AI 中文总结
研究利用多平面光转换实现少模光纤的空分复用量子密钥分发，通过单独单模光纤选择性激发模式，经MPLC分离到不同端口，演示了空间复用BBM92 QKD方案，给出复用链路量子误码率，为相关量子网络架构提供支持。
AI 中文摘要
随着量子密钥分发（QKD）从实验室演示向实际部署发展，量子通信网络越来越需要更高的密钥率以及在多个用户和网络节点之间分发独立密钥的能力。本文提出一种利用多平面光转换（MPLC）对通过少模光纤（FMF）传输的纠缠光子进行解复用的有前景的方法。我们通过实验演示了一种空间复用的BBM92 QKD方案。模式通过单独的单模光纤被选择性激发，随后通过MPLC分离到不同的输出端口。与基于相干模式叠加的高维QKD不同，我们的方法利用可区分的导模作为并行通道，同时保留QKD所需的纠缠。对于复用链路，通道1的量子误码率为$1.9 \pm 0.4\%$，通道2为$6.8 \pm 0.8\%$。这些结果与可扩展量子安全网络、空分复用QKD系统、多用户纠缠分发以及未来量子互联网架构相关，在这些架构中必须实现并行量子通道而不损害安全所需的量子相关性。
英文摘要
As quantum key distribution (QKD) progresses from laboratory demonstrations toward practical deployment, quantum communi- cation networks increasingly require higher key rates and the ability to distribute independent secret keys among multiple users and network nodes. In this paper we present a promsing approach with multi-plane light conversion (MPLC) for demultiplexing entangled photons, transmitted through a few-mode fiber (FMF). We experimentally demonstrated a spatially multiplexed BBM92 QKD scheme. The modes are selectively excited through separate single-mode-fibers and subsequently separated by MPLC into distinct output ports. Unlike high-dimensional QKD based on coherent modal superpositions, our approach exploits distinguishable guided modes as parallel channels while preserving the entanglement required for QKD. For the multiplexed links, we obtain quantum bit error rates of $1.9 \pm 0.4\%$ for the channel 1 and $6.8 \pm 0.8\%$ for the channel 2. These results are relevant for scalable quantum-secured networks, space-division-multiplexed QKD systems, multi-user entanglement distribution, and future quantum internet architectures, where parallel quantum channels must be implemented without compromising the quantum correlations required for security.
