Etched Laser Cavity for EAMR Head Alignment
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Solution Overview
Problem
Conventional energy assisted magnetic recording (EAMR) disk drives face challenges in coupling the laser diode to the trailing edge of the slider, as it occupies valuable space and using smaller lasers may compromise reliability.
Innovation Solution
A method involving etching a substrate to form a trench with specific angles, providing a protective coating, creating a laser cavity, and applying a reflective layer to align and bond the laser diode, enhancing the alignment and efficiency of the laser in the EAMR head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the laser diode is coupled in proximity to the trailing edge of the slider, then the EAMR transducer can function, but the laser occupies valuable space that is normally reserved for contacts to the transducer
Solution Approach 1:
The patent moves the laser diode from the traditional planar mounting location on the trailing edge to a vertically integrated position within a cavity structure. By etching a cavity into the substrate and mounting the laser within this three-dimensional space, the design utilizes the vertical dimension to accommodate the laser without occupying additional lateral space on the trailing edge, thus resolving the space conflict while maintaining transducer functionality
2Area of stationary object
If smaller lasers are used to reduce the occupied space, then the area constraint is satisfied, but the reliability of the EAMR disk drive is compromised
Solution Approach 1:
Instead of reducing laser size, the patent accommodates full-size lasers by transitioning to three-dimensional mounting within etched cavities. This vertical integration allows standard-sized, high-reliability lasers to be positioned within the substrate thickness, eliminating the need to compromise on laser dimensions while still satisfying the trailing edge space constraints
Solution Approach 2:
The laser diode is nested within the etched cavity structure of the substrate. This nesting approach allows the laser to be housed within the existing substrate volume, utilizing the vertical space efficiently. The cavity acts as a container that holds the laser in proximity to the trailing edge without requiring additional lateral space, thus maintaining both space efficiency and laser reliability
3Ease of manufacture
If the laser is mounted in proximity to the trailing surface, then the EAMR transducer can be assembled, but alignment precision between the laser and the waveguide is difficult to achieve
Solution Approach 1:
The patent performs preliminary alignment by etching the cavity at predetermined angles (e.g., 45-degree angles) before laser mounting. These pre-formed angular surfaces serve as built-in alignment references that guide the laser positioning. By establishing the geometric framework in advance during substrate fabrication, the subsequent laser bonding process inherits this precision, eliminating the need for complex post-mounting alignment procedures
Solution Approach 2:
The etched cavity employs asymmetric angular surfaces (such as 45-degree angles) rather than symmetric vertical walls. This asymmetric geometry creates unique alignment features that naturally guide the laser diode into the correct position. The non-uniform angles provide mechanical and optical references that ensure precise alignment between the laser and the waveguide, transforming a precision challenge into a geometric solution
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 approach allows for improved alignment and bonding of the laser diode, enhancing the efficiency of light coupling to the media and protecting the laser diode during fabrication and use, thereby improving the manufacturability and performance of EAMR heads.
Implementation Method 1
applying a reflective layer to align and bond the laser diode, enhancing the alignment and efficiency of the laser in the EAMR head
Data Source
AI summary
A method for providing a capping layer configured for an energy assisted magnetic recording (EAMR) head including at least one slider. The method comprises etching a substrate having a top surface using an etch to form a trench in the substrate, the trench having a first surface at a first angle from the top surface and a second surface having a second angle from the top surface. The method further comprises providing a protective coating exposing the second surface and covering the first surface, removing a portion of the substrate including the second surface to form a laser cavity within the substrate configured to fit a laser therein, and providing a reflective layer on the first surface to form a mirror, the cavity and mirror being configured for alignment of the laser to the laser cavity and to the mirror and for bonding the laser to the laser cavity.