Lightwave Communications

Abstract

Abstract The history of modern lightwave communications systems began at the end of the fifties, with lasers, which were the first optical source with high power and directivity able to be used in a communication system. Gas lasers, needing high supply voltages and relatively large sized, were followed in 1961 by semiconductor lasers, which appeared much more promising, because of their small dimensions and the possibility of modulating them with low currents. More than ten years of research were necessary to achieve reliable enough semiconductor lasers working at ambient temperature.