Amorphous silicon and silicon nitride channel optical waveguides

n this work we report on the characterisation of multimode rectangular ridge waveguides fabricated by Plasma Enhanced Chemical Vapor Deposition and anisotropic etching using different cores, consisting of hydrogenated amorphous silicon and amorphous silicon nitride. The propagation losses have been measured at several wavelengths by an end-fire coupling set-up and compared to intrinsic absorption of the core materials. Two-dimensional photonic crystal structures have been carved onto the channel waveguides by Focused Ion Beam lithography demonstrating the possibility to fabricate complex optical elements merging the consolidated amorphous silicon growth technology with ion-beam nanomachining.