VCSEL Multilayer Mirror Structure for Better Heat Dissipation
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Solution Overview
Problem
Conventional surface-emitting lasers face inefficiencies in heat dissipation due to the low thermal conductivity of materials like Al(0.4-0.6)GaAs used in mirror stacks, which limits the effective dissipation of heat sources in the light emitting area.
Innovation Solution
A surface-emitting laser with a multilayer thermally conductive mirror structure, comprising high and low thermally conductive layers with adjusted thickness and aluminum composition, specifically (n×λ/4) for high thermally conductive layers and (λ/4)-Δλ for low thermally conductive layers, to enhance heat dissipation without affecting current limits or oxidation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Al(0.4-0.6)GaAs material is used for mirror stacks, then the laser structure is simpler, but heat dissipation efficiency is poor
Solution Approach 1:
The patent employs composite mirror layer structures combining AlGaAs layers with different aluminum compositions (Al0.4-0.6GaAs and Al0.9-1.0GaAs) to achieve both optical reflection and thermal conduction functions. The high-aluminum-content layers provide superior thermal conductivity while maintaining optical performance, resolving the contradiction between ease of manufacture and heat dissipation efficiency.
Solution Approach 2:
The patent applies local quality by using different material compositions in different mirror layers. Specifically, Al0.9-1.0GaAs layers are positioned where high thermal conduction is needed, while Al0.4-0.6GaAs layers are used where optical reflection is prioritized. This localized material optimization enables effective heat dissipation without compromising the overall laser performance.
2Temperature
If high heat dissipation nλ/4 material is used for mirror, then heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the mirror layer into multiple sub-layers with alternating high and low aluminum content. This segmentation allows each layer to be optimized for its specific function (thermal conduction or optical reflection) while maintaining the overall λ/4 thickness requirement, thus improving heat dissipation without excessive manufacturing complexity.
Solution Approach 2:
By using composite AlGaAs materials with graded aluminum compositions, the patent achieves high heat dissipation capability within the existing λ/4 layer framework. The composite structure maintains compatibility with standard fabrication processes while enhancing thermal performance, avoiding excessive manufacturing complexity.
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 multilayer thermally conductive mirror structure significantly improves heat dissipation efficiency, effectively managing heat sources in the light emitting area, applicable to both oxidation-type and non-oxidation-type surface-emitting lasers.
Implementation Method 1
the heat sources are mainly dissipated through stacks of mirror layers located above or below the light emitting area... the heat dissipation coefficient of Al(0.4-0.6)GaAs is less than a quarter of that of Al>0.9GaAs
Implementation Method 2
each layer has a thickness of λ/4... The total thickness of the high thermally conductive layer and low thermally conductive layer is λ/4 or n×λ/4
Data Source
AI summary
The surface-emitting laser with a multilayer thermally conductive mirror includes a light-emitting layer, an oxide layer, first and second mirror layers, and first and second contact layers. The light-emitting layer generates light with a wavelength of A. The oxide layer has an oxide aperture to limit the current flowing into the light-emitting layer. The first mirror layer includes a first high thermally conductive layer and a first low thermally conductive layer. The second mirror layer includes a second high thermally conductive layer and a second low thermally conductive layer. The first contact layer is disposed of on one side of the first mirror layer by the first low thermally conductive layer. The second contact layer is disposed on one side of the second mirror layer by the second high thermally conductive layer. The overall light emission and heat dissipation efficiency can be improved.