Coupling Analysis in Concentric Ring Waveguides

Coupled mode theory in dielectric waveguides has been studied for parallel waveguides and for non-parallel waveguides, among bent and straight optical waveguides between two non-concentric bent waveguides or even between concentric ring waveguides. The last case is treated in this work. Results are compared to those obtained by using the finite element method (FEM). We studied the influence of the curvature radius, the separation distance between the waveguides and the refractive index of the inner waveguide in the energy transfer between waveguides. In particular, the mechanism of energy transfer between concentric waveguides was analyzed.