System to deliver light to a slider for heat-assisted recording

1. A recording head comprising:

a tapered waveguide adapted to propagate light from a light source in a direction that is substantially parallel to a surface of a storage medium, the tapered waveguide adapted to output an elliptical beam in a direction that is not parallel to the surface of the storage medium;

a slider waveguide extending substantially normal to a surface of the storage medium; and

a grating adapted to couple the elliptical beam into the slider waveguide.

2. The recording head of claim 1 , wherein the grating comprises a plurality of grooves etched into a surface of the slider waveguide.

3. The recording head of claim 2 , wherein the slider waveguide includes a grating region that comprises a mirror layer, a bottom dielectric layer, a core layer, a top dielectric layer, and an overcoat layer, and wherein the grating is etched into the core layer from the top dielectric layer.

4. The recording head of claim 1 , wherein the elliptical beam has a beam size incident on the grating that is approximately equal to a size of the grating.

5. The recording head of claim 1 , wherein the tapered waveguide has a linear taper to expand the light into the elliptical beam.

6. The recording head of claim 1 , wherein the tapered waveguide has a parabolic taper to produce an elliptical beam having a Gaussian-like amplitude profile and a substantially flat wavefront.

7. A system comprising:

a storage medium;

a recording head that is movable relative to the storage medium and that is adapted to record data to the storage medium, the recording head comprising:

a slider waveguide extending normal to a surface of the storage medium and adapted to direct light onto the surface;

a grating associated with the slider waveguide and adapted to couple the light into the slider waveguide; and

a tapered waveguide to propagate the light from a laser source to an output and to shape the light into a beam onto the grating via the output such that the beam has a beam size that matches a size of the grating.

8. The system of claim 7 , wherein the beam comprises an elliptical beam and wherein the grating is adapted to couple the elliptical beam having an elliptical intensity profile into the slider waveguide.

9. The system of claim 8 , wherein the tapered waveguide includes a beam expander to produce the elliptical intensity profile.

10. The system of claim 9 , wherein the beam expander comprises at least one of a linear taper, a parabolic taper, a mode-index lens, and a diffraction optical element.

11. The system of claim 7 , wherein the tapered waveguide extends in a direction that is substantially normal to the slider waveguide, the tapered waveguide including an end mirror adapted to direct the beam onto the grating.

12. The system of claim 7 , wherein the size of the beam is determined by a mode confinement of the tapered waveguide in a direction normal to the waveguide and by a distance between an end of the tapered waveguide and the grating.

13. The system of claim 7 , wherein the slider waveguide includes a grating region comprising a mirror layer, a bottom dielectric layer, a core layer, a top dielectric layer, and a thick dielectric overcoat layer.

14. The system of claim 13 , wherein the grating is etched into the core layer from the top dielectric layer.

15. The system of claim 7 , wherein the grating comprises a plurality of etched grooves having a depth of approximately 100nm and a periodicity of approximately 750nm.

16. A method comprising:

focusing light from a light source into an elliptical beam via a tapered waveguide;

coupling the elliptical beam from the tapered waveguide into a slider waveguide via a grating, wherein focusing the light from the light source into an elliptical beam comprises the tapered waveguide expanding a width of the light so that the width of the elliptical beam is approximately equal to a width of the grating; and

focusing the elliptical beam into a focused beam via the slider waveguide to locally heat a spot at a surface of a recording media.

17. The method of claim 16 , wherein the tapered waveguide includes a minor adapted to direct the light out of the tapered waveguide and onto the grating of the slider waveguide.

18. The method of claim 16 , wherein the grating is adapted to couple the elliptical beam to the slider waveguide with good optical alignment tolerance.

19. The method of claim 16 , further comprising applying a magnetic field to the spot at the recording media to record data to the recording media.