Semiconductor Laser Resonator with Trench-Defined Protrusions
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Solution Overview
Problem
Semiconductor laser resonators generate a high number of complex resonant modes, making it difficult to select or separate a desired resonant mode from others, which affects the Q-factor and efficiency of the laser device.
Innovation Solution
A semiconductor laser resonator design featuring a gain medium layer with protrusions formed by trenches, a metal layer for beam confinement, and a buffer or dielectric layer to manage optical losses, allowing for the confinement of laser beams as standing waves and optimizing resonant mode selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional semiconductor laser resonator with circular disc or cubic gain medium is used, then the device structure is simple, but the number of resonant modes generated is high and the modes are complicated, making it difficult to select or separate desired modes
Solution Approach 1:
The gain medium layer is segmented into multiple regions by forming protrusions through trenches, dividing the continuous medium into distinct confinement regions. This segmentation creates discrete resonant modes that can be selectively controlled, resolving the contradiction between structural simplicity and mode selection capability.
Solution Approach 2:
The protrusions create local regions with different optical properties (different refractive indices and confinement characteristics) within the gain medium layer. This local quality variation enables specific resonant modes to be confined and selected in particular regions, making mode selection easier while maintaining overall structural simplicity.
2Power
If multiple resonant modes are generated, then the optical gain is enhanced, but the Q-factor decreases due to the complexity and overlap of resonant modes
Solution Approach 1:
By segmenting the gain medium into protrusion regions separated by trenches, the resonator supports multiple discrete resonant modes that are spatially confined. This segmentation prevents mode overlap and coupling, maintaining high Q-factor while allowing multiple modes to contribute to optical gain.
Solution Approach 2:
The trenches act as intermediary elements between protrusion regions, providing optical isolation that prevents unwanted coupling between adjacent resonant modes. This intermediary structure maintains high Q-factor by reducing mode interaction while still allowing multiple modes to exist for enhanced optical gain.
3Power
If the gain medium layer is extended to increase the laser beam generation area, then the optical output power is increased, but the confinement of laser beams as standing waves becomes less effective
Solution Approach 1:
The protrusions create localized regions with enhanced optical confinement properties within the extended gain medium layer. Each protrusion acts as a discrete confinement region where standing waves are effectively formed, maintaining high confinement precision even as the overall device size increases for higher output power.
Solution Approach 2:
The protrusions introduce vertical dimensionality to the beam confinement mechanism by creating raised structures that confine light in the vertical direction through total internal reflection. This dimensional approach enables effective standing wave formation and beam confinement across larger horizontal areas, supporting higher output power while maintaining confinement precision.
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 design enables effective separation of desired resonant modes, improves the Q-factor, and enhances the confinement and efficiency of laser beams, allowing for precise wavelength selection and reduced unwanted resonant modes.
Implementation Method 1
the at least one protrusion is configured to confine the laser beam as a standing wave in the at least one protrusion
Implementation Method 2
a metal layer provided outside the gain medium layer, the metal layer being configured to confine the laser beam generated from the gain medium layer
Implementation Method 3
a buffer layer provided between the gain medium layer and the metal layer, the buffer layer being configured to buffer an optical loss of the laser beam generated from the gain medium layer
Implementation Method 4
a dielectric layer provided outside the gain medium layer, the dielectric layer being configured to confine the laser beam generated from the gain medium layer and having a refractive index different from a refractive index of the gain medium layer
Data Source
Figure 1
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AI summary
A semiconductor laser resonator configured to generate a laser beam includes a gain medium layer including a semiconductor material and comprising at least one protrusion formed by at least one trench to protrude in an upper portion of the gain medium layer. In the semiconductor laser resonator, the at least one protrusion is configured to confine the laser beam as a standing wave in the at least one protrusion.