Tapered Waveguide Assistant Layer for HAMR Light Coupling
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) devices, achieving optimal coupling of light from a laser diode to a near-field transducer is challenging due to mode mismatch and stray light heating, leading to inefficiencies and data errors.
Innovation Solution
A waveguide system with a core layer, an assistant layer, and a middle cladding layer is used, where the core layer has a tapering width and the assistant layer narrows towards the media-facing surface, facilitated by a middle cladding layer that increases the input coupler width without impacting light coupling, enhancing mode matching and reducing stray light heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the input coupler width is increased to improve light coupling efficiency, then coupling efficiency improves, but stray light heating increases
Solution Approach 1:
The assistant layer is divided into multiple segments along the light propagation direction, with each segment having a different width. This segmentation allows the structure to simultaneously provide large coupling area and controlled stray light distribution, resolving the contradiction between coupling efficiency and stray light heating.
Solution Approach 2:
Different regions of the assistant layer are given different local properties through varying widths. The wider regions near the light source maximize coupling efficiency, while narrower regions farther away control stray light heating, creating locally optimized conditions throughout the structure.
2Reliability
If the assistant layer width is increased to improve mode matching, then mode matching improves, but device complexity increases
Solution Approach 1:
The assistant layer width varies dynamically along the light propagation direction rather than remaining constant. This dynamic width variation optimizes mode matching at different positions while maintaining a relatively simple overall waveguide structure without requiring multiple discrete components.
3Object-generated harmful factors
If the coupling end width is increased to reduce stray light, then stray light reduction improves, but coupling efficiency decreases
Solution Approach 1:
The solution transitions from considering only the transverse width dimension to incorporating the longitudinal dimension (along light propagation). By varying width along the propagation direction, the structure achieves both stray light reduction and maintained coupling efficiency through spatial distribution of coupling regions.
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 improves coupling efficiency and reduces energy consumption, minimizing data errors by effectively delivering energy to the near-field transducer, creating a precise hotspot on the recording medium.
Implementation Method 1
a waveguide extending along a light-propagation direction between a light source and a media-facing surface. The waveguide comprises an assistant layer configured to receive light from a light source
Implementation Method 2
the assistant layer comprising a terminating end with a first taper that narrows toward the media-facing surface. A core layer comprises a coupling end configured to receive light from the assistant layer, the coupling end comprising a second taper that widens toward the media-facing surface
Implementation Method 3
A near field transducer is disposed proximate the media-facing surface and configured to receive the light from the core layer
Data Source
AI summary
An apparatus includes a waveguide extending along a light-propagation direction between a light source and a media-facing surface. An assistant layer is configured to receive light from a light source, the assistant layer has a terminating end with a first taper that narrows toward the media-facing surface. A core layer has a coupling end configured to receive light from the assistant layer, the coupling end having a second taper that widens toward the media-facing surface. A middle cladding layer is disposed between the core layer and the assistant layer. A near field transducer is disposed proximate the media-facing surface and configured to receive the light from the core layer.