Optical waveguide structure

摘要

An optical waveguide structure formed on an optical chip comprising a first waveguide layer 3 of a first material supported on a substrate 7 and a second waveguide layer 6 of a second material supported on the first waveguide layer 3. The first waveguide layer 3 is separated from the substrate 7 by an optical confinement layer 8 and the second waveguide layer 6 is separated from the first waveguide layer 3 by an etch-stop layer 9. The etch-stop layer 9 is thin compared to the thickness of the first waveguide layer 3 and/or the second waveguide layer 6 and is of a material which enables it to act as an etch-stop when features are etched in the second waveguide layer 6.)