卷云对自由空间星地量子通信信道的影响

Influence of Cirrus Clouds on Space-to-Earth Quantum Communication Channels in Free Space

卷云对量子通信光信号的传输有极大的影响。根据卷云特性建立了卷云冰晶粒子的分布模型,研究了卷云的消光特性,并根据卷云的散射特性,分析了卷云冰水含量、传输距离、链路消光特性、信道容量和信道纠缠度衰减的定量关系,研究了噪声影响下隐形传态保真度的变化,并进行了仿真实验。实验结果表明,当传输距离为3 km时,在卷云冰水含量(体积质量)为0.4 g·m^(-3)的条件下,对应的链路衰减、信道容量和信道纠缠度分别为0.05 dB·km^(-1)、0.94 dB·km^(-1)和0.52,而在卷云冰水含量(体积质量)为0.1 g·m^(-3)的条件下,对应的链路衰减、信道容量和信道纠缠度分别为0.20 dB·km^(-1)、0.82 dB·km^(-1)和0.07。由实验结果可见,自由空间量子通信信道的性能在卷云的影响下均发生了不同程度的变化。因此,在进行量子通信时,需考虑卷云的影响,根据卷云的变化调整性能参数,以提高通信质量。

Cirrus clouds have a great impact on optical signal transmission in quantum communication.According to the cirrus cloud characteristics,the cirrus cloud ice particle distribution model is established,and the extinction properties of cirrus clouds are investigated.In addition,according to the scattering features,the quantitative relationships among the cirrus cloud ice water content,transmission distance,link extinction characteristics,channel capacity,and channel entanglement attenuation are analyzed.The change of teleportation fidelity under the influence of noise is studied and the simulation experiment is conducted.The experimental results show that when the transmission distance is 3 km and the cirrus cloud ice water content(volume mass)is 0.4 g·m^(-3),the corresponding link attenuation,channel capacity and channel entanglement are 0.05 dB·km^(-1),0.94 dB·km^(-1) and 0.52,respectively.In contrast,they are 0.20 dB·km^(-1),0.82 dB·km^(-1) and 0.07,respectively,when the cirrus cloud ice water content(volume mass)is 0.1 g·m^(-3).From these experimental results,one can see that the performance of the free-space quantum communication channel changes to different degrees under the influence of cirrus clouds.Therefore,the influence of cirrus clouds should be considered in quantum communication,and various performance parameters should be adjusted according to the change of cirrus clouds in order to ensure the communication quality.