OPTICAL CONTROL DEVICE

• US 20100014821A1
• Filed: 01/10/2008
• Published: 01/21/2010
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Tokushima, Masatoshi
• Granted Patent: US 8,208,776 B2
• Time in Patent Office: Days
• US Class Current: 385/129
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02F 2201/06 integrated waveguide
• CPC Class Codes: G02F 2201/20 delay line
• CPC Class Codes: G02F 2202/32 Photonic crystals
• CPC Class Codes: G02F 2203/055 wavelength filtering

Abstract

There is provided an optical control device including a plurality of line-defect waveguides provided in a photonic crystal; each line-defect waveguide including a multiplicity of dielectric pillars with a finite height arranged at lattice points of a two-dimensional Bravais lattice. The optical control device comprises: a first line-defect waveguide; a second line-defect waveguide provided with the dielectric pillars having a thickness different from that of the dielectric pillars of the first line-defect waveguide; and a third line-defect waveguide arranged between the first and second line-defect waveguides and provided with the dielectric pillars whose thicknesses are gradually varied from those of the dielectric pillars of the first line-defect waveguide to those of the dielectric pillars of the second line-defect waveguide along a wave guiding direction.

Claims

1. An optical control device including a plurality of line-defect waveguides provided in a photonic crystal;

each line-defect waveguide including a multiplicity of dielectric pillars with a finite height arranged at lattice points of a two-dimensional Bravais lattice;

said optical control device comprising;

a first line-defect waveguide;

a second line-defect waveguide provided with the dielectric pillars having a thickness different from that of the dielectric pillars of said first line-defect waveguide; and

a third line-defect waveguide arranged between said first and second line-defect waveguides and provided with the dielectric pillars whose thicknesses are gradually varied from those of the dielectric pillars of said first line-defect waveguide to those of the dielectric pillars of said second line-defect waveguide along a wave guiding direction.

2. The optical control device according to claim 1, wherein a further line-defect waveguide, whose dielectric pillars have thicknesses gradually varied along the wave guiding direction, is provided at one end or at each of both ends along the wave guiding direction of said optical control device including said first to third line-defect waveguides.

3. The optical control device according to claim 1, wherein said third line-defect waveguide has a length along the wave guiding direction not less than five times a lattice period.

4. The optical control device according to claim 1, wherein the thicknesses of the dielectric pillars contained in a line defect of said first line-defect waveguide and the dielectric pillars not contained in said line defect are thicker than that of the dielectric pillars contained in a line defect of said second line-defect waveguide and dielectric pillars not contained in said line defect, or the thicknesses of the dielectric pillars contained in a line defect of said second line-defect waveguide and the dielectric pillars not contained in said line defect are thicker than that of the dielectric pillars contained in a line defect of said first line-defect waveguide and dielectric pillars not contained in said line defect.

5. The optical control device according to claim 1, wherein thicknesses of the dielectric pillars contained in the line defect of said first and second line-defect waveguides differ only with respect to those of the dielectric pillars contained in the line defect(s) of said first and second line-defect waveguides, and the thicknesses of dielectric pillars not contained in the line defect(s) of said first and second line-defect waveguides are equal.

6. The optical control device according to claim 1, wherein thicknesses of the dielectric pillars not contained in a line defect of said first and second line-defect waveguides differ only with respect to those of the dielectric pillars not contained in line defect(s) of said first and second line-defect waveguides, and wherein the thicknesses of the dielectric pillars contained in the line defect(s) of said first and second line-defect waveguides are equal.

7. The optical control device according to claim 1, wherein the thicknesses of the dielectric pillars contained in the line defects of said first and second line-defect waveguides change in thickness in opposite directions between the dielectric pillars not contained in the line defect of the first and second line-defect waveguides and the dielectric pillars contained in the line defect of the first and second line-defect waveguides.

