Illumination source and method therefor

• US 7,719,766 B2
• Filed: 06/20/2007
• Issued: 05/18/2010
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Grasser, Regis, Dunphy, James Christopher, Gensler, Steven Werner
• Primary Examiner(s): Choi; William C
• Application Number:
  US11/765,941
• Publication Number:
  US 20080316567A1
• Time in Patent Office: 1,063 Days
• Field of Search: 359/618, 362/551, 362/553, 362/555, 362/559, 362/583, 362/802
• US Class Current: 359/618
• CPC Class Codes: G02B 27/0905 Dividing and/or superposing multiple light beams
• CPC Class Codes: G02B 27/0994 Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/125 Bends, branchings or intersections
• CPC Class Codes: Y10S 362/802 Position or condition responsive switch

Abstract

An illumination source and a method therefor. A light source includes a light circuit configured to process light and direct light, and a lighting element optically coupled to the light circuit to provide multiple colors of light. The light circuit propagates light using light guides. The use of light guides eliminates the use of free space optical elements, enabling the creation of more compact light sources. Furthermore, the use of light guides may enable the creation of light sources with fewer mechanical restrictions, thereby making the light sources potentially more reliable and less expensive.

Claims

1. A light source comprising:

a light circuit configured to process light and propagate light, wherein the light circuit propagates light using light guides, the light circuit comprising;

an integrated light processing element formed on the substrate, the light processing element configured to process light from the lighting element, the light processing element comprising;

a first coupler having a first input and a second input, the first coupler to combine a first light beam at the first input and a second light beam at the second input into a first combined light beam at a first output;

a second coupler having a third input and a fourth input coupled to the first coupler, the second coupler to combine a third light beam at the third input and the first combined light beam at the fourth input into a second combined light beam at a second output;

a first modulator coupled between a first lighting element and the first input of the first coupler, the first modulator configured to selectively block a transmission of the first light beam;

a second modulator coupled between a second lighting element and the second input of the first coupler, the second modulator configured to selectively block a transmission of the second light beam; and

a third modulator coupled between a third lighting element and the third input of the second coupler, the third modulator configured to selectively block a transmission of the third light beam;

an integrated waveguide formed on the substrate, the waveguide to propagate light from the lighting element to the light processing element; and

a lighting element optically coupled to the light circuit, the lighting element to provide multiple colors of light.

2. The light source of claim 1, wherein the lighting element is selected from the group consisting of:

lasers, light emitting diodes, electric arc lamps, solid-state lights, and combinations thereof.

3. The light source of claim 1, wherein the light circuit is a planar lightwave circuit formed on a substrate.

4. The light source of claim 1, wherein the substrate is selected from the group consisting of:

lithium niobate (LNB), ion-doped lithium niobate, lithium tantalite (LTA), lithium triborate (LBO), beta-barium borate (BBO), potassium titanyl phosphate (KTP), and combinations thereof.

5. The light source of claim 1, wherein the first coupler and the second coupler are selected from the group consisting of:

Bragg based couplers, Fabry-Perot based couplers, couplers containing doped regions of the substrate, couplers containing air gaps, couplers containing pre-stressed regions of the substrate, and combinations thereof.

6. The light source of claim 1, wherein the first modulator, the second modulator, and the third modulator are selected from the group consisting of:

Mach-Zender modulators, switchable Bragg gratings, variable couplers, couplers using evanescent waves, and combinations thereof.

7. The light source of claim 1, further comprising a lens optically coupled to an output waveguide of the light processing element, the lens configured to collimate light produced by the light processing element.

8. The light source of claim 1, wherein the light circuit comprises:

a discrete light processing element configured to process light from the lighting element; and

an optical fiber coupled to the light processing element and to the lighting element, the optical fiber to propagate light from the lighting element to the light processing element.

9. The light source of claim 1, further comprising a speckle reduction unit coupled to an output waveguide of the light processing element, the speckle reduction unit comprising:

a plurality of intermediate waveguides, wherein each intermediate waveguide is coupled in parallel to the output waveguide; and

a plurality of electrodes, wherein each electrode is coupled to an intermediate waveguide of the plurality of intermediate waveguides, and wherein each respective electrode creates a phase shift pattern on a propagated light beam propagated by an intermediate waveguide coupled to the electrode.

10. The light source of claim 9, wherein a first phase shift pattern created by an electrode of the plurality of electrodes is different from phase shift patterns created by other electrodes of the plurality of electrodes.

11. A light source comprising:

a light circuit configured to process light and propagate light, wherein the light circuit propagates light using light guides, the light circuit comprising;

an integrated light processing element formed on the substrate, the light processing element configured to process light from the lighting element; and

an integrated waveguide formed on the substrate, the waveguide to propagate light from the lighting element to the light processing element; and

a lighting element optically coupled to the light circuit, the lighting element to provide multiple colors of light; and

a speckle reduction unit coupled to an output waveguide of the light processing element, the speckle reduction unit comprising;

a plurality of intermediate waveguides, wherein each intermediate waveguide is coupled in parallel to the output waveguide; and

a plurality of electrodes, wherein each electrode is coupled to an intermediate waveguide of the plurality of intermediate waveguides, and wherein each respective electrode creates a phase shift pattern on a propagated light beam propagated by an intermediate waveguide coupled to the electrode.

12. The light source of claim 11, wherein the light processing element comprises:

a first coupler having a first input and a second input, the first coupler to combine a first light beam at the first input and a second light beam at the second input into a first combined light beam at a first output; and

a second coupler having a third input and a fourth input coupled to the first coupler, the second coupler to combine a third light beam at the third input and the first combined light beam at the fourth input into a second combined light beam at a second output.

13. The light source of claim 12, wherein the first coupler and the second coupler are selected from the group consisting of:

Bragg based couplers, Fabry-Perot based couplers, couplers containing doped regions of the substrate, couplers containing air gaps, couplers containing pre-stressed regions of the substrate, and combinations thereof.

14. The light source of claim 11, wherein a first phase shift pattern created by an electrode of the plurality of electrodes is different from phase shift patterns created by other electrodes of the plurality of electrodes.

15. The light source of claim 11, wherein the lighting element is selected from the group consisting of:

lasers, light emitting diodes, electric arc lamps, solid-state lights, and combinations thereof.

16. The light source of claim 11, wherein the light circuit is a planar lightwave circuit formed on a substrate selected from the group consisting of:

lithium niobate (LNB), ion-doped lithium niobate, lithium tantalite (LTA), lithium triborate (LBO), beta-barium borate (BBO), potassium titanyl phosphate (KTP), and combinations thereof.

17. The light source of claim 11, further comprising a lens optically coupled to an output waveguide of the light processing element, the lens configured to collimate light produced by the light processing element.

18. The light source of claim 11, wherein the light circuit comprises:

a discrete light processing element configured to process light from the lighting element; and

an optical fiber coupled to the light processing element and to the lighting element, the optical fiber to propagate light from the lighting element to the light processing element.

19. The light source of claim 11, further comprising a lens optically coupled to an output waveguide of the light processing element, the lens configured to collimate light produced by the light processing element.

20. The light source of claim 11, wherein the light circuit comprises:

a discrete light processing element configured to process light from the lighting element; and

an optical fiber coupled to the light processing element and to the lighting element, the optical fiber to propagate light from the lighting element to the light processing element.