Quantum Cascade Laser Ridge With Inclined Embedding Layer
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Solution Overview
Problem
The existing quantum-cascade laser elements face challenges in heat dissipation and suppression of high-order mode oscillation, with a need to improve heat dissipation and stabilize light output with a peak intensity at the central portion of the ridge portion while minimizing high-order mode oscillation.
Innovation Solution
A quantum-cascade laser element is designed with a semiconductor substrate and a semiconductor laminate featuring a ridge portion, an embedding layer with inclined surfaces, and a metal layer on the top surface and inclined surfaces of the ridge portion, which enhances heat dissipation and suppresses high-order mode oscillation while maintaining basic mode stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional quantum-cascade laser element structure is used, then the device is simple to manufacture, but heat dissipation is insufficient
Solution Approach 1:
The embedding layer is divided into multiple portions (first portion, second portion, third portion) with different functions and positions. The first portion is formed on the side surface of the ridge portion for heat dissipation, the second portion extends along the width direction for mode control, and the third portion is formed on the opposite side for additional heat dissipation. This segmentation allows each portion to be optimized for its specific function while maintaining overall structural integrity.
Solution Approach 2:
The embedding layer portions are extended in multiple spatial dimensions: the first portion extends along the light waveguide direction (length dimension), the second portion extends along the width direction (transverse dimension), and the third portion is positioned on the opposite side (depth dimension). This multi-dimensional arrangement maximizes heat dissipation pathways and mode control effectiveness without significantly increasing structural complexity.
2Reliability
If the metal layer is formed only on the top surface of the ridge portion, then the manufacturing process is simple, but high-order mode oscillation cannot be suppressed
Solution Approach 1:
The metal layer is selectively formed on specific surfaces of the embedding layer portions rather than uniformly across the entire structure. The metal layer is deposited on the first portion (side surface), second portion (width direction), and third portion (opposite side), with each location providing localized optical feedback and mode control. This selective metal layer formation suppresses high-order mode oscillation while minimizing unnecessary manufacturing steps.
3Reliability
If the first portion of the embedding layer has a flat surface, then the structure is simple, but the suppression of high-order mode oscillation is insufficient
Solution Approach 1:
The first portion of the embedding layer features an asymmetric surface configuration with a first inclined surface and a second inclined surface that are not mirror images of each other. The first inclined surface is inclined with respect to the side surface of the ridge portion, while the second inclined surface is inclined with respect to the center line. This asymmetric geometry creates different optical path lengths and feedback conditions for different modes, effectively suppressing high-order mode oscillation while maintaining manufacturing feasibility through standard epitaxial growth processes.
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
The solution effectively improves heat dissipation and suppresses high-order mode oscillation, achieving balanced performance in heat management and mode stability.
Implementation Method 1
heat generated in the active layer can be effectively dissipated
Implementation Method 2
the metal layer is formed on the first portion formed on the side surface of the ridge portion. Accordingly, the oscillation of a high-order mode can be suppressed while suppressing a loss in a basic mode
Data Source
AI summary
A quantum-cascade laser element includes: an embedding layer including a first portion formed on a side surface of a ridge portion, and a second portion extending from an edge portion of the first portion along a width direction of a semiconductor substrate; and a metal layer formed at least on a top surface of the ridge portion and on the first portion. A surface of the first portion has a first inclined surface inclined with respect to the side surface to go away from the side surface as going away from the semiconductor substrate, and a second inclined surface located opposite to the semiconductor substrate with respect to the first inclined surface and inclined with respect to a center line to approach the center line as going away from the semiconductor substrate. The metal layer extends over the first inclined surface and the second inclined surface.