title: Efficient coupling of narrow beams into polyimide waveguides by means of grating couplers with high-index coating.
abstract: The effect of a thin high-index coating deposited on polyimide waveguide grating couplers was investigated. A comprehensive numerical study was performed using an efficient simulation tool based on a Floquet-Bloch algorithm, and the results of this study were compared with experimentally obtained values for input coupling efficiencies. The application of a high-index coating permits efficient coupling from narrow beams even in material systems with a low index difference. This not only facilitates a denser integration of grating couplers but also permits low-loss lateral tapering to single-mode waveguides.
authors.affiliation: AIT Austrian Institute of Technology GmbH, Health and Environment Department, Nano Systems, Donau-City-Strasse 1, 1220 Vienna, Austria. roman.bruck@ait.ac.at
authors.forename: Roman
authors.initials: R
authors.lastname: Bruck
authors.forename: Rainer
authors.initials: R
authors.lastname: Hainberger
mesh_terms: D000465:Algorithms; D005583:Fourier Analysis; D055096:Optical Devices / Q000706:statistics & numerical data; D055620:Optical Phenomena; D011108:Polymers; D012825:Silicon; D013499:Surface Properties
chemical_list: D011108:Polymers; D012825:Silicon