Observation of Maker fringes and estimation of χ(3) using picosecond nondegenerate four-wave mixing in AlGaAs waveguides

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Abstract
Nondegenerate four-wave mixing experiments have been conducted in Al0.2Ga0.8As ridge waveguides, using picosecond laser pulses. Maker fringes due to phase-matching requirements were clearly observed, and phase-matched nondegenerate mixing was achieved by utilizing the waveguide geometrical birefringence. Conversion efficiency up to 5×10−3 for a coherent interaction length of 3 mm was obtained. The observed third-order nonlinear susceptibility χ(3)(ω3=ω1+ω1−ω2) does not display any strong resonances and exhibits a relaxation time shorter than 10 ps. From these measurements it is inferred that ‖χ(3)1111‖≥8×10−11 esu, and ‖χ(3)1111/χ(3)2112‖=2.4±0.3 for ω1 and ω2≊1480 meV/ℏ.