume. 7, Issue 6, (2025)

High-rate quantum networks with energy-time entanglement [Early Posting]

Fan Yun-Ru, Zeng Hong, Du Xi-Xian, Guo Kai, Wang Xiaolin, Luo Yue, Wang You, Song Haizhi, Li Hao, You Lixing, Guo Guangcan, Zhou Qiang
Author Affiliations
  • China
  • National University of Defense Technology
  • Southwest Institute of Technical Physics
  • Shanghai Institute of Microsystem and Information Technology
  • Chinese Acad Sci
  • University of Electronic Science and Technology of China
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    Quantum entanglement networks have garnered significant attention due to the inherent security provided by quantum physics. The networks aim to connect a multitude of users with a high secure key rate (SKR). Fully connected networks have been demonstrated using wavelength-division multiplexing architectures. However, the SKR of such networks remains challenging due to the limited brightness of quantum photon-pair sources and the loss introduced by cascaded filtering components. In this work, we present high-rate quantum entanglement networks that leverage a broadband quantum light source with high brightness and an industry-grade flexible wavelength-selective switching technique with uniform loss. By implementing the BBM92 protocol, we achieve a SKR of 28.19 kbps in a four-user network, representing a two-order-of-magnitude improvement over previous implementations. After transmission through a 40-km fiber spool, the SKR remains as high as 3.58 kbps and stays positive over distances up to 250 km. Furthermore, the flexibility of our scheme is illustrated by constructing a six-user network, achieving SKRs of 4.21 kbps and 0.45 kbps without and with a 40-km fiber spool, respectively. These results demonstrate a practical approach to enhancing the SKR and scalability in entanglement-based quantum networks, offering a feasible solution for deploying metropolitan and backbone quantum communication systems.

    Paper Information

    Manuscript Accepted: Jul. 21, 2025

    Posted: Aug. 29, 2025

    DOI: AP