Abstract: Free-space optical communication (FSO) has taken the world into the technological peak where we can fulfil our rapid demand through transmission of optical signals through the atmosphere to provide high data rate and is termed as optical wireless communication. Generally lasers or led are used as transmitters and among which lasers are preferred because of their coherence nature. This paper presents the effects of light and thin fog atmospheric attenuations on a Free Space Optics (FSO) transmission system. We have considered NEW DELHI, INDIA as the place for our study. The real data analysis was collected from INDIAN METROLOGICAL DEPARTMENT (IMD) from the year of 2006 to 2015. We have calculated the average lowest visibility value in kilometres. Overall average value was calculated to be 1.2km. The Optisystem software 7.0 versions were used to simulate and obtain the Q-factor and BER. The transmitted and received power result has been compared for analysis. The maximum Q-factor was obtained i.e.38.8141 for a range of 1km and the attenuation was calculated from the visibility data i.e. 1.7131 dB/km with a data rate of 10Gpbs.

Keywords: FSO, Atmospheric attenuations, visibility, OPTICAL wireless, LASERS, Q-factor, BER, Optisystem etc.