Slotted multimode-interference devices

Abstract

We describe a novel modification of multimode-interference devices that has broad applicability. The modification involves introducing a slot (or slots), of a specific width and effective refractive index and at a specific position, that runs the longitudinal length of the multimode-interference region. Introducing N slots reduces the self-image length by a factor of N + 1. Varying the effective refractive index or width of the slot(s) creates a switch. The slot modification can be accomplished in a variety of ways, actually increases bandwidth, and has good error tolerances.