Modulation Techniques of Free Space Optics using Various Link Ranges

Abstract

Free space optics is the present trend, which enables the communication to achieve the expected data rates for the increasing user demands. The utility of FSO in free space medium enables higher data rates than the conventional microwave links for efficient communication. Several researchers have performed the analysis of free space optics by use of different modulation techniques and optimization of the link budget in free space optical links. In this work, CW laser transmitting source ranging to 10dB of output level, link ranges of 500, 1000 and 1500 mts with attenuation values of 0.2, 0.7 and 0.9 dB/Km respectively are considered. The analysis of free space optics is carried out by using various modulation techniques such as ASK, PSK, FSK, MZ, EA, Dual Drive MZ and it is observed that Dual Drive MZ modulation performs well when compared with the other modulation techniques.