Waveguide of a write head with reduced cross sectional area proximate a near-field transducer

Patent metadata

Field	Value
Publication number	US-2016118069-A1
Application number	US-201514886240-A
Country	US
Kind code	A1
Filing date	Oct 19, 2015
Priority date	Oct 23, 2014
Publication date	Apr 28, 2016
Grant date	—

Abstract

A write head includes a near-field transducer near a media-facing surface of the write head. The write head includes a waveguide having a core with a first side disposed proximate to the near-field transducer. The core overlaps the near-field transducer at a substrate-parallel plane. The core includes one of a step or a taper on a second side facing away from the first side. The step or the taper causes a reduced thickness of the core normal to the substrate-parallel plane. The write head includes a cladding layer that encompassing the second side of the core and that fills in the step or the taper.

First claim

What is claimed is:

1 . A write head, comprising:
a near-field transducer near a media-facing surface of the write head; a waveguide comprising a core with a first side disposed proximate to the near-field transducer, the core overlapping the near-field transducer at a substrate-parallel plane, the core comprising one of a step or a taper on a second side facing away from the first side, the step or the taper causing a reduced thickness of the core normal to the substrate-parallel plane; and a cladding layer that encompassing the second side of the core and that fills in the step or the taper.

2 . The write head of claim 1 , wherein the step or the taper reduces reflections back to a light source optically coupled to the waveguide.

3 . The write head of claim 1 , wherein the step or the taper comprises a rectangular step.

4 . The write head of claim 1 , wherein the step or the taper comprises two rectangular steps that cause the reduced thickness at two outer crosstrack regions of the core, a center region between the two rectangular steps having an unreduced thickness.

5 . The write head of claim 1 , wherein the step or the taper comprises the taper, the taper having a sloped surface at a first angle to the media-facing surface.

6 . The write head of claim 5 , wherein the taper linearly reduces the core to a sharp edge at the media-facing surface.

7 . The write head of claim 1 , wherein the core further comprises a second taper that reduces a cross track width of the core as it approaches the media-facing surface.

8 . The write head of claim 1 , wherein the core further comprises a first crosstrack width over the near-field transducer, a second crosstrack width near the media-facing surface, and a third crosstrack width at an end of the near-field transducer that faces away from the media-facing surface, the first crosstrack width being different than the second and third crosstrack widths.

9 . A write head, comprising:
a near-field transducer near a media-facing surface of the write head; and a waveguide comprising a core having an end portion near the media-facing surface that overlaps the near-field transducer at a substrate-parallel plane, the end portion comprising: a first crosstrack width over the near-field transducer; a second crosstrack width between the media-facing surface and the near-field transducer; and a third crosstrack width at an end of the near-field transducer that faces away from the media-facing surface, the first crosstrack width being different than the second and third crosstrack widths.

10 . The write head of claim 9 , wherein the difference between the first crosstrack width and the second and third crosstrack widths reduces reflections back to a light source optically coupled to the waveguide.

11 . The write head of claim 9 , wherein the first crosstrack width is less than the first and second crosstrack widths.

12 . The write head of claim 11 , wherein the end portion further comprises tapered edges between the near-field transducer and the media-facing surface that result in a reduced cross sectional area of the core as it approaches the media-facing surface.

13 . The write head of claim 12 , wherein a final crosstrack width of the core at the media-facing surface is less than the first crosstrack width.

14 . The write head of claim 11 , wherein the end portion comprises curved concave depressions that result in the first crosstrack width being less than the than the second and third crosstrack widths.

15 . The write head of claim 9 , wherein the first crosstrack width is greater than the first and second crosstrack widths.

16 . The write head of claim 15 , wherein the end portion comprises a constant crosstrack width between the near-field transducer and the media-facing surface.

17 . The write head of claim 15 , wherein the end portion comprises curved, concave, protrusions that result in the first crosstrack width being greater than the than the second and third crosstrack widths.

18 . A write head, comprising:
a near-field transducer near a media-facing surface of the write head; and a waveguide comprising a core having an end portion near the media-facing surface that overlaps the near-field transducer at a substrate-parallel plane, the end portion comprising tapered edges that each reduce a crosstrack width of the core as it approaches the media-facing surface by a value of dX, the value of dX being nominally about 19% of the crosstrack width, the tapered edges beginning at a distance dZ from the media-facing surface, and the tapered edges reducing reflections back to a light source optically coupled to the waveguide.

19 . The write head of claim 18 , wherein the distance dZ is nominally between about 94% and 106% the crosstrack width.

20 . The write head of claim 18 , wherein the core comprises a first side disposed proximate to the near-field transducer, the core comprising one of a step or a taper on a second side facing away from the first side, the step or the taper causing a reduced thickness of the core normal to the substrate-parallel plane.

Assignees

• Seagate Technology Llc

Inventors

• Yang Ruoxi
• Asselin Pierre
• Zhao Yongjun
• Wessel James Gary
• Lee Tae-Woo
• Scholz Werner
• Stageberg Frank Edgar

Classifications

• G11B5/4866 Primary

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

• G11B5/1871 Primary

  Shaping or contouring of the transducing or guiding surface · 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

• 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

• G02B6/1228

  Tapered waveguides, e.g. integrated spot-size transformers (for coupling with fibres G02B6/305) · CPC title