50km无特征源的测量设备无关量子密钥分发实验

Uncharacterized-Source Measurement-Device-Independent Quantum Key Distribution Experiment with Over 50 km Fiber

测量设备无关量子密钥分发协议可以免疫所有测量端的漏洞,极大地推进量子保密通信的实用化进程。美中不足的是,该协议依然对源端有极强的安全性假设。源端设备的非完美性同样会留下多种侧信道,从而威胁系统的实际安全性。针对此问题,提出无特征源测量设备无关量子密钥分发协议。该协议在量子态制备不完美的情况下依然可以提取出安全的密钥,是理论无条件安全性与实际安全性的完美结合。通过三强度诱骗态方法以及自行研制的Sagnac-Asymmetric-Mach-Zehnder编码结构,成功搭建无特征源的测量设备无关量子密钥分发系统,并在长为50.4 km的光纤信道和25 MHz的系统重复频率下达到1.91×10^(-6)的安全密钥分发速率。

The measurement-device-independent quantum key distribution(MDI-QKD)can remove all detector side-channel attacks,which greatly boosts the practical application of the quantum key distribution.However,this protocol still has a strict assumption that the states in source side must be perfectly prepared.The imperfections of the modulators in source side would bring side-channels and threaten the practical security of the system.To protect against state-preparation imperfections,the uncharacterized-source MDI-QKD,which can still generate secret keys when the prepared states are uncharacterized,have been put forward.This protocol is a great combination of the theoretical information security and the practical security.Through the three-intensity decoy state method and the self-developed Sagnac-Asymmetric-Mach-Zehnder coding structure,the measurement device-independent quantum key distribution system without characteristic source is successfully built,and the secure key distribution rate of 1.91×10;is achieved under the fiber channel of 50.4 km and the repetition rate of 25 MHz.