Measurement of third-order optical nonlinear susceptibility using four-wave mixing in a single-mode ridge waveguide

Nondegenerate four-wave mixing in a single-mode ridge waveguide has been demonstrated as a technique for simultaneous measurement of the imaginary component and the absolute magnitude of the third-order nonlinear susceptibility chi((3)). In the same experimenal apparatus, Im chi((3))(omega(2) = omega(1) + omega(2) - omega(1)) was obtained by measuring the pump-induced probe power loss and |chi((3))(omega(3) = omega(1) + omega(1) - omega(2))| was derived from Stokes wave generation efficiency. The ratio of these quantities was obtained without significant system uncertainties. The technique has been applied to AlGaAs/GaAs quantum-well waveguides with picosecond laser pulses. For homega(1) approximately homega(2) approximately 1.43 eV, it was found that Im chi((3)) = (6.1 +/- 0.5) x 10(-11) esu, |chi((3))| = (7.6 +/- 1.7) x 10(-11) esu with a system uncertainty of 25%, and Im chi((3))/|chi((3))| = 0.8 +/- 31%, indicating the dominance of two-photon absorption.