Complex Coupled Mode theory (C-CMT) of planar multilayer waveguides

TL;DR

This paper develops a complex coupled-mode theory for planar multilayer waveguides, incorporating lossy materials and asymmetric structures, and validates it against finite difference methods, advancing integrated optical technology.

Contribution

It introduces a complex coupled-mode theory for asymmetric multilayer waveguides with lossy materials, including metal thin-films, and compares results with finite difference methods.

Findings

The method accurately models bound and leaky modes.

Asymmetric structures influence transmission and reflection.

Validation shows good agreement with finite difference results.

Abstract

The numerical complex coupled-mode method used in a metal thin-film optic element is applied to a planar multilayer optical waveguide. All modes are required to satisfy Helmholtz Vectorial equation in an optical waveguide including bound and leaky modes at forward and backward propagation directions. First-order perturbation theory is developed and applied by means of lossy materials including metal thin-film and perfectly matched layers at the boundaries. our suggested structure discontinues in one direction and gives rise to an asymmetric metal thin-film at the core for investigating the transmission and reflection coefficient using mode-matching theory in two sides of the truncation. Finally, we compared the computed numerical results with the one that we obtained with the finite difference solver method. This study provides several advantages of CCMT in asymmetric temporal optical resonators that are in huge demand for today's integrated optical technology.