Estimation of free space optics systems availability based on meteorological visibility

A number of phenomena in the atmosphere such as scattering, absorption and turbulence can cause large variation in laser beam attenuation. The influence of absorption and turbulence can in some cases be significantly reduced by an appropriate design of free space optics (FSO) systems. Thus, in a typical continental area, where rain, snow or fog occur, scattering is the most important phenomenon causing power losses. Attenuation due to scattering can be expressed as a function of the link distance, wavelength and meteorological visibility. The paper deals with the estimation of FSO availability based on statistical evaluation of visibility data collected at several airports in Europe. The availability is evaluated in dependence on link distance, wavelength and power link margin.