Research in Free Space Optical Data Transfer

In this paper, a review of the progress and initiatives in free space optical data transfer and communications at the Naval Research Laboratory is presented. NRL has been investing in research and development in optical communications and laser ranging, both conventional, and advanced. Efforts include developing amplifiers and components for lasers to be used in long range, one-way and retro-reflected links. NRL has been developing Multiple Quantum Well retromodulators for space-based and terrestrial-based applications as well. These include spacecraft-to-spacecraft data links for navigation and communications, intra-bus networks on spacecraft, and optical tagging. Terrestrial applications in the eyesafe regime have led to additional studies in how the atmosphere affects one-way and modulated retroreflected signals in the maritime environment, in particular. New results from retrodiversity experiments, over-the-water propagation studies, and field tests are discussed.