Method of modifying mode size of an optical beam, using a waveguide mode expander having non-crystalline silicon features

Patent metadata

Field	Value
Publication number	US-10345521-B2
Application number	US-201815980536-A
Country	US
Kind code	B2
Filing date	May 15, 2018
Priority date	May 27, 2014
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A waveguide mode expander couples a smaller optical mode in a semiconductor waveguide to a larger optical mode in an optical fiber. The waveguide mode expander comprises a shoulder and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

First claim

What is claimed is:

1. A method of modifying mode size of an optical beam, comprising:
propagating the optical beam, with an initial mode size, into an input end of a waveguide mode expander, wherein the waveguide mode expander comprises:
a shoulder portion, comprising non-crystalline silicon, that is disposed on a substrate and traverses the substrate from the input end to an output end of the waveguide mode expander, and
a ridge portion, comprising non-crystalline silicon, that is disposed on the shoulder portion;

propagating the optical beam through the waveguide mode expander, wherein at least the ridge portion changes in width from the input end to the output end, so as to modify the optical beam propagating from the input end to the output end from the initial mode size to a final mode size; and
propagating the optical beam, with the final mode size, out of the output end of the waveguide mode expander.

2. The method of claim 1 , wherein the ridge portion becomes wider from the input end to the output end, so that the final mode size is larger than the initial mode size.

3. The method of claim 2 , wherein the ridge portion comprises a plurality of stages disposed atop the shoulder portion, wherein
each of the stages comprises non-crystalline silicon, and
each of the stages becomes wider from a first end to a second end, where the first end of each stage is nearer the input end than the second end along a direction of beam propagation.

4. The method of claim 3 , wherein ones of the stages that are further from the shoulder portion are taller than ones of the stages that are closer to the shoulder portion.

5. The method of claim 2 , wherein propagating the optical beam out of the output end comprises coupling the optical beam into an optical fiber.

6. The method of claim 1 , wherein propagating the optical beam into the input end comprises coupling the optical beam from a waveguide disposed on the substrate into the waveguide mode expander.

7. The method of claim 6 , wherein the waveguide is contiguous with the shoulder portion at the input end.

8. The method of claim 6 , wherein propagating the optical beam into the input end comprises coupling the optical beam through an angled interface between the shoulder portion and the waveguide, wherein the angled interface forms a plane that is not orthogonal with respect to a propagation direction of the optical beam.

9. The method of claim 1 , wherein the ridge portion becomes narrower from the input end to the output end, so that the final mode size is smaller than the initial mode size.

10. The method of claim 9 , wherein propagating the optical beam into the input end comprises coupling the optical beam from an optical fiber into the waveguide mode expander.

11. The method of claim 9 , wherein propagating the optical beam out of the output end comprises coupling the optical beam into a waveguide disposed on the substrate.

12. The method of claim 11 wherein the waveguide is contiguous with the shoulder portion at the output end.

Assignees

• Skorpios Tech Inc

Inventors

• Li Guoliang
• Lambert Damien
• Kumar Nikhil

Classifications

• G02B2006/12152

  Mode converter · CPC title

• G02B2006/12147

  Coupler · CPC title

• G02B6/136

  by etching · CPC title

• G02B6/14 Primary

  Mode converters · CPC title

• G02B6/1228

  Tapered waveguides, e.g. integrated spot-size transformers (for coupling with fibres G02B6/305) · CPC title