自由空间量子密钥分布系统是全球性量子保密通信的关键组成部分之一。因此研究湍流大气信道对量子密钥分布系统性能的影响就非常重要。使用光束近场传播和统计分析的方法定量分析了湍流大气信道对基于BB84协议的自由空间量子密钥分布系统的误码率的影响。数值计算结果表明, 大气衰减系数超过-3 dB/km时, 大气衰减对量子密钥分布系统的误码率影响很大; 在大气传输因子小于0.5的区域, 系统误码率比无湍流影响时的系统误码率高出一个数量级。

Free-space quantum key distribution (QKD) system is one of the key parts of global quantum secure communications. So it is important to analyze the effect of turbulent atmosphere channel on quantum key distribution systems. The effect of turbulent atmosphere channel on quantum bit error rate (QBER) of a free-space QKD system based on BB84 protocol is described quantatively by near-field beam propagation theory and statistical method. The results indicate that, when the atmospheric attenuation coefficient is below -3 dB/km, it has a severe influence on the QBER of a free-space QKD system; and that in the area where atmospheric propagation factor coefficient is less than 0.5, QBER of system is ten times of that of the system operating without turbulence.