New proposal for real time measurements of visibility and signal levels in free space optical systems

The authors demonstrate a new method for recording precision measurements of visibility for free space optics systems correlated with received optical signal levels in three links using different wavelengths. The experimental results had been acquired with the use of the links in near, mid and far infrared transmission windows in the atmosphere. Our results proved that 10 /spl mu/m window is considerable better than the 1600 nm and 800 nm ones in dense and thick fog conditions.