Abstract :
WDM is currently taking over as the leading technology in point-to-point transmission links. For optical implementation of WDM networks, logical functionalities such as wavelength (channel) selection should be carried out in the wavelength domain; thus, the development of dynamic optical devices is required. One key device is a tunable optical filter. Important features of such a filter include low insertion loss, narrow bandwidth, high sidelobe suppression, large dynamic range, fast tuning speed, a simple control mechanism, small size, and cost effectiveness. Here, an extensive overview of the different technologies used to produce tunable optical filters is presented. Among them, fiber filters such as fiber Bragg gratings and fiber Fabry Perot are the most commercialized, yet inherently limited in their dynamic speeds. For high demanding dynamics, micro-machined and acousto-optic filters can offer a good solution for microsecond tuning speeds. Faster tunable devices, in nanosecond tuning speeds, might emerge out of microresonators, electrooptic filters, and active DBR filters
Keywords :
acousto-optical filters; electro-optical filters; optical communication equipment; optical fibre filters; optical tuning; wavelength division multiplexing; acousto-optic filters; active DBR filter; bandwidth; channel selection; control mechanism; cost effectiveness; dense WDM networks; dynamic optical devices; dynamic range; electrooptic filters; fiber Bragg gratings; fiber Fabry Perot; insertion loss; logical functionalities; micro-machined filters; microresonators; microsecond tuning speeds; nanosecond tuning speed; optical implementation; point-to-point transmission links; sidelobe suppression; size; tunable optical filters; tuning speed; wavelength selection; Active filters; Optical devices; Optical fiber devices; Optical fiber filters; Optical fiber networks; Optical filters; Optical losses; Optical tuning; WDM networks; Wavelength division multiplexing;
