Accurate measurement of in-band FWM power in DWDM systems over nonzero dispersion fibers

A novel accurate measurement technique of the in-band four-wave mixing (FWM) power in dense wavelength-division multiplexing (DWDM) over nonzero dispersion fibers is presented. By measuring only two out-of-band FWM terms generated by three fixed channels, the FWM efficiencies on all DWDM channels can be evaluated and the in-band signal-FWM crosstalk ratio can be calculated. A comparison with other known methods proves the better accuracy of the proposed technique.