基于伪态协议的量子密钥分配系统研究

采用包含两个伪态和一个信号态的双伪态协议分析了量子密钥分配系统的性能，比较了双伪态（真空态—弱伪态）和单伪态协议条件下密钥生成率与通信距离的关系，分析了信号态的强度、量子比特误码率、单光子的增益和单光子的误码率对系统密钥生成率的影响，得出密钥生成率的最优化条件，为实现实用安全的量子密钥分配系统奠定理论基础.关键词：伪态协议量子密钥生成率量子比特误码率

Analysis of decoy state quantum-key-distribution system

The security of quantum-key-distribution system is analyzed using the decoy state protocol with two weak decoy states and one signal state. The comparison is based on the key generation rate as a function of distance for two types of decoy states: the vacuum and a weak decoy state, asymptotically approaching the theoretical limit of the most general type of decoy protocol, one-decoy-state protocol. We studied the two-decoy-state protocol in connection with the intensity of signal state, and the gain of signal states, the overall quantum bit error rate, the gain of single-photon states and the error rate of single-photon states and arrived at the optimal condition which maximizes the key generation rate.