Single-, Few-, and Multimode Y-Junctions

The theory of modal propagation through symmetric and asymmetric 2-D weakly guiding Y-junctions is extended to cover few-mode, multimode, and multiarm Y-junctions. A conceptual approach based on the evolution of modal effective indexes and composite supermodes is used to determine the qualitative functionality of these devices, with quantification being determined numerically using the beam propagation method.