Free Space Optical Communication System: Impact of Weather Conditions

Free Space Optics (FSO) is a new frontier for broadband wireless communications. The medium of transmission for an FSO system is the atmospheric channel, which suffers from signal degradation due to various factors. These factors, both internal and external, have an impact on the FSO link's performance. The internal parameters are: wavelength, power and beam divergence angle, while the external parameters are: fog, haze, rain, cloud, and visibility. This paper investigates the visibility effect on FSO systems in fog and haze. We investigate the range of FSO visibility for different beam divergence, bit rate, and optical power under fog and haze weather conditions. The link performance was evaluated using an Optisystem simulator. The quality (Q) factor and received power are used to evaluate the system's performance. Results show that smaller beam divergence gives a better performance as compared to a larger beam divergence.