Wavelength tunable add/drop multiplexer for dense wavelength-division multiplexing using short- and long-period fiber gratings

This work is primarily concerned with the utilization of fiber Bragg gratings (FBGs) and chirped long-period gratings (CLPGs) to realize a novel wavelength-tunable optical add/drop multiplexer (OADM) device. We considered the theory of fiber Bragg gratings and long-period gratings to explain the operation of the new device. The method of strain used for tuning of the fiber Bragg grating, channel isolation, and crosstalk between channels are also discussed.