Semiconductor Laser Current Block Layer for Self-Pulsation
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Solution Overview
Problem
Current semiconductor lasers using nitride semiconductors face limitations in improving performance due to challenges in controlling self-pulsation and coherence, particularly in achieving stable self-pulsation and reducing coherence, which affects their optical output and operational efficiency.
Innovation Solution
Incorporating a current block layer between the active layer and the cladding layer, with additional current block layers on opposite sides, to create a saturable absorbing region that controls carrier density and refractive index oscillation, enabling self-pulsation and reducing coherence by adjusting the formation area and shape of the current block layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current block layer is added between the active layer and cladding layer to control carrier density, then self-pulsation stability is improved, but device complexity increases
Solution Approach 1:
The current block layer is segmented into multiple regions with different areas: a first current block layer in a first region and a second current block layer in a second region. This segmentation allows independent control of carrier density in different regions, enabling stable self-pulsation while maintaining manageable device complexity through modular design
Solution Approach 2:
Different regions of the current block layer are designed with different areas and positions relative to the active layer. The first current block layer has a specific area in the first region, while the second current block layer has a different area in the second region. This local quality variation enables precise control of carrier density distribution, achieving stable self-pulsation characteristics
2Object-affected harmful factors
If the current block layer area is increased to reduce coherence, then speckle pattern impact is reduced, but optical output intensity decreases
Solution Approach 1:
The areas of the current block layers are optimized to specific parameter ranges: the first current block layer has an area of 0.5 μm² to 2.0 μm², and the second current block layer has an area of 0.3 μm² to 1.5 μm². These parameter changes enable reduction of coherence (thereby reducing speckle pattern impact) while maintaining sufficient optical output intensity
Solution Approach 2:
Instead of uniformly increasing the current block layer area throughout, the invention applies partial action by placing current block layers in specific regions (first and second regions) with controlled areas. This partial coverage is sufficient to reduce coherence and speckle pattern impact while avoiding excessive area that would overly diminish optical output intensity
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 allows for stable self-pulsation and reduced coherence, enhancing the semiconductor laser's optical output and operational efficiency by controlling carrier density and refractive index oscillations, thereby improving multimode oscillation and reducing the impact of speckle patterns.
Implementation Method 1
a current block layer between an active layer and a cladding layer... create a saturable absorbing region that controls carrier density and refractive index oscillation
Implementation Method 2
controls carrier density and refractive index oscillation, enabling self-pulsation
Implementation Method 3
semiconductor laser using a nitride semiconductor... capable of a self-pulsation operation
Data Source
AI summary
The characteristics of a semiconductor laser are improved. In a semiconductor laser having an n type cladding layer, an active layer, and a p type cladding layer, a current block layer is provided. For example, the current block layer is arranged partially between the p type cladding layer and the active layer, and in the overlapping region of the p type cladding layer and the active layer. Thus, in a current narrowing region of the overlapping region of the p type cladding layer and the active layer, the current block layer is arranged, thereby to suppress the current injected into a part of the active layer. This results in the formation of a saturable absorbing region, which causes a difference in intensity of the optical output of the semiconductor laser. This can implement self-pulsation.