针对基于弱相干光源(WCS)和轨道角动量(OAM)的测量设备无关量子密钥分配(MDI-QKD)协议的密钥生成率较低的问题,研究了基于奇相干光源(OCS)和OAM的MDI-QKD协议,并对其性能参数进行了分析。分析了密钥生成率、探测器的品质因子与安全传输距离之间的关系,并对比了基于OCS和OAM的MDI-QKD协议与基于WCS和OAM的MDI-QKD协议的性能优劣。仿真结果表明,随着安全传输距离的增大,密钥生成率减小。采用OCS大大减少了多光子脉冲数,弥补了WCS的不足,而采用OAM解决了基的依赖性缺陷问题,从而增大了最大安全传输的距离,该研究为实用的量子密钥分配协议提供了重要的理论参考。

In view of the problem of the low key generation rate for the measurement device independent quantum key distribution (MDI-QKD) protocol based on weak coherent sources (WCS) and orbital angular momentum (OAM), the MDI-QKD protocol based on odd coherent sources (OCS) and OAM is investigated, and its performance and parameters are analyzed. The relationships between key generation rate, quality factor of detector and secure transmission distance are investigated. The performance comparison between the MDI-QKD protocol based on OCS and OAM and the MDI-QKD protocol based on WCS and OAM is compared. The simulation results show that the key generation rate decreases with the increase of secure transmission distance. The adoption of OCS makes up the deficiency of WCS and reduces the photon number greatly, while the adoption of OAM can solve the problem of the dependence defect of the base and increase the maximum secure transmission distance, which provides an important theoretical reference for the practical quantum key distribution protocol.