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arXiv · 2308.14385

A cost-efficient quantum access network with qubit-based synchronization

Chunfeng Huang·Ye Chen·Tingting Luo·Wenjie He·Xin Liu·Zhenrong Zhang·Kejin Wei
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Abstract

Quantum Key Distribution (QKD) is a physical layer encryption technique that enables two distant parties to exchange secure keys with information-theoretic security. In the last two decades, QKD has transitioned from laboratory research to real-world applications, including multi-user quantum access networks (QANs). This network structure allows users to share a single-photon detector at a network node through time-division multiplexing, thereby significantly reducing the network cost. However, current QAN implementations require additional hardware for auxiliary tasks such as time synchronization. To address this issue, we propose a cost-efficient QAN that uses qubit-based synchronization. In this approach, the transmitted qubits facilitate time synchronization, eliminating the need for additional synchronization hardware. We tested our scheme by implementing a network for two users and successfully achieved average secure key rates of $53.84$ kbps and $71.90$ kbps for each user over a 50-km commercial fiber spool. In addition, we investigated the capacity of the access network under cross-talk and loss conditions. The simulation results demonstrate that this scheme can support a QAN with 64 users with key rates up to 1070~bps. Our work provides a feasible and cost-effective way to implement a multi-user QKD network, further promoting the widespread application of QKD.

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Chunfeng Huang, Ye Chen, Tingting Luo, Wenjie He, Xin Liu, Zhenrong Zhang, Kejin Wei. 2023-08-28. A cost-efficient quantum access network with qubit-based synchronization. https://doi.org/10.1007/s11433-023-2302-8

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