Cladding Reflector for HAMR Laser Feedback Suppression
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) systems, reflections of energy from the recording medium back to the energy source cause optical feedback, leading to laser instability and dynamic intensity noise, which affects the quality of magnetic transitions written to the recording medium.
Innovation Solution
Incorporating a reflector in the waveguide's cladding layer, positioned proximate to the near-field transducer, to reduce reflections by interfering with the returning energy and minimizing its impact on the energy source, thereby suppressing optical feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflector is added to the waveguide's cladding layer to suppress optical feedback, then laser stability is improved, but device complexity increases
Solution Approach 1:
A reflector is introduced as an intermediary component within the waveguide's cladding layer. This reflector mediates the interaction between the recording medium and the laser source by reflecting returning light away from the laser, thereby suppressing optical feedback while maintaining the waveguide's core functionality for delivering energy to the near-field transducer.
2Reliability
If a reflector is positioned proximate to the near-field transducer to reduce reflections, then optical feedback is suppressed, but near-field transducer efficiency decreases
Solution Approach 1:
The reflector is strategically positioned within the cladding layer at a specific location proximate to the near-field transducer. This localized placement creates a spatially differentiated structure where the reflector affects only the specific region where reflected light from the recording medium would otherwise return to the laser, minimizing interference with the near-field transducer's primary function while still achieving optical feedback suppression.
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 reflector effectively suppresses optical feedback, reducing the percentage of light returning to the laser diode and maintaining near-field transducer efficiency, resulting in improved data recording quality with minimal penalties in terms of efficiency.
Implementation Method 1
Incorporating a reflector in the waveguide's cladding layer, positioned proximate to the near-field transducer, to reduce reflections by interfering with the returning energy
Implementation Method 2
a waveguide that delivers energy from an energy source. The waveguide has a first cladding layer, a second cladding layer, and a core between the top cladding layer and the bottom cladding layer
Implementation Method 3
A near-field transducer is configured to receive the energy from the waveguide and deliver the energy to a recording medium
Implementation Method 4
A curved reflector is positioned centrally within the solid immersion mirror in a bottom cladding layer. The curved reflector reflecting the energy away from the near-field transducer
Data Source
AI summary
An apparatus includes a waveguide that has a core between the first and second cladding layers. A near-field transducer in the first cladding layer is configured to receive the energy from the waveguide and deliver the energy to a recording medium. A reflector in the second cladding layer is configured to reduce reflection of the energy from the recording medium back to an energy source.