经典-量子共信道同传是量子保密通信的关键应用技术之一,能够解决量子信息与经典信息需不同 光纤分别传输的难点,显著降低应用成本。针对基于波分复用技术的连续变量量子密钥与经典信息同传方 案,定量分析了系统拉曼散射噪声特性,在前向和后向两种不同经典信息传输模式下,仿真对比研究了拉 曼散射噪声对系统安全密钥率的影响。结果表明:经典信息采用前向传输模式时系统安全密钥率明显大于 后向传输模式;在固定信道输入功率时,短距离通信时拉曼散射噪声对安全密钥率的影响较小,随距离增 长,拉曼噪声影响不可忽略;固定通信距离时,一定数值范围内的额外噪声对系统的安全密钥率影响较小, 通信距离为50 km时,此数值为0.07N0。

The multiplexed classical and quantum transmission was one of the key application technologies of quantum secret communications, which can solve the problem that quantum information and classical information need different optical fibers to transmit, and significantly reduce the application cost. Aiming at the scheme of multiplex continuous variable quantum key with classical information based on WDM technology, characteristics of Raman scattering noise in the system are analyzed quantitatively. Influence of Raman scattering noise on the system security key rate is studied by simulation under two different classical information transmission modes of forward and backward. Results show that the secure key rate in the forward classical transmission mode system is larger than that in the backward classical transmission mode system significantly. When the channel input power is fixed, the influence of Raman scattering noise on the security key rate is small in short range communication, and the influence is not negligible with increasing of the distance. When the communication distance is fixed, the additional noise in a certain numerical range has less influence on the system security key rate, and the value is 0.07N0 when the communication distance is 50 km.