Photonic integrated circuit illuminator

1. An apparatus comprising:

a photonic integrated circuit (PIC), the PIC including a laser source and at least one waveguide, the at least one waveguide including optical turning features, the at least one waveguide configured to propagate light transmitted by the laser source along a first axis parallel to a top surface of the PIC, and the optical turning features configured to divert the light to form collimated light beams that propagate along a second axis to exit the at least one waveguide and the top surface; and

a diffractive optical element (DOE) positioned over the top surface of the PIC along the second axis and configured to diffract the collimated light beams and output the diffracted collimated light beams.

2. The apparatus of claim 1 , wherein the laser source comprises a light emitting surface perpendicular to the top surface of the PIC; and

wherein the laser source is configured to emit the light via the light emitting surface to the at least one waveguide.

3. The apparatus of claim 1 , wherein the DOE is configured to diffract the collimated light beams to form structured light having pre-determined patterns for image-based depth sensing.

4. The apparatus of claim 1 , wherein the DOE is configured to diffract the collimated light beams to project a blanket of diffused light for time-of-flight measurement.

5. The apparatus of claim 1 , wherein the optical turning features are configured such that the second axis is perpendicular to the top surface of the PIC.

6. The apparatus of claim 1 , wherein the optical turning features include optical gratings; and

wherein a distance between two of the optical gratings along the first axis is configured based on a target beam width along the first axis.

7. The apparatus of claim 1 , wherein the at least one waveguide comprises a plurality of waveguides arranged along a third axis, the third axis being perpendicular to the first axis and parallel with the top surface of the PIC, each of the plurality of waveguides comprising optical turning features;

wherein each of the plurality of waveguides is configured to propagate the light transmitted by the laser source along the first axis parallel with the top surface of the PIC; and

wherein the optical turning features of the plurality of waveguides are configured to divert the light propagated in the plurality of waveguides to form a two-dimensional array of collimated light beams that propagate along the second axis to exit the plurality of waveguides and the top surface of the PIC.

8. The apparatus of claim 7 , wherein a distance between two of the plurality of waveguides along the third axis is configured based on a target beam width along the third axis.

9. The apparatus of claim 7 , further comprising a star coupler coupled with the laser source with the plurality of waveguides.

10. The apparatus of claim 7 , wherein an angle between the top surface of the PIC and the second axis along which the two-dimensional array of collimated light beams propagate is adjustable.

11. The apparatus of claim 10 , further comprising a plurality of phase shifters;

wherein each of the plurality of phase shifters is coupled with each of the plurality of waveguides; and

wherein each of the plurality of phase shifter is configured to introduce a phase delay in each of the collimated light beams that exits from the each of the plurality of waveguides.

12. The apparatus of claim 11 , further comprising a phase shifter controller;

wherein the phase shifter controller is configured to set the phase delay at each of the plurality of phase shifters to set the angle between the second axis and the top surface.

13. The apparatus of claim 1 , wherein the PIC includes a Silicon substrate.

14. The apparatus of claim 1 , wherein the laser source comprises materials from one of Groups III, IV, or V.

15. The apparatus of claim 1 , wherein the DOE comprises a lens.

16. The apparatus of claim 1 , wherein the DOE comprises a light diffuser panel.

17. An apparatus, comprising:

an illuminator comprising:

a photonic integrated circuit (PIC), the PIC including a laser source and at least one waveguide, the at least one waveguide including optical turning features, the at least one waveguide configured to propagate light transmitted by the laser source along a first axis parallel to a top surface of the PIC, and the optical turning features configured to divert the light to form collimated light beams that propagate along a second axis to exit the at least one waveguide and the top surface; and

a diffractive optical element (DOE) over the top surface of the PIC along the second axis and configured to diffract the collimated light beams and project the diffracted collimated light beams towards an object;

an optical sensor configured to generate a detection output based on detecting at least part of the diffracted collimated light beams reflected off the object; and

a controller configured to determine a depth of the object with respect to the apparatus based on the detection output.

18. The apparatus of claim 17 , wherein the DOE is configured to diffract the collimated light beams to form structured light having pre-determined patterns;

wherein the optical sensor further comprises a pixel array configured to obtain an image of the pre-determined patterns on a surface of the object based on detecting at least part of the diffracted collimated light beams reflected off the surface of the object; and

wherein the controller is configured to estimate a distance between the illuminator and each of a plurality of positions on the surface of the object based on the image to determine the depth.

19. The apparatus of claim 17 , wherein the DOE is configured to diffract the collimated light beams to form a blanket of light;

wherein the optical sensor is configured to determine time-of-arrival information of photons of the blanket of light reflected off a surface of the object; and

wherein the controller is configured to estimate a distance between the illuminator and each of a plurality of positions on the surface of the object based on the time-of-arrival information.

20. A method, comprising:

controlling a laser source of a photonic integrated circuit (PIC) to transmit light;

propagating, by at least one waveguide of the PIC, the light along a first axis parallel to a top surface of the PIC;

diverting, by optical turning features of the at least one waveguide of the PIC, the light from the first axis to a second axis as collimated light beams to exit the at least one waveguide and the top surface;

diffracting, by a diffracted optical element (DOE) positioned over the top surface of the PIC along the second axis, the collimated light beams to form output light; and

projecting, by the DOE, the output light.