Optimal Power Transfer Through Atmospheric Turbulence Using State Knowledge

The design of a laser transmitter that achieves maximum power transfer through the earth's turbulent atmosphere is considered. It is shown that optimum power transfer would be realized with an adaptive system that uses the appropriate beacon signal to probe the channel state. This result is applied to show that the average power gain of the optimal earth-to-space optical link is the diffraction-limited gain for the apertures in vacuum. For large transmitting apertures the percentage fluctuation about this mean gain goes to zero. Thus the fundamental limitation on power transfer imposed by the turbulence is considerably milder than had been thought.