Optical grating coupling for interferometric waveguides in heat assisted magnetic recording heads

• US 8,923,102 B1
• Filed: 09/25/2013
• Issued: 12/30/2014
• Est. Priority Date: 07/16/2013
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Western Digital Corporation
• Inventors: Shi, Zhong, Mallary, Michael L.
• Primary Examiner(s): HUBER, PAUL W
• Application Number:
  US14/037,331
• Time in Patent Office: 461 Days
• Field of Search: None
• US Class Current: 369/13.33
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G11B 2005/0021 Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal
• CPC Class Codes: G11B 5/314 where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers G11B5/3196 takes precedence
• CPC Class Codes: G11B 5/6088 Optical waveguide in or on flying head

Abstract

A heat-assisted magnetic recording (HAMR) transducer is coupled with a laser for providing energy and has an air-bearing surface (ABS) configured to reside in proximity to a media during use. The HAMR transducer includes a write pole, at least one coil, a waveguide optically coupled with the laser and a grating. The write pole is configured to write to a region of the media. The coil(s) energize the write pole. The waveguide includes arms that have an optical path difference. The grating is optically coupled with the laser. The waveguide is optically coupled with the grating and receives light from the grating.

Claims

1. A heat assisted magnetic recording (HAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the HAMR transducer comprising:

a write pole configured to write to a region of the media;

at least one coil for energizing the write pole;

a grating optically coupled with the laser; and

an interferometric waveguide (IWG) optically coupled with the grating and having a plurality of arms, the plurality of arms having an optical path difference.

2. The HAMR transducer of claim 1 wherein the IWG is a tapered interferometric waveguide (ITWG) having a tapered region including an entrance distal from the ABS, a bottom proximate to the ABS, a first side and a second side opposite to the first side, at least a portion of the first side and at least a portion of the second side converging such that the first side is closer to the second side at the bottom than at the entrance.

3. The HAMR transducer of claim 2 wherein the at least the portion of the first side and the at least the portion of the second side converge in accordance with a function having at least one term having an order greater than one.

4. The HAMR transducer of claim 1 wherein the order is at least two such that the at least one term includes a quadratic term.

5. The HAMR transducer of claim 1 wherein the grating further includes a bottom reflector.

6. The HAMR transducer of claim 5 wherein the bottom reflector includes at least one of a Bragg reflector and a mirror.

7. The HAMR transducer of claim 1 further comprising:

a reflector, the grating residing between the reflector and the IWG.

8. The HAMR transducer of claim 7 wherein the reflector includes at least one of a Bragg reflector and a mirror.

9. The HAMR transducer of claim 7 wherein the reflector is substantially parallel to the ABS.

10. The HAMR transducer of claim 7 wherein the reflector is substantially perpendicular to the ABS.

11. The HAMR transducer of claim 1 further comprising:

a near-field transducer (NFT), a portion of the NFT residing at the ABS, a portion of the energy from the laser traveling through the plurality of arms of the IWG forming an interference pattern at the NFT such that the NFT couples part of the portion of the energy from the grating to the media.

12. A heat assisted magnetic recording (HAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the HAMR transducer comprising:

a write pole configured to write to a region of the media;

at least one coil for energizing the write pole;

a coupling grating optically coupled with the laser, the coupling grating including an optical grating and a bottom reflector, the optical grating residing between the laser and the bottom reflector;

a tapered interferometric waveguide (ITWG) optically coupled with the grating, the ITWG including a tapered region and a plurality of arms, the tapered region including an entrance distal from the ABS, a bottom proximate to the ABS, a first side and a second side opposite to the first side, at least a portion of the first side and at least a portion of the second side converging in accordance with a function such that first side is closer to the second side at the bottom than at the entrance, the function including a quadratic term, the plurality of arms having an optical path difference;

a reflector, the coupling grating residing between the reflector and the ITWG; and

a near-field transducer (NFT), a portion of the NFT residing at the ABS, a portion of the energy from the laser traveling through the plurality of arms of the ITWG forming an interference pattern at the NFT such that the NFT couples part of the portion of the energy from the grating to the media.

13. A heat assisted magnetic recording (HAMR) disk drive comprising:

a media for storing data;

a slider having an air-bearing surface (ABS) configured to reside in proximity to the media during use;

a laser coupled with the slider for providing energy; and

a HAMR transducer coupled with the slider and including a write pole, at least one coil, a grating, and an interferometric waveguide (IWG), the write pole being configured to write to a region of the media, the at least one coil for energizing the write pole, the grating being optically coupled with the laser, the IWG being optically coupled with the grating and having a plurality of arms, a portion of the energy from the laser being coupled into the grating, into the IWG from the grating and directed toward the ABS along each of the plurality of arms, the plurality of arms having an optical path difference.

14. A method for providing a heat assisted magnetic recording (HAMR) transducer coupled with a laser for providing energy and having an air-bearing surface (ABS) configured to reside in proximity to a media during use, the method comprising:

providing a write pole configured to write to a region of the media;

providing at least one coil for energizing the write pole;

providing a grating optically coupled with the laser; and

providing an interferometric waveguide (IWG) optically coupled with the grating and having a plurality of arms, a portion of the energy from the laser being coupled into the grating, into the IWG from the grating and directed toward the ABS along each of the plurality of arms, the plurality of arms having an optical path difference.

15. The method of claim 14 wherein the IWG is a tapered interferometric waveguide (ITWG) having a tapered region including an entrance distal from the ABS, a bottom proximate to the ABS, a first side and a second side opposite to the first side, at least a portion of the first side and at least a portion of the second side converging such that the first side is closer to the second side at the bottom than at the entrance.

16. The method of claim 15 wherein the at least the portion of the first side and the at least the portion of the second side converge in accordance with a function having at least one quadratic term.

17. The method of claim 14 wherein the grating further includes a bottom reflector.

18. The method of claim 17 wherein the bottom reflector includes at least one of a Bragg reflector and a mirror.

19. The method of claim 14 further comprising:

providing a side reflector, the grating residing between the side reflector and the IWG.

20. The method of claim 19 wherein the side reflector includes at least one of a Bragg reflector and a mirror.

21. The method of claim 19 wherein the side reflector is substantially parallel to the ABS.

22. The method of claim 19 wherein the side reflector is substantially perpendicular to the ABS.

23. The method of claim 14 further comprising:

providing a near-field transducer (NFT), a portion of the NFT residing at the ABS, a portion of the energy from the laser traveling through the plurality of arms of the IWG forming an interference pattern at the NFT such that the NFT couples part of the portion of the energy from the grating to the media.