Integrated DBR Laser Stabilizes HAMR Write Head Power
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Solution Overview
Problem
Existing heat-assisted magnetic recording (HAMR) systems face challenges due to power fluctuations caused by mode hopping in Fabry Perot laser diodes, which degrade the quality of magnetic recording.
Innovation Solution
A magnetic write head design incorporating a reflector and a semiconductor laser diode gain region that optimizes optical energy to a single lasing mode over a large current and temperature range, reducing power fluctuations by suppressing the number of modes available for lasing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Fabry Perot laser diodes are used to generate laser beams for heating media surface, then laser generation is achieved, but power fluctuations occur due to mode hopping
Solution Approach 1:
The patent changes the operating parameters of the laser diode by forcing it to operate in multimode at high frequencies, which fundamentally alters the lasing behavior to suppress mode hopping and stabilize power output during HAMR operations
Solution Approach 2:
The patent applies high frequency pulsing to the laser diode operation, creating periodic modulation that prevents mode hopping by maintaining the laser in a multimode state, thereby stabilizing the power output
2Reliability
If high frequency pulsing of laser diode is applied to reduce mode hopping impact, then power stability is improved, but magnetic recording quality is degraded
Solution Approach 1:
The patent dynamically adjusts the laser diode operation by applying high frequency pulsing that adapts the lasing characteristics to maintain stability while minimizing impact on recording quality through optimized pulse parameters
3Productivity
If magnetic bit dimensions are reduced to increase storage density, then storage capacity is improved, but thermal stability is reduced due to superparamagnetic limit
Solution Approach 1:
The patent utilizes thermal phase transition by heating the media surface above the Curie temperature to temporarily reduce coercivity during writing, then allowing cooling to restore high coercivity and ensure thermal stability of the stored data
Solution Approach 2:
The patent maintains continuous thermal assistance during the writing process by sustaining laser heating throughout the bit formation process, ensuring stable magnetic transition and data recording
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the stability and quality of magnetic recording by maintaining consistent power levels, thereby improving data storage density and thermal stability.
Implementation Method 1
A semiconductor laser diode gain region protrudes out of the surface opposite the media facing surface, and the reflector optimizes the optical energy generated in the semiconductor laser diode gain region to be a single lasing optical mode
Implementation Method 2
a reflector extending from the surface opposite the media facing surface toward the media facing surface. The semiconductor laser diode gain region is aligned with the reflector
Implementation Method 3
a near field transducer disposed proximate the media facing surface
Implementation Method 4
Heating of the media surface has been accomplished by a number of techniques such as focused laser beams or near-field optical sources
Data Source
AI summary
Embodiments disclosed herein generally relate to a magnetic write head including a media facing surface and a surface opposite the media facing surface. The magnetic write head further includes a reflector extending from the surface opposite the media facing surface toward the media facing surface. A semiconductor laser diode gain region protrudes out of the surface opposite the media facing surface, and the reflector helps optimizing the optical energy generated in the semiconductor laser diode gain region to be a single mode over a large current and temperature range.