为了提高测量设备无关量子密钥分发(MDI-QKD)系统的整体性能,利用修正相干态光 源(MCS)可以优化光子数分布率的性质,设计了一种基于MCS的MDI-QKD系统。基于全局估计的 计算方法推导了密钥生成率与传输距离的关系,保证了在密性放大计算过程中单光子信息的充 分利用,得到较为精确的密钥率下限值。通过仿真分析将所提出的系统与基于预报单光子源(HSPS)的 MDI-QKD系统性能进行对比,结果表明MCS光源比HSPS光源的传输距离提高了9%,有效改善了系统性能。

In order to improve the overall performance of measurement-device-independent quantum key distribution (MDI-QKD), the properties of photon number distribution can be optimized by using the modified coherent source (MCS), and a MDI-QKD system is designed based on MCS. The relationship between key generation rate and transmission distance is derived based on calculation method of global estimation. The full use of single photon information during privacy amplification calculation stage is ensured, and the more accurate lower limit value of key rate is obtained. The performances of proposed system and MDI-QKD system based on heralded single photon source (HSPS) are compared by simulation analysis. Results show that the transmission distance of MCS light source is increased by 9% than that of HSPS light source, and the system performance is improved effectively.