自然环境中多因子对自由空间量子通信性能的影响

Influences of Multiple Factors of Natural Environment on the Performance of Free Space Quantum Communication

根据大气中尺寸与光波长相近的各粒子的粒度谱分布函数,分析了大气湿度、粒子浓度、光信号波长和粒子直径等因子与量子弱相干光信号的衰减关系.讨论了多环境因子对大气能见度的影响,得到平流层量子通信中大气能见度和探测望远镜倾角对链路衰减的影响,量子信号传输误码率、保真度与大气能见度和传输距离的定量关系.仿真实验表明,随着大气湿度和粒子浓度的增加,量子信号传输的链路衰减逐渐增加,当光信号波长与粒子直径相近时,衰减最显著;在传输距离为15km,望远镜倾角为90°的前提下,当大气能见度分别为5km和15km时,链路衰减依次为18.9dB和14.2dB,信道误码率分别为0.010 5和0.009 9,信号保真度分别为0.22和0.71.

According to the particle size distribution function of the particles whose sizes are near to the wavelength of light,the relationships between quantum weak coherent optical signal attenuation and the atmospheric humidity,particle concentration,light signal wavelength,the particle diameter were analyzed.The effect of those environmental factors on the atmospheric visibility was discussed,and the influence of the atmospheric visibility and the angle of the telescope on the link attenuation for stratospheric quantum communication was analyzed.Meanwhile the quantitative relationships among quantum bit error rate,fidelity of the quantum signal and atmospheric visibility,transmission distance were put out and simulated.The simulation results show that,with the increase of atmospheric humidity and particle concentration,the link attenuation of quantum signal transmission is increasing,especially when the wavelength of optical signal is almost the same as the particle diameter,the link attenuation is the most significant.Under the premise of the transmission distance is 15 km and the angle of the telescope is 90,when the atmospheric visibility is 5km and 15 km,the link attenuation,the quantum bit error rate and the fidelity of the quantum signal are 18.9dB and 14.2dB,0.0105 and 0.0099,0.22and 0.71,respectively.