Dense wavelength division multiplexing (DWDM) is the key technology in optical fiber communication, and the arrayed waveguide gratings (AWG's) have wide applications in WDM systems.
Advanced technologies like digital mobile communications, SDH, dense WDM, etc. have found wide application and high and new technologies like B-ISDN and ATM are on trial over the network.
Repeater optical amplifiers for WDM optical communications systems have wide gain spectrums and, therefore, can simultaneously provide gain over the range of wavelengths used in the WDM system.