Apparatus and Method for Differential Thermal Optical Switch Control

Abstract

Embodiments are provided for an apparatus and method for differential thermal optical switch control. The optical switch is operated based on the interferometric principle by modifying the optical phase between waves propagating in waveguides via refractive index change in the waveguides using the thermo-optic effect. A heat pump designed as part of the optical switch is used to generate a temperature difference across the waveguides based on the thermo-electric effect. The thermo-electric effect is obtained using thermo-electric material or elements, also referred to as Peltier elements. An embodiment apparatus includes a dielectric base, a pair of waveguides extended in parallel on the dielectric base, and on the dielectric base a thermo-electric material in contact with the pair of waveguides. Additionally, a pair of electrodes extended, on the thermo-electric material, next to and along the length of the waveguides.

What is claimed is: 
     
         1 . An optical interferometer comprising:
 a first waveguide disposed on a substrate, the first waveguide having a plurality of straight segments, each segment of the straight segments connected to a subsequent segment of the straight segments by respective curved segments having one of a smaller radius of curvature and a larger radius of curvature;   a second waveguide disposed on the substrate, the second waveguide having a plurality of straight segments, each segment of the straight segments connected to a subsequent segment of the straight segments by respective curved segments having one of a smaller radius of curvature and a larger radius of curvature, the straight segments of the second waveguide interleaved with and parallel to the straight segments of the first waveguide, the curved segments having a smaller radius of curvature of the first waveguide nested within the curved segments having a larger radius of curvature of the second waveguide, the curved segments having a smaller radius of curvature of the second waveguide nested within the curved segments having a larger radius of curvature of the first waveguide;   a single continuous layer of a thermo-electric material disposed on the substrate, the thermo-electric material in contact with the first waveguide and the second waveguide, the thermo-electric material extending at least between outer sides of and across both the first waveguide and the second waveguide, the thermo-electric material extending along the length of each of the plurality of straight segments of the first waveguide and the second waveguide; and   a pair of electrodes disposed on the thermo-electric material, the pair of electrodes next to first waveguide and the second waveguide and extending along the length of each of the plurality of straight segments of the first waveguide and the second waveguide.   
     
     
         2 . The optical interferometer of  claim 1  wherein the first waveguide and the second waveguide are of a substantially equal length. 
     
     
         3 . The optical interferometer of  claim 1  wherein the curved segments having a smaller radius of curvature of the first and second waveguides have a substantially equal radius of curvature. 
     
     
         4 . The optical interferometer of  claim 1  wherein the curved segments having a larger radius of curvature of the first and second waveguides have a substantially equal radius of curvature. 
     
     
         5 . The optical interferometer of  claim 1  further comprising:
 a splitter coupled to a first end of the first and second waveguides; 
 an input signal waveguide coupled to the splitter on an opposite end of the splitter from the first and second waveguides; 
 a coupler coupled to a second end of the first and second waveguides; and 
 an output signal waveguide coupled to the coupler on an opposite end of the coupler from the first and second waveguides. 
 
     
     
         6 . The optical interferometer of  claim 1 , wherein the thermo-electric material is a semiconductor layer between the substrate and the first and second waveguides. 
     
     
         7 . The optical interferometer of  claim 1 , wherein the pair of electrodes extend between the first and second waveguides, and next to inner edges of the first and second waveguides. 
     
     
         8 . The optical interferometer of  claim 7 , further comprising a second pair of electrodes disposed on the thermo-electric material, the second pair of electrodes extending along the length of each of the plurality of straight segments of the first waveguide and the second waveguide, the second pair of electrodes next to outer edges of the first and second waveguides. 
     
     
         9 . The optical interferometer of  claim 1 , wherein the pair of electrodes are next to outer edges of the first and second waveguides. 
     
     
         10 . The optical interferometer of  claim 1 , wherein the first and second waveguides are composed of one of Silicon Oxide (SiO 2 ), Silicon Nitride (SiN), or Silicon (Si). 
     
     
         11 . The optical interferometer of  claim 1  wherein the substrate is a dielectric base. 
     
     
         12 . The optical interferometer of  claim 11 , wherein the dielectric base is composed of one of Silicon Oxide (SiO 2 ) or glass. 
     
     
         13 . The optical interferometer of  claim 1 , wherein the thermo-electric material is n-type or p-type doped Silicon.