Scattering parameters of a non-reciprocal magneto-optical integrated coupler used as an isolator

We theoretically investigate a non-reciprocal magneto-optical integrated slab directional coupler. The scattering parameters of the structure are derived in the frame of the Coupled-Mode Theory (CMT). By properly designing the coupler, it is possible to achieve a perfect non-reciprocity (with 100% contrast) between the two directions of propagation. Other operating points can also be defined, especially since modal dispersion in the spectral domain is naturally taken into consideration.