Optical coupler for heterogeneous integration

1. Apparatus comprising:

a silicon-based platform containing a silicon-based waveguide;

an introduced semiconductor device heterointegrated on the silicon-based platform; and

a polymeric waveguide optically coupled to the introduced semiconductor device and overlying at least a portion of the silicon-based waveguide, wherein:

the polymeric waveguide is conformed as a multimode interference (MMI) coupler between the introduced semiconductor device and the silicon-based waveguide; and

at least the polymeric waveguide is tapered with a shape that effectuates optical coupling to the silicon-based waveguide.

2. The apparatus of claim 1 , wherein the introduced semiconductor device is an active III-V optoelectronic device.

3. The apparatus of claim 1 , wherein the introduced semiconductor device is a III-V laser.

4. The apparatus of claim 1 , wherein an adhesion layer joins the introduced III-V device to the silicon-based platform.

5. The apparatus of claim 1 , wherein the polymeric waveguide comprises polyimide.

6. The apparatus of claim 1 , wherein both the polymeric waveguide and the silicon-based waveguide are tapered with shapes that effectuate optical coupling between said polymeric waveguide and said silicon-based waveguide.

7. The apparatus of claim 1 , wherein the silicon-based waveguide comprises silicon nitride.

8. The apparatus of claim 1 , wherein the polymeric waveguide is arranged for lateral optical coupling with the introduced semiconductor device and for vertical optical coupling with the silicon-based waveguide.

9. The apparatus of claim 1 , wherein the polymeric waveguide has a horizontal midplane and is arranged such that optical coupling between the polymeric waveguide and the introduced semiconductor device is effectuated principally at a height above the midplane.

10. The apparatus of claim 1 , wherein:

the introduced semiconductor device is a III-V laser with at least one operating frequency;

the introduced semiconductor device has an undercladding with a thickness τ;

light at the operating frequency has an in-material wavelength λ m within the undercladding; and

the thickness τ is at least twice the wavelength λ m .

11. The apparatus of claim 1 , wherein the introduced semiconductor device comprises an undercladding and a metal contact layer that underlies the undercladding.

12. The apparatus of claim 1 , wherein the taper is less than 200 μm long.

13. The apparatus of claim 1 , wherein the taper is less than 100 μm long.

14. The apparatus of claim 1 , wherein the introduced semiconductor device is a III-V laser adapted for operation in the wavelength range from 1.5 μm to 1.6 μm, and wherein the taper is less than 200 μm long.

15. The apparatus of claim 1 , wherein the introduced semiconductor device is a III-V laser adapted for operation in the wavelength range from 1.5 μm to 1.6 μm, and wherein the taper is less than 100 μm long.

16. The apparatus of claim 1 , wherein the taper is non-adiabatic.

17. The apparatus of claim 1 , wherein the polymeric waveguide and the silicon-based waveguide are both tapered with non-adiabatic tapers that effectuate optical coupling between said polymeric waveguide and said silicon-based waveguide.

18. The apparatus of claim 1 , wherein the shape that effectuates optical coupling to the silicon-based waveguide has undulant sidewalls.

19. The apparatus of claim 18 , wherein the shape having undulant sidewalls is a product of adjoint shape optimization.