Turbulence strength experimental measurements for improved detection in free space optical communications

Laser communication link performance in free space depends heavily on atmospheric conditions present on the propagation path. Distortions due to atmospheric turbulence, such as scintillation and beam wander, greatly diminish signal detection and performance. With the final goal of improving the communication link, experimental measurements and analysis of turbulence strength are presented as metrics for determining the system’s detection limits. Experimental optical trials were recorded over a 1-km horizontal path in order to study the intensity fluctuations, beam dance, and the spatial spectrum properties under different regimes. By taking into account wind speed and vibrations of the building where the measurements were carried on, correlations between variables are shown with the use of a photodetector, and a 2D lateral effect position sensor.