Impact of Rain in Single and Multiple Beam Wavelength Division Multiplexing Free Space Optical Systems

Abstract

Free Space Optics (FSO) has received much attention in recent years as a cost – effective, licence free and wide-bandwidth access technique for high data rates applications.Attenuation due to different weather conditions plays a significant role in the performance of the Free Space Optical Communication (FSO).The hybrid WDM FSO network is proposed to provide a significant improvement in the link distance, received power and BER.Single beam FSO and Multiple beam FSO system is designed, analyzed and compared to produce the best system capable of tackling the effect of atmospheric weather conditions by using OptiSystem7.0 as simulation tool to simulate the link for the data-rate of 10 Gb/s with input power 40 dBm. It was realized that four-beam FSO system can operate successfully for a link distance of 8.5k m at BER of 10-6with a received optical power of -23.7 dBm for light rain and link distance of 6 km at BER of 10-6 with a received optical power of -23.2 dBm for medium rain,and link distance of 3 km at BER of 10-8 with a received optical power of –19.9 dBm for heavy rain providing the fact that multi beam FSO is sensitive even to very low optical power.