Analytical model for the coupling constant of a directional coupler in terms of slab waveguides
Résumé
We present an analytical model for a generic two-wave directional coupler, in the conceptual frame of coupled single-mode planar (slab) waveguides. The modal relation of dispersion is expressed exactly under a matrix form. In the simplest symmetric configuration, the lift of degeneracy between the propagation constants of the even (slow) and odd (fast) supermodes is the exact image of the coupling constant.