Communications Technology Handbook, 2nd Edition

25 Optical communications, devices and systems

As worldwide communications develop, the radio section of the electromagnetic spectrum is quickly becoming saturated. Even the use of metallic conductors is being overloaded. Wide band analogue and high speed digital signals are extremely bandwidth hungry. The conventional electronic communications services are therefore becoming very expensive to support under such pressures. Historically, communications have been driven to higher and higher frequencies in order to meet this growing demand. Light beams that can be simply switched on and off, or even deflected, have long been used for low speed signalling purposes, but now the concept of guided light energy using optical glass or plastic is set ...