Chiang Mai Journal of Science

The coupled mode equations incoporating the intensity dependent refractive index (IDRI) nonlinear optical effect of the medium was applied to a basic study of beam propagation in a symmetrically configured five - layer planar structure composed of two optically coupled waveguides with identical optically nonlinear guiding media. The three cladding layers are constituted of linear optical materials of the same refractive index. The result of this study demonstrates the feasibility of developing an optical device serving both as an all optical directional coupler and optical switch employing the basic multilayer planar structure considered in this study. Restricting ourselves to the lowest TE waveguide modes, the power transfer efficiency and coupling length L_c were determined and described as functions of the light intensity and the waveguide parameters such as the waveguide separation and the refractive indices.