Wang Bi-Xiao, Mao Yingqiu, Shen Lei, Zhang Lei, Lan Xiao-Bo, Ge Dawei, Gao Yuyang, Li Juhao, Tang Yan-Lin, Tang Shi-Biao, Zhang Jun, Chen Teng-Yun, Pan Jian-Wei
Opt Express. 2020 Apr 27;28(9):12558-12565. doi: 10.1364/OE.388857.
Quantum key distribution (QKD) is one of the most practical applications in quantum information processing, which can generate information-theoretical secure keys between remote parties. With the help of the wavelength-division multiplexing technique, QKD has been integrated with the classical optical communication networks. The wavelength-division multiplexing can be further improved by the mode-wavelength dual multiplexing technique with few-mode fiber (FMF), which has additional modal isolation and large effective core area of mode, and particularly is practical in fabrication and splicing technology compared with the multi-core fiber. Here, we present for the first time a QKD implementation coexisting with classical optical communication over weakly-coupled FMF using all-fiber mode-selective couplers. The co-propagation of QKD with one 100 Gbps classical data channel at -2.60 dBm launched power is achieved over 86 km FMF with 1.3 kbps real-time secure key generation. Compared with single-mode fiber using wavelength-division multiplexing, given the same fiber-input power, the Raman noise in FMF using the mode-wavelength dual multiplexing is reduced by 86% in average. Our work implements an important approach to the integration between QKD and classical optical communication and previews the compatibility of quantum communications with the next-generation mode division multiplexing networks.
量子密钥分发（QKD）是量子信息处理中最实际的应用之一，它能够在远程用户之间生成信息理论上安全的密钥。借助波分复用技术，QKD已与经典光通信网络集成。采用少模光纤（FMF）的模-波长双复用技术可进一步改进波分复用，该技术具有额外的模式隔离和较大的模式有效纤芯面积，与多芯光纤相比，在制造和熔接技术方面尤其实用。在此，我们首次展示了一种使用全光纤模式选择耦合器，在弱耦合FMF上与经典光通信共存的QKD实现方案。在86公里的FMF上，实现了QKD与一个发射功率为-2.60 dBm的100 Gbps经典数据通道的同向传播，并实时生成了1.3 kbps的安全密钥。与使用波分复用的单模光纤相比，在相同的光纤输入功率下，采用模-波长双复用的FMF中的拉曼噪声平均降低了86%。我们的工作实现了QKD与经典光通信集成的一种重要方法，并展望了量子通信与下一代模式分割复用网络的兼容性。
