Analysis of dielectric waveguide bends and curved coupler structures using finite difference beam propagation method

Abstract

In this thesis, implicit finite difference beam propagation method based on Crank Nicholson discretization procedure is implemented and applied to the analysis of propagation of optical beams in an orthogonal bend and a curved coupler structure. The efficiency factor which accounts for the power loss as a result of the bend is calculated for different waveguide width values and compiired with analytic solutions in the analysis of the orthogonal bend. Also, the effect of the rotation of the etched semiconductor-air interface from its ideal position is examined. In the curved coupler analysis, the bend loss and the variation of lower transfer ratios for different values of minimum distance that separates the branches of the structure are investigated and compared with analytic solutions. On both structure, the evolution of the Gaussian beam in the positive ^-direction is obtained.