Free-space high-speed laser communication link across the Chesapeake Bay

Abstract

The Naval Research Laboratory (NRL) has established a free-space laser communication link across 16.2 km of the Chesapeake Bay between the Chesapeake Bay Detachment of NRL and Tilghman Island. The transmitter consists of a modulated 1550 nm oscillator amplified to 2 watts in an erbium doped fiber amplifier developed at NRL. The beam is fiber coupled to a 4 inch collimating lens on a remotely controllable gimbal mount. The beam is transmitted to a retro-reflector array at Tilghman Island and back to the receiver at CBD (32.4 km round trip). The receiver consists of a 16" Meade telescope either directly or fiber coupled to a variety of fast photo-detectors. Experiments have been conducted to study the stability and quality of the link. These include: bit-error rate measurements, probability density functions, power spectrum densities, and angle of arrival measurements of the received signal. Results of these experiments are presented.