Artificial Generation of Mie Scattering Conditions for FSO Fog Chambers

Abstract

Terrestrial Free Space Optical (FSO) systems aim to provide an ultra-broadband connectivity within core, metro and access networks. While FSO is considered as a promising solution that meets the data throughput demands of new 5G and Internet of Things (IoT) era, the adverse atmospheric effects and in particular Mie scattering (fog), impose significant risks for communication outage events. In order to foresee and evaluate those fog-related issues within an optical wireless link, the current paper reports on experimental setup utilizing artificial fog sources based on mixture of different highly purified glycols and water. As means of determining the approach feasibility, both atmospheric microphysics by means of empirical modified Gamma Particle Size Distribution (PSD) fog functions and Mie theory are used to estimate the artificially simulated Mie scattering attenuation of glycol-water fluids characterized by their complex refractive indices. The obtained results for moderate continental fog and different glycol concentration demonstrate 69.7 dB/km FSO losses at average which outcome coincides with a naturally occurred fog event. Moreover, all results are compared with analyzed PSDs obtained based on laser diffraction system for two types of fog machines that operate with the considered glycol-water fluids.