HAMR Laser Heater Stabilizes Power Output
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Solution Overview
Problem
Heat-assisted magnetic recording (HAMR) heads in hard disk drives face performance issues due to sudden changes in laser power, known as mode hops, which affect the accuracy of data writing and retrieval, leading to reduced areal density capability and potential data errors.
Innovation Solution
Incorporating a laser heater that applies heat to the laser during and between write operations to stabilize its power output, reducing the occurrence of mode hops and improving the consistency of data writing and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser is used to heat the magnetic disk in HAMR, then the areal density capability is improved, but mode hops cause power variations that reduce writing accuracy and retrieval accuracy
Solution Approach 1:
The patent implements a feedback control system that monitors laser power output and adjusts the laser heater accordingly. When mode hops cause power variations, the feedback mechanism detects these changes and modifies the heater power to compensate, maintaining stable laser operation and consistent writing accuracy throughout the HAMR process
Solution Approach 2:
The patent changes the temperature parameter of the laser by applying controlled heating. By adjusting the laser heater power, the system modifies the laser's operating temperature to counteract mode hop effects and maintain stable emission characteristics, thereby improving power stability without sacrificing areal density capability
2Quantity of substance
If laser power is increased to improve areal density, then more data can be stored, but mode hops become more frequent and harmful
Solution Approach 1:
The patent converts the harmful effect of mode hops into a beneficial control mechanism. By using the laser heater to actively manage laser temperature and compensate for mode hop-induced power variations, the system transforms what would be detrimental power instability into an opportunity for enhanced power stability and more reliable high-density data storage
3Device complexity
If no temperature control is applied to the laser, then the device complexity is reduced, but power variations occur that degrade performance
Solution Approach 1:
The patent makes the laser heater serve multiple functions: it pre-heats the laser before operation, maintains optimal operating temperature during writing, and compensates for mode hop effects. This multi-functionality allows a single component to address multiple performance issues without proportionally increasing device complexity
Solution Approach 2:
The laser heater acts as an intermediary between the power source and the laser. It provides a buffer that smooths out power delivery to the laser, preventing direct power variations from causing mode hops and maintaining consistent writing performance while adding minimal system complexity
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
The use of a laser heater in the HAMR head helps maintain a consistent temperature for the laser, reducing power variations and enhancing the areal density capability and overall performance of the HAMR head by minimizing mode hops and associated data errors.
Implementation Method 1
The laser heater is configured to apply heat to the laser during and/or between writes
Implementation Method 2
a laser configured to emit electromagnetic radiation
Implementation Method 3
light emitted from the laser may couple to the NFT to produce localized surface plasmons (LSPs)
Implementation Method 4
Energy of the LSPs may then be emitted by the NFT to produce the hot spot on the magnetic disk
Data Source
AI summary
A heat-assisted magnetic recording head includes a slider body, a laser, a submount, and a laser heater. The slider body is configured to contain components of the heat-assisted magnetic recording head. The laser is configured to emit electromagnetic radiation. The submount is configured to couple the laser to the slider body. The laser heater is configured to apply heat to the laser. The laser heater disposed on a surface of the slider body.