Semiconductor Laser With Segmented Light Guide Layers
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Solution Overview
Problem
Conventional semiconductor laser devices face challenges in increasing power conversion efficiency while reducing threshold current and improving slope efficiency, as they struggle to achieve both simultaneously due to limitations in light confinement and mode expansion.
Innovation Solution
A semiconductor laser device is designed with a first-order or higher-order mode allowed in the crystal growth direction, featuring a first conductive semiconductor substrate, conductive clad layers, light guide layers, and a low refractive index layer between the clad and guide layers, where the second light guide layer has a higher refractive index than the first, and the active layer is positioned closer to the p-type clad layer, optimizing layer thickness and refractive indices to enhance light confinement and carrier distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional light guide layer structures are used, then manufacturing is simpler, but power conversion efficiency cannot be increased while reducing threshold current and improving slope efficiency
Solution Approach 1:
The light guide layer is divided into a first light guide layer and a second light guide layer with different refractive indices. This segmentation allows independent optimization of light confinement in different regions, enabling simultaneous reduction of threshold current and improvement of slope efficiency, thereby resolving the contradiction between power conversion efficiency and structural complexity.
Solution Approach 2:
Different regions of the light guide layer are assigned different refractive indices: the first light guide layer has a lower refractive index to reduce threshold current, while the second light guide layer has a higher refractive index to improve slope efficiency. This local quality differentiation enables the device to achieve high power conversion efficiency without excessive structural 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
This configuration reduces threshold current and improves slope efficiency, resulting in high power conversion efficiency by increasing light confinement and displacing the active layer position to maximize light intensity distribution and carrier absorption.
Implementation Method 1
a first conductive low refractive index layer having a lower refractive index than a refractive index of the first conductive clad layer is provided between the first conductive clad layer and the first light guide layer
Implementation Method 2
A refractive index of the second light guide layer is higher than a refractive index of the first light guide layer
Data Source
AI summary
A semiconductor laser device includes a first conductivity type semiconductor substrate, a first conductivity type cladding layer, a first light guide layer, an active layer, a second light guide layer, and a second conductivity type cladding layer laminated on the semiconductor substrate in that order. The semiconductor laser device supports at least one of a first-order and higher-order mode of oscillation in the semiconductor laser in crystal growth direction of the active layer. The first light guide layer is thicker than the second light guide layer. A first conductivity type low refractive index layer having a lower refractive index than refractive index of the first conductivity type cladding layer, is disposed between the first conductivity type cladding layer and the first light guide layer. The refractive index of the second light guide layer is higher than the refractive index of the first light guide layer.