Polymer waveguide based biosensor

Abstract

Planar-integrated optical biosensors based on the interferometric evanescent wave sensing principle facilitate highly sensitive label-free detection of biomolecules. In this work, we present a novel polymer waveguide device concept that allows for cost effective fabrication of disposable sensor chips by utilizing injection moulding and spin-coating. Surface grating couplers are used in combination with lateral tapers to couple light in and out of the biosensor. The coupling strength of these polymer gratings is increased by applying a thin inorganic high-index coating, which allows reducing the grating size and thus achieving efficient lateral tapering into single mode waveguides. The sensor concept, design of the waveguide components as well as first experimental results of the injection moulding process, the grating couplers and the Mach-Zehnder interferometers are presented.