Hybrid optical beam steering

• US 10,684,531 B1
• Filed: 02/22/2019
• Issued: 06/16/2020
• Est. Priority Date: 02/22/2019
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Ziemkiewicz, Michael, Dunn, Tyler Adam, Anderson, Michael Howard, Davis, Scott Robert
• Primary Examiner(s): Lepisto, Ryan A
• Assistant Examiner(s): Chiem, Erin D
• Application Number:
  US16/283,229
• Time in Patent Office: 480 Days
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G02B 26/0883 the refracting element being a prism
• CPC Class Codes: G02B 26/106 having diffraction gratings as scanning elements, e.g. holographic scanners holographic optical elements G02B5/32, holography G03H
• CPC Class Codes: G02B 26/108 having one or more prisms as scanning elements
• CPC Class Codes: G02F 1/1326 Liquid crystal optical waveguides or liquid crystal cells specially adapted for gating or modulating between optical waveguides
• CPC Class Codes: G02F 1/2955 by controlled diffraction or phased-array beam steering controlled diffraction for optical waveguide switching G02F1/313
• CPC Class Codes: G02F 2201/122 having a particular pattern
• CPC Class Codes: G02F 2203/24 beam steering

Abstract

A light beam can be steered using a non-mechanical beam steerer structure. For example, a combination of sub-aperture and full-aperture beam steering structures can be used (e.g., corresponding to regions of controlled variation in an index of refraction). The sub-aperture elements can include tapered structures defining a saw-tooth or triangular footprint in the plane in which the in-plane steering is performed. Respective rows of sub-aperture tapered structures can be configured to controllably steer the light beam in the first in-plane direction, wherein at least one row of sub-aperture tapered structures defines a first base region edge that is tipped at a first specified in-plane angle relative to a second base region edge defined by another row. Use of the tipped configuration can simplify a configuration of the beam steerer structure, such as allowing a configuration lacking a compensation plate at the input.

Claims

1. A beam steering apparatus for adjusting an angle of a light beam, the beam steering apparatus comprising:

a first beam steering portion comprising at least two rows of sub-aperture tapered structures configured to controllably steer the light beam in a first in-plane direction using an adjustable index of refraction, wherein at least one row amongst the at least two rows of sub-aperture tapered structures is tipped at a first specified in-plane angle relative to another row amongst the at least two rows, the first specified in-plane angle oriented in the first in-plane direction; and

a second beam steering portion comprising full-aperture beam steering elements to controllably refract the light beam in the first in-plane direction using an adjustable index of refraction.

2. The beam steering apparatus of claim 1, wherein the first beam steering portion comprises at least one row of the sub-aperture tapered structures that is tipped at a second specified in-plane angle with respect to another row amongst the at least two rows, the second specified in-plane angle corresponding to a second in-plane direction opposite the first in-plane direction.

3. The beam steering apparatus of claim 1, wherein the full-aperture beam steering elements of the second beam steering portion are configured to controllably refract the light beam in the first in-plane direction and in a second in-plane direction opposite the first in-plane direction.

4. The beam steering apparatus of claim 1, wherein the first beam steering portion is configured to provide discrete adjustment of an in-plane angle of the light beam in increments that are coarser than an angular steering resolution provided by the second beam steering portion.

5. The beam steering apparatus of claim 4, wherein the first beam steering portion is configured to provide selectable steering of the light beam to discretely-defined in-plane angular positions in response to a first control signal;

and

wherein the second beam steering portion is configured to provide selectable steering of the light beam about the discretely-defined in-plane angular positions in response to a second control signal.

6. The beam steering apparatus of claim 1, wherein at least two adjacent rows amongst the at least two rows of sub-aperture tapered structures comprise a pair of rows comprising:

a first row arranged to receive light at interconnected sub-aperture tapered structures comprising the first row, and to provide light toward a direction of distal peaks of tapered structures comprising the first row; and

a second row arranged to receive light from a direction of peaks of tapered structures comprising the second row, the tapered structures comprising the second row arranged having peaks facing corresponding distal peaks of the first row;

wherein a distance between respective facing distal peaks varies according to the specified in-plane angle.

7. The beam steering apparatus of claim 6, wherein the at least two rows comprise multiple pairs of rows.

8. The beam steering apparatus of claim 7, wherein the at least two rows comprise a first pair of rows and a second pair of rows, the second pair of rows tipped at the first specified in-plane angle relative to the first pair of rows.

