Silicon electro-optical modulator

Patent metadata

Field	Value
Publication number	US-9939666-B2
Application number	US-201414298859-A
Country	US
Kind code	B2
Filing date	Jun 6, 2014
Priority date	Jun 6, 2013
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

Disclosed are designs and methods of fabrication of silicon carrier-depletion based electro-optical modulators having doping configurations that produce modulators exhibiting desirable modulation efficiency, optical absorption loss and bandwidth characteristics. The disclosed method of fabrication of a modulator having such doping configurations utilizes counter doping to create narrow regions of relatively high doping levels near a waveguide center.

First claim

The invention claimed is:

1. A silicon electro-optical modulator structure comprising:
a waveguide central core region including a depletion region;
adjacent to one side of the central core region is formed:
a P+ region formed adjacent to the depletion region;
a P− region formed adjacent to the P+ region;
a P++ region formed adjacent to the P− region; and
a P+++ region formed adjacent to the P++ region,

adjacent to the other side of the central core region is formed:
a N+ region formed adjacent to the depletion region;
a N− region formed adjacent to the N+ region;
a N++ region formed adjacent to the N− region; and
a N+++ region formed adjacent to the N++ region.

2. The silicon electro-optical modulator structure of claim 1 , wherein said P+ and N+ regions exhibit doping levels of substantially 2E18 cm −3 or greater, said P− and N− regions exhibit doping levels of substantially 3E17 cm −3 , said P++ and N++ regions exhibit doping levels of substantially 5E18 cm −3 , and said P+++ and said N+++ regions exhibit doping levels of substantially 2E20 cm −3 .

3. An electro-optical modulator, comprising:
a semiconductor material waveguide having first, second, third, and fourth doped regions of a same dopant type,
wherein the first doped region is closest to a center of the waveguide compared to the second, third, and fourth doped regions, wherein the first, second, third, and fourth doped regions are laterally arranged in that order from the center of the waveguide laterally outward,
wherein the third doped region has a greater doping concentration than the first doped region, the first doped region has a greater doping concentration than the second doped region, and the fourth doped region has a greater doping concentration than the third doped region.

4. The electro-optical modulator of claim 3 , wherein the third doped region is outside an optical mode field in the semiconductor material waveguide.

5. The electro-optical modulator of claim 3 , wherein the second doped region extends from a core of the semiconductor material waveguide to a slab of the semiconductor material waveguide.

6. The electro-optical modulator of claim 3 , wherein the first and second doped regions are at least partially within a ridge of the semiconductor material waveguide.

7. The electro-optical modulator of claim 3 , wherein the first doped region has a width of 150 nm or less.

8. The electro-optical modulator of claim 3 , wherein a doping concentration of the second doped region is a concentration of net activated dopants.

9. The electro-optical modulator of claim 3 , wherein the same dopant type of the first, second, third, and fourth doped regions is n-type.

10. The electro-optical modulator of claim 3 , wherein the same dopant type of the first, second, third, and fourth doped regions is p-type.

Assignees

• Acacia Communications Inc
• Acacia Communications Inc

Inventors

• Chen Long

Classifications

• G02F2001/0156

  Physics · mapped topic

• G02B6/134

  by substitution by dopant atoms · CPC title

• G02F1/025 Primary

  in an optical waveguide structure (G02F1/017, {G02F1/2257} take precedence) · CPC title

• G02F1/0156

  using free carrier absorption · CPC title