实用被动调制量子密钥分发系统中分束器存在波长依赖性,窃听者据此攻击分束器,以获取密钥信息并且不被发现,而且光纤中存在瑞利散射导致误码率增大。文中提出波分复用器方案来保障量子密钥分发的安全性,并且通过双波长交叉传递来降低误码率。方案中借助于波分复用器将不同波长的光子进行分离,只对部分波长的光子进行偏振测量,Alice和Bob可以通过公共信道分析误码率和收益,得出是否存在窃听者。

In the practical Quantum Key Distribution (QKD) systems,the beam splitter which made by the Fused Biconical Taper (FTP) technology has wavelength dependent property. So Eve will get almost all of the secret information without being discovered in this way. In this paper,we proposed a solution for beating the beam splitter attack. Quantum Bit Error Rate (QBER) could increase with Rayleigh scattering effect in the fiber channel,but in our schemes this effect could do very less by different wavelength photos. Wavelength Division Multiplexing (WDM) would separate photos by their different wavelength,and Bob can choose some reliable photos for QKD. Eve won’t catch anything about the secret information.