Optical Fibre Communication Systems for Voice and Video Signals—State-of-the Art
S.L. Maskara · IETE Technical Review · 1984
The optical fibre communication systems have a tremendous potential of carrying a large number of voice and video signals. Many fibre systems have already been installed and many more are planned and are under development. They are useful for all kinds of applications, such as submarine communications, intercity long haul communications, metropolitan trunking systems, subscriber loops and military communications in a telecommunication network. These applications and some of the new customer services which can be provided by fibre optic systems are reviewed. Current trends in the development of the components such as the optical sources, detectors and fibres are presented. Sources and detectors at long wavelengths, 1300 and 1600 nm range, where the fibre attenuation and dispersion are minimum, and the single-mode fibres are in advanced stages of development. Far greater repeater spacings than possible with metallic cables, would be achieved by using them in optical fibre systems. The ever-growing demand on telecommunication services can be met by a two-prong approach: (i) exploiting new wideband media like optical fibres and (ii) compression of bandwidths of the voice and the video signals at the source. Techniques of bandwidth reduction and progress made in generation of digital speech and picture signals at low bit rates are reviewed. Multiplexing methods and various line codes used in baseband transmission systems arc summarized.