泡沫覆盖不规则海面的空-水量子密钥分发

Air-Water Quantum Key Distribution on Irregular Sea Surface Covered with Foams

基于光子量子特性,综合考虑泡沫粒径分布、散射系数、泡沫层厚度及入射角、风速的影响,建立了一种泡沫-不规则海面的复合模型。给出了空-水量子密钥分发(QKD)系统的误码率公式,结合蒙特卡罗算法模拟研究了各参量对光子偏振量子态、QKD误码率及传输距离的影响,分析了泡沫-不规则海面下4强度BB84空-水QKD系统的性能。研究结果表明,偏振误码率随泡沫层厚度、散射系数、光源入射角的增大而增大;风速增大导致空-水QKD系统的量子误码率增大,安全传输距离减小;随着泡沫层厚度的增大,空-水QKD系统的密钥生成率和安全传输距离减小。当泡沫层厚度增至6cm并考虑最大偏振误码率时,最大安全距离由144m降至101.3m,但仍满足水下航行器100m的安全潜深要求。

A foam-irregular-sea-surface hybrid model is established based on the quantum properties of photons and with the consideration of the influences of the foam particle size distribution,scattering coefficient,foam layer thickness,incident angle and wind speed.The error rate formula for an air-water quantum key distribution（QKD）system is obtained.Combining with the Monte Carlo algorithm,the influence of each parameter on the photon polarization state,QKD error rate and transmission distance is simulated and discussed.The performance of the four-intensity BB84 air-water QKD system under the foam-irregular-sea-surface is analyzed.The research results show that,the polarization error rate increases with the increase of the foam layer thickness,scattering coefficient and light incident angle.Besides,the increase of wind speed leads to the rise of the quantum bit error rate of the airwater QKD system and the reduction of the secure transmission distance.Meanwhile,the key generation rate and the secure transmission distance of the air-water QKD system decrease as the foam layer thickness increases,and the maximum secure distance is reduced from 144 mto 101.3 m when the foam layer thickness increases to 6 cm and the maximum polarization error rate is considered,but it still satisfies the requirement of the 100 msafety depth for the underwater vehicles.