Method for aligning electro-optic device with optical fiber array with optical grating couplers

• US 9,529,165 B1
• Filed: 06/30/2015
• Issued: 12/27/2016
• Est. Priority Date: 06/30/2015
• Status: Active Grant

• Current Assignee: Stmicroelectronics Crolles 2 SAS (STMicroelectronics NV)
• Original Assignee: Stmicroelectronics Crolles 2 SAS (STMicroelectronics NV)
• Inventors: Lemaitre, Patrick, Carpentier, Jean-Francois
• Primary Examiner(s): Kianni, Kaveh C
• Application Number:
  US14/755,437
• Publication Number:
  US 20170003462A1
• Time in Patent Office: 546 Days
• Field of Search: 385/16, 385/37
• US Class Current: 1/1
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4222 by observing back-reflected light
• 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 6/4227 Active alignment methods, e.g. procedures and algorithms
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G02B 6/425 Optical features semiconductor laser arrays H01S5/40; hybrid LED arrays H01L25/0753; monolithic LED arrays H01L27/153

Abstract

A method is for aligning an electro-optic device. The method may include initially positioning an optical fiber array adjacent to optical grating couplers, and actively aligning the optical fiber array relative to the optical grating couplers in a yaw direction and a roll direction to determine a yaw and roll alignment at a first operating wavelength. The method may include actively aligning the optical fiber array relative to optical grating couplers in an x direction and a y direction to determine a first x and y alignment at the first operating wavelength, determining a second operating wavelength, and actively aligning the optical fiber array again relative to the optical grating couplers in the x direction and y direction to determine a second x and y alignment at the second operating wavelength.

Claims

1. A method for aligning an electro-optic device comprising a photonic chip having a plurality of optical grating couplers at a surface of the photonic chip, and an optical fiber array comprising a plurality of optical fibers and a body retaining proximal ends of the plurality of optical fibers in side-by-side relation, the method comprising:

initially positioning the optical fiber array adjacent the plurality of optical grating couplers;

actively aligning the optical fiber array relative to the plurality of optical grating couplers in a yaw direction and a roll direction to determine a yaw and roll alignment at a first operating wavelength;

after determining the yaw and roll alignment at the first operating wavelength, actively aligning the optical fiber array relative to the plurality of optical grating couplers in an x direction and a y direction to determine a first x and y alignment at the first operating wavelength;

determining a second operating wavelength by determining a peak power transmission value and associated peak power wavelength while performing a spectral sweep, the associated peak power wavelength defining the second operating wavelength; and

actively aligning the optical fiber array again relative to the plurality of optical grating couplers in the x direction and y direction to determine a second x and y alignment at the second operating wavelength.

2. The method of claim 1 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the yaw direction and the roll direction comprises coupling a plurality of photodiodes respectively to proximal ends of the plurality of optical fibers.

3. The method of claim 1 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the yaw direction and the roll direction comprises determining an optimum yaw and roll position based upon each optical fiber having a same threshold power.

4. The method of claim 1 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the x direction and the y direction comprises launching an optical signal from a single optical grating coupler from the plurality of optical grating couplers to a single photodiode.

5. The method of claim 4 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the x direction and the y direction comprises using an optical splitter coupled between the distal end of an optical fiber and the single photodiode.

6. The method of claim 1 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the x direction and the y direction comprises launching an optical signal from an optical source to a single optical grating coupler from the plurality of the optical grating couplers.

7. The method of claim 1 wherein determining the first x and y alignment at the first operating wavelength comprises determining an optimum x and y alignment based upon a threshold average power through the plurality of optical grating couplers and the optical fiber array.

8. The method of claim 1 further comprising geometrically aligning the optical fiber array in a pitch direction.

9. The method of claim 1 wherein determining the second operating wavelength comprises determining an optimum wavelength based upon a threshold power through the plurality of optical grating couplers and the optical fiber array.

10. The method of claim 1 wherein each optical fiber comprises a single mode optical fiber.

19. The method of claim 1 further comprising activating an optical source coupled to the optical fiber array before the actively aligning of the optical fiber array relative to the plurality of optical grating couplers in the yaw direction and the roll direction.

20. The method of claim 1 wherein adjacent optical fibers of the plurality of optical fibers have alignment mismatch.

21. The method of claim 1 further comprising mounting the optical fiber array onto a 5-axis probe support device.

11. A method for aligning an electro-optic device comprising a photonic chip having a plurality of optical grating couplers at a surface of the photonic chip, and an optical fiber array comprising a plurality of optical fibers and a body retaining proximal ends of the plurality of optical fibers in side-by-side relation, the method comprising:

initially positioning the optical fiber array adjacent the plurality of optical grating couplers;

geometrically aligning the optical fiber array in a pitch direction;

actively aligning the optical fiber array relative to the plurality of optical grating couplers in a yaw direction and a roll direction to determine a yaw and roll alignment at a first operating wavelength, the actively aligning comprising coupling a plurality of photodiodes respectively to proximal ends of the plurality of optical fibers;

after determining the yaw and roll alignment at the first operating wavelength, actively aligning the optical fiber array relative to the plurality of optical grating couplers in an x direction and a y direction to determine a first x and y alignment at the first operating wavelength;

determining a second operating wavelength by determining a peak power transmission value and associated peak power wavelength while performing a spectral sweep, the associated peak power wavelength defining the second operating wavelength; and

actively aligning the optical fiber array again relative to the plurality of optical grating couplers in the x direction and y direction to determine a second x and y alignment at the second operating wavelength.

12. The method of claim 11 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the yaw direction and the roll direction comprises determining an optimum yaw and roll position based upon each optical fiber having a same threshold power.

13. The method of claim 11 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the x direction and the y direction comprises launching an optical signal from a single optical grating coupler from the plurality of the optical grating couplers to a single photodiode.

14. The method of claim 13 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the x direction and the y direction comprises using an optical splitter coupled between the distal end of an optical fiber and the single photodiode.

15. The method of claim 11 wherein actively aligning the optical fiber array relative to the plurality of optical grating couplers in the x direction and the y direction comprises launching an optical signal from an optical source to a single optical grating coupler from the plurality of the optical grating couplers.

16. The method of claim 11 wherein determining the first x and y alignment at the first operating wavelength comprises determining an optimum x and y alignment based upon a threshold average power through the plurality of optical grating couplers and the optical fiber array.

17. The method of claim 11 wherein determining the second operating wavelength comprises determining an optimum wavelength based upon a threshold power through the plurality of optical grating couplers and the optical fiber array.

18. The method of claim 11 wherein each optical fiber comprises a single mode optical fiber.