US Patent 7920794 Free space optical communication

Free space optical communication systems, methods, and apparatuses are provided. A system embodiment includes a photodetector for receiving a beacon signal transmitted from a ground communication apparatus, a light source for emitting a light beam toward a source of the beacon signal, where the light beam includes a signal to be transmitted, and a high speed tracking actuator coupled to the light source for moving the light source to maintain the light beam in a direction toward the source of the beacon signal transmitted from the ground communication apparatus.