BLIP condition in point-to-point optical communication

Analysis of the signal-to-noise ratio of optical point detectors under conditions of large background radiation (BLIP detection) gives relations describing the background limit to the sensitivity of point-to-point optical communication systems. In narrowband applications, noise-equivalent-power (NEP) has a utility for study of the point BLIP detector which is equivalent to that of the detectivity D^*for large area BLIP detectors; for wide bandwidths, a more suitable parameter is the retrieval efficiency β of the receiver. Each of these is expressed in terms of DBLIP^*, a quantity graphed in references on infrared detectors. A numerical exmple shows that even on the surface of the earth, broadband point-to-point communications may well be receiver limited rather than background limited.