Mode splitter between TE and TM polarization for heat-assisted magnetic recording

Patent metadata

Field	Value
Publication number	US-10062400-B1
Application number	US-201715658636-A
Country	US
Kind code	B1
Filing date	Jul 25, 2017
Priority date	Jul 25, 2017
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

An apparatus includes a first waveguide core extending along a light-propagation direction and configured to receive light from a light source at a combined transverse electric (TE) mode and a transverse magnetic (TM) mode. A second waveguide core is spaced apart from the first waveguide core and is configured to couple light at a TM mode to the second waveguide core. A near-field transducer (NFT) is disposed at a media-facing surface of a write head, the NFT receiving the light from the first waveguide core or the second waveguide core and heating a magnetic recording medium in response thereto.

First claim

What is claimed is:

1. An apparatus comprising:
a first waveguide core extending along a light-propagation direction and configured to receive light from a light source at a combined transverse electric (TE) mode and a transverse magnetic (TM) mode;
a second waveguide core spaced apart from the first waveguide core by a gap, the second waveguide core configured to couple light at a TM mode to the second waveguide core, the gap having a width that is substantially constant along an entire length of the second waveguide core; and
a near-field transducer (NFT) at a media-facing surface of a write head, the NFT receiving the light from the first waveguide core or the second waveguide core and heating a magnetic recording medium in response thereto.

2. The apparatus of claim 1 , wherein the second waveguide core is spaced apart from the first waveguide core by a gap that increases in width along the light propagation direction.

3. The apparatus of claim 1 , wherein the NFT receives substantially TM mode light from the second waveguide core.

4. The apparatus of claim 1 , wherein at least one of the first waveguide core and the second waveguide core comprises a curve.

5. The apparatus of claim 1 , wherein at least one of the first waveguide core and the second waveguide core comprises TaOx.

6. The apparatus of claim 1 , wherein the first waveguide core has a different cross-sectional width than that of the second waveguide core.

7. The apparatus of claim 1 , wherein the first waveguide core has a smaller cross-sectional width than that of the second waveguide core.

8. The apparatus of claim 1 , further comprising one or more cladding layers surrounding the first waveguide core and the second waveguide core.

9. The apparatus of claim 1 , wherein, the light output from the second waveguide core is at least 90% TM mode.

10. A method comprising:
receiving light from a light source at a combined transverse electric (TE) mode and a transverse magnetic (TM) mode;
coupling TM mode light to a second waveguide core from the first waveguide core, the second waveguide core spaced apart from the first waveguide core by a gap having a width that is substantially constant along an entire length of the second waveguide core;
delivering light received from the first waveguide core or the second waveguide core to a near-field transducer (NFT) at a media-facing surface of a write head; and
heating a magnetic recording medium in response to delivering the light.

11. The method of claim 10 , wherein the NFT receives substantially TE mode light from the first waveguide core or substantially TM mode light from the second waveguide core.

12. The method of claim 11 , wherein, the NFT receives light that is at least 90% TE mode from the first waveguide core or light that is at least 90% TM mode light from the second waveguide core.

13. An apparatus comprising:
a first waveguide core extending along a light-propagation direction and configured to receive light from a light source at a combined transverse electric (TE) mode and a transverse magnetic (TM) mode;
a second waveguide core spaced apart from the first waveguide core, the second waveguide core configured to couple light at a TM mode to the second waveguide core from the first waveguide core, an input end of the second waveguide core curving away from the first waveguide core; and
a near-field transducer (NFT) at a media-facing surface of a write head, the NFT receiving substantially TM mode light from the second waveguide core and heating a magnetic recording medium in response thereto.

14. The apparatus of claim 13 , wherein at least one of the first waveguide core and the second waveguide core comprises a curve.

15. The apparatus of claim 13 , wherein the first waveguide core has a smaller cross-sectional width than that of the second waveguide core.

16. The apparatus of claim 13 , wherein the second waveguide core is spaced apart from the first waveguide core by a gap that increases in width along the light propagation direction.

17. The apparatus of claim 13 , further comprising one or more cladding layers surrounding the first waveguide core and the second waveguide core.

18. The apparatus of claim 13 , wherein the NFT receives light that is at least 90% TM mode light from the second waveguide core.

19. The apparatus of claim 13 , wherein at least one of the first waveguide core and the second waveguide core comprises an s-bend at a terminal end.

20. The apparatus of claim 13 , wherein the first waveguide core comprises a first s-bend and the second waveguide core comprises a second s-bend, the first and second s-bends having substantially the same width.

Assignees

• Seagate Technology Llc

Inventors

• Harvey Christopher Neil
• Goggin Aidan Dominic
• Hamilton Kelly Elizabeth
• Mefuz Reyad

Classifications

• G11B5/314

  where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers (G11B5/3196 takes precedence) · CPC title

• G11B5/4866 Primary

  the arm comprising an optical waveguide, e.g. for thermally-assisted recording · CPC title

• G11B5/6088 Primary

  Optical waveguide in or on flying head · CPC title

• G11B2005/0021

  Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal · CPC title

• G11B7/126

  Circuits, methods or arrangements for laser control or stabilisation · CPC title