Dual-polarization grating coupler

Patent metadata

Field	Value
Publication number	US-12265263-B2
Application number	US-202117567020-A
Country	US
Kind code	B2
Filing date	Dec 31, 2021
Priority date	Jan 4, 2021
Publication date	Apr 1, 2025
Grant date	Apr 1, 2025

Abstract

An optical grating coupler includes a primary layer formed of a material having a first refractive index. A first plurality of scattering elements is formed within the primary layer. The first plurality of scattering elements has a second refractive index that is different than the first refractive index. A secondary layer is formed over the primary layer. The secondary layer is formed of a material having a third refractive index. A second plurality of scattering elements is formed within the secondary layer. The second plurality of scattering elements has a fourth refractive index that is different than the third refractive index. The fourth refractive index is different than the second refractive index. At least some of the second plurality of scattering elements at least partially overlap corresponding ones of the first plurality of scattering elements.

First claim

What is claimed is:

1. An optical grating coupler, comprising:
a primary layer formed of a material having a first refractive index, the primary layer having a top surface;
a first plurality of scattering elements formed within the primary layer, the first plurality of scattering elements having a second refractive index that is different than the first refractive index, wherein each of the first plurality of scattering elements has a cross-shaped cross-section oriented parallel to the top surface of the primary layer;
a secondary layer formed over the primary layer, the secondary layer formed of a material having a third refractive index, the secondary layer having a top surface; and
a second plurality of scattering elements formed within the secondary layer, the second plurality of scattering elements having a fourth refractive index that is different than the third refractive index, wherein the fourth refractive index is different than the second refractive index, wherein each of the second plurality of scattering elements has a cross-shaped cross-section oriented parallel to the top surface of the secondary layer, wherein at least some of the second plurality of scattering elements at least partially overlap corresponding ones of the first plurality of scattering elements.

2. The optical grating coupler as recited in claim 1 , wherein the first plurality of scattering elements are positioned symmetrically on each side of a vertical plane of symmetry that bisects the optical grating coupler, and wherein the second plurality of scattering elements are positioned symmetrically on each side of the vertical plane of symmetry.

3. The optical grating coupler as recited in claim 2 , wherein the first plurality of scattering elements and the second plurality of scattering elements are collectively formed and positioned to scatter both a first incoming light beam and a second incoming light beam into an off-chip beam of light.

4. The optical grating coupler as recited in claim 3 , wherein the first incoming light beam is received through a first lateral side of the optical grating coupler, wherein the second incoming light beam is received through a second lateral side of the optical grating coupler, wherein the first and second lateral sides of the optical grating coupler are adjacent sides along an outer perimeter of the optical grating coupler, wherein the first lateral side of the optical grating coupler is on a first side of the vertical plane of symmetry, and wherein the second lateral side of the optical grating coupler is on a second side of the vertical plane of symmetry.

5. The optical grating coupler as recited in claim 4 , wherein the first lateral side of the optical grating coupler is optically coupled to a first optical waveguide taper, the first incoming light beam received through the first optical waveguide taper, and wherein the second lateral side of the optical grating coupler is optically coupled to a second optical waveguide taper, the second incoming light beam received through the second optical waveguide taper.

6. The optical grating coupler as recited in claim 4 , wherein the first and second pluralities of scattering elements are arranged to include a first section of scattering element groups positioned along the first and second lateral sides of the optical grating coupler, wherein the first and second pluralities of scattering elements are arranged to include a second section of scattering element groups positioned behind the first section of scattering element groups in a direction away from the first and second lateral sides of the optical grating coupler, wherein the first and second pluralities of scattering elements are arranged to include a third section of scattering element groups positioned behind the second section of scattering element groups in the direction away from the first and second lateral sides of the optical grating coupler, wherein the first and second pluralities of scattering elements are arranged to include a fourth section of scattering element groups positioned behind the third section of scattering element groups in the direction away from the first and second lateral sides of the optical grating coupler.

7. The optical grating coupler as recited in claim 6 , wherein each scattering element group is a pair of scattering elements that includes a corresponding scattering element of the first plurality of scattering elements and a corresponding scattering element of the second plurality of scattering elements.

8. The optical grating coupler as recited in claim 6 , wherein the scattering elements of the first plurality of scattering elements in the second section of scattering element groups are larger than the scattering elements of the first plurality of scattering elements in the first section of scattering element groups, and wherein the scattering elements of the second plurality of scattering elements in the second section of scattering element groups are larger than the scattering elements of the second plurality of scattering elements in the first section of scattering element groups.

9. The optical grating coupler as recited in claim 8 , wherein the scattering elements of the first plurality of scattering elements in the third section of scattering element groups are larger than the scattering elements of the first plurality of scattering elements in the second section of scattering element groups, and wherein the scattering elements of the second plurality of scattering elements in the third section of scattering element groups are larger than the scattering elements of the second plurality of scattering elements in the second section of scattering element groups.

10. The optical grating coupler as recited in claim 9 , wherein the scattering elements of the first plurality of scattering elements in the fourth section of scattering element groups are larger than the scattering elements of the first plurality of scattering elements in the third section of scattering element groups, and wherein the scattering elements of the second plurality of scattering elements in the fourth section of scattering element groups are larger than the scattering elements of the second plurality of scattering elements in the third section of scattering element groups.

11. The optical grating coupler as recited in claim 1 , wherein the first plurality of scattering elements are positioned on respective gridpoints of a grid.

12. A method for combining light beams, comprising:
having an optical grating coupler that includes a primary layer formed of a material having a first refractive index, the primary layer having a top surface, the optical grating coupler including a first plurality of scattering elements formed within the primary layer, the first plurality of scattering elements having a second refractive index that is different than the first refractive index, wherein each of the first plurality of scattering elements has a cross-shaped cross-section oriented parallel to the top surface of the primary layer, the optical grating coupler including a second layer formed over the primary layer, the second layer formed of a material having a third refractive index, the secondary layer having a top surface, the optical grating coupler including a second plurality of scattering elements formed within the secondary layer, the second plurality of scattering elements having a fourth refractive index that is different than the third refractive index, wherein the fourth refractive index is different than the second refractive index, wherein each of the second plurality of scattering elements has a cross-shaped cross-section oriented parallel to the top surface of the seco

Assignees

• Ayar Labs Inc

Inventors

• Fini john
• Krishnamoorthy Uma

Classifications

• G02B6/2726

  in or on light guides, e.g. polarisation means assembled in a light guide · CPC title

• G02B6/124

  Geodesic lenses or integrated gratings · CPC title

• G02B6/12002

  Three-dimensional structures · CPC title

• G02B6/30

  for use between fibre and thin-film device · CPC title

• G02B6/34 Primary

  utilising prism or grating {(G02B6/293 takes precedence)} · CPC title