Spectral analysis and implementation of secure chaotic free-space optical communication systems

This paper aims to present a Lorenz chaotic free-space optical (FSO) communication system (LC-FSO-CS), and to study the impact of FSO channel on a transmitted Lorenz chaotic signal infused by an arbitrary random binary message. It examines and corroborates the LC-FSO-CS by an analytical approach, using autocorrelation and power spectral density in the presence of the channel’s multiplicative noise. To achieve this task, the paper exploits an autocorrelation model for the multiplicative scintillation noise while approximating the transmitted chaotic signal modeled by a quasirandom telegraph signal. The method presented here considers the effect of the additive noise in the FSO channel as negligible, while successfully employing the linear system concepts and logarithmic operation to analyze the influence of scintillation noise on the transmitted chaotic waveform. The emphasis of this work is on last-mile FSO communication with simulation experiments performed and results presented throughout the paper to validate the LC-FSO-CS.