Nonlinear measurement of mid-infrared absorption in AlO(x) waveguides

We report a quantitative study on the absorption of oxidized-AlAs (AlO(x)) integrated thin layers in the mid-infrared range (2-4 mu m). An AlO(x) absorption coefficient of 1600 cm(-1) is measured in a nonlinear waveguide, by investigating the phase-matching bandwidth of parametric fluorescence. Since mid-infrared optical losses of the idler mode are inferred from the corresponding signal features in the 1-2 mu m range, our technique takes advantage of common near-infrared sources and detectors. (C) 2008 American Institute of Physics.