Free space optical communication link and atmospheric effects: Single aperture and arrays

Free space optical (FSO) communication systems offer several advantages over conventional radio frequency (RF) systems but, because of shorter wavelength, are subject to various atmospheric effects. Particularly significant in this regard is the signal fading below a prescribed threshold value owing primarily to optical scintillations associated with the received signal. In this paper we utilize some recent advances in the modeling of optical scintillation under weak-to-strong fluctuations associated with terrestrial links and examine fade probability and bit error-rate (BER) for direct detection systems using a single large aperture receiver and the BER for an array of smaller receiver apertures.