On wafer laser stability control for heat-assisted magnetic recording

Patent metadata

Field	Value
Publication number	US-10692525-B2
Application number	US-201816136389-A
Country	US
Kind code	B2
Filing date	Sep 20, 2018
Priority date	Sep 20, 2018
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

An apparatus includes a substrate. A laser is formed on a non-self supporting structure and bonded to the substrate. A waveguide is deposited proximate the laser. The waveguide is configured to communicate light from the laser to a near-field transducer that directs energy resulting from plasmonic excitation to a recording medium. A light detector is configured to detect an amount of light. At least one laser heater is disposed proximate the laser. A controller is configured to control current supplied to the at least one heater based on the detected amount of light.

First claim

The invention claimed is:

1. An apparatus, comprising:
a substrate;
a laser formed on a non-self supporting stricture and bonded to the substrate;
a waveguide deposited proximate the laser, the waveguide configured to communicate light from the laser to a near-field transducer that directs energy resulting from plasmonic excitation to a recording medium;
a light detector configured to detect an amount of light fluctuation;
at least one laser heater disposed proximate the laser; and
a controller configured to:
determine if the amount of light fluctuation is greater than or equal to about 1%;

control current supplied to the at least one heater if it has been determined that the amount of light fluctuation is greater than or equal to about 1%.

2. The apparatus of claim 1 , wherein the light detector is configured to detect the amount of light fluctuation while writing data to the recording medium.

3. The apparatus of claim 1 , wherein the controller is configured to determine that a laser mode hop has occurred based on the detected amount of light fluctuation.

4. The apparatus of claim 3 , wherein the controller is configured to determine that a laser mode hop has occurred if the detected light fluctuation is greater than 1%.

5. The apparatus of claim 1 , wherein the controller is disposed in a recording head.

6. The apparatus of claim 1 , wherein the light detector is a photodetector.

7. The apparatus of claim 1 , wherein the light detector is a bolometer.

8. The apparatus of claim 1 , wherein the controller is configured to control current supplied to the at least one heater to bring the temperature of the laser to a predetermined temperature range.

9. A system, comprising:
a recording head comprising:
a substrate;
a laser formed on a non-self supporting structure and bonded to the substrate;
a waveguide deposited proximate the laser, the waveguide configured to communicate light from the laser to a near-field transducer that directs energy resulting from plasmonic excitation to a recording medium; and
a light detector configured to detect an amount of light fluctuation;

at least one laser heater disposed proximate the laser; and
a controller configured to:
determine if the amount of light fluctuation is greater than or equal to about 1%;
control current supplied to the at least one if it has been determined that the amount of light fluctuation is greater than or equal to about 1%.

10. The system of claim 9 , wherein the light detector is configured to detect the amount of light fluctuation while writing data to the recording medium.

11. The system of claim 9 , wherein the controller is configured to determine that a laser mode hop has occurred based on the detected amount of light fluctuation.

12. The system of claim 11 , wherein the controller is configured to determine that a laser mode hop has occurred if the detected amount of light fluctuates by at least 1%.

13. The system of claim 9 , wherein the controller is disposed in a recording head.

14. The system of claim 9 , wherein the light detector is a photodetector.

15. The system of claim 9 , wherein the light detector is a bolometer.

16. The system of claim 9 , wherein the controller is configured to control current supplied to the at least one heater to bring the temperature of the laser to a predetermined temperature range.

17. A method comprising:
detecting an amount of light fluctuation proximate a waveguide of a recording head;
determining whether the amount of light fluctuation detected is greater than or equal to about 1%;
if it is determined that the amount of light fluctuation detected is greater than or equal to about 1%, adjusting a current provided to a laser heater for an on-wafer laser of the recording head.

18. The method of claim 17 , wherein detecting the amount of light fluctuation proximate the waveguide comprises detecting the amount of light proximate the waveguide during a writing operation of the recording head.

19. The method of claim 17 further comprising determining that a laser mode hop has occurred if it is determined that the amount of light fluctuation detected is greater than or equal to the threshold.

20. The method of claim 17 , wherein adjusting the current provided to a laser heater for an on-wafer laser of the recording head comprises adjusting the current supplied to the laser heater to bring the temperature of the laser to a predetermined temperature.

Assignees

• Seagate Technology Llc

Inventors

• Goggin Aidan Dominic
• Gubbins Mark Anthony
• Callan Kelly Elizabeth
• Mehfuz Reyad
• Mooney Marcus B
• El Hallak Fadi
• Mcelhinney Paula Frances

Classifications

• G11B5/4866 Primary

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

• G11B7/1263

  Power control during transducing, e.g. by monitoring · 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

• G11B5/6088

  Optical waveguide in or on flying head · CPC title

• G11B7/126 Primary

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