TAR Slider Integrating External-Cavity VCSEL Laser Diode
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Solution Overview
Problem
Integrating a more powerful external-cavity VCSEL laser diode with a length of at least 300 μm into a thermally-assisted recording (TAR) slider is challenging due to mechanical support, electrical connection, and heat sink requirements, especially when the laser's power output is insufficient for current TAR disk drives, and the limited surface area at the trailing or top surfaces of the slider poses issues.
Innovation Solution
A TAR slider with an integrated external-cavity VCSEL laser diode, where the laser diode is supported by a carrier attached to the front end and an optical body made of transparent material is attached to the trailing end, directing the laser beam to a grating coupler and near-field transducer, maintaining the slider's height and avoiding increased disk-to-disk spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a longer external-cavity VCSEL laser diode (at least 300 μm) is integrated into the slider, then the laser power output is improved to achieve adequate 50 mW for TAR disk drives, but the mechanical support, electrical connection, and heat sink requirements become more difficult to satisfy
Solution Approach 1:
The slider is divided into functional zones: the front end accommodates the laser diode and optical components, the trailing end houses the TAR head components, and the intermediate region provides structural support and heat dissipation pathways. This segmentation allows each component to be optimally positioned without interfering with others.
Solution Approach 2:
An optical body made of transparent material serves as an intermediary component between the laser diode and the grating coupler. This optical body directs the laser beam through refraction and reflection, enabling proper beam coupling while isolating the heat-generating laser from the sensitive TAR head components.
2Ease of manufacture
If the laser diode is attached to the trailing end of the slider, then mechanical support is simplified, but the limited surface area for attachment and heat interference with write and read heads becomes problematic
Solution Approach 1:
The laser diode is extracted from the traditional trailing end location and repositioned to the front end of the slider. This extraction removes the heat source from proximity to the write and read heads, eliminating thermal interference while maintaining mechanical support through the front-end carrier structure.
Solution Approach 2:
The optical body acts as a thermal barrier and optical intermediary, directing laser radiation toward the grating coupler while blocking heat transfer to the TAR head components located at the trailing end.
3Ease of manufacture
If the slider height is increased to accommodate the longer laser diode, then the laser diode can be properly supported, but the disk-to-disk spacing increases which would undesirably increase the overall size of the disk drive
Solution Approach 1:
Instead of increasing slider height in the vertical dimension, the solution utilizes the longitudinal dimension by positioning the laser diode at the front end and using an optical body to redirect the beam. This allows the laser diode to be accommodated within the existing slider footprint without increasing disk-to-disk spacing.
Solution Approach 2:
The optical body serves as a space-efficient intermediary that redirects the laser beam without requiring additional vertical clearance, enabling proper laser coupling while maintaining compact disk drive dimensions.
4Device complexity
If a conventional VCSEL with short length (about 100 μm) is used, then the slider integration is simple, but the power output of about 10 mW is insufficient for current TAR disk drives requiring about 50 mW
Solution Approach 1:
The laser diode parameters are changed by transitioning from a conventional VCSEL to an external-cavity VCSEL configuration, increasing the cavity length from 100 μm to at least 300 μm. This parameter change enables higher power output (50 mW) while maintaining integration through proper optical coupling mechanisms.
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
Enables the integration of a longer laser diode without increasing the slider's height, ensuring adequate power output for TAR disk drives while maintaining the disk drive's size and preventing heat from affecting the write and read heads.
Implementation Method 1
An optical body formed of material, like glass or plastic, that is transparent to the laser radiation is attached to the slider trailing end. The optical body has an input surface for receipt of the laser radiation from the laser diode, an output surface for directing the laser radiation to the grating coupler
Implementation Method 2
The optical body has an input surface for receipt of the laser radiation from the laser diode, an output surface for directing the laser radiation to the grating coupler, and at least one reflective surface for turning the laser radiation from the input surface to the output surface
Implementation Method 3
The grating coupler receives the laser radiation and turns it into the waveguide
Implementation Method 4
an optical waveguide with a near-field transducer (NFT) directs radiation from a laser to heat localized regions of the magnetic recording layer on the disk
Implementation Method 5
an optical waveguide with a near-field transducer (NFT) directs radiation from a laser to heat localized regions of the magnetic recording layer on the disk
Implementation Method 6
A TAR slider with an integrated external-cavity VCSEL laser diode, where the laser diode is supported by a carrier attached to the front end
Data Source
AI summary
A thermally-assisted recording (TAR) slider has an integrated TAR head and an integrated long laser diode, like an external-cavity VCSEL. The TAR head is integrated with the slider at the trailing end and includes an optical waveguide having a grating coupler oriented in a plane generally parallel to the slider trailing end, and a near-field transducer (NFT) at the slider air-bearing surface (ABS) and coupled to the waveguide. A carrier is attached to the slider front end and supports the external-cavity VCSEL so that the linear path of its output laser beam is directed from the slider front end to the slider trailing end. An optical body is attached to the slider trailing end and has an input surface for receipt of the laser radiation from the laser diode, an output surface for directing the laser radiation to the grating coupler, and at least one reflective surface for turning the laser radiation from the input surface to the output surface.