Abstract: Silicon photonic integrated circuit (PIC) on a multi-zone semiconductor on insulator (SOI) substrate having at least a first zone and a second zone. Various optical devices of the PIC may be located above certain substrate zones that are most suitable. A first length of a photonic waveguide structure comprises the crystalline silicon and is within the first zone, while a second length of the waveguide structure is within the second zone. Within a first zone, the crystalline silicon layer is spaced apart from an underlying substrate material by a first thickness of dielectric material. Within the second zone, the crystalline silicon layer is spaced apart from the underlying substrate material by a second thickness of the dielectric material.

Abstract: Embodiments of the present disclosure are directed to low numerical aperture (NA) optical couplers, or spot size converters, that include a lateral taper section and/or a vertical adiabatic taper section. In embodiments, the optical couplers may be positioned on a silicon substrate proximate to V-grooves within the substrate to contain optical fibers to self-align and to couple with the optical couplers. Other embodiments may be described and/or claimed.