Nitride Semiconductor Laser Refractive Index Differential
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Solution Overview
Problem
Existing nitride semiconductor laser elements with diffraction grating layers face challenges in achieving a satisfactory refractive index differential and high reproducibility, leading to increased complexity in mass production and performance variability, particularly in obtaining single-frequency emission for long-distance optical communications.
Innovation Solution
A nitride semiconductor laser element is designed with recessed and raised portions in the first and second semiconductor layers, where a region with a higher aluminum mixed crystal ratio is disposed on the raised portions and/or between them, enhancing the refractive index differential and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If recessed and raised portions are precisely formed to increase depth for refractive index differential, then diffraction grating effect is improved, but manufacturing complexity and difficulty increase
Solution Approach 1:
The patent applies local quality by forming a high-refractive-index material layer specifically in the recessed portions of the diffraction grating, rather than uniformly throughout the structure. This localized application of high refractive index material (such as TiO2, Ta2O5, or SiO2) creates the necessary refractive index differential only where needed for diffraction, avoiding the need to increase overall grating depth and simplifying manufacturing processes.
Solution Approach 2:
The patent changes the refractive index parameter by introducing materials with different refractive indices into the diffraction grating structure. By selecting high-refractive-index materials for the recessed portions and controlling their thickness and distribution, the patent achieves effective refractive index differential without requiring deep recesses, thereby reducing processing complexity while maintaining diffraction performance.
2Manufacturing precision
If recessed and raised portions are formed with precise depth, then diffraction grating effect is satisfied, but mass production reproducibility deteriorates
Solution Approach 1:
The patent applies local quality by forming a high-refractive-index material layer specifically in the recessed portions of the diffraction grating, rather than uniformly throughout the structure. This localized application of high refractive index material (such as TiO2, Ta2O5, or SiO2) creates the necessary refractive index differential only where needed for diffraction, avoiding the need to increase overall grating depth and simplifying manufacturing processes.
Solution Approach 2:
The patent applies preliminary action by forming the high-refractive-index material layer in the recessed portions before final grating structure completion. This preliminary formation of the refractive index-modified regions establishes a robust foundation for diffraction performance that is less sensitive to subsequent manufacturing variations, improving reproducibility in mass production.
3Manufacturing precision
If diffraction grating effect is enhanced by increasing recessed portion depth, then single-frequency emission is achieved, but threshold current increases
Solution Approach 1:
The patent changes the refractive index parameter by introducing materials with different refractive indices into the diffraction grating structure. By selecting high-refractive-index materials for the recessed portions and controlling their thickness and distribution, the patent achieves effective refractive index differential without requiring deep recesses, thereby reducing processing complexity while maintaining diffraction performance.
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 effectively increases the refractive index differential in the diffraction grating, lowers the threshold current, and stabilizes the laser performance, enabling single-mode oscillation and improved reproducibility in nitride semiconductor laser elements.
Implementation Method 1
a region with a higher aluminum mixed crystal ratio than the semiconductor layer that embeds the recessed and raised portions is disposed on the top faces of the raised portions
Data Source
AI summary
A nitride semiconductor laser element includes a substrate and a nitride semiconductor layer in which a first semiconductor layer, an active layer, and a second semiconductor layer are laminated in this order on the substrate. At least one of the first semiconductor layer and the second semiconductor layer includes a first section forming recessed and raised portions and a second section embedding the recessed and raised portions of the first section. A region with a higher aluminum mixed crystal ratio than the second section that embeds the recessed and raised portions is disposed on top faces of the raised portions. The nitride semiconductor layer defines resonant planes, and the recessed and raised portions are formed in a shape of stripes that extend substantially parallel to the resonant planes.