Polarization properties of a fiber-to-asymmetric planar waveguide coupler

A coupled mode model describing the light transfer between a single-mode fiber and a planar asymmetric waveguide, which takes into account the two dimensions of the waveguide cross sections, as well as the TE or TM polarization of the planar waveguide modes, is presented. This model is applied to the practical case of a distributed (curved fiber) coupler, and the possibility of light modulation by changing the refractive index: of the cover medium is pointed out. The action of such a coupler as a polarizer, which could be externally driven, is also considered.< >