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

• US 9,747,928 B1
• Filed: 09/25/2014
• Issued: 08/29/2017
• Est. Priority Date: 09/25/2014
• 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: Ruan, Huanxiang, Chia, Galvin, Balasubramaniam, Prakash, Haralson, Phillip S., Hogg, Dennis W.
• Primary Examiner(s): Pendleton, Dionne H
• Application Number:
  US14/497,285
• Time in Patent Office: 1,069 Days
• CPC Class Codes: G06K 15/1214 by feedback
• CPC Class Codes: G11B 19/041 Detection or prevention of read or write errors
• 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
• CPC Class Codes: G11B 5/455 Arrangements for functional testing of heads; Measuring arrangements for heads
• CPC Class Codes: G11B 7/00456 Recording strategies, e.g. pulse sequences G11B7/0062 takes precedence
• CPC Class Codes: G11B 7/00458 Verification, i.e. checking data during or after recording
• CPC Class Codes: G11B 7/1263 Power control during transducing, e.g. by monitoring

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 when executing a first write operation, and the first write operation is paused when a transient increase in the output power of the laser is detected. In another embodiment, a write-verify of the written data is executed when a transient decrease in the output power of the laser is detected.

Claims

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 first write power to the laser and execute a first write operation;

detect a first transient increase in an output power of the laser during the first write operation; and

pause the first write operation when the first transient increase in the output power of the laser is detected,

wherein after pausing the first write operation the control circuitry is further configured to;

decrease power applied to the laser for a cool-down interval; and

after the cool-down interval, apply the first write power to the laser and execute a second write operation after the cool-down interval.

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 second write operation completes the first write operation.

4. The data storage device as recited in claim 1, wherein the control circuitry is further configured to execute at least one read operation during the cool-down interval.

5. The data storage device as recited in claim 1, wherein the control circuitry is further configured to:

detect a second transient increase in the output power of the laser during the second write operation; and

recalibrate the write power of the laser when the second transient increase in the output power of the laser is detected.

6. The data storage device as recited in claim 1, wherein when the first transient increase 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 6, wherein

when the first transient increase in the output power of the laser is detected the control circuitry is further configured to enable a write-verify mode of the data storage device.

8. The data storage device as recited in claim 1, wherein when the first transient increase 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 adjusting a fly height of the first head and adjusting the write power applied to the laser.

9. 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 increase 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.

10. A method of operating a data storage device, the method comprising:

applying a first write power to a laser of a first head and executing a first write operation, wherein the laser is configured to heat a first disk surface while writing data to the first disk surface;

detecting a first transient increase in an output power of the laser during the first write operation; and

pausing the first write operation when the first transient increase in the output power of the laser is detected,

wherein after pausing the first write operation the method further comprises;

decreasing power applied to the laser for a cool-down interval; and

after the cool-down interval, applying the first write power to the laser and executing a second write operation after the cool-down interval.

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

12. The method as recited in claim 10, wherein the second write operation completes the first write operation.

13. The method as recited in claim 10, further comprising executing at least one read operation during the cool-down interval.

14. The method as recited in claim 10, further comprising:

detecting a second transient increase in the output power of the laser during the second write operation; and

recalibrating the write power of the laser when the second transient increase in the output power of the laser is detected.

15. The method as recited in claim 10, wherein when the first transient increase 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.

16. The method as recited in claim 15, wherein

when the first transient increase in the output power of the laser is detected the method further comprises enabling a write-verify mode of the data storage device.

17. The method as recited in claim 10, wherein when the first transient increase in the output power of the laser is detected the method further comprising retrying at least part of the first write operation by adjusting a fly height of the first head and adjusting the write power applied to the laser.

18. The method as recited in claim 10, wherein when the first transient increase 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.

19. 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;

detect a first transient increase in an output power of the laser during the first write operation; and

when the first transient increase in the output power of the laser is detected, pause the first write operation and 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.

20. 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, wherein the laser is configured to heat a first disk surface while writing data to the first disk surface;

detecting a first transient increase in an output power of the laser during the first write operation; and

when the first transient increase in the output power of the laser is detected, pausing the first write operation and 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.

21. 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;

detect a first transient increase in an output power of the laser during the first write operation; and

when the first transient increase in the output power of the laser is detected, pause the first write operation and retry at least part of the first write operation by adjusting a fly height of the first head and adjusting the write power applied to the laser.

22. 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, wherein the laser is configured to heat a first disk surface while writing data to the first disk surface;

detecting a first transient increase in an output power of the laser during the first write operation; and

when the first transient increase in the output power of the laser is detected, pausing the first write operation and retrying at least part of the first write operation by adjusting a fly height of the first head and adjusting the write power applied to the laser.

23. 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;

a second disk surface;

a second head actuated over the second disk surface; and

control circuitry configured to;

apply a write power to the laser and execute a first write operation;

detect a first transient increase in an output power of the laser during the first write operation; and

when the first transient increase in the output power of the laser is detected, pause the first write operation and retry at least part of the first write operation by writing data to the second disk surface.

24. 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, wherein the laser is configured to heat a first disk surface while writing data to the first disk surface;

detecting a first transient increase in an output power of the laser during the first write operation; and

when the first transient increase in the output power of the laser is detected, pausing the first write operation and retrying at least part of the first write operation by writing data to a second disk surface.