Method and apparatus for incorporating a low contrast interface and a high contrast interface into an optical device

An apparatus, comprising:

• a semiconductor material including a plurality of regions through which an optical beam is directed;
• an insulator disposed proximate to the plurality of regions of the semiconductor material, the insulator having a refractive index substantially different than a refractive index of the semiconductor material, such that high contrast interfaces are defined between the semiconductor material and the insulator;
• and
• a doped region disposed between at least two of the plurality of regions of the semiconductor material, the doped region including the semiconductor material and a dopant material and having a refractive index slightly different than the refractive index of the semiconductor material, such that low contrast interfaces are defined between the semiconductor material and the doped region, the optical beam to be directed through the doped region from one of the plurality of regions to another of the plurality of regions with at least one of optical coupling or evanescent coupling depending on an incident angle of the optical beam relative to the low contrast interface.