Reducing the effect of scintillation in FSO system using coherent based homodyne detection

Free Space Optics is a highly demanded, short range wireless technology in which scintillation plays a major role of deteriorating the signal. Scintillation causes intensity fluctuations in the received signal due to variation in refractive index which highly distorts the signal. In this paper, a modified FSO system has been proposed using coherent-based Homodyne detection. Homodyne detection is a well-known and effective method of mixing signal field and a reference field from local oscillator via a square law detector that helps in overcoming the effect of scintillation. The performance comparison in terms of bit error rate, Q-factor and eye diagram of Homodyne detection and Direct detection has been investigated for moderate strength of scintillation.