VCSEL Transverse Mode Adjustment Section
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Solution Overview
Problem
Existing Vertical Cavity Surface Emitting Lasers (VCSELs) face challenges in achieving high output of the fundamental transverse mode while preventing oscillation of the high-order transverse mode, as previous methods often inadvertently reduce the gain of the fundamental mode in the process.
Innovation Solution
The VCSEL design incorporates a transverse mode adjustment section with high and low reflectance areas, where the high reflectance area is positioned in a region opposing the center of the current injection region and the low reflectance area is positioned in a region without the high reflectance area, effectively reducing the gain of high-order transverse modes while minimizing the impact on the fundamental mode's gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflectance adjustment layer is provided in the central part of the light emitting aperture to prevent high-order transverse mode oscillation, then single transverse mode oscillation is realized, but oscillation of the fundamental transverse mode is also prevented, making it difficult to obtain high output
Solution Approach 1:
The patent applies local quality by creating distinct high reflectance and low reflectance areas within the transverse mode adjustment section. The high reflectance area is positioned in a first opposed region opposing the center point of the current injection region, while the low reflectance area is positioned in another opposed region. This spatial differentiation of reflectance properties allows selective control over different transverse modes without uniformly suppressing the fundamental mode, thereby resolving the contradiction between mode stability and output power.
2Reliability
If the center point of the high reflectance area is arranged in a region different from the first opposed region, then high-order transverse mode oscillation is suppressed, but the gain of the fundamental transverse mode may be reduced
Solution Approach 1:
The patent employs asymmetry by deliberately positioning the center point of the high reflectance area in a region different from the first opposed region opposing the center point of the current injection region. This asymmetric arrangement creates a non-uniform reflectance distribution that selectively suppresses high-order transverse modes while preserving the gain of the fundamental transverse mode, thus resolving the contradiction between mode suppression effectiveness and fundamental mode power.
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 allows for high output of the fundamental transverse mode while significantly reducing the oscillation of high-order transverse modes, maintaining the gain of the fundamental mode and preventing distortion in the near-field pattern.
Implementation Method 1
The transverse mode adjustment section has a high reflectance area and a low reflectance area. The high reflectance area is formed in a region including a first opposed region opposing to a center point of the current injection region, and a center point of the high reflectance area is arranged in a region different from the first opposed region.
Data Source
AI summary
A Vertical Cavity Surface Emitting Laser (VCSEL) capable of providing high output of fundamental transverse mode while preventing oscillation of high-order transverse mode is provided. The VCSEL includes a semiconductor layer including an active layer and a current confinement layer, and a transverse mode adjustment section formed on the semiconductor layer. The current confinement layer has a current injection region and a current confinement region. The transverse mode adjustment section has a high reflectance area and a low reflectance area. The high reflectance area is formed in a region including a first opposed region opposing to a center point of the current injection region. A center point of the high reflectance area is arranged in a region different from the first opposed region. The low reflectance area is formed in a region where the high reflectance area is not formed, in an opposed region opposing to the current injection region.