Short haul digital laser link in the atmospheric channel

The design of a digital laser communication link operating in a short (780m) atmospheric channel is presented. The laser wavelength is 0.63[mu] and the data transmission rate is 20 Kbps. The system utilizes binary ON-OFF modulation of the carrier intensity with direct detection by means of an aperture averaging receiver. Performance data has been obtained and probability of error curves plotted for operation during daytime as well as at nights.