title: Subwavelength index engineered surface grating coupler with sub-decibel efficiency for 220-nm silicon-on-insulator waveguides.
abstract: Surface grating couplers are fundamental components in chip-based photonic devices to couple light between photonic integrated circuits and optical fibers. In this work, we report on a grating coupler with sub-decibel experimental coupling efficiency using a single etch process in a standard 220-nm silicon-on-insulator (SOI) platform. We specifically demonstrate a subwavelength metamaterial refractive index engineered nanostructure with backside metal reflector, with the measured peak fiber-chip coupling efficiency of -0.69 dB (85.3%) and 3 dB bandwidth of 60 nm. This is the highest coupling efficiency hitherto experimentally achieved for a surface grating coupler implemented in 220-nm SOI platform.
authors.forename: Daniel
authors.initials: D
authors.lastname: Benedikovic
authors.forename: Pavel
authors.initials: P
authors.lastname: Cheben
authors.forename: Jens H
authors.initials: JH
authors.lastname: Schmid
authors.forename: Dan-Xia
authors.initials: DX
authors.lastname: Xu
authors.forename: Boris
authors.initials: B
authors.lastname: Lamontagne
authors.forename: Shurui
authors.initials: S
authors.lastname: Wang
authors.forename: Jean
authors.initials: J
authors.lastname: Lapointe
authors.forename: Robert
authors.initials: R
authors.lastname: Halir
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ortega-Moñux
authors.forename: Siegfried
authors.initials: S
authors.lastname: Janz
authors.forename: Milan
authors.initials: M
authors.lastname: Dado