OPTICAL COUPLING STRUCTURE

• US 20080279505A1
• Filed: 05/09/2007
• Published: 11/13/2008
• Est. Priority Date: 05/09/2007
• Status: Active Grant

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Alcatel NV (Nokia Corporation)
• Inventors: Rasras, Mahmoud, Gill, Douglas M., Patel, Sanjay
• Granted Patent: US 7,616,854 B2
• Time in Patent Office: Days
• US Class Current: 385/50
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305

Abstract

The present invention provides an apparatus and method for operation therefore. The apparatus, in one embodiment, includes an optical coupling structure disposed within a cladding region, wherein the optical coupling structure includes a first guiding portion and a second guiding portion. In this embodiment the first guiding portion has a first end proximate a core of a planar waveguide, and a second end proximate the second guiding portion and having a first thickness. Moreover, in this embodiment the second guiding portion has a first end proximate the first guiding portion and a second end, the second end of the second guiding portion having a second thickness less than the first thickness.

Claims

1. An apparatus, comprising:

an optical coupling structure disposed within a low refractive index cladding region, wherein the optical coupling structure includes a first guiding portion and a second guiding portion;

the first guiding portion having a first end proximate a core of a planar waveguide, and a second end proximate the second guiding portion and having a first thickness; and

the second guiding portion having a first end proximate the first guiding portion and a second end, wherein the second end of the second guiding portion has a second thickness less than the first thickness.

2. The apparatus of claim 1 wherein the first end has a cross-sectional area that approximates that of the core of the planar waveguide.

3. The apparatus of claim 1 wherein the optical coupling structure comprises silicon.

4. The apparatus of claim 1 wherein an entire length of the first guiding portion has the first thickness and an entire length of the second guiding portion has the second thickness.

5. The apparatus of claim 4 wherein a thickness transition between the first guiding portion and the second guiding portion is abrupt.

6. The apparatus of claim 1 wherein the first end of the first guiding portion has a first width and the second end of the first guiding portion has a second width less than the first width.

7. The apparatus of claim 6 wherein there is a gradual decrease in width between the first end of the first guiding portion and the second end of the first guiding portion.

8. The apparatus of claim 1 wherein the first end of the second guiding portion has a first width and the second end of the second guiding portion has a second width less than the first width.

9. The apparatus of claim 8 wherein there is a gradual decrease in width between the first end of the second guiding portion and the second end of the second guiding portion.

10. The apparatus of claim 1 wherein the first end of the first guiding portion has a first width and the second end of the first guiding portion has a second width less than the first width, and the first end of the second guiding portion has a third width and the second end of the second guiding portion has a fourth width less than the third width, and further wherein the third width is greater than the second width.

11. The apparatus of claim 1 wherein the second end of the first guiding portion extends over a portion of the second guiding portion.

12. The apparatus of claim 1 wherein the second end of the second guiding portion is proximate to a core of an optical fiber.

13. The apparatus of claim 12 wherein a cross-sectional area of the second end of the second guiding portion is less than about 1 percent of a cross-sectional area of the core of the optical fiber.

14. The apparatus of claim 12 wherein the planar waveguide, the optical coupling structure and the core of the optical fiber form at least a portion of an optical communications system.

15. A method for operating an apparatus, comprising:

sending an optical signal through a core of an optical fiber; and

coupling the optical signal from the core of the optical fiber to a core of a planar waveguide using an optical coupling structure disposed within a lower refractive index cladding region, the optical coupling structure including;

a first guiding portion having a first end proximate the core of a planar waveguide and a second end having a first thickness; and

a second guiding portion having a first end proximate the first guiding portion and a second end proximate the core of the optical fiber, wherein the second end of the second guiding portion has a second thickness less than the first thickness.

16. The method of claim 15 wherein the first end has a cross-sectional area that approximates that of the core of the planar waveguide.

17. The method of claim 15 wherein the optical coupling structure comprises silicon.

18. The method of claim 15 wherein the first end of the first guiding portion has a first width and the second end of the first guiding portion has a second width less than the first width, and the first end of the second guiding portion has a third width and the second end of the second guiding portion has a fourth width less than the third width, and further wherein the third width is greater than the second width.

19. The method of claim 15 wherein the second end of the first guiding portion extends over a portion of the second guiding portion.

20. The method of claim 15 wherein a cross-sectional area of the second end of the second guiding portion is less than about 1 percent of a cross-sectional area of the core of the optical fiber.