Energy assisted magnetic recording disk drive using modulated laser light

• US 8,891,341 B1
• Filed: 03/11/2013
• Issued: 11/18/2014
• Est. Priority Date: 03/11/2013
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Krichevsky, Alexander, Mallary, Michael L., Zong, Fenghua
• Primary Examiner(s): Dinh, Tan X
• Application Number:
  US13/794,166
• Time in Patent Office: 617 Days
• Field of Search: 369/13.33, 369/13.13
• US Class Current: 369/13.33
• CPC Class Codes: G11B 2005/0021 Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal
• CPC Class Codes: G11B 5/02 Recording, reproducing, or erasing methods; Read, write or erase circuits therefor

Abstract

A method and system provide a heat assisted magnetic recording (HAMR) disk drive including a media. The HAMR disk drive also includes a slider, at least one laser, at least one HAMR head on the slider and at least one electro-optical modulator (EOM) optically coupled with the laser(s) and coupled with the slider. The at least one laser and the at least one EOM are coupled to provide a modulated energy output. The at least one EOM controls the modulated energy output to have a characteristic waveform shape. The at least one HAMR head includes at least one waveguide, a write pole, and at least one coil for energizing the write pole. The at least one waveguide receives the modulated energy output and directs the modulated energy output toward the media.

Claims

1. A heat assisted magnetic recording (HAMR) disk drive including a media comprising:

a slider;

at least one laser coupled with the slider;

at least one electro-optical modulator (EOM) optically coupled with the at least one laser and coupled with the slider, the at least one laser and the at least one EOM being coupled to provide a modulated energy output, the at least one EOM controlling the modulated energy output to be a pulsed output having a characteristic waveform shape for energy versus time; and

at least one HAMR head on the slider, the at least one HAMR head including at least one waveguide, a write pole, and at least one coil for energizing the write pole, the at least one waveguide for receiving the modulated energy output and directing the modulated energy output toward the media.

2. The HAMR disk drive of claim 1 wherein the EOM is an electro-absorption modulator.

3. The HAMR disk drive of claim 1 wherein the characteristic waveform is at least one of an impulse function, a square wave, a square wave with leading edge overshoot, a square wave with a trailing edge overshoot, a sawtooth, an inverted sawtooth and at least one sine wave.

4. The HAMR disk drive of claim 1 wherein the characteristic waveform includes at least one harmonic of a periodic wave.

5. The HAMR disk drive of claim 4 wherein the at least one harmonic includes a first harmonic and a third harmonic.

6. The HAMR disk drive of claim 5 wherein the periodic wave is a square wave.

7. The HAMR disk drive of claim 1 wherein the characteristic waveform includes at least one impulse function.

12. The HAMR disk drive of claim 1 wherein the HAMR head further includes:

at least one near-field transducer (NFT) coupled with the at least one waveguide, the characteristic waveform shape being configured to minimize average heating of the at least one NFT.

13. The HAMR disk drive of claim 12 wherein the characteristic waveform shape is at least one of a sawtooth and an inverted sawtooth.

14. The HAMR disk drive of claim 1 wherein the characteristic waveform shape is configured to optimize a temperature of the media.

15. The HAMR disk drive of claim 1 wherein the characteristic waveform shape is configured to optimize a power of the laser.

16. The HAMR disk drive of claim 14 wherein the characteristic waveform shape is a square wave.

17. The HAMR disk drive of claim 1 wherein the characteristic waveform shape is configured to optimize temperature jitter of the media.

18. The HAMR disk drive of claim 1 wherein the characteristic waveform shape includes a plurality of harmonics of a square wave.

8. A heat assisted magnetic recording (HAMR) disk drive including a media comprising:

a slider;

at least one laser coupled with the slider;

at least one electro-optical modulator (EOM) optically coupled with the at least one laser and coupled with the slider, the at least one laser and the at least one EOM being coupled to provide a modulated energy output, the at least one EOM controlling the modulated energy output to have a characteristic waveform shape; and

at least one HAMR head on the slider, the at least one HAMR head including at least one waveguide, a write pole, and at least one coil for energizing the write pole, the at least one waveguide for receiving the modulated energy output and directing the modulated energy output toward the media;

wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a global peak and a plurality of local peaks, the HAMR head being configured to write to the media in a write band corresponding to a time range and a temperature range between two of the plurality of local peaks.

9. A heat assisted magnetic recording (HAMR) disk drive including a media comprising:

a slider;

at least one laser coupled with the slider;

at least one electro-optical modulator (EOM) optically coupled with the at least one laser and coupled with the slider, the at least one laser and the at least one EOM being coupled to provide a modulated energy output, the at least one EOM controlling the modulated energy output to have a characteristic waveform shape; and

at least one HAMR head on the slider, the at least one HAMR head including at least one waveguide, a write pole, and at least one coil for energizing the write pole, the at least one waveguide for receiving the modulated energy output and directing the modulated energy output toward the media;

wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a global peak, a first local peak having a first local maximum, a second local peak having a second local maximum, the first local peak adjoining the global and the second local peak adjoining the first local peak, the HAMR head being configured to write to the media in a write band corresponding to a time range and a temperature range between the first local peak and the second local peak.

10. The HAMR disk drive of claim 9 wherein the first local peak occurs after the global and the second local peak occurs after the first local peak.

