MULTIMODE OPTICAL COUPLER INTERFACES

• US 20110235968A1
• Filed: 03/29/2010
• Published: 09/29/2011
• Est. Priority Date: 03/29/2010
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: NA, YUN-CHUNG, YIN, TAO
• Granted Patent: US 8,488,923 B2
• Time in Patent Office: Days
• US Class Current: 385/28
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/26 Optical coupling means G02B6/36, G02B6/42 take precedence
• CPC Class Codes: G02B 6/2808 using a mixing element which evenly distributes an input signal over a number of outputs
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide

Abstract

Optical interfaces that may be employed between large-core optical fibers and chip-scale optoelectronic devices. Described herein are couplers that improve the tolerance of misalignment when a single mode (SM) fiber is used as waveguide input. This enables the possibility of passive/automatic alignment and therefore reduces the production cost. The coupler also serves as a spot-size converter that reduces the spot size and is suitable for applications where a waveguide mode with small cross-section area is of particular importance. One such example can be a waveguide-based SiGe or III-V semiconductor photodetector in which the vertical size of its waveguide mode should be as small as few microns.

Claims

1. An multi-mode optical coupler comprising:

an input multi-mode waveguide to receive an optical signal from a single mode optical fiber;

one or more single mode output waveguides optically coupled with the input multi-mode waveguide, the one or more single mode output waveguides to receive the excited multiple modes caused by fiber misalignment.

2. The multi-mode optical coupler of claim 1 wherein the one or more single mode output waveguides is embedded within or on top of the input multi-mode waveguide.

3. The multi-mode optical coupler of claim 1 wherein the one or more single mode output waveguides comprise single mode waveguides having adiabatically tapered widths.

4. The multi-mode optical coupler of claim 1 wherein the multi-mode input waveguide is at least ten times thicker than the one or more single mode output waveguides.

5. The multi-mode optical coupler of claim 1 wherein the multi-mode input waveguide comprises a silicon (Si) optical waveguide.

6. The multi-mode optical coupler of claim 1 wherein the multi-mode input waveguide comprises an aluminum gallium arsenide (AlGaAs) waveguide.

7. The multi-mode optical coupler of claim 1 wherein the one or more single mode output waveguides comprise aluminum arsenide (AlAs) optical waveguides.

8. The multi-mode optical coupler of claim 1 wherein the one or more single mode output waveguides comprise silicon germanium (SiGe) optical waveguides.

9. The multi-mode optical coupler of claim 8 wherein the one or more SiGe single mode output waveguides have a composition of Si_xGe_1-x.

10. An optical system comprising:

a single mode optical fiber to transmit an optical signal;

an input multi-mode waveguide to receive the optical signal from the single mode optical fiber;

one or more single mode output waveguides having adiabatically tapered widths optically coupled with the input multi-mode waveguide, the one or more single mode output waveguides to receive the excited multiple modes caused by fiber misalignment.

11. The optical system of claim 10 wherein the one or more single mode output waveguides is embedded within or on top of the input multi-mode waveguide.

12. The optical system of claim 10 wherein the multi-mode input waveguide is at least ten times thicker than the one or more single mode output waveguides.

13. The optical system of claim 10 further comprising one or more optoelectronic devices optically coupled with the one or more output waveguides.

14. The optical system of claim 10 wherein the multi-mode input waveguide comprises a silicon (Si) optical waveguide.

15. The optical system of claim 10 wherein the multi-mode input waveguide comprises an aluminum gallium arsenide (AlGaAs) waveguide.

16. The optical system of claim 10 wherein the one or more single mode output waveguides comprise aluminum arsenide (AlAs) optical waveguides.

17. The optical system of claim 10 wherein the one or more single mode output waveguides comprise silicon germanium (SiGe) optical waveguides.

18. The optical system of claim 17 wherein the one or more SiGe single mode output waveguides have a composition of Si_xGe_1-x.

19. A method for manufacturing a multi-mode optical coupler, the method comprising:

creating a multi-mode silicon (Si) strip waveguide on a silicon dioxide (SiO₂) substrate; and

creating a plurality of silicon germanium (SiGe) output waveguides on a face of the Si strip waveguide opposite the SiO₂ substrate, wherein the output waveguides have adiabatically tapered widths.

20. The method of claim 19 wherein the multi-mode input waveguide is at least ten times thicker than the output waveguides.

21. The method of claim 19 wherein the SiGe output waveguides have a composition of Si_xGe_1-x.

22. A method for manufacturing a multi-mode optical coupler, the method comprising:

creating a multi-mode silicon (Si) strip waveguide on a silicon dioxide (SiO₂) substrate; and

creating a single silicon germanium (SiGe) output waveguide on a face of the Si strip waveguide opposite the SiO₂ substrate, wherein the output waveguides have adiabatically tapered widths.

23. The method of claim 22 wherein the multi-mode input waveguide is at least ten times thicker than the output waveguide.

24. The method of claim 22 wherein the SiGe output waveguides have a composition of Si_xGe_1-x.