Heat-Assisted Magnetic Recording Head Laser Alignment
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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 increased energy loss and difficulty in generating near-field light with sufficient intensity due to complex optical path requirements and precision alignment issues.
Innovation Solution
A heat-assisted magnetic recording head design that incorporates an edge-emitting laser diode fixed to a slider with an external mirror, allowing for easy alignment and a shortened optical path by using an oblique reflecting surface to direct laser light efficiently into the waveguide, thereby facilitating the generation of near-field light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the light source is placed away from the slider, then the optical path can be extended to guide light, but energy loss of light increases due to extended optical path including mirror, lens, and optical fiber
Solution Approach 1:
The patent merges the light source with the slider by fixing the laser diode directly to the slider body, eliminating the need for external optical components and extended optical paths. This integration reduces light energy loss while maintaining the ability to guide light to the waveguide through direct coupling.
2Loss of energy
If the light source is fixed to the slider, then the optical path is shortened and energy loss is reduced, but alignment between the emission part and the waveguide becomes difficult due to precision requirements
Solution Approach 1:
The patent introduces a light guiding part as an intermediary component between the laser diode and the waveguide. This light guiding part facilitates alignment by providing a structured interface that guides the laser light into the waveguide, reducing the direct alignment precision requirements between the laser diode emission part and the waveguide input.
Solution Approach 2:
The patent employs an external mirror positioned at an angle to reflect laser light into the waveguide. This approach changes the alignment dimension by using angular reflection rather than direct linear alignment, making it easier to couple light from the laser diode into the waveguide while maintaining a compact structure.
3Ease of operation
If complex optical elements are used to guide light from the light source to the waveguide, then light can be directed to the waveguide, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates complex optical elements such as lenses and optical fibers from the system. By using direct coupling between the laser diode and waveguide, or simple light guiding structures integrated into the slider, the patent achieves light guidance without the complexity of multiple optical components.
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 design enhances the alignment precision and reduces energy loss, allowing for effective generation of near-field light with high intensity, improving the efficiency of heat-assisted magnetic recording.
Implementation Method 1
an external mirror provided outside the slider... using an oblique reflecting surface to direct laser light efficiently into the waveguide
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.
Implementation Method 3
In an edge-emitting laser diode, the emission part for emitting the laser light is located in an end face that lies at an end of the laser diode in a direction parallel to the plane of an active layer. The emission part emits the laser light in the direction parallel to the plane of the active layer.
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 provided outside the slider. The slider includes a magnetic pole, a waveguide, and a near-field light generating element. The laser diode includes: an emitting end face that lies at an end in a direction parallel to the plane of an active layer and includes a laser-light emission part; and a mounting surface that lies at an end in a direction perpendicular to the plane of the active layer and faces the slider. The external mirror includes: a first reference surface that is parallel to the emitting end face and faces the emitting end face; a second reference surface that is parallel to the mounting surface and faces toward the same direction as the mounting surface does; and a reflecting surface that connects the first and second reference surfaces to each other and reflects the laser light emitted from the emission part toward the waveguide.