Non-Planarized VCSEL Structure for Current Confinement and Bandwidth
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Solution Overview
Problem
Existing VCSEL designs face challenges in achieving high optical output efficiency and high modulation bandwidth due to issues with current blocking regions and optical mode confinement.
Innovation Solution
A non-planarized VCSEL design is introduced, featuring a blocking region and conductive channel cores formed by implantation and etching, which creates a heterojunction for selective current guidance and allows for non-planarized mirror layers with stepped periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional VCSEL designs with planarized mirror layers are used, then manufacturing simplicity is maintained, but optical output efficiency and modulation bandwidth are limited
Solution Approach 1:
The mirror layers are segmented into different regions with different numbers of periods - a first region with a first number of periods and a second region with a second number of periods. This segmentation allows each region to be optimized for its specific function, improving optical output efficiency while managing structural complexity through functional division.
Solution Approach 2:
Different regions of the mirror layers are assigned different local qualities in terms of the number of periods, creating zones with varying optical properties. This local quality variation enables enhanced optical confinement and output efficiency in specific areas without requiring complete restructuring of the entire device.
2Productivity
If higher data transmission rates and distances are achieved in optical networks, then network performance improves, but copper wire network limitations are exceeded requiring advanced laser technology
Solution Approach 1:
The VCSEL design incorporates dynamic characteristics through the heterogeneous mirror layer structure that enables high-speed modulation. The different period regions respond dynamically to electrical signals, allowing high data transmission rates while maintaining signal integrity and reliability through optimized optical confinement.
3Quantity of substance
If dense VCSEL arrays are implemented to increase emitters per unit area, then device density improves, but thermal management and defect formation become critical challenges
Solution Approach 1:
The mirror layers are segmented into different regions with different numbers of periods - a first region with a first number of periods and a second region with a second number of periods. This segmentation allows each region to be optimized for its specific function, improving optical output efficiency while managing structural complexity through functional division.
Solution Approach 2:
Different regions of the mirror layers are assigned different local qualities in terms of the number of periods, creating zones with varying optical properties. This local quality variation enables enhanced optical confinement and output efficiency in specific areas without requiring complete restructuring of the entire device.
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 design enhances fiber optic transceiver reliability, electro-optical bandwidth, and link distances, while also enabling higher maximum power per VCSEL and more emitters per unit area in dense arrays, with improved thermal conductivity and reduced defect formation.
Implementation Method 1
a blocking region and conductive channel cores formed by implantation and etching
Implementation Method 2
the injected minority carriers form a population inversion in the quantum wells that produces optical gain. Optical gain occurs when photons in the active region stimulate electrons to recombine with holes in the conduction band to the valance band, which produces additional photons
Implementation Method 3
By using a sufficient number of alternating layers, a high percentage of light can be reflected by the mirror
Implementation Method 4
As light passes from a layer of one index of refraction to another, a portion of the light is reflected
Data Source
Figure 1
Figure 2~2B
Figure 2C
AI summary
A non-planarized VCSEL can include: a blocking region over or under an active region, the blocking region having a first thickness; one or more conductive channel cores in the blocking region, the one or more conductive channel cores having a second thickness that is larger than the first thickness, wherein the blocking region is defined by having an implant and the one or more conductive channel cores are devoid of the implant, wherein the blocking region is lateral the one or more conductive channel cores, the blocking region and one or more conductive channel cores being an isolation region; and a non-planarized semiconductor region of one or more non-planarized semiconductor layers over the isolation region. The VCSEL can include a planarized bottom mirror region below the active region and a non-planarized top mirror region above the isolation region, or a non- planarized bottom mirror region below the active region.