Crosstalk in WDM systems caused by cross-phase modulation in erbium-doped fiber amplifiers

We show experimentally that cross-phase modulation (XPM) in erbium-doped fiber amplifiers (EDFAs) may cause crosstalk between channels transmitted over conventional fiber. As this effect is constant over a large range of wavelength separations, it is capable of creating interference between a large number of channels. In some important cases, XPM originating in the EDF may become comparable in significance to that originating in the transmission fiber.