Surface-Emitting Laser Emitter Layout for Stable VCSEL Beam Modes
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Solution Overview
Problem
Conventional VCSEL devices face issues with increased divergence angle and beam pattern splitting due to higher mode shift when high current is applied or aperture size increases, leading to instability and reliability concerns.
Innovation Solution
A surface emitting laser device design with a trench region disposed inside a virtual triangle connecting the centers of multiple emitters, featuring a polygonal aperture shape and controlled trench geometry to maintain mode stability and prevent void generation in the passivation layer, thereby ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high current is applied or aperture size is increased to improve light output, then luminous intensity is improved, but higher mode shift occurs causing divergence angle increase and beam pattern splitting
Solution Approach 1:
The patent applies local quality by introducing a trench structure specifically at the aperture edge region rather than uniformly modifying the entire device. This localized structural modification creates optimal optical confinement exactly where needed at the emission region, suppressing higher-order modes locally while maintaining overall high current operation and large aperture size for high luminous intensity.
Solution Approach 2:
The patent changes the geometric parameter of the aperture from a conventional circular shape to a polygonal shape with multiple sides. This parameter change modifies the optical mode distribution and confinement characteristics, enabling stable single-mode operation even under high current conditions and large aperture sizes, thereby preventing divergence angle increase and beam pattern splitting while maintaining high luminous intensity.
2Illumination intensity
If aperture size is increased to improve light output, then luminous intensity is improved, but higher mode shift occurs causing beam pattern splitting
Solution Approach 1:
The trench structure is locally introduced at the aperture edge to modify optical confinement specifically in the region most prone to higher-order mode generation. This localized modification suppresses mode splitting and maintains beam pattern integrity even when the overall aperture size is large for high luminous intensity output.
Solution Approach 2:
Changing the aperture shape parameter from circular to polygonal fundamentally alters the optical mode structure and confinement. This geometric parameter change enables large aperture operation while maintaining stable beam patterns by suppressing higher-order mode excitation through the modified boundary conditions imposed by the polygonal geometry.
3Ease of manufacture
If conventional VCSEL design is used to simplify manufacturing, then ease of manufacture is improved, but void generation occurs in the passivation layer reducing reliability
Solution Approach 1:
The trench structure is introduced as a localized feature in the passivation layer formation process. This local modification allows the use of standard semiconductor fabrication techniques while preventing void generation specifically at the critical aperture edge region, thereby maintaining ease of manufacture through conventional processes while significantly improving reliability.
Data Source
AI summary
An embodiment relates to a surface emitting laser device and a light emitting device including the same. The surface emitting laser device according to the embodiment includes: a first emitter having a first aperture and a first insulating region; a second emitter having a second aperture and a second insulating region and disposed adjacent to the first emitter; a third emitter having a third aperture and a third insulating region and disposed adjacent to the first emitter and the second emitter; and a first trench region disposed between the first emitter and the third emitter. The first trench region is disposed inside a virtual triangle connecting a center of the first aperture of the first emitter, a center of the second aperture of the second emitter, and a center of the third aperture of the third emitter.