The Naval Center for space Technology at the Naval Research Laboratory reports the latest results from the long range, mnaritime, free space lasercom test facility located between Chesapeake Beach, MD and Tilghman Island, MD. The two sections of the facility are seperated by 16.2 km of the Chesapeake Bay. Using a new OC-48 reciever developed by NRL's Optical Science Division with sensitivityof 33-dBm for 10(-9) bit error rate at 2.5 Gbps, we have closed a 32.4 km maritime lasercom link (round trip across the Chesapeake Bay) and performed bit error rate testing while transmitting 1.13 Terabytes of data. Bit error rate testing was also performed at lower data rates when atmospheric conditions were not favourable for high speed (2.5Gbps), including testing at 150 Mbps through light fog and rain. In addition, we have set up a system for digitizing and transmitting full-color, uncompressed, video along with six audio channels and three RS-232 data channels over the maritime link. The digital link operated at 311 Mbps and could be maintained indefinitely, depending on atmospheric conditions. Several complete videos were transmitted in entirety or in part as well as live video from handheld camcorder to test the system operation and robustness. The transmitter and reciever were co-located on the western shore of the bay at the NRL Chesapeake Bay Detatchment. The data for both the bit error rate testing and the video was transmitted across the bay and returned from an array of retroreflectors located on a tower at Tilghman Island on the shore. The lasercom links were closed with static pointing and with no active atmospheric aberration mitigation such as adabtive optics or fast steering mirrors on the reciever optics.
