Wide-beam atmospheric optical communication for aircraft application using semiconductor diodes

Design considerations for atmospheric optical communication systems using wide divergent beams are described. This new approach can eliminate the need for complex gimbaled pointing and tracking mountings. Communicating systems have been designed and built using both infrared LED and cw and pulsed laser diodes operating in the wavelength range of lambda = 0.8-0.9 microm. Both single-channel and multichannel receivers were designed with fields of view (FOVs) ranging from 0.4 to 24 degrees. Receiver performances were compared for a range close to 1 km under various ambient conditions. Laboratory simulation experiments were used to determine the operating margin and expected SNRs resulting from various design considerations. The need for narrow spectral bandwidth and wide-angle FOV interference filters is pointed out. The systems designed in the present work were low data rate (a few kbit/sec) communication systems and are suitable for aircraft-to-aircraft data exchange or voice communication.