Mao Yingqiu, Wang Bi-Xiao, Zhao Chunxu, Wang Guangquan, Wang Ruichun, Wang Honghai, Zhou Fei, Nie Jimin, Chen Qing, Zhao Yong, Zhang Qiang, Zhang Jun, Chen Teng-Yun, Pan Jian-Wei
Opt Express. 2018 Mar 5;26(5):6010-6020. doi: 10.1364/OE.26.006010.
Quantum key distribution (QKD) provides information-theoretic security based on the laws of quantum mechanics. The desire to reduce costs and increase robustness in real-world applications has motivated the study of coexistence between QKD and intense classical data traffic in a single fiber. Previous works on coexistence in metropolitan areas have used wavelength-division multiplexing, however, coexistence in backbone fiber networks remains a great experimental challenge, as Tbps data of up to 20 dBm optical power is transferred, and much more noise is generated for QKD. Here we present for the first time, to the best of our knowledge, the integration of QKD with a commercial backbone network of 3.6 Tbps classical data at 21 dBm launch power over 66 km fiber. With 20 GHz pass-band filtering and large effective core area fibers, real-time secure key rates can reach 4.5 kbps and 5.1 kbps for co-propagation and counter-propagation at the maximum launch power, respectively. This demonstrates feasibility and represents an important step towards building a quantum network that coexists with the current backbone fiber infrastructure of classical communications.
量子密钥分发（QKD）基于量子力学定律提供信息理论安全性。在实际应用中降低成本并提高鲁棒性的需求推动了对QKD与单根光纤中密集经典数据流量共存的研究。先前关于城域共存的工作使用了波分复用，然而，骨干光纤网络中的共存仍然是一个巨大的实验挑战，因为要传输高达20 dBm光功率的Tbps数据，并且会为QKD产生更多噪声。据我们所知，在此我们首次展示了QKD与一个商业骨干网络的集成，该骨干网络在66公里光纤上以21 dBm发射功率传输3.6 Tbps的经典数据。通过20 GHz通带滤波和大有效纤芯面积光纤，在最大发射功率下，同向传播和反向传播的实时安全密钥率分别可达4.5 kbps和5.1 kbps。这证明了可行性，并代表着朝着构建一个与当前经典通信骨干光纤基础设施共存的量子网络迈出了重要一步。