8. An optical control device including a plurality of line-defect waveguides provided in a photonic crystal;

each line-defect waveguide including a multiplicity of dielectric pillars with a finite height arranged at lattice points of a two-dimensional Bravais lattice;

said optical control device comprising;

a first line-defect waveguide;

a second line-defect waveguide provided with dielectric pillars having cross-sectional shapes different from those of the dielectric pillars of said first line-defect waveguide; and

a third line-defect waveguide arranged between said first and second line-defect waveguides and provided with the dielectric pillars whose cross-sectional shapes are gradually varied from those of the dielectric pillars of said first line-defect waveguide to those of the dielectric pillars of said second line-defect waveguide in the course from said first line-defect waveguide towards said second line-defect waveguide along the wave guiding direction.

9. The optical control device according to claim 8, wherein a further line-defect waveguide, whose dielectric pillars have cross-sectional shapes gradually varied along the wave guiding direction, is provided at one end or at each of both ends along the wave guiding direction of said optical control device including said first to third line-defect waveguides.

10. The optical control device according to claim 8, wherein said third line-defect waveguide has a length along the wave guiding direction not less than five times a lattice period.

11. The optical control device according to claim 8, wherein the cross-sectional shapes of the dielectric pillars contained in the line defect of said first and second line-defect waveguides differ only with respect to those of the dielectric pillars contained in the line defect of said first and second line-defect waveguides, and wherein the cross-sectional shapes of dielectric pillars not contained in the line defect of said first and second line-defect waveguides are equal.

12. The optical control device according to claim 8, wherein

the cross-sectional shapes of the dielectric pillars not contained in the line defect of said first and second line-defect waveguides differ only with respect to those of dielectric pillars not contained in the line defect of said first and second line-defect waveguides, and wherein the cross-sectional shapes of the dielectric pillars contained in the line defects of said first and second line-defect waveguides are equal.

13. The optical control device according to claim 8, wherein, wherein, in said first and second line-defect waveguides, the cross-sectional shapes of the dielectric pillars contained in the line defects are equal to the cross-sectional shapes of the dielectric pillars not contained in the line defects.

14. The optical control device according to claim 8, wherein, in at least one of the first and second line-defect waveguides, the cross-sectional shapes of the dielectric pillars contained in the line defect are different from the cross-sectional shapes of the dielectric pillars not contained in the line defects.

15. An optical control device including a plurality of line-defect waveguides provided in a photonic crystal;

each line-defect waveguide including a multiplicity of dielectric pillars with a finite height arranged at lattice points of a two-dimensional Bravais lattice;

said optical control device comprising;

a first line-defect waveguide;

a second line-defect waveguide provided with the dielectric pillars that have lattice point intervals (that is, local lattice constants) different from those of the dielectric pillars of said first line-defect waveguide; and

a third line-defect waveguide arranged between said first and second line-defect waveguides and provided with dielectric pillars whose lattice point intervals are gradually varied from the those of the dielectric pillars of said first line-defect waveguide to the those of the dielectric pillars of said second line-defect waveguide in the course from said first line-defect waveguide towards said second line-defect waveguide, along the wave guiding direction.

16. The optical control device according to claim 15 wherein a further line-defect waveguide, whose lattice point intervals have cross-sectional shapes gradually varied along the wave guiding direction, is provided at one end or at each of both ends along the wave guiding direction of said optical control device including said first to third line-defect waveguides.

17. The optical control device according to claim 15, wherein said third line-defect waveguide has a length along the wave guiding direction not less than five times a lattice period.

18. The optical control device according to claim 15, wherein the lattice point intervals of the dielectric pillars contained in the line defect of said first and second line-defect waveguides differ only with respect to those of the dielectric pillars contained in the line defect of said first and second line-defect waveguides, and wherein the lattice point intervals of dielectric pillars not contained in the line defect of said first and second line-defect waveguides are equal.

19. The optical control device according to claim 15, wherein only lattice point intervals of the dielectric pillars not contained in the line defect of said first and second line-defect waveguides differ, and wherein the lattice point intervals of the dielectric pillars contained in the line defect(s) of said first and second line-defect waveguides are equal.

20. The optical control device according to claim 15, wherein, in said first and second line-defect waveguides, the lattice point intervals of the dielectric pillars contained in the line defects are equal to the lattice point intervals of the dielectric pillars not contained in the line defects.

21-24. -24. (canceled)