Tapered Optical Waveguide for Magnetic Recording Coercivity Reduction
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Solution Overview
Problem
Existing optical waveguide designs for near-field light emission are inefficient in delivering light to magnetic recording layers, leading to suboptimal coercivity reduction and data retention in magnetic storage devices.
Innovation Solution
An optical output device featuring a tapered core with a higher refractive index embedded in a clad, combined with a light-transmitting layer of different refractive index, which cuts across the optical path at the end-point, optimizing light transmission and coercivity reduction in magnetic recording layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional optical waveguide is used for near-field light emission, then light can be transmitted to the magnetic recording layer, but the light delivery efficiency is insufficient leading to suboptimal coercivity reduction
Solution Approach 1:
The patent applies parameter changes by modifying the refractive index distribution within the optical waveguide structure. Specifically, it introduces a light-transmitting layer with a refractive index higher than the surrounding clad layers, creating a refractive index gradient that optimizes light confinement and transmission. This parameter modification directly addresses the insufficient light delivery efficiency while ensuring effective coercivity reduction in the magnetic recording layer.
Solution Approach 2:
The patent employs composite materials by combining multiple layers with different refractive indices: a core layer, clad layers, and an intermediate light-transmitting layer. This composite structure creates optimal conditions for near-field light emission by strategically positioning materials with varying optical properties, thereby improving both light delivery efficiency and the effectiveness of coercivity reduction.
2Loss of energy
If the light-transmitting layer thickness is not optimized, then the structure remains simple, but light transmission efficiency and data retention are suboptimal
Solution Approach 1:
The patent specifies precise parameter ranges for the light-transmitting layer thickness (50-200 nm) to optimize light transmission efficiency. By establishing this specific parameter window, the invention achieves high light delivery efficiency while providing clear manufacturing guidelines that balance performance optimization with fabrication feasibility, avoiding excessive complexity in thickness control.
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
Enhances the efficiency of light delivery to magnetic recording layers, improving coercivity reduction and data retention by adjusting the film thickness of the light-transmitting layer, thereby increasing resistance to heat fluctuations.
Implementation Method 1
an optical waveguide which tapers toward the end thereof is widely known. Such an optical waveguide is widely used when producing near-field light
Implementation Method 2
When a recording layer is heated by near-field light, the coercivity of the recording layer decreases
Implementation Method 3
When a recording layer is heated by near-field light, the coercivity of the recording layer decreases
Implementation Method 4
a light-transmitting layer which is composed of a material different from said material having said second refractive index and cuts across an optical path at the end-point thereof
Data Source
AI summary
An optical device includes a clad composed of a material having a first refractive index, a core which is embedded in the clad, composed of a material having a second refractive index different from the first refractive index, and tapers toward the end-point thereof, and a light-transmitting layer which is composed of a material different from the material having the second refractive index and cuts across an optical path at the end-point thereof.