11. A heat assisted magnetic recording (HAMR) disk drive including a media comprising:

a slider;

at least one laser coupled with the slider;

at least one electro-optical modulator (EOM) optically coupled with the at least one laser and coupled with the slider, the at least one laser and the at least one EOM being coupled to provide a modulated energy output, the at least one EOM controlling the modulated energy output to have a characteristic waveform shape; and

at least one HAMR head on the slider, the at least one HAMR head including at least one waveguide, a write pole, and at least one coil for energizing the write pole, the at least one waveguide for receiving the modulated energy output and directing the modulated energy output toward the media;

wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a global peak and a plurality of local peaks, the HAMR head being configured to write to the media in a write band corresponding to a time range and a temperature range after the global peak and between the global peak and one of the plurality of local peaks.

19. A method for fabricating a heat assisted magnetic recording (HAMR) disk drive including a media comprising:

providing a slider;

providing at least one laser coupled with the slider;

providing at least one electro-optical modulator (EOM) optically coupled with the at least one laser and coupled with the slider, the at least one laser and the at least one EOM being coupled to a modulated energy output, the at least one EOM controlling the modulated energy output to be a pulsed output having a characteristic waveform shape for energy versus time; and

providing at least one HAMR head on the slider, the at least one HAMR head including at least one waveguide, a write pole, and at least one coil for energizing the write pole, the at least one waveguide for receiving the modulated energy output and directing the modulated energy output toward the media.

20. The method of claim 19 wherein the characteristic waveform is at least one of a square wave, a square wave with leading edge overshoot, a square wave with a trailing edge overshoot, a sawtooth, an inverted sawtooth and a sine wave.

21. The method of claim 19 wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a global peak and a plurality of local peaks, the HAMR head being configured to write to the media in a write band corresponding to a time range and a temperature range between two of the plurality of local peaks.

22. The method of claim 19 wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a maximum peak, a first local peak having a first local maximum, a second local peak having a second local maximum, the first local peak adjoining the maximum and the second local peak adjoining the first local peak, the HAMR head being configured to write to the media in a write band corresponding to a time range and a temperature range between the first local peak and the second local peak.

23. The method of claim 19 wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a global peak and a plurality of local peaks, the HAMR head being configured to write to the media in a write band corresponding to a time range and a temperature range after the global peak and between the global peak and one of the plurality of local peaks.

24. The method of claim 19 wherein the step of providing the HAMR head further includes:

providing at least one near-field transducer (NFT) coupled with the at least one waveguide, the characteristic waveform shape being configured to minimize average heating of the at least one NFT.

25. A method for writing to a media in a heat assisted magnetic recording (HAMR) disk drive, the HAMR disk drive including at least one laser and at least one HAMR head having at least one waveguide and at least one write pole therein, the method comprising:

energizing the laser to provide energy;

controlling at least one electro-optical modulator (EOM) optically coupled with the at least one laser to provide a modulated energy output using the energy, the at least one EOM controlling the modulated energy output to be a pulsed output having a characteristic waveform shape for energy versus time, the modulated energy being optically coupled into the at least one waveguide and being provided from the waveguide to the media; and

energizing the at least one write pole to record data to the media when the media has at least a particular temperature.

26. The method of claim 25 wherein the characteristic waveform is at least one of an impulse function, a square wave, a square wave with leading edge overshoot, a square wave with a trailing edge overshoot, a sawtooth, an inverted sawtooth and a sine wave.

27. The method of claim 25 wherein the characteristic waveform includes at least one harmonic of a periodic wave.

28. The method of claim 25 wherein the at least one harmonic includes a first harmonic and a third harmonic.

29. The method of claim 28 wherein the periodic wave is a square wave.

30. The method of claim 25 wherein the characteristic waveform includes at least one impulse function.

34. The method of claim 25 wherein the characteristic waveform shape is configured to optimize a temperature of the media.

35. The method of claim 25 wherein the characteristic waveform shape is configured to optimize a power of the laser.

36. The method of claim 25 wherein the characteristic waveform shape is configured to optimize temperature jitter of the media.

31. A method for writing to a media in a heat assisted magnetic recording (HAMR) disk drive, the HAMR disk drive including at least one laser and at least one HAMR head having at least one waveguide and at least one write pole therein, the method comprising:

energizing the laser to provide energy;

controlling at least one electro-optical modulator (EOM) optically coupled with the at least one laser to provide a modulated energy output using the energy, the at least one EOM controlling the modulated energy output to have a characteristic waveform shape, the modulated energy being optically coupled into the at least one waveguide and being provided from the waveguide to the media; and

energizing the at least one write pole to record data to the media when the media has at least a particular temperature;

wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a global peak and a plurality of local peaks and wherein the step of energizing the at least one write pole further includes;

writing to the media in a write band corresponding to a time range and a temperature range between two of the plurality of local peaks.

32. A method for writing to a media in a heat assisted magnetic recording (HAMR) disk drive, the HAMR disk drive including at least one laser and at least one HAMR head having at least one waveguide and at least one write pole therein, the method comprising:

energizing the laser to provide energy;

controlling at least one electro-optical modulator (EOM) optically coupled with the at least one laser to provide a modulated energy output using the energy, the at least one EOM controlling the modulated energy output to have a characteristic waveform shape, the modulated energy being optically coupled into the at least one waveguide and being provided from the waveguide to the media; and

energizing the at least one write pole to record data to the media when the media has at least a particular temperature

wherein the media experiences a time varying temperature based on the modulated energy output, the time varying temperature having a maximum peak, a first local peak having a first local maximum, a second local peak having a second local maximum, the first local peak adjoining the maximum and the second local peak adjoining the first local peak and wherein the step of energizing the at least one write pole further includes;

writing to the media in a write band corresponding to a time range and a temperature range between the first local peak and the second local peak.

33. The method of claim 32 wherein the first local peak occurs after the maximum and the second local peak occurs after the first local peak.