Coupling lens aberration correction through grating design in a switched focal plane array

Patent metadata

Field	Value
Publication number	US-10838150-B2
Application number	US-201816202254-A
Country	US
Kind code	B2
Filing date	Nov 28, 2018
Priority date	Nov 28, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A coupling interface arrangement is described for a photonic integrated circuit (PIC) device. The PIC includes an interface coupling surface having optical grating elements arranged to form optical output locations that produce corresponding light output beams. A coupling lens couples the light output beams into a conjugate plane at a far-field scene characterized by one or more optical aberrations that degrade optical resolution of the light outputs. The optical grating elements are configured to correct for the one or more optical aberrations.

First claim

What is claimed is:

1. A coupling interface arrangement for a photonic integrated circuit (PIC), the arrangement comprising:
a PIC including an interface coupling surface having a plurality of optical grating elements arranged to form a plurality of optical output locations configured to produce corresponding light output beams; and
a coupling lens configured for coupling the light output beams into a conjugate plane at a far-field scene characterized by one or more optical aberrations that degrade optical resolution of the light outputs;
wherein the optical grating elements are configured to correct for the one or more optical aberrations.

2. The arrangement according to claim 1 , wherein the optical grating elements are characterized by a grating tooth width, a grating period, and a grating thickness, at least one of which is configured to correct for the optical aberrations of the light output beams.

3. The arrangement according to claim 1 , wherein the PIC includes a plurality of optical waveguides configured to deliver light to the optical output locations and characterized by a waveguide geometry configured to correct for the optical aberrations of the light output beams.

4. The arrangement according to claim 3 , wherein the PIC is characterized by a grating-waveguide spacing configured to correct for the optical aberrations of the light output beams.

5. The arrangement according to claim 1 , wherein the coupling lens is characterized by a curved focal plane, and wherein the plurality of optical grating elements are configured to control focus of the light output beams to correct for the curved focal plane.

6. The arrangement according to claim 1 , wherein the plurality of optical grating elements are periodic grating elements.

7. The arrangement according to claim 1 , wherein the plurality of optical grating elements are aperiodic grating elements.

8. The arrangement according to claim 1 , wherein the PIC is configured as part of a monostatic optical system.

9. The arrangement according to claim 1 , wherein the PIC is configured as part of a bistatic optical system.

10. The arrangement according to claim 1 , wherein the coupling lens is a telecentric lens for coupling light output beams with chief ray optic axes perpendicular to the interface coupling surface.

11. The arrangement according to claim 1 , wherein the coupling lens is a conventional lens for coupling light output beams with chief ray optic axes at various different angles relative to perpendicular to the interface coupling surface.

12. The arrangement according to claim 1 , further comprising:
a planar lens array with a plurality of lens elements of differing focal lengths located between the interface coupling surface and the coupling lens configured to match the focal planes of the PIC and coupling lens.

13. The arrangement according to claim 12 , wherein the PIC is characterized by a field-of-view, and wherein the optical grating elements and the planar lens array are organized to shift the focal plane of pixels at different points within the field of view.

14. The arrangement according to claim 1 , further comprising:
a holographic element located between the interface coupling surface and the coupling lens configured to cooperate with the optical grating elements to adjust the phase and intensity profiles of the light output beams to correct for the one or more optical aberrations.

15. The arrangement according to claim 1 , wherein the optical grating elements are configured to match a numerical aperture of the light output beams from the PIC with a numerical aperture of the coupling lens.

16. The arrangement according to claim 1 , wherein the PIC is characterized by a field-of-view, and wherein the optical grating elements are organized into a plurality of grating subsets each optimized for a different range in the field of view.

17. A coupling interface arrangement for a photonic integrated circuit (PIC), the arrangement comprising:
a PIC including an interface coupling surface having a plurality of optical grating elements arranged to form a plurality of optical input locations configured to receive light input beams to the PIC; and
a coupling lens configured for delivering the light input beams to the optical input locations by optically shaping optical communications signals from a conjugate plane at a far-field scene characterized by one or more optical aberrations that degrade optical resolution of the light input beams;
wherein the optical grating elements are configured to correct for the one or more optical aberrations.

18. The arrangement according to claim 17 , wherein the optical grating elements are characterized by a grating tooth width, a grating period, and a grating thickness, at least one of which is configured to correct for the optical aberrations of the light input beams.

19. The arrangement according to claim 17 , wherein the PIC includes a plurality of optical waveguides configured to receive light at the optical input locations and characterized by a waveguide geometry configured to correct for the optical aberrations of the light input beams.

20. The arrangement according to claim 19 , wherein the PIC is characterized by a grating-waveguide spacing configured to correct for the optical aberrations of the light input beams.

21. The arrangement according to claim 17 , wherein the coupling lens is characterized by a curved focal plane, and wherein the plurality of optical grating elements are configured to control focus of the light input beams to correct for the curved focal plane.

22. The arrangement according to claim 17 , wherein the plurality of optical grating elements are periodic grating elements.

23. The arrangement according to claim 17 , wherein the plurality of optical grating elements are aperiodic grating elements.

24. The arrangement according to claim 17 , wherein the PIC is configured as part of a monostatic optical system.

25. The arrangement according to claim 17 , wherein the PIC is configured as part of a bistatic optical system.

26. The arrangement according to claim 17 , wherein the coupling lens is a telecentric lens for coupling light input beams with chief ray optic axes perpendicular to the interface coupling surface.

27. The arrangement according to claim 17 , wherein the coupling lens is a conventional lens for coupling light input beams with chief ray optic axes at various different angles relative to perpendicular to the interface coupling surface.

28. The arrangement according to claim 17 , further comprising:
a planar lens array with a plurality of lens elements of differing focal lengths located between the interface coupling surface and the coupling lens configured to match the focal planes of the PIC and coupling lens.

29. The arrangement according to claim 28 , wherein the PIC is characterized by a field-of-view, and wherein the optical grating elements and the planar lens array are organized to shift the focal plane of pixels at different points within the field of view.

30. The arrangement according to claim 17 , further comprising:
a holographic element located between the interface coupling surface and the coupling lens configured to cooperate with the optical grating elements to adjust the phase and intensity profiles of the light output beams to correct for the one or more op

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Moebius Michael G
• Byrnes Steven J
• Spector Steven J
• Rogomentich Francis J
• Sinclair Matthew A

Classifications

• G02B6/124 Primary

  Geodesic lenses or integrated gratings · CPC title

• G02B2006/12107

  Grating · CPC title

• G02B2006/12147

  Coupler · CPC title

• G02B6/34 Primary

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

• G02B27/0037

  with diffracting elements (G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876) · CPC title