Angled Waveguide for HAMR Laser Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current heat-assisted magnetic recording (HAMR) technologies face instability issues due to reflected light from the recording medium causing laser instability, as the fundamental TE00 mode is not efficiently converted to the desired higher-order TE10 mode for effective energy delivery to the recording medium.
Innovation Solution
An angled waveguide and near-field transducer configuration within the recording head, where the waveguide is tilted at an oblique angle to reduce reflection back to the laser, and a mode converter converts the light from the TE00 to the TE10 mode for efficient energy delivery to the recording medium, utilizing a core and cladding structure with dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a normal waveguide configuration is used, then the structure is simple and alignment is easy, but reflected light from the recording medium causes laser instability
Solution Approach 1:
The waveguide is tilted at an oblique angle (e.g., 5-15 degrees) relative to the media-facing surface, breaking the symmetric normal incidence configuration. This asymmetric orientation causes reflected light to diverge at angles that do not couple back into the waveguide, thereby reducing reflection-induced laser instability while maintaining a relatively simple overall structure.
Solution Approach 2:
The solution introduces a spatial dimension change by tilting the waveguide in the cross-track direction. Instead of relying solely on the vertical dimension (normal to the surface), the waveguide is oriented with respect to both the vertical and horizontal dimensions, directing reflected light away from the laser source through angular separation in three-dimensional space.
2Reliability
If the fundamental TE00 mode is used, then coupling to the laser is efficient, but conversion to the desired higher-order TE10 mode is not efficient
Solution Approach 1:
A mode converter is introduced as an intermediary component between the laser and the waveguide. This mode converter transforms the fundamental TE00 mode from the laser into the desired higher-order TE10 mode, enabling efficient coupling and energy delivery to the recording medium while maintaining a manageable device structure.
Solution Approach 2:
The mode converter utilizes changes in waveguide parameters (such as width, height, or refractive index distribution) along its length to gradually transform the optical mode from TE00 to TE10. This parameter transformation enables efficient mode conversion through controlled variations in the waveguide's physical characteristics.
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 configuration significantly reduces laser instability by minimizing the reflection of the TE10 mode back to the laser source, while maintaining near-field transducer efficiency, thereby enhancing the areal data density and reliability of the recording process.
Implementation Method 1
The waveguide includes top and bottom cladding layers and a core disposed on a substrate-parallel plane therebetween
Implementation Method 2
a mode order converter configured to convert the energy from the first mode to a second mode
Implementation Method 3
a near-field transducer located proximate the core and proximate the media-facing surface
Data Source
AI summary
An apparatus has an input surface configured to receive energy emitted from an energy source in a first mode. A mode order converter is configured to convert the energy from the first mode to a second mode. The waveguide of the apparatus has an input end disposed proximate the input surface and configured to receive the energy in the first mode. The waveguide has an output end disposed proximate a media-facing surface and configured to deliver energy in the second mode. The output end is at an oblique angle to a cross-track line at an intersection of the media-facing surface and a substrate-parallel plane.