HAMR Laser Diode Current Control for Temperature Compensation
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Solution Overview
Problem
The performance of Heat Assisted Magnetic Recording (HAMR) devices varies with temperature changes due to the effects on the laser diode, leading to variations in laser power output, which affects data storage quality and requires frequent and impractical bit error rate and adjacent track interference measurements.
Innovation Solution
A method to measure current temperature and calculate the threshold laser diode power output in idle mode, determining if a change in laser diode current is needed to maintain performance by comparing the current and new laser diode currents, and adjusting the laser diode current accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent bit error rate and adjacent track interference measurements are performed to monitor data storage quality, then measurement precision is improved, but device complexity and time consumption increase significantly
Solution Approach 1:
The system continuously monitors temperature and automatically adjusts laser diode current based on pre-stored threshold values, creating a closed-loop feedback mechanism that maintains optimal data storage performance without requiring frequent manual measurements
Solution Approach 2:
The system performs self-adjustment by automatically detecting temperature changes and modifying laser parameters accordingly, eliminating the need for external measurement equipment and manual intervention to maintain data storage quality
2Reliability
If laser diode current is adjusted frequently to compensate for temperature variations, then data storage performance is maintained, but device complexity and operational complexity increase
Solution Approach 1:
Threshold laser power output values for different temperatures are pre-calculated and stored in memory before actual operation, allowing the system to quickly adjust laser current based on current temperature without complex real-time calculations
Solution Approach 2:
The patent replaces complex manual measurement and adjustment mechanisms with automated electronic temperature sensing and digital signal processing to determine and apply optimal laser current settings
3Reliability
If temperature monitoring and laser parameter adjustment are performed continuously, then data storage quality is maintained, but energy consumption increases
Solution Approach 1:
The system performs temperature monitoring and laser parameter adjustment at periodic intervals rather than continuously, reducing energy consumption while maintaining data storage quality through regular checks and adjustments
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 approach ensures consistent data storage performance across temperature changes by compensating for variations in laser power output, reducing bit error rates and adjacent track interference without degrading drive performance.
Implementation Method 1
a laser diode for heating the medium while writing data
Implementation Method 2
measure a current temperature of the data storage device while in idle
Data Source
AI summary
A current temperature of a data storage device having a heat assisted recording (HAMR) device is measured while in idle. A threshold laser diode power output of the HAMR device is calculated at the current temperature when there is a change between a previous temperature and the current temperature. A new laser diode current that produced the calculated threshold laser diode power output is applied to the HAMR device when there is a change between the currently applied laser diode current and the new laser diode current.