Optical alignment using multimode edge couplers

• US 9,335,480 B1
• Filed: 03/17/2015
• Issued: 05/10/2016
• Est. Priority Date: 03/17/2015
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Celo, Dritan
• Primary Examiner(s): Ullah, Akm Enayet
• Assistant Examiner(s): Mooney, Michael
• Application Number:
  US14/660,061
• Time in Patent Office: 420 Days
• Field of Search: 385/14, 385/24, 385/27, 385/43, 385 49- 52, 385129-132
• US Class Current: 1/1
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/29344 operating by modal interference or beating, i.e. of transverse modes, e.g. zero-gap directional coupler, MMI
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide
• CPC Class Codes: G02B 6/3656 the additional structures being micropositioning, with microactuating elements for fine adjustment, or restricting movement, into two dimensions, e.g. cantilevers, beams, tongues or bridges with associated MEMs
• CPC Class Codes: G02B 6/42 Coupling light guides with opto-electronic elements
• CPC Class Codes: G02B 6/4225 by a direct measurement of the degree of coupling, e.g. the amount of light power coupled to the fibre or the opto-electronic element
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections

Abstract

An edge coupling method comprising positioning a first photonic device such that a first edge coupler of the first photonic device is at least partially aligned with a first alignment waveguide of a second photonic device and such that a second edge coupler of the first photonic device is at least partially aligned with a second alignment waveguide of the second photonic device, wherein the first edge coupler widens towards an edge of the first photonic device and the second edge coupler widens towards the edge, and wherein the first edge coupler and the second edge coupler are optically coupled to each other by an interconnect, transmitting a light through the first alignment waveguide, detecting the light at the second alignment waveguide, and aligning the first photonic device and the second photonic device based on the detecting.

Claims

1. An edge coupling method comprising:

positioning a first photonic device such that a first edge coupler of the first photonic device is at least partially aligned with a first alignment waveguide of a second photonic device and such that a second edge coupler of the first photonic device is at least partially aligned with a second alignment waveguide of the second photonic device, wherein the first edge coupler widens towards an edge of the first photonic device and the second edge coupler widens towards the edge, and wherein the first edge coupler and the second edge coupler are optically coupled to each other by an interconnect;

transmitting a light through the first alignment waveguide;

detecting the light at the second alignment waveguide; and

aligning the first photonic device and the second photonic device based on the detecting.

2. The method of claim 1, wherein the first edge coupler and the second edge coupler are configured to excite a fundamental mode and a first-order mode for the light.

3. The method of claim 1, wherein the first edge coupler and the second edge coupler are configured to not excite a second-order mode for the light or a higher-order mode for the light.

4. The method of claim 1, wherein the first photonic device comprises at least one single-mode waveguide, and wherein the second photonic device comprises at least one single-mode waveguide.

5. The method of claim 1, wherein detecting the light comprises determining a light power output for the light.

6. The method of claim 1, wherein aligning the first photonic device and the second photonic device comprises positioning the first photonic device and the second photonic device to reduce a light power output loss for the light.

7. The method of claim 1, wherein aligning the first photonic device and the second photonic device comprises adjusting a lateral offset between the first photonic device and the second photonic device.

8. The method of claim 1, wherein the first alignment waveguide and the second alignment waveguide are multimode waveguides.

9. The method of claim 1, wherein the first alignment waveguide and the second alignment waveguide are single-mode waveguides.

10. An apparatus comprising:

an edge;

an interconnect comprising a first end and a second end;

a first edge coupler optically coupled to the first end and comprising a first tapered waveguide that widens towards the edge;

a second edge coupler optically coupled to the second end and comprising a second tapered waveguide that widens towards the edge; and

a first single-mode waveguide physically coupled to the edge.

11. The apparatus of claim 10, wherein the first single-mode waveguide comprises an endpoint coupled to the edge, and wherein the endpoint is positioned between the first edge coupler and the second edge coupler.

12. The apparatus of claim 11, wherein the first edge coupler and the second edge coupler are configured to excite a fundamental mode for a light and a first-order mode for the light.

13. The apparatus of claim 11, wherein the first edge coupler and the second edge coupler are configured to not excite a second-order mode for a light or higher-order modes for the light.

14. The apparatus of claim 11, further comprising:

an adjuster coupled to the first edge coupler, wherein a first output of the adjuster optically couples the first edge coupler to the interconnect; and

a light path optically coupled to a second output of the adjuster, wherein the light path diverts at least a portion of a light from the interconnect.

15. The apparatus of claim 14, further comprising a photodetector optically coupled to the light path, wherein the photodetector is configured to generate an electrical signal in response to detecting the light.

16. The apparatus of claim 14, wherein the adjuster comprises a multimode interference (MMI) splitter, and wherein the MMI splitter is configured to adjust a phase shift between a fundamental mode of the light and a first-order mode of the light.

17. The apparatus of claim 11, further comprising a fiber array that comprises a second single-mode waveguide, a first alignment waveguide, and a second alignment waveguide, wherein the first alignment waveguide is optically coupled to the first edge coupler, and wherein the second alignment waveguide is optically coupled to the second edge coupler.

18. An apparatus comprising:

an interconnect;

a first edge coupler that widens towards an edge and is optically coupled to the interconnect and configured to;

receive a light; and

allow a fundamental mode of the light and a first-order mode of the light to pass to the interconnect; and

a second edge coupler that widens towards the edge and is optically coupled to the interconnect and configured to;

receive the fundamental mode of the light and the first-order mode of the light from the interconnect; and

output the fundamental mode of the light and the first-order mode of the light; and

a single-mode waveguide.

19. The apparatus of claim 18, wherein the single-mode waveguide comprises an endpoint coupled to an edge, and wherein the endpoint is positioned between the first edge coupler and the second edge coupler.

20. The apparatus of claim 18, further comprising:

an adjuster optically coupled to the first edge coupler and comprising a first output and a second output, wherein the first output optically couples the first edge coupler to the interconnect; and

a light path optically coupled to the second output, wherein the light path diverts at least a portion of the fundamental mode of the light and the first-order mode of the light away from the interconnect.