Wang Chao, Song Xiao-Tian, Yin Zhen-Qiang, Wang Shuang, Chen Wei, Zhang Chun-Mei, Guo Guang-Can, Han Zheng-Fu
Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Phys Rev Lett. 2015 Oct 16;115(16):160502. doi: 10.1103/PhysRevLett.115.160502. Epub 2015 Oct 15.
Measurement-device-independent quantum key distribution (MDI QKD) is a substantial step toward practical information-theoretic security for key sharing between remote legitimate users (Alice and Bob). As with other standard device-dependent quantum key distribution protocols, such as BB84, MDI QKD assumes that the reference frames have been shared between Alice and Bob. In practice, a nontrivial alignment procedure is often necessary, which requires system resources and may significantly reduce the secure key generation rate. Here, we propose a phase-coding reference-frame-independent MDI QKD scheme that requires no phase alignment between the interferometers of two distant legitimate parties. As a demonstration, a proof-of-principle experiment using Faraday-Michelson interferometers is presented. The experimental system worked at 1 MHz, and an average secure key rate of 8.309 bps was obtained at a fiber length of 20 km between Alice and Bob. The system can maintain a positive key generation rate without phase compensation under normal conditions. The results exhibit the feasibility of our system for use in mature MDI QKD devices and its value for network scenarios.
测量设备无关量子密钥分发（MDI QKD）是朝着实现远程合法用户（爱丽丝和鲍勃）之间密钥共享的实用信息理论安全性迈出的重要一步。与其他标准的设备相关量子密钥分发协议（如BB84）一样，MDI QKD假定爱丽丝和鲍勃之间已经共享了参考系。在实际应用中，通常需要一个复杂的对准过程，这需要系统资源，并且可能会显著降低安全密钥生成率。在此，我们提出一种相位编码的参考系无关MDI QKD方案，该方案不需要两个遥远合法方的干涉仪之间进行相位对准。作为演示，展示了一个使用法拉第 - 迈克尔逊干涉仪的原理验证实验。实验系统工作频率为1 MHz，在爱丽丝和鲍勃之间光纤长度为20 km时，获得了平均8.309 bps的安全密钥率。该系统在正常条件下无需相位补偿就能保持正的密钥生成率。结果表明了我们的系统用于成熟MDI QKD设备的可行性及其在网络场景中的价值。
