METHOD AND SYSTEM FOR MULTIPLEXER WAVEGUIDE COUPLING

• US 20100119229A1
• Filed: 04/04/2008
• Published: 05/13/2010
• Est. Priority Date: 04/05/2007
• Status: Active Grant

• Current Assignee: Genexis B.V. (Genexis Sweden AB), IMEC International, Universiteit Gent Vzw
• Original Assignee: Genexis B.V. (Genexis Sweden AB), IMEC International, Universiteit Gent Vzw
• Inventors: Roelkens, Gunther, Van den Hoven, Gerard Nicolaas, Van Thourhout, Dries, Baets, Roel
• Granted Patent: US 8,594,503 B2
• Time in Patent Office: Days
• US Class Current: 398/79
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/126 using polarisation effects G02B6/1226 takes precedence
• CPC Class Codes: G02B 6/29317 Light guides of the optical fibre type
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4213 the intermediate optical elements being polarisation selective optical elements G02B6/27 takes precedence
• CPC Class Codes: G02B 6/4215 the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers G02B6/4246 takes precedence

Abstract

An optical device for optically multiplexing or demultiplexing light of different predetermined wavelengths is provided, the optical device comprising at least one first waveguide (11) and at least one second waveguide (12) formed on a substrate (10), wherein the at least one first waveguide and the at least one second waveguide intersect at an intersection, comprising a diffraction grating structure (13) formed at the intersection. There exists a first wavelength or wavelength band travelling within the first waveguide (11) exciting the grating structure and being diffracted an angle corresponding to an outcoupling direction and there exists a second wavelength or wavelength band, different from the first wavelength or wavelength band, travelling within the second waveguide (12) exciting the grating structure and being diffracted at an angle corresponding to the same outcoupling direction. The two radiation beams comprising radiation of two different wavelengths or wavelength bands are spatially separated into the optical waveguides (11 and 12) or combined into single outcoupling direction, e.g. into a single optical element, e.g. a single optical fiber (21). An optical device may be used in local access communications such as fiber to the home, office or curb applications.

Claims

1. An optical device for all-optically multiplexing or demultiplexing light of substantially different predetermined wavelengths, the optical device comprising:

at least one first dielectric waveguide formed on a substrate;

at least one second dielectric waveguide formed on said substrate, said at least one first dielectric waveguide and said at least one second dielectric waveguide intersecting at an intersection; and

a diffraction grating structure formed at said intersection, wherein said diffraction grating structure is adapted for diffracting light of a first predetermined wavelength from said at least one first dielectric waveguide in a coupling direction, and for diffracting light of a second predetermined wavelength from said at least one second dielectric waveguide in substantially the same coupling direction which is substantially different from the normal direction on the average plane defined by the grating structure, the first predetermined wavelength and the second predetermined wavelength being substantially different.

2. The optical device according to claim 1, wherein said diffraction grating structure is adapted to couple out light in said coupling direction by having at least one predetermined grating period, grating depth, grating layer thickness or grating duty cycle.

3. The optical device according to claim 1, further comprising:

an optical coupling element coupled with said intersection, said optical coupling element providing an optical path in said coupling direction such that light of said first predetermined wavelength is coupled between said at least one first dielectric waveguide and said optical coupling element and such that light of said second predetermined wavelength is coupled between said at least one second dielectric waveguide and said optical coupling element.

4. The optical device according to claim 1, said at least one first dielectric waveguide comprising one first dielectric waveguide and said at least one second dielectric waveguide comprising one second dielectric waveguide.

5. The optical device according to claim 4, said one first dielectric waveguide and said one second dielectric waveguide intersecting substantially under a straight angle.

6. The optical device according to claim 1, wherein said diffraction grating structure is a one-dimensional grating structure.

7. The optical device according to claim 1, said at least one first dielectric waveguide comprising two first dielectric waveguides, wherein said optical device is adapted for coupling light of said first predetermined wavelength incident on the diffraction grating structure from said coupling direction as orthogonally polarized optical modes to each of said two first dielectric waveguides, the light having the same single mode in each of said two first dielectric waveguides.

8. The optical device according to claim 1, said at least one second dielectric waveguide comprising two second dielectric waveguides, wherein said optical device is adapted for coupling light of said second predetermined wavelength incident on the diffraction grating structure from said coupling direction as orthogonally polarized optical modes to each of the two second dielectric waveguides, the light having the same single mode in each of the two second dielectric waveguides.

9. The optical device according to claim 8, wherein said diffraction grating structure is a two-dimensional grating structure.

10. The optical device according to claim 1, wherein said at least one first dielectric waveguide and said at least one second dielectric waveguide are selected from the group consisting of channel waveguides, slab waveguides, ridge waveguides and strip loaded waveguides.

11. The optical device according to claim 1, wherein at least one of said at least one first dielectric waveguide and said at least one second dielectric waveguide is adapted for supporting TE polarized light or quasi TE polarized light.

