title: Higher-order four-wave mixing and its effect in WDM systems.
abstract: Higher-order four-wave mixing effects are evaluated in WDM systems. Calculated and measured results show that higher-order FWM crosstalk, though small compared to the first-order FWM crosstalk, could be significant in unequal channel-spacing WDM systems where the first-order FWM is not a problem.
authors.forename: S
authors.initials: S
authors.lastname: Song