| CPC G02B 6/14 (2013.01) [G02B 6/1228 (2013.01)] | 20 Claims |
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1. A device comprising:
first, second, third and fourth elements fabricated on a common substrate;
wherein the first element comprises an active waveguide structure supporting a first optical mode, the second element comprises a passive waveguide structure supporting a second optical mode, the third element, at least partly butt-coupled to the first element, comprises an intermediate waveguide structure supporting intermediate optical modes, and a fourth element comprising TCO material that is attached to the first element;
wherein, if the first optical mode differs from the second optical mode by more than a predetermined amount, a tapered waveguide structure in at least one of the second and third elements facilitates efficient adiabatic transformation between the second optical mode and one of the intermediate optical modes;
wherein no adiabatic transformation occurs between any of the intermediate optical modes and the first optical mode; and
wherein mutual alignments of the first, the second and the third elements are defined using lithographic alignment marks that facilitate precise alignment between layers formed during processing steps of fabricating the first, the second and the third elements.
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