Abstract

The potentials for and limitations to the use of intensity fluctuations of laser beams propagating through a turbulent atmosphere for generating random data when keying in confidential optical communication systems are analyzed. The technique is based on the reciprocity theorem for optical fields. Light propagation in a system of two transceivers directed at each other, the signals from which are distorted by an atmospheric channel, is numerically simulated. An experimental setup is created; the generation of random correlated signals in this system is experimentally studied. A need for low-pass filtration of signals received is experimentally ascertained. The efficiency of this filtration is estimated. The dependences of the correlation coefficient on the geometrical parameters of the system and turbulent conditions along the propagation path are derived from the numerical simulation in a wide range of distances, aperture radii, and turbulence strength values. Theoretical results are shown to be in a good agreement with the results of laboratory experiments.

中文翻译：

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激光收发系统中形成密码密钥的强度相关性分析

摘要

分析了在机密光通信系统中进行键控时通过湍流传播的激光束强度波动的可能性和局限性，以生成随机数据。该技术基于光学场的互易定理。数值模拟了两个互相指向的收发器在系统中的传播，其中的信号被大气通道扭曲。实验设置已创建；实验研究了该系统中随机相关信号的产生。实验确定了对接收信号的低通滤波的需求。估计该过滤的效率。相关系数对系统的几何参数和沿传播路径的湍流条件的依赖性是通过在较大的距离，孔径半径和湍流强度值范围内的数值模拟得出的。理论结果表明与实验室实验的结果非常吻合。