We propose a quantum-classical access network architecture based on multicore fiber to scale up the number of quantum key distribution (QKD) users. Quantum signals are integrated with classical signals in both feeder and drop fibers to save deployment cost since access networks are cost-sensitive. To increase the secure key rate (SKR) of QKD, we show that wavelength-time division multiplexing is suitable for quantum signals, which are required to support a large number of quantum users. Also, we propose a core and wavelength assignment scheme to alleviate spontaneous Raman scattering and intercore cross talk noise, which are the main impairment sources to QKD in this quantum-classical network. Finally, we experimentally show the performance of QKD in the proposed quantum-classical access network in terms of noise and channel loss. The experiment results are consistent with our analysis. The characteristics of the SKRs prove the superiority of wavelength-time division multiplexing. The properties of spontaneous Raman scattering in the feeder and drop fibers are shown in the experiments through the quantum bit error rates in different experimental conditions, which verifies the effectiveness of the proposed core and wavelength assignment scheme.

中文翻译：

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量子信号波分时分多路复用的基于多核光纤的量子经典接入网架构

我们提出了一种基于多核光纤的量子经典访问网络体系结构，以扩大量子密钥分发（QKD）用户的数量。由于接入网对成本敏感，因此在馈线和引入光纤中都将量子信号与经典信号集成在一起，以节省部署成本。为了提高QKD的安全密钥率（SKR），我们证明了波长时分复用适用于支持大量量子用户的量子信号。此外，我们提出了一种核心和波长分配方案，以缓解自发拉曼散射和核心间串扰噪声，这是该量子古典网络中QKD的主要损害源。最后，我们从噪声和信道损耗方面实验性地证明了所提出的量子经典接入网中QKD的性能。实验结果与我们的分析一致。SKR的特性证明了波分时分复用的优越性。通过在不同实验条件下的量子比特误码率实验，表明了馈线和分支光纤中自发拉曼散射的特性，这验证了所提出的纤芯和波长分配方案的有效性。