Assistant waveguides for evaluating main waveguide coupling efficiency and diode laser alignment tolerances for hard disk
View Patent ↗A heat assisted magnetic recording (HAMR) transducer on a slider and including first and second opposing surfaces, wherein the first surface is aligned to an air bearing surface (ABS) of the slider and the second surface is aligned to a surface of the slider opposite the ABS, a target waveguide having an entrance at the second surface, the target waveguide being configured to direct energy provided by a light source from the entrance toward the first surface, wherein the target waveguide expands in cross-section area with distance from the entrance to form an inverse taper waveguide, a plurality of assistant waveguides each having an entrance at the second surface, wherein the plurality of assistant waveguides are configured to direct energy to the plurality of output devices.
1. A heat assisted magnetic recording (HAMR) transducer on a slider comprising:
first and second opposing surfaces, wherein the first surface is aligned to an air bearing surface (ABS) of the slider and the second surface is aligned to a surface of the slider opposite the ABS;
a target waveguide having an entrance at the second surface, the target waveguide being configured to direct energy provided by a light source from the entrance toward the first surface, wherein the target waveguide expands in cross-section area with distance from the entrance to form an inverse taper waveguide; and
a plurality of assistant waveguide each having an entrance at the second surface, wherein the plurality of assistant waveguides are configured to direct energy to a plurality of output devices.
2. The HAMR transducer of claim 1 , wherein the light source comprises a laser diode.
3. The HAMR transducer of claim 1 , wherein the assistant waveguides are arranged at the second surface at a separation distance of at least one and one-half micron to receive light by direct illumination from the light source, while not exhibiting directional coupling between the target waveguide and any of the assistant waveguides.
4. The HAMR transducer of claim 1 , wherein each of the assistant waveguides comprises a cross-section area at the entrance larger than a cross-section area of the target waveguide entrance.
5. The HAMR transducer of claim 1 , wherein each of the assistant waveguides comprises a forward taper that initially decreases in cross-section area with distance from the entrance.
6. The HAMR transducer of claim 1 , wherein each of the plurality of assistant waveguides is configured to have a portion with an expanded cross-section to couple to an output device.
7. The HAMR transducer of claim 6 , wherein the expanded portion of each of the assistant waveguides couple to a grating to direct the light from the assistant waveguide to the output device.
8. The HAMR transducer of claim 1 , further comprising a multimode interference splitter to split light from the target waveguide, and a plurality of optical waveguides to deliver the split light to the first surface at a convergent point.
9. The HAMR transducer of claim 8 , wherein the plurality of optical waveguides comprises two waveguides, and wherein the multimode interference splitter is configured to split the light into the two waveguides.
10. The HAMR transducer of claim 8 further comprising a near field transducer at the convergent point.
11. A method for aligning a light source to a target waveguide in a heat assisted magnetic recording (HAMR) transducer on a slider, the HAMR transducer comprising a first and second opposing surfaces, wherein the first surface is aligned to an air bearing surface (ABS) of the slider and the second surface is aligned to a surface of the slider opposite the ABS, the method comprising:
aligning an entrance of the target waveguide on the second surface of the HAMR transducer to the light source to direct light toward the first surface of the HAMR transducer, wherein the target waveguide expands in cross-section area with distance from the entrance to form an inverse taper waveguide;
monitoring energy received at a plurality of output devices from a plurality of assistant waveguides in the HAMR transducer, each of the plurality of assistant waveguides having an entrance at the second surface of the HAMR transducer to receive portions of the light directly from the light source; and
adjusting the alignment on the basis of the energy monitored at the output devices.
12. The method of claim 11 , wherein the light source comprises a laser diode.
13. The method of claim 11 , wherein the assistant waveguides are arranged at the second surface of the HAMR transducer at a distance of at least one and one-half micron to receive the light by direct illumination from the light source, while not exhibiting directional coupling between the target waveguide and any of the assistant waveguides.
14. The method of claim 13 , wherein each of the assistant waveguides comprises a cross-section area at the entrance larger than a cross-section area of the target waveguide entrance.
15. The method of claim 13 , wherein each of the assistant waveguides comprises a forward taper that initially decreases in cross-section area with distance from the entrance.
16. The method of claim 15 , comprising outputting light to an output device corresponding to each of the assistant waveguides, wherein each of the plurality of assistant waveguides is configured to have a portion with an expanded cross-section arranged with the output device.
17. The method of claim 16 , wherein the expanded portion of each of the assistant waveguides couple to a grating to direct the light from the assistant waveguide to the output device.
18. The method of claim 11 , comprising:
splitting the light beam with a multimode interference splitter from the target waveguide; and
delivering the split light to the first surface at a convergent point.
19. The method of claim 18 , wherein the plurality of optical waveguides comprises two waveguides, and wherein the multimode interference splitter is configured to split the light into the two optical waveguides.
20. The method of claim 18 , further comprising a near field transducer at the convergent point.
21. A hard disk drive comprising a heat assisted magnetic recording (HAMR) transducer on a slider, the HAMR transducer comprising:
first and second opposing surfaces, wherein the first surface is aligned to an air bearing surface (ABS) of the slider and the second surface is aligned to a surface of the slider opposite the ABS;
a target waveguide having an entrance at the second surface, the target waveguide being configured to direct energy provided by a light source from the entrance toward the first surface, wherein the target waveguide expands in cross-section area with distance from the entrance to form an inverse taper waveguide;
a plurality of assistant waveguides each having an entrance at the second surface, wherein the plurality of assistant waveguides are configured to direct energy to a plurality of output devices.