Mode splitter for heat-assisted magnetic recording

Patent metadata

Field	Value
Publication number	US-2020152230-A1
Application number	US-201916714919-A
Country	US
Kind code	A1
Filing date	Dec 16, 2019
Priority date	Jul 25, 2017
Publication date	May 14, 2020
Grant date	—

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 transverse electric (TE) mode; a second waveguide core spaced apart from the first waveguide core, the second waveguide core configured to couple light at a TE mode to the second waveguide core while light at a TM mode is coupled to the first waveguide core, the first waveguide core having a first s-bend at a terminal end and the second waveguide core comprising a second s-bend at the terminal end, wherein the second waveguide core is spaced apart from the first waveguide core by a gap that does not decrease in width along the light propagation direction and a profile of the first s-bend is the same as the profile of the second s-bend; 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 NET receives substantially TM mode light from the first 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 , wherein the light source and the NFT are offset.

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

10 . The apparatus of claim 1 , wherein the first s-bend is a substantial mirror image of the second s-bend.

11 . A method comprising:
receiving light from a light source at a transverse electric (TE) mode; coupling TE mode light to a second waveguide core from the first waveguide core while coupling light at a TM mode to the first waveguide core, the second waveguide core spaced apart from the first waveguide core, the first waveguide core having a first s-bend at a terminal end and the second waveguide core comprising a second s-bend at the terminal end, wherein the second waveguide core is spaced apart from the first waveguide core by a gap that does not decrease in width along the light propagation direction and a profile of the first s-bend is the same as the profile of the second s-bend; 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.

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

13 . The method of claim 11 , wherein the first s-bend is a substantial mirror image of the second s-bend.

14 . An apparatus comprising:
a first waveguide core extending along a light-propagation direction and configured to receive light from a light source at a transverse electric (TE) mode; a second waveguide core spaced apart from the first waveguide core, the second waveguide core configured to couple light at a TE mode to the second waveguide core from the first waveguide core while light at a TM mode is coupled to the first waveguide core, the first waveguide core having a first s-bend at a terminal end and the second waveguide core comprising a second s-bend at the terminal end, wherein the second waveguide core is spaced apart from the first waveguide core by a gap that does not decrease in width along the light propagation direction and a profile of the first s-bend is the same as the profile of the second s-bend; and a near-field transducer (NFT) at a media-facing surface of a write head, the NFT receiving substantially TM mode light from the first waveguide core and heating a magnetic recording medium in response thereto.

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

16 . The apparatus of claim 14 , wherein the first waveguide core has a smaller cross-sectional width than that of the second waveguide core.

17 . The apparatus of claim 14 , 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.

18 . The apparatus of claim 14 , wherein the light source and the NFT are offset.

19 . The apparatus of claim 14 , wherein the NFT receives light that is at least 90% TM mode light from the first waveguide core.

20 . The apparatus of claim 14 , wherein the first s-bend is a substantial mirror image of the second s-bend.

Assignees

• Seagate Technology Llc

Inventors

• Harvey Christopher Neil
• Goggin Aidan Dominic
• Callan Kelly Elizabeth
• Mehfuz Reyad

Classifications

• G11B2005/0021

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

• 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

• G11B7/126

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

• G11B5/6088 Primary

  Optical waveguide in or on flying head · CPC title