Data storage device modifying write operation when a laser mode hop is detected

Patent metadata

Field	Value
Publication number	US-9972344-B2
Application number	US-201715657353-A
Country	US
Kind code	B2
Filing date	Jul 24, 2017
Priority date	Sep 25, 2014
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A data storage device is disclosed comprising a first head actuated over a first disk surface, wherein the first head comprises a laser configured to heat the first disk surface while writing data to the first disk surface. A write power is applied to the laser and a first write operation is executed to write first data to the first disk surface during a first revolution of the first disk surface. A first transient decrease in an output power of the laser is detected during the first write operation, and when the first transient decrease in the output power of the laser is detected during the first write operation, a write-verify of the first data is executed during a second revolution of the first disk surface.

First claim

What is claimed is:

1. A data storage device comprising:
a first disk surface;
a first head actuated over the first disk surface, wherein the first head comprises a laser configured to heat the first disk surface while writing data to the first disk surface; and
control circuitry configured to:
apply a write power to the laser and execute a first write operation to write first data to the first disk surface during a first revolution of the first disk surface;
detect a first transient decrease in an output power of the laser during the first write operation; and
when the first transient decrease in the output power of the laser is detected during the first write operation, execute a write-verify of the first data during a second revolution of the first disk surface.

2. The data storage device as recited in claim 1 , wherein the first head further comprises a photodiode configured to detect the output power of the laser.

3. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to retry the first write operation when the write-verify fails.

4. The data storage device as recited in claim 3 , wherein the control circuitry is further configured to:
detect a second transient decrease in the output power of the laser during a second write operation following the first write operation; and
recalibrate the write power of the laser when the second transient decrease in the output power of the laser is detected.

5. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to recalibrate the write power of the laser when the write-verify fails.

6. The data storage device as recited in claim 1 , wherein when the first transient decrease in the output power of the laser is detected the control circuitry is further configured to adjust a pre-lase parameter of the laser, wherein the pre-lase parameter consists of at least one of:
a pre-lase power applied to the laser preceding a write operation to warm up the laser; and
a pre-lase interval that the pre-lase power is applied to the laser preceding the write operation to warm up the laser.

7. The data storage device as recited in claim 1 , wherein when the first transient decrease in the output power of the laser is detected the control circuitry is further configured to retry at least part of the first write operation by decreasing a fly height of the first head and increasing the write power applied to the laser.

8. The data storage device as recited in claim 1 , wherein:
the data storage device further comprises a second head actuated over a second disk surface; and
when the first transient decrease in the output power of the laser is detected the control circuitry is further configured to retry at least part of the first write operation by writing data to the second disk surface.

9. A method of operating a data storage device, the method comprising:
applying a write power to a laser of a first head and executing a first write operation to write first data to a first disk surface during a first revolution of the first disk surface, wherein the laser is configured to heat the first disk surface while writing data to the first disk surface;
detecting a first transient decrease in an output power of the laser during the first write operation; and
when the first transient decrease in the output power of the laser is detected during the first write operation, executing a write-verify of the first data during a second revolution of the first disk surface.

10. The method as recited in claim 9 , wherein the first head further comprises a photodiode configured to detect the output power of the laser.

11. The method as recited in claim 9 , further comprising retrying the first write operation when the write-verify fails.

12. The method as recited in claim 11 , further comprising:
detecting a second transient decrease in the output power of the laser during a second write operation following the first write operation; and
recalibrating the write power of the laser when the second transient decrease in the output power of the laser is detected.

13. The method as recited in claim 9 , further comprising recalibrating the write power of the laser when the write-verify fails.

14. The method as recited in claim 9 , wherein when the first transient decrease in the output power of the laser is detected the method further comprises adjusting a pre-lase parameter of the laser, wherein the pre-lase parameter consists of at least one of:
a pre-lase power applied to the laser preceding a write operation to warm up the laser; and
a pre-lase interval that the pre-lase power is applied to the laser preceding the write operation to warm up the laser.

15. The method as recited in claim 9 , wherein when the first transient decrease in the output power of the laser is detected the method further comprises retrying at least part of the first write operation by decreasing a fly height of the first head and increasing the write power applied to the laser.

16. The method as recited in claim 9 , wherein when the first transient decrease in the output power of the laser is detected the method further comprises retrying at least part of the first write operation by writing data to a second disk surface.

Assignees

• Western Digital Tech Inc

Inventors

• Ruan Huanxiang
• Chia Galvin
• Balasubramaniam Prakash
• Haralson Phillip S
• Hogg Dennis W

Classifications

• G11B7/00456

  Recording strategies, e.g. pulse sequences (G11B7/0062 takes precedence) · CPC title

• G06K15/1214

  by feedback · CPC title

• G11B7/00458 Primary

  Verification, i.e. checking data during or after recording · 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

• G11B19/041

  Detection or prevention of read or write errors · CPC title