Abstract: Strong atmospheric turbulence (disturbance due to rain, fog, haze etc.) is a major problem in optical communication system. In this paper, the performance analysis of an optical communication system with Free Space Optics (FSO), Optical Wireless Communication (OWC) and Single Mode Fiber (SMF) in weak atmospheric turbulence has been analysed. Data stream is transmitted at 20Gbps using different channels under attenuation 1dB/km, 2dB/km and 3dB/km. Comparison is made in terms of Q factor, BER and received optical power. It is found that the signal can be transmitted with better Q factor, least BER and high received power with OWC system.

Keywords: FSO, OWC, SMF, Quality Factor, Bit Error Rate.