Optical communications: past, present and future

A quiet revolution is taking place in communications technology, where light is replacing its low-frequency counterparts, the radio wave and signals by wire. The author traces the development of optical communication technology from simple beginnings using fire and beacons, through early valve and solid-state devices to integrated optics and advanced fibre systems. Because of the very rapid growth in the area recently, only a sample of current developments can be presented. Leading-edge developments are considered in the light of current and advancing technologies