title: Parabolic tapered structure for an ultracompact multimode interference coupler.
abstract: A parabolic tapered structure based on general interference has been proposed and studied theoretically with silica waveguides of silicon oxinitride (SiON) core by using a mathematical model based on sinusoidal modes for the reduction of coupling length of a 2x2 multimode interference (MMI) coupler. The coupling behaviors of the proposed structure are compared with those of other MMI structures. It is seen that the beat length for the proposed tapered MMI coupler is approximately half of that of a conventional MMI coupler. The effect of power imbalance on the fabrication tolerance of a 3 dB coupler using the proposed tapered structure is also studied and compared with that of other MMI structures.
authors.affiliation: Department of Electronics and Communication Engineering, Tezpur University, Assam, India. pps@tezu.ernet.in
authors.forename: P P
authors.initials: PP
authors.lastname: Sahu