Subcarrier multiplexing in optical communication networks

The bandwidth capability of optical communication networks continues to increase. Optical fibres have low attenuation windows of many thousands of gigahertz and individual optical sources can now be modulated at rates well above 20 GHz. This is much faster than the switching rates of the electronic components needed to achieve multiplexing in applications such as time division multiplexing (TDM). Subcarrier multiplexing, which uses analogue intensity modulation of optical sources with readily available microwave components, can provide an elegant method of using the optical bandwidth and is capable of graceful evolution for future networks