Patent ID: 9726818
Date: 2017-08-08
CPC Classifications: G01S,G02B,G02F,H01L

Claim:
1. An optical phase shifter comprising a photonic waveguide for conducting light having a first wavelength and light having a second wavelength, the waveguide comprising superposed first and second strips of light conducting semiconductor materials having first and second refractive indexes, wherein the second wavelength is shorter than the first wavelength and the second refractive index is higher than the first refractive index, wherein the width and height of the first strip of light conducting semiconductor material are such that the first strip of light conducting semiconductor material is adapted to support an optical mode of the first wavelength by said first strip of light conducting semiconductor material and the width and height of the second strip of light conducting semiconductor material are such that the second strip of light conducting semiconductor material is adapted to support an optical mode of the second wavelength by said second strip of light conducting semiconductor material but is too narrow to support an optical mode of the first wavelength by said second strip of light conducting semiconductor material; wherein: the first and second strips of light conducting semiconductor materials comprise each a layer of thermo-optic material; the phase shifter further comprising first and second temperature control elements arranged for controllably changing the temperature of the thermo-optic material of the first and second strips of light conducting semiconductor materials.