Long-term analysis of atmospheric effects on free space optical links

Free space optical links provide a high data rate transmission through free space. The biggest disadvantage is a high impact of real atmosphere on availability of the links. This contribution shows results from the 4 years measurement (1.2009-12.2012) on experimental dual-wavelength optical link. The measurement site on the Milesovka Mt. is very specific. The link is very often in the middle of low cloudiness reaching the top of the mountain. Thanks to that we can measure the attenuation caused by the clouds. Our results show that the attenuation is higher comparing to the theoretical model that uses visibility as a parameter. On the other hand the measured rain attenuation is in agreement with the model determined by Carbonneau in France.