High-performance optical amplifier for WDM communication systems

Gain equalization of an EDFA is performed by introducing spectrally designed all-fiber filters in the midstage of a dual-stage fiber amplifier. Two types of filters are studied: a cascade of narrow-band Bragg gratings for discrete equalization of a finite number of channels and a wide-band Bragg grating performing equalization over the whole 1539 nm to 1557 nm range. In future work, it is planned to use the discrete Bragg grating configuration to simultaneously perform Dispersion compensation (D), Equalization (E) and Stabilization of gain (S) and Channel dropping (C) in a dual-stage EDFA. Integration of these functions will result in a high performance amplifier called the DESC-EDFA.