Coupling coefficients for imperfect asymmetric slab waveguides

This paper presents a collection of formulas that are necessary for the treatment of radiation and mode conversion phenomena of imperfect asymmetric slab waveguides. The coupled mode theory of dielectric waveguides is briefly reviewed, and general expressions for the coupling coefficients are given. The field expression of the guided and the radiation TE and TM modes of the asymmetric slab waveguide are stated, and are used to derive formulas for the coupling coefficient for slight core boundary irregularities.