量子密钥分配在实际应用中会受到有限探测器死时间的影响,当信号脉冲发送速率过大时,探测器测量失败的概率增加,安全密钥生成速率降低。对标记配对相干态光源下测量设备无关量子密钥分配的有限探测器死时间问题进行了分析。研究并仿真了安全密钥生成速率与信号发送速率的关系。考虑探测器死时间时,基于标记配对相干态光源的测量设备无关量子密钥分配协议的安全密钥生成速率比基于弱相干光源的测量设备无关量子密钥分配协议的安全密钥生成速率高。分析了有限探测器死时间τ分别为50,100,150 ns时安全密钥生成速率的情况。结果表明,有限探测器死时间越大,安全密钥生成速率的极限值越低。安全密钥生成速率的极限与有限探测器死时间的关系为8.1×10 3/τ。

In its practical applications, quantum key distribution is affected by the finite detector dead time. When the signal pulse transmission rate is too large, the probability of detector's measurement failure increases and the security key generation rate decreases. In this paper, the finite detector dead time problem is analyzed for measurement-device-independent quantum key distribution under the heralded pair coherent state photon source. The relationship between the security key generation rate and the signal transmission rate is studied and simulated. Considering the detector's dead time, the secure key generation rate of the measurement-device-independent quantum key distribution protocol based on the heralded pair coherent state photon source is higher than that of the measurement-device-independent quantum key distribution protocol based on the weak coherent state photon source. In addition, the security key generation rates are analyzed with the respective finite detector's dead time τ of 50, 100, and 150 ns. The results show that the higher the detector's dead time is, the lower the limit value of the security key generation rate is. The relation between the limit value of the security key generation rate and the finite detector's dead time is 8.1×10 ³/τ.