A RIB OPTICAL WAVE-GUIDE WITH CUTOFF MESA ISOLATION

A rib optical waveguide using the concept of optical cutoff to provide isolation between adjacent waveguides in a photonic integrated circui t is disclosed, Due to the evanescent nature of light propagation in c utoff waveguides, this cutoff mesa rib waveguide permits fabrication o f single-moded rib waveguides with minimal self-interference and cross talk by means of light guided in a remaining slab waveguide, Design ru les are given and operation of a single-moded cut-off mesa rib wavegui de and an MZI using this waveguide are demonstrated.