A U.S. Air Force Research Laboratory (AFRL) researcher is leading a team investigating long-distance, mobile optical links that are essential for secure quantum communications capabilities in theatre. Dr. David Hughes and his Air Force Office of Scientific Research-funded (AFOSR) team have conducted high-data-rate experiments using an optical laser link, a tool that exploits the quantum noise of light for higher security. The system uses adaptive optics for transmission of high-data-rate video and audio signals over long distances.

AOptix Technologies, a developer of ultra-high-bandwidth laser communication solutions for government and commercial markets, has teamed with AFOSR and AFRL to conduct flight tests at 10,000 ft to evaluate the performance of the high-altitude, air-to-ground, quantum communications links.

The challenges so far with free space optical links, which use fibre optics for transmission, have been the turbulence or distortions from temperature differences that cause motion or wind in the atmosphere. “When you transmit information through turbulence, it’s distorted,” said Hughes. “You have to overcome that by using adaptive optics to rectify the distortion and get a better quality signal.”

Hughes and his team are said to have established an optical link without distortion in test situations at a distance of 35km in stationary and flight situations. The next flight test will aim for increased altitudes to demonstrate further air-to-ground distances. “If we can now put one link on the ground and one on a demo aircraft, it wouldn’t take much to apply the technology to operational aircraft for the Air Force,” said Hughes.