Polarization dependence of ultrafast nonlinear refraction in an AlGaAs waveguide at the half-band gap

Abstract

We have obtained the polarization dependence of ultrafast nonlinear refraction by measuring the orientational dependence of self-phase modulation and cross-phase modulation in an Al0.18Ga0.82As waveguide at a frequency just beneath the two-photon absorption edge. It was found that nonlinear refraction exhibits a considerable anisotropy in accordance with theoretical calculations for GaAs. It was also found, as predicted, that perpendicular cross-phase modulation behaves differently from the isotropic Kleinmann result appropriate to silica fibers.