LOW LOSS DIRECTIONAL COUPLING BETWEEN HIGHLY DISSIMILAR OPTICAL WAVEGUIDES FOR HIGH REFRACTIVE INDEX INTEGRATED PHOTONIC CIRCUITS

• US 20130322813A1
• Filed: 12/29/2011
• Published: 12/05/2013
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: Socpra Sciences Et Gnie S.E.C.
• Original Assignee: Socpra Sciences Et Gnie S.E.C.
• Inventors: Grondin, Etienne, Aimez, Vincent, Ares, Richard, Beaudin, Guillaume, Charette, Paul G.
• Granted Patent: US 8,787,712 B2
• Time in Patent Office: Days
• US Class Current: 385/14
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 2006/12061 Silicon
• CPC Class Codes: G02B 2006/12147 Coupler
• CPC Class Codes: G02B 6/1223 high refractive index type, i.e. high-contrast waveguides
• CPC Class Codes: G02B 6/2821 using lateral coupling between contiguous fibres to split or combine optical signals
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/3652 the additional structures being prepositioning mounting areas, allowing only movement in one dimension, e.g. grooves, trenches or vias in the microbench surface, i.e. self aligning supporting carriers
• CPC Class Codes: G02B 6/3692 with surface micromachining involving etching, e.g. wet or dry etching steps surface micromachining involving subtractive techniques B81C1/00055

Abstract

An optocoupler, an optical interconnect and method of manufacture providing same are provided for coupling an optical signal between a high refractive index waveguide of an integrated circuit and a waveguide external to the integrated circuit. The optocoupler includes a thinned high refractive index waveguide having a thickness configured to exhibit an effective refractive index substantially matching a refractive index of the external waveguide.

Claims

1. An integrated circuit physical optical Input/Output (I/O) interface for coupling at least one mode of an optical signal between a waveguide external to the integrated circuit and a high refractive index waveguide internal to the integrated circuit, the physical optical interface comprising:

an I/O waveguide conveying an external optical signal near the integrated circuit along an external signal path, said I/O waveguide having a first refractive index; and

a high refractive index coupler waveguide forming part of the integrated circuit and conveying an internal optical signal along an internal signal path, said high refractive index waveguide having a second bulk refractive index substantially dissimilar from said first refractive index, said high refractive index waveguide having at least a portion with a thickness configured to exhibit an effective refractive index substantially matching said first refractive index of said I/O waveguide, said high refractive index waveguide and said I/O waveguide being arranged substantially parallel and in proximity with an overlap therebetween along said portion having said thickness to permit tunnel coupling of said at least one mode of said optical signal between said internal signal path and said external signal path.

2. An integrated circuit physical optical I/O interface as claimed in claim 1, said high refractive index waveguide comprising a material having a bulk refractive index greater than 2.

3. An integrated circuit physical optical I/O interface as claimed in claim 1, said I/O waveguide comprising a dielectric material having a refractive index lower than 2.

4. An integrated circuit physical optical I/O interface as claimed in claim 1, said I/O waveguide comprising an optical fiber having a core refractive index lower than 2.

7. An integrated circuit physical optical I/O interface as claimed in claim 1, said high refractive index waveguide thickness being further configured to modify said bulk refractive index to substantially match said I/O waveguide refractive index.

8. An integrated circuit physical optical I/O interface as claimed in claim 1, comprising an optical fiber I/O waveguide having a sufficiently thin cladding providing a tunneling distance at least of a length sufficient to provide coupling with said high refractive index waveguide.

9. An integrated circuit physical optical I/O interface as claimed in claim 1, comprising a waveguide separation layer between said high refractive index waveguide and said I/O waveguide, said waveguide separation layer providing a tunneling distance.

10. An integrated circuit physical optical I/O interface as claimed in claim 1, wherein said coupling is configured to employ evanescent field waveguide coupling.

11. An integrated circuit physical optical I/O interface as claimed in claim 8, said high refractive index waveguide thickness being configured to select one of a TE and a TM incident optical signal polarization.

12. An integrated circuit physical optical I/O interface as claimed in claim 11, said TM optical signal polarization being selected while employing a greater high refractive index waveguide thickness than a high refractive index waveguide thickness necessary to select said TE optical signal polarization.

13. An integrated circuit physical optical I/O interface as claimed in claim 11, comprising a coupling structure configured for simultaneous TE and TM optical signal polarization coupling.

14. An integrated circuit physical optical I/O interface as claimed in claim 11, said coupling structure being configured to simultaneously couple each of said TE and TM optical signal polarization into corresponding waveguides.

15. An integrated circuit physical optical I/O interface as claimed in claim 11 comprising a signal recombination structure.

16. An integrated circuit physical optical I/O interface as claimed in claim 11, said coupling structure being configured to sequentially couple each of said TE and TM optical signal polarization into a single waveguide.

17. An integrated circuit physical optical I/O interface as claimed in claim 1, said I/O waveguide comprising an intermediary waveguide and an external optical fiber, said intermediary waveguide having an effective refractive index substantially similar to the external optical fiber refractive index.

18. An integrated circuit physical optical I/O interface as claimed in claim 1, said integrated circuit including a layered structure, said layered structure comprising an optical fiber core alignment structure.

19. An integrated circuit physical optical I/O interface as claimed in claim 18, said external optical fiber comprising a circular cross-section cladding, and said alignment structure comprising a V-shaped optical fiber grove.

21. An integrated circuit physical optical I/O interface as claimed in claim 14, said coupling structure being further configured to provide said substantially parallel and proximal arrangement over a controlled coupling length providing coupling control.

5-6. -6. (canceled)

20. (canceled)

22-29. -29. (canceled)

30. An optical signal coupler for coupling at least one mode of an optical signal between at least one Input/Output (I/O) waveguide and at least one high refractive index waveguide forming part of an integrated circuit, each of said at least one I/O waveguide conveying an external optical signal along an external signal path, said I/O waveguide having a first bulk refractive index, each said high refractive index waveguide conveying an internal optical signal along an internal signal path, said high refractive index waveguide having at least a portion with a thickness configured to exhibit an effective refractive index substantially matching said first refractive index of said I/O waveguide, said coupler comprising:

each said second bulk refractive index being substantially dissimilar from said first refractive index; and

at least one alignment structure for positioning said at least one I/O waveguide with respect to said corresponding high refractive index waveguide substantially in parallel, in proximity and with an overlap therebetween along said portion having said thickness to permit tunnel coupling of said at least one mode of said optical signal between said external signal path and said internal signal path.

31. A coupler as claimed in claim 30, said coupler forming part of integrated circuit packaging of said integrated circuit, said coupler being configured as one of:

a complementary structure completing said integrated circuit packaging during assembly; and

an integral structure completing said integrated circuit packaging during wafer level manufacture.

32. A coupler as claimed in claim 31, said complementary structure comprising a snap-on device.

33. A coupler as claimed in claim 32, comprising an external optical fiber corresponding to an I/O waveguide, said coupler being configured receive said at least one external optical fiber laterally from at least one side of said integrated circuit.

34-60. -60. (canceled)