Adaptive Beam Divergence for Inter-UAV Free Space Optical Communications

Research in the area of free space optical communications is largely based on fixed point-to-point link or long range link for space applications, employing a single beam divergence for the applications. For short-range inter-Unmanned Aerial Vehicle (UAV) optical communications, a single beam divergence employed in the link may limit the transmission distance between UAVs. To address this problem, adaptive beam divergence is required. Several methods to implement this in the form of beam divergence changing mechanisms are proposed in this paper. It is shown how adaptive beam divergence will reduce the requirements of other system parameters such as receive aperture diameter, transmit power and pointing ability.