Group delay dispersion performance requirement for optical cross connects and add-drop multiplexers in ultralong-haul DWDM transport systems

The system penalty of undesirable chromatic group delay dispersion in wavelength-selective optical cross connects (OXCs) and add-drop multiplexers (OADMs) is the critical design constraint for 10- and 40-Gb/s transparent ultralong-haul dense wavelength-division-multiplexing network systems. Although narrow-featured dispersion within the passband of OXCs and OADMs causes a relatively small penalty, its system penalty is often overestimated when a wavelength-independent uniform dispersion model is applied. Considering a model that represents an arbitrary dispersion function, we assess generalized requirements for the narrow-featured dispersion impairment, and propose the sliding-window group delay ripple as the measure of system penalty estimation.