Two dimensional optical phased arrays using edge-coupled integrated circuits

1. An apparatus comprising:

a first integrated circuit comprising:

a plurality of sets of optical waveguides, each set of optical waveguides including a plurality of optical waveguide segments, and

a plurality of optical emitter elements arranged over a first surface of the first integrated circuit, each optical emitter element coupled to a distal end of one of the optical waveguide segments;

a second integrated circuit comprising:

a plurality of optical phase shifters that each provide a phase-shifted optical wave that is coupled to the first integrated circuit from a first edge surface of the second integrated circuit; and

a third integrated circuit comprising:

a plurality of optical phase shifters that each provide a phase-shifted optical wave that is coupled to the first integrated circuit from a first edge surface of the third integrated circuit;

wherein

the first edge surface of the second integrated circuit is in proximity to a row of proximal ends of the optical waveguide segments of a first set of the plurality of sets of optical waveguides, and

the first edge surface of the third integrated circuit is in proximity to a row of proximal ends of the optical waveguide segments of a second set of the plurality of sets of optical waveguides.

2. The apparatus of claim 1 , wherein the second integrated circuit and the third integrated circuit are each substantially perpendicular to the first integrated circuit.

3. The apparatus of claim 1 , wherein, in each set of optical waveguides, the plurality of optical waveguide segments in that set of optical waveguides are substantially parallel to each other.

4. The apparatus of claim 3 , wherein all of the plurality of optical waveguide segments in all of the sets of optical waveguides are substantially parallel to each other.

5. The apparatus of claim 3 , wherein, in each set of optical waveguides, a plurality of optical waveguide segments in that set of optical waveguides have a different length from each other.

6. The apparatus of claim 5 , wherein the plurality of optical emitter elements coupled to the distal ends of the optical waveguide segments in at least one of the sets of optical waveguides are arranged to emit optical waves from the first surface of the first integrated circuit along a line that is between 5 and 60 degrees relative to each of the parallel optical waveguide segments.

7. The apparatus of claim 1 , wherein at least a first of the phase-shifted optical waves coupled to the first integrated circuit from the first edge surface of the second integrated circuit is coupled to a proximal end of a first optical waveguide segment of the first set of the plurality of sets of optical waveguides in a first layer of the first integrated circuit.

8. The apparatus of claim 7 , wherein the first phase-shifted optical wave is coupled to the proximal end of the first optical waveguide segment by a portion of a waveguide in a second layer of the first integrated circuit that is closer to a surface of the first integrated circuit than the first layer of the first integrated circuit.

9. The apparatus of claim 7 , wherein the first phase-shifted optical wave is coupled to the proximal end of the first optical waveguide segment by a reflective surface in the first integrated circuit configured to redirect the phase-shifted optical wave into the proximal end of the first optical waveguide segment.

10. The apparatus of claim 1 , wherein the first surface of the first integrated circuit is a surface adjacent to the first edge surface of the second integrated circuit and the first edge surface of the third integrated circuit.

11. The apparatus of claim 1 , wherein the first surface of the first integrated circuit is a surface opposite from a surface adjacent to the first edge surface of the second integrated circuit and the first edge surface of the third integrated circuit.

12. The apparatus of claim 1 , wherein

the second integrated circuit comprises:

a first optical distribution network of waveguide splitters that provide optical waves to the plurality of optical phase shifters of the second integrated circuit; and

the third integrated circuit comprises:

a second optical distribution network of waveguide splitters that provide optical waves to the plurality of optical phase shifters of the third integrated circuit.

13. The apparatus of claim 12 , wherein the first optical distribution network and the second optical distribution network are coupled to an optical waveguide in the first integrated circuit.

14. The apparatus of claim 1 , wherein

the second integrated circuit is coupled to a fourth integrated circuit that provides electrical control signals to the plurality of optical phase shifters of the second integrated circuit; and

the third integrated circuit is coupled to a fifth integrated circuit that provides electrical control signals to the plurality of optical phase shifters of the third integrated circuit.

15. The apparatus of claim 1 , wherein the second integrated circuit and the third integrated circuit are included in a stack of phase shifter integrated circuits providing phase-shifted optical waves that form a structure that has a surface that includes edge surfaces of all of the phase shifter integrated circuits.

16. The apparatus of claim 15 , wherein

the second integrated circuit includes a plurality of trenches filled with conductive material that end at the surface of the structure; and

the third integrated circuit includes a plurality of trenches filled with conductive material that end at the surface of the structure.

17. The apparatus of claim 16 , a plurality of conductive pads are formed on the surface of the structure in contact with the ends of the trenches of the second integrated circuit and the ends of the trenches of the third integrated circuit.

18. An apparatus comprising:

a first integrated circuit comprising:

a plurality of sets of optical waveguides, each set of optical waveguides including a plurality of optical waveguide segments, and

a plurality of optical emitter elements arranged over a first surface of the first integrated circuit, each optical emitter element coupled to a distal end of one of the optical waveguide segments, with a plurality of the optical emitter elements spaced at a first pitch; and

a second integrated circuit comprising:

a plurality of optical phase shifters that each provide a phase-shifted optical wave that is coupled to the first integrated circuit from a first edge surface of the second integrated circuit, with a plurality of the optical phase shifters spaced at a second pitch substantially equal to the first pitch;

wherein

the first edge surface of the second integrated circuit is in proximity to a row of proximal ends of the optical waveguide segments of a first set of the plurality of sets of optical waveguides.

19. The apparatus of claim 18 , wherein the second integrated circuit is substantially perpendicular to the first integrated circuit.

20. A method comprising:

forming a first integrated circuit comprising:

a plurality of sets of optical waveguides, each set of optical waveguides including a plurality of optical waveguide segments, and

a plurality of optical emitter elements arranged over a first surface of the first integrated circuit, each optical emitter element coupled to a distal end of one of the optical waveguide segments, with a plurality of the optical emitter elements spaced at a first pitch; and

attaching a second integrated to the first integrated circuit, the second integrated circuit comprising:

a plurality of optical phase shifters that each provide a phase-shifted optical wave that is coupled to the first integrated circuit from a first edge surface of the second integrated circuit, with a plurality of the optical phase shifters spaced at a second pitch substantially equal to the first pitch;

wherein

the first edge surface of the second integrated circuit is in proximity to a row of proximal ends of the optical waveguide segments of a first set of the plurality of sets of optical waveguides.