Observation of WDM crosstalk in passive semiconductor waveguides

We show that passive InP-InGaAsP waveguides exhibit high nonlinear loss due to the highly energetic carriers generated by two-photon absorption. We have further demonstrated, for the first time, that due to this effect, severe crosstalk occurs between wavelength channels when they are transmitted through a semiconductor waveguide operated in the transparency region, at power levels used in typical wavelength-division-multiplexed (WDM) systems. Some solutions are proposed.