title: Dual-mode waveguide crossing utilizing taper-assisted multimode-interference couplers.
abstract: A dual-mode waveguide crossing is proposed and realized for the application of on-chip multimode interconnection. The present structure is realized by two 90° crossed multimode-interference (MMI) couplers. By properly choosing the width and length of the MMI section, the self-images for both the incident TM0mode and the TM1mode could be at the center of the crossing. The characterization results for the fabricated device show that low insertion loss below ∼1.5  dB and low crosstalk below ∼-18  dB can be achieved over a large bandwidth more than 80 nm for both the TM0and TM1modes.
authors.forename: Hongnan
authors.initials: H
authors.lastname: Xu
authors.forename: Yaocheng
authors.initials: Y
authors.lastname: Shi