Quantum Cascade Laser Distributed Bragg Reflector
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Solution Overview
Problem
The production of quantum cascade lasers with distributed Bragg reflectors faces challenges in mechanical strength and durability due to damage during etching, leading to decreased yield and reflectivity issues.
Innovation Solution
A quantum cascade laser design featuring a distributed Bragg reflection structure with a semiconductor wall made of a single semiconductor material, optically coupled to the end facet of the laser structure, and including a high-refractive-index portion and a low-refractive-index portion, optimized for etching to enhance mechanical strength and reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the stacked semiconductor layer is etched deeply to form the distributed Bragg reflector and mesa waveguide simultaneously, then the reflectivity is improved, but the mechanical strength and production yield decrease due to damage to the side surface
Solution Approach 1:
The patent divides the distributed Bragg reflector structure into separate components: a semiconductor wall formed first, and then the stacked semiconductor layer formed separately. This segmentation allows the semiconductor wall to provide structural support while the stacked layer provides optical functionality, resolving the contradiction between deep etching for reflectivity and mechanical strength preservation.
Solution Approach 2:
The semiconductor wall is formed in advance before the stacked semiconductor layer is processed. This preliminary action creates a robust structural foundation that can withstand subsequent etching processes, enabling deep etching to achieve high reflectivity without compromising the overall mechanical strength of the device.
2Manufacturing precision
If the stacked semiconductor layer is etched to substrate level, then the distributed Bragg reflector is formed with high reflectivity, but the production yield decreases due to etching-related damage
Solution Approach 1:
By segmenting the structure into a pre-formed semiconductor wall and a separately processed stacked semiconductor layer, the patent enables independent optimization of each component. The semiconductor wall can be formed with precise dimensions before the stacked layer is etched to substrate level, maintaining high reflectivity while reducing cumulative damage and improving production yield.
3Manufacturing precision
If the semiconductor wall is made close to the end facet, then the optical coupling is improved, but the mechanical durability decreases due to etching damage
Solution Approach 1:
The semiconductor wall is formed in advance as a robust structural element before the stacked semiconductor layer is processed. This preliminary formation allows the wall to be positioned close to the end facet for optimal optical coupling while its pre-formed structure provides mechanical durability that withstands subsequent etching and handling 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 improves the mechanical strength and production yield of the quantum cascade laser while maintaining high reflectivity, reducing the impact of etching-related damage and light absorption, resulting in a more durable and efficient device.
Implementation Method 1
a distributed Bragg reflection structure disposed on the principal surface in the first region of the substrate, the distributed Bragg reflection structure including a semiconductor wall made of a single semiconductor material, the distributed Bragg reflection structure being optically coupled to the end facet of the laser structure
Data Source
AI summary
A quantum cascade laser includes a substrate having a principal surface including first and second regions arranged along a first axis; a laser structure disposed on the principal surface in the second region, the laser structure having an end facet intersecting the first axis, the laser structure including a stripe-shaped stacked semiconductor layer extending along the first axis; and a distributed Bragg reflection structure disposed on the principal surface in the first region, the distributed Bragg reflection structure including a semiconductor wall made of a single semiconductor material, the distributed Bragg reflection structure being optically coupled to the end facet of the laser structure. The semiconductor wall has first and second side surfaces that intersect the first axis and extend along a second axis intersecting the principal surface. The semiconductor wall is located away from the end facet of the laser structure.