Performance evaluation of free space optical communication under the weak turbulence regime

This paper experimentally investigates the performance of an FSO communications system by increasing the link length under an indoor laboratory controlled turbulence condition. A plane mirror is used to increase the link length by means of optical beam reflection. The experimental results show that the turbulence strength is highly dependent on the link length. The measured scintillation index (SI) for a link of 6 meters long with no reflection is 0.043, which increases to 0.56 with reflection for a link of 12 meters. Furthermore, the Q-factor is measured as a performance metric for the FSO link with and without the reflected beams for different SI values. The results show that the performance of the FSO link with reflection deteriorates very rapidly with the Q-factor being halved compared at SI of 0.01.