VCSEL Coupling-Out Facet Layout for Stable Laser Modes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing VCSELs face challenges in stabilizing specific laser modes due to inefficient light extraction and reflection patterns, leading to instability in laser emission.
Innovation Solution
The VCSEL design incorporates at least two coupling-out facets on the outer face, positioned at locations matching intensity maxima of the laser mode, with higher facet reflectivity than the surrounding emission region, and non-circular outer contours to enhance mode stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional VCSEL design with a single circular emission region is used, then the device structure is simple, but the laser mode stability is poor due to inefficient light extraction and reflection patterns
Solution Approach 1:
The emission region is divided into multiple discrete coupling-out facets (at least two) positioned at specific locations on the outer face. Each facet corresponds to intensity maxima of the desired laser mode, segmenting the light extraction process to stabilize the particular laser mode while reducing unwanted modes.
Solution Approach 2:
Different regions of the emission face are assigned different reflectivity properties. The coupling-out facets have higher facet reflectivity than the surrounding emission region, creating local quality variations that promote light reflection at specific intensity maxima locations while allowing extraction in other areas.
2Productivity
If the coupling-out facets have high reflectivity to stabilize the laser mode, then light extraction efficiency improves, but the device complexity increases due to the need for precise facet positioning and shaping
Solution Approach 1:
The coupling-out facets are designed with non-circular outer contours, breaking the rotational symmetry of conventional VCSELs. This asymmetric geometry, combined with specific positioning at intensity maxima locations, creates favorable reflection patterns that stabilize the laser mode while improving light extraction efficiency.
Solution Approach 2:
The invention transitions from a conventional single circular emission region to multiple discrete facets distributed across the outer face. This dimensional redistribution of the emission area allows selective light extraction at different spatial locations, improving efficiency while the non-circular contours add geometric complexity for mode stabilization.
3Reliability
If multiple coupling-out facets with non-circular contours are implemented, then diffraction effects are reduced and mode stabilization is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The coupling-out facets are pre-positioned at locations that match the intensity maxima of the desired laser mode. This preliminary positioning, determined through mode analysis, ensures that the facets are located where they will most effectively stabilize the particular laser mode, reducing the need for post-manufacturing adjustments.
Solution Approach 2:
The invention changes the geometric parameters of the emission region from a single circular shape to multiple facets with non-circular contours. By optimizing the position, size, and shape parameters of these facets, the design achieves mode stabilization while the parameter variations can be controlled through standard semiconductor fabrication techniques.
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 effectively stabilizes the specific laser mode by promoting light reflection at intensity maxima, resulting in improved light extraction and reduced diffraction effects, thereby enhancing the overall efficiency and stability of the VCSEL.
Implementation Method 1
The at least two coupling-out facets have a facet reflectivity that is higher than a surface reflectivity of a remaining of the emission region
Implementation Method 2
an active layer arranged between the inner Bragg mirror and the coupling-out mirror for generating light
Implementation Method 3
The at least two coupling-out facets have a non-circular outer contour
Data Source
AI summary
A vertical cavity surface emitting laser (VCSEL) includes a main body having a resonator for forming a particular laser mode. The resonator has an inner Bragg mirror and a coupling-out mirror which is adjacent to an outer face of the main body, and an active layer arranged between the inner Bragg mirror and the coupling-out mirror for generating light. On the outer face, an emission region is provided that has at least two coupling-out facets positioned at locations on the outer face that match locations of intensity maxima of the particular laser mode such that the particular laser mode is stabilized. The at least two coupling-out facets have a facet reflectivity that is higher than a surface reflectivity of a remaining of the emission region. The at least two coupling-out facets have a non-circular outer contour.