Bottom-Emitting VCSEL Reflective End With Phase-Matched Metal Layers
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Solution Overview
Problem
Existing bottom emitting VCSELs face challenges in achieving high reflectivity at the reflective end without increasing the thickness or mirror periods of the second mirror stack.
Innovation Solution
Incorporating a phase matching layer and a first metal layer with specific thicknesses in the reflective end, where the phase matching layer is between the active region and the first metal layer, to achieve a combined reflectivity of at least a predetermined threshold for the emission wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness or mirror periods of the second mirror stack are increased to improve reflectivity, then the reflectivity of the reflective end is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness of the phase matching layer and first metal layer to achieve optimal reflectivity. By adjusting these dimensional parameters, the patent achieves high reflectivity without increasing the overall device complexity or mirror stack thickness, directly resolving the technical contradiction between reliability and device complexity
Solution Approach 2:
The patent uses composite materials by combining a phase matching layer with specific dielectric material and a first metal layer with particular reflectivity properties. This composite structure at the reflective end achieves superior optical performance through material composition rather than increasing structural complexity, effectively resolving the contradiction between reflectivity and device complexity
2Reliability
If the thickness of the phase matching layer and first metal layer is optimized, then the reflectivity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific parameter ranges for the phase matching layer thickness and first metal layer thickness that balance reflectivity performance with manufacturability. By defining optimized parameter windows rather than single values, the patent reduces manufacturing precision requirements while maintaining high reflectivity, resolving the technical contradiction between reliability and manufacturing precision
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 enhances the reflectivity of the reflective end without increasing the thickness or mirror periods of the second mirror stack, thereby improving the performance of bottom emitting VCSELs.
Implementation Method 1
a reflective end configured to reflect the laser light toward the substrate. The active region is between the first mirror stack and the reflective end
Data Source
AI summary
A VCSEL can include: a substrate that passes light therethrough; a phase matching layer over a top mirror stack; a first metal layer over the phase matching layer; and an end metal region over the first metal layer. The phase matching layer and first metal layer have a cooperative thickness to provide reflectivity of at least a predetermined reflectivity threshold for the emission wavelength. A method of making a VCSEL can include: providing a substrate; forming a first mirror stack above the substrate; forming an active region above the first mirror stack; and forming a reflective end above the active region, the reflective end having a phase matching layer and a first metal layer. The phase matching layer and first metal layer have a combined thickness for the reflective end to have a reflectivity of at least a predetermined reflectivity threshold for an emission wavelength of the VCSEL.