12. The optical device according to claim 1, wherein said diffraction grating structure is a periodic grating structure or a non-periodic grating structure.

13. The optical device according to claim 1, wherein said diffraction grating structure is a periodic grating structure or a non-periodic grating structure, made of a pattern of elliptically shaped structures.

14. The optical device according to claim 3, wherein said optical coupling element comprises an optical fiber or an optical dielectric waveguide.

15. The optical device according to claim 3, wherein said optical coupling element is coupled with said intersection by physical abutment.

16. The optical device according to claim 1, wherein said substrate comprises an additional stack of layers forming a substrate reflector under said diffraction grating structure.

17. The optical device according to claim 1, wherein said at least one first dielectric waveguide comprises a first lateral spot-size converter and wherein said at least one second dielectric waveguide comprises a second lateral spot-size converter, said first lateral spot-size converter and said second lateral spot-size converter coupling said optical device to one or more integrated optical circuits.

30. The use of the optical device according to claim 1, whereby said first predetermined wavelength is between 1250 nm and 1350 nm and whereby said second predetermined wavelength is between 1455 nm and 1605 nm.

31. The use of the optical device according to claim 1 in local access communications such as fiber to the home, office or curb applications.

18. A method for designing an optical device for optically multiplexing or demultiplexing light of substantially different predetermined wavelengths, the method comprising:

determining a direction at which light of a first predetermined wavelength is diffracted from a first dielectric waveguide by a diffraction grating, for a range of diffraction gratings having different grating structures;

determining a direction at which light of a second predetermined wavelength is diffracted from a second dielectric waveguide by said diffraction grating, for said range of diffraction gratings having different diffraction grating structures, the second predetermined wavelength being substantially different from the first predetermined wavelength; and

selecting a grating structure for which the diffraction of light of said first predetermined wavelength from said first dielectric waveguide occurs in a coupling direction and diffraction of light of said second predetermined wavelength from said second dielectric waveguide occurs in substantially the same coupling direction which is substantially different from the normal direction on the average plane defined by the grating structure.

19. The method for designing an optical device according to claim 18, wherein selecting said grating structure comprises selecting at least one of the grating period, the grating depth, the grating layer thickness and the grating duty cycle.

20. A computer program product for executing a method for designing an optical device according to claim 18.

21. A machine readable data storage device storing the computer program product of claim 20.

22. Transmission of the computer program product of claim 20 over a local or wide area telecommunications network.

23. A method for optical multiplexing or demultiplexing, the method comprising:

providing at least one first dielectric waveguide on a substrate;

providing at least one second dielectric waveguide on said substrate, said at least one first dielectric waveguide and said at least one second dielectric waveguide intersecting at an intersection;

providing a diffraction grating structure at said intersection;

diffracting light of a first predetermined wavelength at said diffraction grating structure; and

diffracting light of a second predetermined wavelength at said diffraction grating structure, the second predetermined wavelength being substantially different from the first predetermined wavelength,

wherein said diffraction grating structure is adapted for diffracting light of said first predetermined wavelength from said at least one first dielectric waveguide in a coupling direction, and diffracting light of said second predetermined wavelength from said at least one second dielectric waveguide in the same coupling direction which is substantially different from the normal direction to the average plane defined by the grating structure.

24. The method for optical multiplexing or demultiplexing according to claim 23, wherein said diffraction grating structure is adapted for coupling out light in said coupling direction by adapting at least one of the grating period, the grating depth, the grating layer thickness and the grating duty cycle.

25. The method for optical multiplexing or demultiplexing according to claim 23, the method further comprising coupling an optical coupling element with said intersection, said optical coupling element providing an optical path in the coupling direction.

26. The method for optical multiplexing or demultiplexing according to claim 23, wherein providing at least one first dielectric waveguide comprises providing one first dielectric waveguide and wherein providing at least one second dielectric waveguide comprises providing one second dielectric waveguide.

27. The method for optical multiplexing or demultiplexing according to claim 26, wherein said one first dielectric waveguide and said one second dielectric waveguide intersect substantially under a straight angle.

28. The method for optical multiplexing or demultiplexing according to claim 23, wherein providing at least one first dielectric waveguide comprises providing two first dielectric waveguides and wherein diffracting light of a first predetermined wavelength at said diffraction grating structure comprises coupling light of said first predetermined wavelength as orthogonally polarized optical modes to each of said two first dielectric waveguides, the light having the same single mode in each of said two first dielectric waveguides.

29. The method for optical multiplexing or demultiplexing according to claim 23, wherein providing at least one second dielectric waveguide comprises providing two second dielectric waveguides and wherein diffracting light of a second predetermined wavelength at the diffraction grating structure comprises coupling light of said second predetermined wavelength as orthoghonally polarized optical modes to each of said two second dielectric waveguides, the light having the same single mode in each of said two second dielectric waveguides.