title: Efficient, broadband and compact metal grating couplers for silicon-on-insulator waveguides.
abstract: Compact metal grating couplers for efficient and broadband coupling between optical fibers and silicon-on-insulator waveguides are proposed and demonstrated. Simulation results for silver, gold, aluminum and copper grating couplers are presented. Using a uniform silver grating, coupling efficiencies are calculated as high as 60 % at a wavelength of 1.55 mum. Metal grating couplers require only one single etching or lift-off step and are therefore very easy to fabricate. As a proof of principle, a gold grating coupler for near-vertical fiber-to-waveguide coupling was fabricated using e-beam writing and lift-off, demonstrating 34 % coupling efficiency and a 1 dB-bandwidth of 40 nm. Measurement data and simulation results are in good agreement.
authors: Stijn
authors: S
authors: Scheerlinck
authors: Jonathan
authors: J
authors: Schrauwen
authors: Frederik
authors: F
authors: Van Laere
authors: Dirk
authors: D
authors: Taillaert
authors: Dries
authors: D
authors: Van Thourhout
authors: Roel
authors: R
authors: Baets