Multiple-Tipped Spot Size Converter for HAMR Laser Coupling
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Solution Overview
Problem
Current heat-assisted magnetic recording (HAMR) heads face inefficiencies due to asymmetric laser diode profiles and misalignment issues, leading to coupling losses and increased manufacturing costs.
Innovation Solution
A magnetic write head design featuring a spot-size converter (SSC) with a multiple-tipped first end, which improves laser beam coupling efficiency and misalignment tolerance by matching the asymmetric laser diode profile, incorporating a primary waveguide and secondary waveguides to enhance optical field focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a symmetric SSC mode profile is used, then the SSC structure is simple, but coupling loss increases due to mismatch with asymmetric laser diode profile
Solution Approach 1:
The patent applies asymmetry by designing the SSC with an asymmetric mode profile that matches the asymmetric laser diode emission profile. This is achieved by configuring the waveguide dimensions, refractive indices, and geometric parameters of the SSC to create an asymmetric fundamental mode that couples more efficiently with the asymmetric laser beam, thereby reducing coupling loss while maintaining reasonable structural complexity.
2Loss of energy
If tight alignment tolerance is required between laser diode and SSC, then coupling efficiency is maximized, but manufacturing cost increases
Solution Approach 1:
The patent applies preliminary action by pre-matching the asymmetric mode profile of the SSC to the asymmetric profile of the laser diode during the design and fabrication stage. This preliminary configuration of the SSC parameters (waveguide width, height, refractive index distribution) ensures that the modes are naturally aligned, providing inherent tolerance to misalignment and reducing the need for costly post-assembly alignment adjustments.
3Loss of energy
If tight alignment tolerance is required between laser diode and SSC, then coupling efficiency is maximized, but manufacturing yield decreases
Solution Approach 1:
The asymmetric SSC design inherently accommodates the asymmetric laser diode profile, creating a robust coupling interface that is less sensitive to alignment variations. This asymmetric configuration with matched mode profiles provides a larger effective alignment window, allowing for greater tolerance in assembly processes and thereby improving manufacturing yield without sacrificing coupling efficiency.
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 multi-tipped SSC design enhances coupling efficiency and misalignment tolerance, leading to improved performance and reduced manufacturing costs in HAMR heads.
Implementation Method 1
SSC converts a highly-divergent output of an external semiconductor laser diode into a well-confined mode that couples into the NFT
Implementation Method 2
The NFT is a plasmonic nano-antenna that further focuses the light into an ultra-small spot-size for high-density magnetic recording
Implementation Method 3
uses heat to lower the effective coercivity of a localized region on the magnetic media surface and writes data within this heated region
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 also includes a SSC having a first end extending to the surface opposite the media facing surface. The first end of the SSC has at least two tips. The multiple-tipped first end of the SSC is configured to receive a laser beam and the laser beam coupling efficiency is improved by having the multiple-tipped first end.