Quantum Cascade Laser Integrated Lens Beam Collimation
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Solution Overview
Problem
Laser light emitted from quantum cascade lasers diverges, leading to reduced optical coupling efficiency with light-receiving devices due to the inherent spread angle, which affects the performance in applications such as industrial processing and optical measurements.
Innovation Solution
A quantum cascade laser design incorporating a semiconductor plano-convex lens positioned on the semiconductor substrate alongside the mesa waveguide, where the lens receives and condenses the emitted laser light, preventing divergence and enhancing optical coupling efficiency by aligning the optical axes of the mesa waveguide and lens with high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser light is emitted from the output face of the quantum cascade laser, then laser light generation is achieved, but the laser light diverges and optical coupling efficiency with light-receiving devices is reduced
Solution Approach 1:
A plano-convex lens is introduced as an intermediary optical element between the laser output face and the light-receiving device. The lens receives diverging laser light through its entrance surface and emits condensed light through its convex surface, effectively mediating the beam propagation to achieve collimation and improve optical coupling efficiency without modifying the laser structure itself
2Productivity
If a lens is added to condense laser light, then beam divergence is reduced and optical coupling efficiency is improved, but device complexity increases
Solution Approach 1:
The plano-convex lens is merged with the semiconductor substrate by providing it on a second region of the principal surface of the substrate, integrating the optical condensing function directly into the laser device structure. This combination eliminates the need for separate external lens assemblies and reduces overall device complexity while maintaining the beam condensation function
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 condenses diverging laser light, improving optical coupling efficiency and maintaining a collimated beam, thereby enhancing the performance and efficiency of quantum cascade lasers in various applications.
Implementation Method 1
a lens having an entrance surface and a convex surface, the entrance surface receiving the laser light from the output face, and the convex surface emitting the laser light after being condensed by the lens
Data Source
AI summary
A quantum cascade laser includes a laser structure having an output face for emitting laser light in a first direction; and a lens having an entrance surface and a convex surface, the entrance surface receiving the laser light from the output face, and the convex surface emitting the laser light after being condensed by the lens. The laser structure includes a semiconductor substrate and a mesa waveguide provided on a first region of a principal surface of the semiconductor substrate, the mesa waveguide extending in the first direction. The lens includes a semiconductor and is provided on a second region of the principal surface of the semiconductor substrate. The first region and the second region are arranged in the first direction.