Back to results
US 9,792,949 B1Granted
Laser mode hopping detection method and apparatus for a heat-assisted magnetic recording device
AssigneeSeagate Technology LLC
InventorsMinjie Ma, Tim Rausch, Edward Charles Gage, Pu-Ling Lu
Life of this patent
Estimating the term…
Abstract
An apparatus and method provide for performing, using a heat-assisted magnetic recording head, multiple sequential writes to a recording medium, and recording a metric of write performance for each of the writes. The apparatus and method further provide for calculating fluctuations in the metric, detecting whether the head has a laser mode hopping problem using the metric fluctuations, and categorizing a severity of the laser mode hopping problem.
Claims20
A method, comprising:
- performing, using a heat-assisted magnetic recording head, multiple writes to a recording medium;
- recording a metric of write performance for each of the writes;
- calculating fluctuations in the metric;
- detecting whether the head has a laser mode hopping (LMH) problem using the metric fluctuations;
- and
- categorizing a severity of the LMH problem as one of:
- an acceptable or nonexistent LMH problem;
- a non-severe or nonexistent LMH problem with self-heating of a laser diode of the head;
- and
- a severe LMH problem.
7 more elements
An apparatus, comprising:
- a heat-assisted magnetic recording head comprising a reader, a writer, and a near-field transducer optically coupled to a laser diode via an optical waveguide;
- and
- a controller of the head configured to:
- perform multiple writes to a recording medium;
- record a metric of write performance for each of the writes;
- calculate fluctuations in the metric;
- detect whether the laser diode has a laser mode hopping (LMH) problem using the metric fluctuations;
- and
- categorize a severity of the LMH problem as one of:
- an acceptable or nonexistent LMH problem;
- a non-severe or nonexistent LMH problem with self-heating of a laser diode of the head;
- and
- a severe LMH problem.
10 more elements
Dependencies are inferred from the claim text.