Active-passive photonic integrated circuit platform

Abstract

A device has a plurality of waveguide structures including two active (one of which comprises two sub-layers), two passive, and three intermediate waveguide structures on a common substrate. At least partial butt coupling between active and intermediate waveguide structures, and tapering in the intermediate and/or passive waveguide structures at each junction therebetween facilitates efficient optical mode transformations as optical signals travel through the device, either from a first sub-layer of the first active waveguide structure through the other sub-layer, then sequentially though a first intermediate waveguide structure, a passive waveguide structure, a second intermediate waveguide structure, a second active waveguide structure, a third intermediate structure, and a second passive waveguide structure; or in reverse from the second passive waveguide structure back through to the first sub-layer of the first active waveguide structure. Lithographic alignment marks facilitate precise mutual alignments between layers defining each of the waveguide structures.