Design of strip-loaded weak-guiding multimode interference structure for an optical router

We introduce a new multimode interference structure that can be used as an integrated optical router. This structure is based on the existence of a first cross state in weakly guiding multimode waveguides. Such a cross image, not expected by the self-imaging technique, is tested by rigorous modal analysis as well as the nonmodal beam propagation method. We show that the quality of this image could be enhanced by strip loading the multimode section of the structure. Making use of this image, we propose a new optical router based on the large nonlinearity associated with the blockaded reservoir and quantum-well electron transfer structure.