Power penalty for optical signals due to dispersion slope in WDM filter cascades

We calculate the receiver power penalty due to the accumulated dispersion slope of optical filter cascades in wavelength-division-multiplexed optical networks. For flat-top fiber Bragg grating and thin-film filters, dispersive rather than amplitude filter effects dominate the cascade power penalty, which increases with dispersion slope and signal frequency detuning from the cascade zero-dispersion point. The dispersion slope of these filters varies as the inverse cube of their bandwidth, using increased penalties for narrow filters in systems with small channel spacing, For a 60-GHz-wide Bragg grating filter with a 1.3-ns/nm/sup 2/ dispersion slope, a cascade of 26 filters can be tolerated at 10 Gbit/s with /spl plusmn/5 GHz allowed detuning. Optically preamplified receivers have significantly larger dispersion penalties than thermal-noise-limited receivers.