Degenerate four-wave mixing geometry in thin-film waveguides for nonlinear material characterization.

We demonstrate experimentally a new degenerate four-wave mixing (DFWM) geometry in waveguides that permits the simultaneous determination of the nonlinear refractive index, the absorption, and the response time of the thin-film materials. The geometry consists of two guided pumps in a planar waveguide with an unguided probe. We achieve nonlinear characterization by measuring only the DFWM signal and the guided pump power at the waveguide output. The technique has been tested on a polymeric film (di-alkylaminonitro- stilbene).