Change in Irradiance PDF of Gaussian Beam with Increasing Aperture Size and its Effect on Direct Detection FSOC Metrics

Large apertures are used in FSOC systems to increase signal and reduce scintillation. Based on simulations of a realistic FSOC system using a Gaussian beam we found significant changes in the empirical PDF with increasing aperture size. We compare the fit of PDFs to data and the effect of PDF choice on <BER> and fade probability of a direct detection FSOC system.