Patent ID: 7643710

Claim:
A coupler for optical communication comprising: a first optical waveguide of a first semiconductor material and a first semiconductor layer, the first optical waveguide having a first end to optically couple to a first external device and a second end, the second end having a taper with a tip at the second end; a second optical waveguide of a second semiconductor material and a second semiconductor layer, the second optical waveguide being optically coupled to the taper of the first optical waveguide, the second optical waveguide having a first end and a second end, the second end having a taper with a tip at the second end; and a third optical waveguide of a third semiconductor material, the third optical waveguide being optically coupled to the taper of the second optical waveguide, the third optical waveguide having a larger cross-sectional area than the first and the second optical waveguides to optically couple to a second external device having a larger cross-sectional area than the first external device.