用于BB84相位编码量子密钥分发系统的不间断式主动相位补偿方案

Uninterrupted active phase compensation scheme for BB84 phase encoding quantum key distribution system

提出一种新的不间断的主动相位补偿方案,在进行量子密钥分发的同时统计不匹配基量子比特在干涉仪不同输出端口上的随机计数分布,给出了由不匹配基量子比特统计数值计算相位漂移参数的计算公式,并由统计数值计算得到相位漂移参数。结果表明:该方案允许系统并行处理量子密钥分发与相位补偿,也充分利用了在原BB84协议中会被丢弃的不匹配基量子比特信息。

BB84 phase encoding quantum key distribution systems can distribute shared secret keys between remote commu nication parties via optic fiber channel with provable security. However, performance of these systems usually suffers from the phase shift in realistic running environment. The existing active phase compensation schemes for these systems have to break the key distribution process to measure phase drift parameters, leading to decrease the final key generation rate of system. A new un~ interrupted scheme is proposed to address this problem. The proposed scheme allows the system to run phase compensation process and key distribution process simultaneously by collecting and analyzing the quantum bits with incompatible basis during the quantum key distribution process, which is supposed to be discarded in the classical BB84 quantum key distribution protocol. The bit value carried by the quantum bits with incompatible basis is used in the proposed scheme to calculate the phase shift parameters with the statistic of the random distribution of these bits on the different port of the interferometer.