Abstract

Grating-assisted waveguides are integrated optics devices potentially useful in sensor, communication and signal processing applications. To design such devices with specific performance characteristics, an accurate theoretical tool to predict their optical behavior is essential. In this work, we have analyzed ion-exchanged channel waveguides with grating. We first use the finite-difference method to determine the index profile of the ion-exchanged glass waveguides. We employ a modified Crank-Nicholsen scheme called Altemating-Direction-Implicit method to solve the interdiffusion problem and to calculate the index profile. Then, we employ the scaler finite-element (FEM) to solve the scaler wave equiation and to calculate propagation constants and mode profiles of hte waveguides modes. We use four-node rectangular elements with bilinear approximation functions. The eigenvalue problem is solved using a simultaneous iteration technique. Finally, the coupled-mode theory is employed to analyze the channel waveguides with grating. The grating is treated as a perturbation of the waveguide on which it is fabricated. The details of calculation and the effect of different device parameters on waveguide behavior will be discussed.

© 1990 Optical Society of America