Cylindrical Semiconductor Laser Diode Resonator Design
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Solution Overview
Problem
Conventional semiconductor laser diodes are complex and expensive to manufacture, requiring large dimensions and mirrored surfaces for resonator effects, making them unsuitable for small-scale, cost-effective integration in microtechnological applications.
Innovation Solution
A semiconductor laser diode with a cylindrical semiconductor layer sequence, featuring a rotationally symmetrical active zone for total reflection and a decoupling structure at the exit point to enhance radiation coupling, utilizing a passivation layer and local p-doping to reduce non-radiative losses, and a carrier with a lower refractive index contact layer for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor laser diodes use mirrored surfaces and Bragg structures for resonator effects, then resonator performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the complex mirrored surfaces and Bragg structures from the resonator design. Instead of using traditional mirror-based resonators, the invention employs a simple cylindrical cavity formed by the semiconductor layer sequence itself, where the cylindrical outer surface provides the necessary optical confinement through total internal reflection, thereby removing unnecessary complex components while maintaining resonator functionality
Solution Approach 2:
The patent applies local quality by creating a cylindrical outer surface with specific optical properties. The cylindrical geometry provides continuous total internal reflection along the circumference, creating a resonator effect localized to the cylindrical boundary. This local geometric feature replaces the need for distributed Bragg reflectors and mirrored surfaces throughout the device structure
2Reliability
If conventional semiconductor laser diodes use large dimensions for resonator structures, then resonator stability is improved, but integration in microtechnological applications becomes difficult
Solution Approach 1:
The patent employs spheroidality by using a cylindrical outer surface instead of flat or angular geometries. The curved cylindrical surface enables continuous total internal reflection of optical waves, creating stable resonator modes in a compact volume. The curvature of the cylindrical boundary provides optical confinement similar to spherical resonators, achieving stable resonance with much smaller dimensions than conventional planar resonator structures
Solution Approach 2:
The patent transitions from two-dimensional planar resonator structures to a three-dimensional cylindrical geometry. By utilizing the radial dimension of the cylindrical outer surface, the invention creates optical confinement in all three spatial dimensions, enabling stable resonator operation in a compact volume suitable for microtechnological integration
3Manufacturing precision
If conventional semiconductor laser diodes use complex manufacturing processes for resonator structures, then resonator precision is improved, but manufacturing cost and time increase
Solution Approach 1:
The patent merges the resonator structure formation with the semiconductor layer growth process itself. The cylindrical outer surface is formed as an integral part of the semiconductor layer sequence during epitaxial growth or subsequent processing, eliminating the need for separate resonator fabrication steps. This integration of resonator formation into the manufacturing process achieves precise cylindrical geometry while simplifying production
Solution Approach 2:
The patent utilizes parameter changes in the semiconductor layer structure to achieve the resonator effect. By controlling the refractive index distribution within the semiconductor layers and at the cylindrical outer surface, the invention creates total internal reflection conditions without requiring additional mirrored surfaces. The refractive index contrast between the semiconductor material and the surrounding medium provides the necessary optical confinement
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 enables the production of compact, cost-effective semiconductor laser diodes with efficient radiation generation and emission, suitable for microtechnology integration by minimizing non-radiative recombination and optimizing resonator performance.
Implementation Method 1
the active zone comprises an outer surface which is symmetrical with respect to the cylinder axis and which, during operation of the semiconductor laser diode, forms a resonator by total reflection of radiation generated in the active zone
Data Source
Figure 1~2b
Figure 3a~3b
AI summary
The invention relates to a semi-conductor laser diode (10) comprising a semi-conductor layer sequence (1) with an active zone (4), wherein the semi-conductor layer sequence (1) is cylindrical, a cylinder axis (z) of said semi-conductor layer sequence (1) is perpendicular to a layer plane of the semi-conductor layer sequence (1), and the semi-conductor laser diode (10) emits a beam, generated during operation, perpendicularly to the cylinder axis (z) of the semi-conductor layer sequence (1).