Characterization of fog-induced attenuation for optimizing optical propagation links in Nigeria

Fog -Induced Attenuation (FIA) is crucial in assessing the performance of Free -Space Optics (FSO) systems for optimal results. The goal of this work is to characterize FIA seasonally and yearly at the selected optical wavelengths over selected locations in Nigeria. FIA has been analyzed using five (5) years (2012-2016) visibility measurements data for Abuja, Ikeja, Jos, Port Harcourt, Ilorin, Makurdi, and Sokoto locations in Nigeria. The visibility re -analysis data were obtained from achieves of the European Center for Medium -Range Weather Forecasts (ECMWF).over the selected locations. The characterization has been based on three different frequencies and their respective optical wavelengths (850 nm/352 THz, 1300 nm/230 THz, and 1550 nm/193 THz). The sensitivity of the FIA to cloud cover rate (information on visibility range) and the comprehensive cumulative distribution rate at the selected frequencies were also examined. The results show that a minimal FIA of about 0.4 dB/km can be achieved at 1550 nm/193 THz for optimal link planning and design of FSO communication links in Nigeria. However, attenuation of 0.25 dB/km can be achieved at link availability of 99.99 % for FSO transmission in the commercial city of Lagos (Ikeja) at the same 1550 nm/193 THz under bad weather conditions. However, due to additional dust in the region, FIA can extend up to 0.6 dB/km in Sokoto (arid region) under the same conditions. The variation pattern in the arid region and the associated ones will require a high -power laser with special mitigation techniques to improve the chances of link availability for optimal performance.