9. The beam steering apparatus of claim 1, wherein the sub-aperture tapered structures have a pitch such that an angle of a sub-aperture portion of the light beam steered by a respective one of the sub-aperture tapered structures corresponds to an angle of a diffractive order of a row of the sub-aperture tapered structures comprising the respective one.

10. The beam steering apparatus of claim 1, comprising:

a waveguide core configured to guide the light beam along a length of a waveguide; and

a cladding including an electro-optic material, the cladding configured to interact with a portion of the light beam guided by the waveguide;

wherein the first beam steering portion comprises electrodes defining the sub-aperture tapered structures.

11. The beam steering apparatus of claim 10, wherein the second beam steering portion comprises electrode defining the full-aperture beam steering elements.

12. An optical waveguide for performing beam steering of a light beam, the optical waveguide comprising:

a waveguide core configured to guide the light beam along a length of a waveguide;

a cladding including an electro-optic material, the cladding configured to interact with a portion of the light beam guided by the waveguide;

an electrode arrangement configured to adjust an angle of the light beam in an in-plane direction by adjusting an index of refraction of the electro-optic material, wherein the electrode arrangement comprises;

a first beam steering portion comprising at least two rows of sub-aperture tapered electrodes configured to control steering the light beam in a first in-plane direction, wherein at least one row amongst the at least two rows of sub-aperture tapered structures is tipped at a first specified in-plane angle relative to a another row amongst the at least two rows, the first specified in-plane angle oriented in the first in-plane direction; and

a second beam steering portion comprising full-aperture beam steering electrodes configured to control refraction of the light beam in the first in-plane direction.

13. The optical waveguide of claim 12, wherein the full-aperture beam steering electrodes of the second beam steering portion are configured to control refraction of the light beam in the first in-plane direction and in a second in-plane direction opposite the first in-plane direction.

14. The optical waveguide of claim 12, wherein the first beam steering portion is configured to provide selectable steering of the light beam to discretely-defined in-plane angular positions in response to a first control signal;

and

wherein the second beam steering portion is configured to provide selectable steering of the light beam about the discretely-defined in-plane angular positions in response to a second control signal.

15. The optical waveguide of claim 12, wherein at least two adjacent rows amongst the at least two rows of sub-aperture tapered electrodes comprise a pair of rows comprising:

a first row arranged to receive light at interconnected sub-aperture tapered electrodes comprising the first row, and to provide light toward a direction of distal peaks of tapered electrodes comprising the first row; and

a second row arranged to receive light from a direction of peaks of tapered electrodes comprising the second row, the tapered electrodes comprising the second row arranged having peaks facing corresponding distal peaks of the first row;

wherein a distance between respective facing distal peaks varies according to the specified in-plane angle.

16. The optical waveguide of claim 12, wherein the at least two rows comprise multiple pairs of rows;

and

wherein the at least two rows comprise a first pair of rows and a second pair of rows, the second pair of rows tipped at the first specified in-plane angle relative to the first pair of rows.

17. A method for adjusting an angle of a light beam using a beam steering apparatus, the method comprising:

controllably steering the light beam in a first in-plane direction using a first beam steering portion comprising at least two rows of sub-aperture tapered structures, wherein at least one row amongst the at least two rows of sub-aperture tapered structures is tipped at a first specified in-plane angle relative to another row amongst the at least two rows, the first specified in-plane angle oriented in the first in-plane direction; and

controllably steering the light beam in the first in-plane direction using a second beam steering portion comprising full-aperture beam steering elements to refract the light beam in the first in-plane direction.

18. The method of claim 17, wherein the first beam steering portion is configured to provide adjustment of an in-plane angle of the light beam in angular increments that are coarser than an angular steering resolution provided by the second beam steering portion.

19. The method of claim 18, comprising:

generating a first control signal electrically coupled to electrode structures comprising the first beam steering portion to provide selectable steering of the light beam to discretely-defined in-plane angular positions; and

generating a second control signal electrically coupled to electrode structures comprising the second beam steering portion to provide selectable steering of the light beam about the discretely-defined in-plane angular positions.

20. The method of claim 18, comprising coupling the light beam into a waveguide;

wherein controllably steering the light beam using the first and second beam steering portions comprises adjusting an index of refraction of an electro-optic material forming at least a portion of a cladding, the cladding configured to interact with a portion of the light beam guided by the waveguide.