VCSEL Resonator Structure for Stable Transverse Mode Emission
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Solution Overview
Problem
Vertical cavity surface emitting devices, such as surface emitting lasers, face challenges in maintaining stable light emission patterns and high-quality output, especially under varying environmental conditions like high temperatures, with existing configurations often leading to early deterioration and complex manufacturing processes.
Innovation Solution
A vertical cavity surface emitting device is designed with a substrate, multilayer film reflecting mirrors, semiconductor layers of opposing conductivity types, and a resonator structure featuring low and high resistance regions in the p-type semiconductor layer, where the high resistance region is depressed and inactivated to enhance electrical resistance and current confinement, allowing for stable transverse mode emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a resonator is configured to generate light in a desired transverse mode, then the far-field pattern stability is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by creating a depressed region with different electrical properties (higher resistance) in the p-type semiconductor layer. This localized modification confines carriers to specific regions, stabilizing the transverse mode and far-field pattern without requiring complex overall device architecture changes.
2Reliability
If the surface emitting laser is designed for high quality and stable output under various environments, then the reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent changes the electrical resistance parameter by creating a depressed region where impurities are inactivated. This parameter change (from low to high resistance) enables stable operation under various environmental conditions including high temperature, while the manufacturing process remains relatively simple using standard semiconductor fabrication techniques.
3Stability of the object's composition
If additional insulating layers and complex structures are added to stabilize transverse mode, then the far-field pattern stability is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The patent extracts the need for additional insulating layers by using the depressed region structure itself to provide both the transverse mode stabilization and the necessary electrical isolation. This eliminates the need for separate insulating layer deposits, simplifying the manufacturing process while achieving the desired stability.
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 stabilizes the transverse mode of the laser beam, achieves high output power, and simplifies the manufacturing process by reducing the need for additional insulating layers, resulting in a high-quality, cost-effective, and environmentally robust light-emitting device.
Implementation Method 1
impurities of the second conductivity type is inactivated in the high resistance region such that the high resistance region has an electrical resistance higher than an electrical resistance of the low resistance region
Implementation Method 2
A resonator is constituted between the second multilayer film reflecting mirror and the first multilayer film reflecting mirror
Data Source
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AI summary
A vertical cavity surface emitting device includes a substrate, a first multilayer film reflecting mirror formed on the substrate, a first semiconductor layer formed on the first multilayer film reflecting mirror and having a first conductivity type, a light-emitting layer formed on the first semiconductor layer, and a second semiconductor layer formed on the light-emitting layer and having a second conductivity type opposite to the first conductivity type of the first semiconductor layer. The second semiconductor layer includes a low resistance region and a high resistance region on an upper surface. The high resistance region is depressed from the low resistance region toward the light-emitting layer outside the low resistance region and impurities of the second conductivity type is inactivated in the high resistance region such that the high resistance region has an electrical resistance higher than an electrical resistance of the low resistance region. The vertical cavity surface emitting device includes a light-transmitting electrode layer in contact with the low resistance region and the high resistance region, the light-transmitting electrode layer being formed on the upper surface of the second semiconductor layer, and a second multilayer film reflecting mirror formed on the light-transmitting electrode layer. A resonator is constituted between the second multilayer film reflecting mirror and the first multilayer film reflecting mirror.