Laser boost and duration optimization

Patent metadata

Field	Value
Publication number	US-10657987-B1
Application number	US-201816207912-A
Country	US
Kind code	B1
Filing date	Dec 3, 2018
Priority date	Oct 13, 2015
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

This disclosure is related to systems, devices, processes, and methods to optimize a laser power boost amplitude, a laser power boost duration, or both in a heat-assisted data recording device, such as in heat-assisted magnetic recording (HAMR). The amplitude and duration for the laser power boost may be determined for a specific portion of a write operation, such as a first sector of the write operation. During operation of a data storage device, the laser power boost may provide additional power to the laser for the specific portion. Once the laser power boost duration has elapsed, the data storage device may continue providing power to the laser at the normal power input range of the laser. The laser power boost settings may be determined on a per head per zone basis, per track basis, or another configuration.

First claim

What is claimed is:

1. An apparatus comprising:
a controller configured to:
determine a first laser power boost setting to be applied during writing of data to a data storage medium;
initiate a laser-assisted data recording system to perform a single write operation;
compensate for a higher bit error rate in a first sector of the single write operation by adjusting a laser power during the single write operation, including:
write a first sector of the single write operation while the laser-assisted data recording system implements a first laser power based on the first laser power boost setting; and
write one or more second sectors of the single write operation while the laser-assisted data recording system implements a second laser power less than the first laser power.

2. The apparatus of claim 1 comprising the controller further configured to:
determine a duration during which to apply the first laser power boost setting;
write at least a portion of the first sector at the first laser power based on the duration; and
write a remainder of the single write operation at the second laser power after an expiration of the duration.

3. The apparatus of claim 2 comprising the controller further configured to vary an amount of the duration.

4. The apparatus of claim 1 comprising the controller further configured to vary an amount of the first laser power for write operations to different locations of the data storage medium.

5. The apparatus of claim 1 further comprising the controller configured to:
perform a first laser calibration at a first granularity; and
determine the first laser power boost setting after the first laser calibration.

6. The apparatus of claim 5 further comprising the controller configured to:
perform a second laser calibration at a second granularity, the second granularity finer than the first granularity;
determine a second laser power boost setting after the second laser calibration; and
implement the second laser power boost setting instead of the first laser power boost setting when the second laser power boost setting results in a smaller change in amplitude of a written signal than the first laser power boost setting provides.

7. The apparatus of claim 1 further comprising:
a preamplifier coupled to the controller as part of the laser-assisted data recording system, the preamplifier configured to:
amplify a write signal and provide the write signal to a write element to store data to the data storage medium;
provide a power signal to a laser heating element of the laser-assisted data recording system, the laser heating element configured to heat a localized area of the data storage medium in relation to the write element;

the preamplifier including multiple registers programmable by the controller to set an amplitude of the power signal and a duration of the power signal; and
the controller configured to selectively program a specific combination of the multiple registers to set a pre-determined amplitude and a pre-determined duration of the power signal.

8. The apparatus of claim 7 comprising the controller further configured to:
iteratively test each amplitude register setting and each duration register setting combination of the preamplifier;
determine a change in amplitude of a written test signal for each iteration of the test; and
select the amplitude register setting and the duration register setting that produced a minimum change in the amplitude of the written test signal.

9. A method comprising:
performing a single write operation via a laser-assisted data recording system, including compensating for a higher bit error rate in a first sector of the single write operation by adjusting a laser power during the single write operation, the single write operation including:
writing a first sector of the single write operation while the laser-assisted data recording system applies a first laser power; and
writing one or more second sectors of the single write operation while the laser-assisted data recording system implements a second laser power less than the first laser power.

10. The method of claim 9 further comprising:
determining a laser power boost to apply relative to the second laser power to generate the first laser power based on a first value stored in a first register.

11. The method of claim 10 further comprising:
determining a duration for which to apply the first laser power based on a second value stored in a second register.

12. The method of claim 11 further comprising:
writing at least a portion of the first sector at the first laser power based on the duration; and
writing a remainder of the single write operation at the second laser power after an expiration of the duration.

13. The method of claim 9 further comprising:
adjusting an amount of the first laser power based on a target zone of a disc recording medium that the single write operation is directed to store data to, a zone including a plurality of concentric data storage tracks less than all data storage tracks on a surface of the disc recording medium, the adjusting including:
determining whether the target zone is a first zone or a second zone;
applying a first power quantity for the first laser power when the single write operation is directed to the first zone; and
applying a second power quantity when the single write operation is directed to the second zone.

14. The method of claim 9 further comprising:
performing a first laser calibration at a first granularity; and
determining the first laser power based on the first laser calibration.

15. The method of claim 14 further comprising:
performing a second laser calibration at a second granularity, the second granularity finer than the first granularity;
determining a modified laser power setting after the second laser calibration; and
implementing the modified laser power setting instead of the first laser power when the modified laser power setting results in a smaller change in amplitude of a written signal than the first laser power provides.

16. An apparatus comprising:
a heat-assisted magnetic recording (HAMR) data storage device including:
a disc data storage medium;
a controller configured to:
perform a single write operation using a laser to heat a portion of the disc data storage medium to facilitate recording data;
compensate for a higher bit error rate in a first sector of the single write operation by adjusting a laser power setting during the single write operation, including:
writing at least a portion of the first sector of the single write operation by applying a first laser power setting to the laser; and
writing one or more second sectors of the single write operation by applying a second laser power setting less than the first laser power setting to the laser.

17. The apparatus of claim 16 comprising the controller further configured to:
determine a laser power boost to apply relative to the second laser power to generate the first laser power based on a first value stored in a first register.

18. The apparatus of claim 16 comprising the controller further configured to:
determine a duration for which to apply the first laser power setting based on a value stored in a register;
write at least the portion of the first sector at the first laser power setting based on the duration; and
write a remainder of the single write operation at the second laser power setting after the expiration of the duration.

19. The apparatus of claim 16 comprising the contr

Assignees

• Seagate Technology Llc

Inventors

• Chu Alfredo Sam
• Martens Franklin P
• Jacobs Aaron

Classifications

• G11B5/4555

  by using a spin-stand, i.e. a spinning disc or simulator · CPC title

• G11B5/012 Primary

  Recording on, or reproducing or erasing from, magnetic disks (G11B17/00, G11B19/00 take precedence) · 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

• G11B5/5534

  Initialisation, calibration, e.g. cylinder "set-up" · CPC title

• G11B5/455

  Arrangements for functional testing of heads; Measuring arrangements for heads · CPC title