Multimode interference couplers

Abstract

Experimental results are presented on a new type of planar (Multimode Interference) coupler. Two-mode interference (TMI) couplers (Fig. la) were reported already in 1977 as an alternative to weak synchronous couplers,1 they are shorter and less sensitive to variations in the fabrication process, and thus have a potential for application without trimming or tuning facility. Further, they exhibit less polarization dependence.