Liu Hui, Wang Wenyuan, Wei Kejin, Fang Xiao-Tian, Li Li, Liu Nai-Le, Liang Hao, Zhang Si-Jie, Zhang Weijun, Li Hao, You Lixing, Wang Zhen, Lo Hoi-Kwong, Chen Teng-Yun, Xu Feihu, Pan Jian-Wei
Shanghai Branch, Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China.
CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China.
Phys Rev Lett. 2019 Apr 26;122(16):160501. doi: 10.1103/PhysRevLett.122.160501.
Measurement-device-independent quantum key distribution (MDI-QKD) can eliminate all detector side channels and it is practical with current technology. Previous implementations of MDI-QKD all used two symmetric channels with similar losses. However, the secret key rate is severely limited when different channels have different losses. Here we report the results of the first high-rate MDI-QKD experiment over asymmetric channels. By using the recent 7-intensity optimization approach, we demonstrate>10×higher key rate than the previous best-known protocols for MDI-QKD in the situation of large channel asymmetry, and extend the secure transmission distance by more than 20-50 km in standard telecom fiber. The results have moved MDI-QKD towards widespread applications in practical network settings, where the channel losses are asymmetric and user nodes could be dynamically added or deleted.
测量设备无关量子密钥分发（MDI-QKD）可以消除所有探测器侧信道，并且在当前技术下具有实用性。MDI-QKD以前的实现都使用了两个具有相似损耗的对称信道。然而，当不同信道具有不同损耗时，密钥率会受到严重限制。在此，我们报告了首个在非对称信道上进行的高速MDI-QKD实验结果。通过使用最近的7强度优化方法，我们证明在大信道不对称情况下，密钥率比之前MDI-QKD最知名协议高出10倍以上，并在标准电信光纤中将安全传输距离延长了20至50多公里。这些结果使MDI-QKD朝着在实际网络环境中的广泛应用迈进，在这种环境中，信道损耗是不对称的，并且用户节点可以动态添加或删除。
