Edge-Emitting Laser Diode Alignment in HAMR Heads
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Solution Overview
Problem
Existing heat-assisted magnetic recording technologies face challenges in aligning edge-emitting laser diodes with waveguides efficiently, leading to energy loss and reduced near-field light intensity due to complex optical paths and precision alignment issues.
Innovation Solution
A heat-assisted magnetic recording head design incorporating an edge-emitting laser diode fixed to a slider with an external mirror, where the laser diode's emitting end face is parallel to the slider's surface, and the external mirror reflects the laser light obliquely to shorten the optical path and facilitate alignment, ensuring the laser light enters the waveguide effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the light source is placed away from the slider, then the laser diode can be positioned independently, but the optical path becomes extended requiring mirrors, lenses, and optical fibers which increases energy loss
Solution Approach 1:
The laser diode is integrated directly onto the slider substrate, merging the light source with the recording head assembly. This eliminates the need for separate optical components and extended optical paths, thereby reducing energy loss while maintaining positioning capability
2Loss of energy
If the light source is fixed to the slider, then the optical path is shortened reducing energy loss, but precision alignment of the laser diode emission part with the waveguide becomes difficult
Solution Approach 1:
A reflection mirror is introduced as an intermediary component between the laser diode and the waveguide. The mirror redirects the laser light at a 45-degree angle to enter the waveguide, providing an intermediate optical path that simplifies alignment requirements while maintaining a compact structure with reduced energy loss
3Volume of moving object
If an edge-emitting laser diode is used with emission part facing the waveguide, then compact structure is achieved, but the optical path becomes complex and alignment becomes difficult
Solution Approach 1:
The reflection mirror serves as an intermediary that simplifies the optical path configuration. By positioning the mirror at a 45-degree angle, the laser light is redirected perpendicular to the slider surface to enter the waveguide, reducing optical path complexity and alignment difficulty while maintaining a compact footprint
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 simplifies the alignment of laser light with the waveguide, reduces energy loss, and enhances the intensity of near-field light generated for heat-assisted magnetic recording, improving data recording density and thermal stability.
Implementation Method 1
the external mirror reflects the laser light obliquely to shorten the optical path and facilitate alignment
Implementation Method 2
The laser light applied to the plasmon antenna excites surface plasmons on the plasmon antenna. The surface plasmons propagate to the near-field light generating part of the plasmon antenna, and the near-field light generating part generates near-field light based on the surface plasmons
Data Source
AI summary
A heat-assisted magnetic recording head includes a slider, an edge-emitting laser diode fixed to the slider, and an external mirror fixed to the laser diode. The laser diode has: an emitting end face that includes an emission part for emitting laser light; a mounting surface that lies at an end in a direction perpendicular to the plane of an active layer and faces the slider; and a rear surface opposite to the mounting surface. The external mirror includes: a first to-be-fixed part disposed along the emitting end face; a second to-be-fixed part disposed along the rear surface; and a coupling part that couples the first and second to-be-fixed parts to each other. The first to-be-fixed part has a reflecting surface that reflects the laser light emitted from the emission part toward the waveguide.