Surface-Emitting Laser Mesa Layout for Uniform Edge Emission
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Solution Overview
Problem
Conventional surface emitting laser elements exhibit variations in light emission intensity between light emitting units adjacent to the second region and those in other regions.
Innovation Solution
The design incorporates a protruding portion in the second region with a larger recess depth for outermost peripheral mesas, narrowing the current path to the second region, thereby reducing variations in light emission intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a bar-shaped active region is used in conventional laser elements, then the laser oscillation mode is stable, but the emission area is limited and cannot be easily increased
Solution Approach 1:
The patent divides the active region into multiple independent bar-shaped segments arranged in a matrix pattern. Each segment can be independently controlled and contributes to the overall emission area. This segmentation allows the emission area to be increased by adding more segments without requiring a complete redesign of the cavity structure.
Solution Approach 2:
Multiple bar-shaped active regions are nested within a single resonator cavity, with each bar positioned at specific locations along the optical axis. This nesting approach allows multiple emission sources to coexist within one cavity, effectively increasing the total emission area while maintaining a compact structure.
2Area of stationary object
If multiple bar-shaped active regions are arranged in a matrix to increase emission area, then the emission area increases, but the manufacturing precision requirements become more stringent
Solution Approach 1:
The patent applies different properties to different parts of the active region. Each bar-shaped active region has optimized dimensions and positioning tailored to its specific location within the matrix. This local optimization allows each segment to contribute maximally to the overall emission area while accommodating variations in positioning tolerances.
Solution Approach 2:
The patent uses multiple bar-shaped active regions with individual emission areas that may be smaller than a single large continuous region. By using multiple smaller regions (partial action), the system achieves a larger total emission area while reducing the precision requirements for each individual region, as the errors in positioning individual bars do not propagate across the entire emission area.
3Area of stationary object
If the active region is extended in the longitudinal direction to increase emission area, then the emission area increases, but the laser oscillation mode becomes unstable and side modes appear
Solution Approach 1:
Instead of using a single long continuous active region that would support multiple longitudinal modes, the patent segments the active region into multiple shorter bar-shaped sections. Each segment is too short to support independent longitudinal mode oscillation, but collectively they provide a large total emission area. The segmented structure enforces single-mode operation while achieving high emission area through the multiplicity of segments.
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 configuration suppresses the concentration of current on outermost peripheral mesas, maintaining consistent light emission intensity across all mesas, thereby reducing variations.
Implementation Method 1
an active region (330) having a laser oscillation function in a longitudinal direction
Implementation Method 2
a diffraction order selection layer (320) that selects a specific diffraction order of surface-emitted light
Implementation Method 3
surface-emitted light
Data Source
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AI summary
The present technology provides a surface emitting laser element capable of reducing variation in light emission intensity between light emitting units adjacent to the second region and light emitting units other than the light emitting units. A surface emitting laser element according to the present technology includes: a substrate; an electrode provided on one surface of the substrate; a first region which is provided on a side of the one surface opposite to a side of the electrode and in which a plurality of light emitting units having mesas is arranged; and a second region disposed around the first region on a side of the one surface opposite to the side of the electrode, in which a depth dimension of a second recess portion defined by a mesa adjacent to the second region among the mesas of the plurality of light emitting units and the second region is larger than a depth dimension of a first recess portion defined by two mesas adjacent to each other among the mesas of the plurality of light emitting units.