Analysis of SiO2/TiO2-SiO2/SiO2 coupled parallel waveguide structures using computer aided design techniques

The analysis of two coupled parallel rib waveguides of SiO2/TiO2-SiO2/SiO2 on silicon substrate is presented. The indigenously developed beam propagation method (BPM) simulation tools are applied to observe the power coupling between two identical parallel rib waveguides and to study the dependence of the coupling length on various parameters of the rib waveguides including the refractive indices, rib height, guide thickness, clad thickness and separation between them. The designs for the 3 dB coupler and demultiplexer for DWDM, based on the symmetric directional coupler, are optimized for minimum dimensions using the techniques, for the first time. The optimum device length for 3 dB coupler was calculated to be 650 mu m with 0.016 dB losses. The 1.3 mu m and 1.304 mu m demultiplexer has been designed with the optimized device length of 1.02 mm and the losses less than 0.40 dB at both the wavelengths. (C) 2000 Elsevier Science B.V. All rights reserved.