Analysis of Rain Visibility Attenuation on Free Space Optics (FSO) for South African Weather Conditions

The Free Space Optics (FSO) is a high-speed connectivity system that has the same advantages of speed and bandwidth as that of optic fiber. In comparison to optic fiber, FSO is the preferred choice when it comes to cost and deployment period. However, one of the main challenges with FSO is the changing weather conditions that affect the signal since the transmitted signal is radiated through the atmosphere. This investigation focuses on examining the variables that influence the reduction of visibility at different wavelengths: 750nm, 780nm, 850nm, and 1550nm. The locations of interest concerning visibility and rain data are Pretoria, Upington, Bloemfontein, and Cape Town in the Republic of South Africa. Results indicate that fog attenuates the signal more when compared to rain. Furthermore, signals transmitted at 1550nm will attenuate the signal less when compared to the other wavelengths of interest.