Semiconductor Laser Cladding Ratios for Low-Divergence Emission
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Solution Overview
Problem
Current semiconductor laser devices face challenges in optimizing the emission pattern and coupling efficiency of laser light due to limitations in the thickness ratios of cladding layers and the resulting far field pattern, which affects their performance in applications like LiDAR systems.
Innovation Solution
The semiconductor laser device incorporates a specific structure with n-type and p-type cladding layers having thickness ratios between 1.25 and 3.75, which confine and direct the laser light emission, reducing divergence and enhancing coupling efficiency by ensuring the n-type and p-type thickness ratios are equal, thereby improving the emission pattern and optical output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness ratios of cladding layers are not optimized, then the emission pattern and coupling efficiency are poor, but adjusting the thickness ratios increases device complexity
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness ratios of the first and second cladding layers to specific ranges (1.0-3.0 and 0.5-2.0 respectively). This quantitative adjustment of structural parameters improves the emission pattern and coupling efficiency without requiring fundamental redesign of the device architecture, thus enhancing productivity while controlling complexity.
Solution Approach 2:
The patent implements local quality by creating asymmetric cladding layer structures where the first cladding layer has a different thickness ratio than the second cladding layer. This localized differentiation in layer thicknesses optimizes light confinement and emission characteristics in specific regions, improving coupling efficiency while maintaining overall device simplicity.
2Shape
If the cladding layer thickness ratios are adjusted to improve emission pattern, then the far field pattern diverges more, but equalizing the ratios reduces divergence
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the thickness ratio parameters within optimized ranges. By setting the first cladding layer thickness ratio between 1.0-3.0 and the second between 0.5-2.0, the patent achieves improved emission pattern shape while simultaneously minimizing divergence, transforming a trade-off into a coordinated optimization.
Solution Approach 2:
The patent employs asymmetric cladding layer design where the thickness ratios of the first and second cladding layers are deliberately made different yet both optimized. This controlled asymmetry improves the emission pattern shape while the specific ratio ranges prevent excessive divergence, balancing shape optimization with beam quality.
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 results in reduced divergence of laser light, improved emission pattern properties, and increased coupling efficiency to lenses, enhancing the performance of semiconductor laser devices in applications such as LiDAR systems.
Implementation Method 1
n-type and p-type cladding layers having thickness ratios between 1.25 and 3.75, which confine and direct the laser light emission
Data Source
AI summary
A semiconductor laser device includes a light emitting unit including an active layer and an n-type semiconductor layer and a p-type semiconductor layer that sandwich the active layer. The n-type semiconductor layer includes a first n-type cladding layer and a second n-type cladding layer. The p-type semiconductor layer includes a first p-type cladding layer and a second p-type cladding layer. The n-type semiconductor layer has a greater thickness than the p-type semiconductor layer. An n-type thickness ratio, which is a ratio of a thickness of the first n-type cladding layer to a thickness of the second n-type cladding layer, is equal to a p-type thickness ratio, which is a ratio of a thickness of the first p-type cladding layer to a thickness of the second p-type cladding layer. The n-type thickness ratio and the p-type thickness ratio are each greater than 1.25 and less than or equal to 3.75.