Ring resonator with integrated detector for monitoring light comprising an annular detection region that is physically isolated from a waveguide core

A ring resonator, comprising:

• an annular waveguide formed of a first semiconductor material, wherein the annular waveguide comprises a waveguide base and a waveguide core narrower than the waveguide base;
• an outer contact region comprising a first-type doping and disposed annularly and at least partially surrounding an outer annular surface of the waveguide base;
• an inner contact region comprising a second-type doping and disposed annularly contacting an inner annular surface of the waveguide base;
• and
• an annular detector region formed of a second semiconductor material and disposed annularly at a distance from and covering at least a portion of a surface of the waveguide core and contacting the outer contact region, wherein the annular detector region comprises a radial region formed over the waveguide core and a vertical region extending from the radial region via a region between the outer contact region and the waveguide base, wherein the vertical region extends up to a predetermined depth into a substrate through a base oxide layer, wherein the annular waveguide, the outer contact region, the inner contact region, and the annular detector region are formed over the base oxide layer disposed on the substrate.

A method comprising:

• providing a wafer comprising a foundation semiconductor layer;
• forming an annular waveguide in the foundation semiconductor layer, the annular waveguide comprising a waveguide base and a waveguide core narrower than the waveguide base;
• forming an outer contact region in the foundation semiconductor layer, the outer contact region comprising a first-type doping and disposed annularly and at least partially surrounding an outer annular surface of the waveguide base;
• forming an inner contact region in the foundation semiconductor layer, the inner contact region comprising a second-type doping and disposed annularly contacting an inner annular surface of the waveguide base;
• and
• forming an annular detector region annularly at a distance from and covering at least a portion of a surface of the waveguide core and contacting the outer contact region, wherein the annular detection region is physically isolated from the waveguide core.