GaN Laser Asymmetric Light Guide Layers
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Solution Overview
Problem
The existing nitride semiconductor laser devices face challenges in reducing threshold current due to light absorption and asymmetry in light guide layer thickness, leading to increased lasing threshold and reduced light passing through the active layer.
Innovation Solution
A GaN-based semiconductor laser device is designed with an n-type cladding layer, a first light guide layer, an active layer, and a p-type cladding layer, where the first light guide layer's thickness is between 65% and 85% of the total light guide layer thickness, and both layers contain indium, optimizing the refractive index differences and crystal stiffness to minimize light absorption and asymmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the film thickness of the n-side light guide layer is increased to decrease light absorption, then the threshold current decreases, but the position deviation of the active layer increases causing decreased light passing ratio
Solution Approach 1:
The patent applies asymmetry by setting the n-side light guide layer thickness to 65-85% of the total light guide layer thickness, creating an optimized asymmetric structure that balances light absorption reduction with active layer positioning. This asymmetric thickness distribution resolves the contradiction by preventing excessive position deviation while still reducing overall light absorption.
Solution Approach 2:
The patent changes the thickness parameter of the n-side light guide layer to a specific range (65-85% of total thickness) to optimize performance. This parameter adjustment resolves the contradiction by finding the optimal balance point where light absorption is sufficiently reduced without causing excessive position deviation of the active layer.
2Loss of energy
If the film thickness of the n-side light guide layer is made larger than the p-side, then light absorption is reduced, but the threshold current increases due to decreased light passing ratio
Solution Approach 1:
The patent implements a controlled asymmetric structure where the n-side light guide layer is thicker than the p-side, but within an optimized range (65-85% of total thickness). This resolves the contradiction by preventing the asymmetry from becoming excessive, thereby maintaining a high light passing ratio through the active layer while still reducing overall light absorption.
Solution Approach 2:
The patent optimizes the thickness parameter of the n-side light guide layer to fall within 65-85% of the total light guide layer thickness. This parameter optimization resolves the contradiction by ensuring that light absorption is reduced without causing such significant position deviation that the light passing ratio and threshold current are adversely affected.
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 the threshold current by minimizing light absorption and maintaining high light passing through the active layer, enabling efficient emission in the green region with reduced operating voltage.
Implementation Method 1
both contain indium, wherein each of indium compositions of the first and second light guide layers is not less than 2% and not more than 6%
Implementation Method 2
an active layer of a GaN-based semiconductor provided on the first light guide layer; a lasing wavelength of the active layer is not less than 400 nm and not more than 550 nm
Data Source
AI summary
A gallium nitride-based semiconductor laser device with reduced threshold current. The gallium nitride-based semiconductor laser device is provided with an n-type cladding layer, an n-side light guide layer, an active layer, a p-side light guide layer, and a p-type cladding layer. The n-side light guide layer and the p-side light guide layer both contain indium. Each of indium compositions of the n-side light guide layer and the p-side light guide layer is not less than 2% and not more than 6%. A film thickness of the n-type cladding layer is in the range of not less than 65% and not more than 85% of a total of the film thickness of the n-type cladding layer and a film thickness of the p-type cladding layer.