Dispersion in cascaded-grating based add/drop filters

Summary form only given. Fiber Bragg gratings are often used for routing in WDM lightwave systems. A fiber grating, operating in reflection, permits adding or dropping a selected channel while other channels are transmitted through the grating. Bragg gratings exhibit strong dispersion in transmission at wavelengths close to the stop band. As a result, dispersion-induced degradation of the transmitted adjacent channels becomes an issue for the performance of WDM systems. Add/drop filters designed to add or drop multiple channels typically make use of cascaded fiber gratings. Because each transmitted channel may then pass through numerous gratings, the cumulative dispersive effects would limit the bit rate, or the transmission distance, in practice. In this paper, we consider the impact of such cumulative dispersion on the performance of the WDM networks.