Contraction of Aluminum Oxide Thin Layers in Optical Heterostructures

O. Durand, F. Wyckzisk, J. Olivier, M. Magis, P. Galtier, A. De Rossi, M. Calligaro, V. Ortiz, V. Berger, G. Leo, and G. Assanto

Appl. Phys. Lett. 83, 2554-6 (2003)


We precisely determine the contraction of AlAs in multilayer optical waveguides, associated to selective oxidation of AlAs/GaAs epitaxial heterostructures. The average thickness of each layer was determined via X-ray reflectometry before and after oxidation, yielding an induced shrinkage of 11.4% 0.7% normal to the stack. The modal effective indices of the waveguide were evaluated via distributed coupling in the near infrared. The achieved accuracy is compatible with form-birefringent phase matching in AlGaAs guided-wave frequency converters.