Dense WDM systems rely on the ability to pack many wavelength channels in a given spectral bandwidth. This implies that very good optical filters are needed to separate these channels, while not disturbing adjacent channels. In this paper we discuss the dispersive properties of optical filters (their phase response) and their impact on DWDM systems. We review recent theoretical and experimental results demonstrating the detrimental effects of filter dispersion on data transmission. We also address ways of mitigating filter dispersion using linear phase filters and phase-only (all-pass) filters.
© 1999 Optical Society of America