Four-wave mixing in optical links using quasi-distributed optical amplifiers

We investigate efficiency of four-wave mixing (FWM) generation in quasi-distributed erbium-doped fiber (EDF) sections under general power evolution conditions. Measured FWM efficiencies are found to be in a good agreement with newly developed formulae applicable to waveguides with spatially and spectrally varying gain. Inoue's work describing FWM process in multiple amplified spans is generalized. A new theory of FWM generation in optical links amplified by a set of quasi-distributed nodes is developed and used to analyze multiple span L-band link.