VCSEL Resonator Extension Area for Beam Quality and Lifespan
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Solution Overview
Problem
Vertical cavity surface emitting lasers (VCSELs) face challenges in extending their lifespan while reducing resistance and heat dissipation, and improving optical output and electrostatic discharge resistance, particularly when the oxidized aperture diameter is reduced, leading to increased optical loss and reduced lifespan.
Innovation Solution
The VCSEL design incorporates a long resonator structure with a resonator extension area made of materials like GaInP, which suppresses the generation of deep levels and crystal defects, allowing for increased oxidized aperture diameter and optical output, and reduces element resistance by using n-type resonator extension areas and selectively oxidizing the current narrowing layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the oxidized aperture diameter is reduced to achieve single transverse mode operation, then the beam quality is improved, but the optical loss increases and lifespan decreases
Solution Approach 1:
The patent changes the physical parameters of the resonator by extending its length and introducing a resonator extension area with different material properties (GaInP or AlGaAs). This parameter change allows the aperture diameter to be increased while maintaining single transverse mode operation, thereby resolving the contradiction between beam quality and lifespan.
Solution Approach 2:
The patent extends the resonator in the vertical dimension by adding a resonator extension area below the active layer. This dimensional extension provides additional optical path length that compensates for the increased aperture size, allowing both improved beam quality and extended lifespan to be achieved simultaneously.
2Measurement precision
If the oxidized aperture diameter is reduced to achieve single transverse mode operation, then the beam quality is improved, but the optical output decreases
Solution Approach 1:
The patent modifies the resonator length parameter and introduces a resonator extension area with specific material properties. These parameter changes enable the aperture diameter to be increased, which directly increases the optical output while the extended resonator length maintains the single transverse mode condition for beam quality.
Solution Approach 2:
The patent uses composite material structures in the resonator extension area, combining GaInP or AlGaAs layers with different optical properties. This composite structure enables tailored optical characteristics that support both high optical output through larger aperture and maintained beam quality through controlled mode selection.
3Power
If a long resonator structure is introduced to increase aperture diameter, then the optical output is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the resonator structure into distinct functional areas: the active layer region and the resonator extension area. This segmentation allows independent optimization and fabrication of each section, reducing overall manufacturing complexity while achieving the long resonator structure needed for high optical output.
Solution Approach 2:
The patent employs parameter changes in the form of standard semiconductor layer thicknesses and material compositions that can be fabricated using existing semiconductor manufacturing processes. By adjusting these parameters within conventional process capabilities, the long resonator structure is achieved without proportionally increasing manufacturing complexity.
4Power
If the resonator length is increased to maintain single transverse mode with larger aperture, then the optical output is improved, but the element resistance increases
Solution Approach 1:
The patent applies local quality by introducing n-type doping specifically in the resonator extension area while keeping other regions differently doped or undoped. This localized doping strategy reduces element resistance in the resonator extension region without adversely affecting the electrical characteristics of the active layer and other critical regions, thereby resolving the contradiction between optical output and element resistance.
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
The long resonator structure enhances optical output, extends the lifespan of VCSELs, and improves electrostatic discharge resistance by suppressing deep level generation and maintaining the reliability of the active layer, enabling high-speed modulation and efficient light emission.
Implementation Method 1
The resonator extension area contains a material in which an energy level with a crystal defect is higher than a general energy level without the crystal defect
Implementation Method 2
vertical cavity surface emitting laser includes a substrate, a first semiconductor multilayer reflector, a resonator, and a second semiconductor multilayer reflector. The resonator includes an active layer formed on the first semiconductor multilayer reflector
Implementation Method 3
The first semiconductor multilayer reflector of a first conduction type is configured by stacking a pair of a high refractive index layer having a relatively high refractive index and a low refractive index layer having a relatively low refractive index
Implementation Method 4
The second semiconductor multilayer reflector of a second conduction type is configured by stacking a pair of the high refractive index layer having the relatively high refractive index and the low refractive index layer having the relatively low refractive index
Implementation Method 5
selectively oxidizing the current narrowing layer
Data Source
AI summary
A vertical cavity surface emitting laser includes a first semiconductor multilayer reflector, a resonator, and a second semiconductor multilayer reflector. The first semiconductor multilayer reflector is formed on a substrate and is configured by stacking a high refractive index layer having a relatively high refractive index and a low refractive index layer having a relatively low refractive index. The resonator includes an active layer formed on the first semiconductor multilayer reflector. The second semiconductor multilayer reflector is configured by stacking the high refractive index layer and the low refractive index layer. The resonator includes a pair of spacer layers disposed vertically on the active layer and a resonator extension area formed at one side of the pair of spacer layers. The resonator extension area contains a material in which an energy level with a crystal defect is higher than a general energy level without the crystal defect.