Patent ID: 8582937

Claim:
A device, comprising: a substrate having a surface; a first ring waveguide and a second ring waveguide on the surface; a first p-doped region inside the first ring waveguide and a second p-doped region inside the second ring waveguide; a first n-doped region interposed between the first ring waveguide and the second ring waveguide, a second n-doped region outside the first ring waveguide, a third n-doped region outside the second ring waveguide; a first linear waveguide located on the surface adjacent to the first ring waveguide and the second ring waveguide; a fourth n-doped region on the surface located adjacent to the first linear waveguide; a control circuit configured to modulate light in the first linear waveguide using a voltage source, a first electrical connection to the first p-doped region, a second electrical connection to the second p-doped region, and a third electrical connection to the first n-doped region, and a feedback control circuit configured to control a temperature of the first and second ring waveguide, wherein the temperature of the first and second ring waveguides is modified based on a difference between the scattered light detected by a plurality of optical detectors.