Multi-semiconductor slab electro-optic modulator and process for using the same

1. An apparatus, comprising:

a substrate having a surface;

an optical waveguide having a ridge-shaped semiconductor optical core, the ridge-shaped semiconductor optical core being located over the surface, and not including a p-n junction;

a first semiconductor slab being in contact with a first portion of the ridge-shaped semiconductor optical core, wherein the first semiconductor slab includes a first relatively low doped region proximate the ridge-shaped semiconductor optical core and a first relatively high doped region distal the ridge-shaped semiconductor optical core, and further wherein a peak dopant level of the first relatively low doped region and a peak dopant level of the first relatively high doped region are greater than a peak dopant level of the ridge-shaped semiconductor optical core, and further wherein an interface where the first semiconductor slab contacts the ridge-shaped semiconductor optical core does not form a p-n junction; and

a second semiconductor slab being in contact with a second portion of the ridge-shaped semiconductor optical core, the second semiconductor slab being farther from the surface than the first semiconductor slab.

2. The apparatus as recited in claim 1 wherein the first semiconductor slab is located directly on the surface and the second semiconductor slab is located above the first semiconductor slab.

3. The apparatus as recited in claim 2 wherein the first and second semiconductor slabs are spatially separated from one another by a distance ranging from about 100 nm to about 250 nm.

4. The apparatus as recited in claim 1 wherein the first relatively low doped region has a dopant level at least three times lower than a dopant level of the first relatively higher doped region.

5. The apparatus as recited in claim 4 wherein the second semiconductor slab includes a second relatively low doped region proximate the ridge-shaped semiconductor optical core and a second relatively high doped region distal the ridge-shaped semiconductor optical core, the second relatively low doped region having a dopant level at least three times lower than a dopant level of the second relatively higher doped region.

6. The apparatus as recited in claim 1 wherein the second semiconductor slab includes a relatively low doped region proximate the ridge-shaped semiconductor optical core and a relatively high doped region distal the ridge-shaped semiconductor optical core, the relatively low doped region having a dopant level at least three times lower than a dopant level of the relatively higher doped region.

7. The apparatus as recited in claim 1 further including:

a third semiconductor slab being in contact with a third portion of the ridge-shaped semiconductor optical core opposite the first portion; and

a fourth semiconductor slab being in contact with a fourth portion of the ridge-shaped semiconductor optical core opposite the second portion, the fourth semiconductor slab being farther from the surface than the third semiconductor slab.

8. The apparatus as recited in claim 7 wherein the first and third semiconductor slabs are doped with a dopant and the second and fourth semiconductor slabs are doped with an opposite charge-type dopant.

9. The apparatus as recited in claim 1 wherein no physical interface exists where the first semiconductor slab contacts the first portion and wherein a physical interface does exist where the second semiconductor slab contacts the second portion.

10. The apparatus as recited in claim 1 wherein each of the ridge-shaped semiconductor optical core, first semiconductor slab and second semiconductor slab comprise silicon.

11. The apparatus as recited in claim 1 , further including an optical fiber coupled to the optical waveguide, wherein the optical waveguide and the optical fiber form at least a portion of an optical communications system.

12. An apparatus, comprising:

a substrate having a surface;

an optical waveguide having a ridge-shaped semiconductor optical core, the ridge-shaped semiconductor optical core being located over the surface, and not including a p-n junction;

a first semiconductor slab being in contact with a first portion of the ridge-shaped semiconductor optical core; and

a second semiconductor slab being in contact with a second portion of the ridge-shaped semiconductor optical core, the second semiconductor slab being farther from the surface than the first semiconductor slab, wherein the second semiconductor slab includes a relatively low doped region proximate the ridge-shaped semiconductor optical core and a relatively high doped region distal the ridge-shaped semiconductor optical core, wherein a dopant profile of the semiconductor optical core differs from a dopant profile of the relatively low doped region and the relatively high doped region.

13. The apparatus as recited in claim 12 wherein the relatively low doped region has a dopant level at least three times lower than a dopant level of the relatively higher doped region.

14. The apparatus as recited in claim 1 wherein the ridge-shaped semiconductor optical core comprises an intrinsic semiconductor material.

15. The apparatus as recited in claim 1 wherein the peak dopant level of the first relatively low doped region ranges from about 1×10 16 atoms/cm 3 to about 5×10 18 atoms/cm 3 and the peak dopant level of the first relatively high doped region ranges from about 5×10 18 atoms/cm 3 to about 5×10 20 atoms/cm 3 .

16. An apparatus, comprising: a substrate having a surface; an optical waveguide having a ridge-shaped semiconductor optical core, the ridge-shaped semiconductor optical core being located over the surface and comprising an intrinsic semiconductor material; a first semiconductor slab being in contact with a first portion of the ridge-shaped semiconductor optical core, wherein the first semiconductor slab includes a first relatively low doped region proximate the ridge-shaped semiconductor optical core and a first relatively high doped region distal the ridge-shaped semiconductor optical core, and further wherein an interface where the first semiconductor slab contacts the ridge-shaped semiconductor optical core does not form a p-n junction, wherein a dopant profile of the semiconductor optical core differs from a dopant profile of the relatively low doped region and the relatively high doped region; and a second semiconductor slab being in contact with a second portion of the ridge-shaped semiconductor optical core, the second semiconductor slab being farther from the surface than the first semiconductor slab.

17. The Apparatus of claim 1 wherein the semiconductor optical core comprises an intrinsic semiconductor material.

18. The Apparatus of claim 12 wherein the semiconductor optical core comprises an intrinsic semiconductor material.