VCSEL Multiple Gain Layers Vertical Power Scaling
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Solution Overview
Problem
Conventional high power VCSEL systems rely on increasing the lateral dimensions of chips, which limits power output due to constraints in transverse and longitudinal dimensions, resulting in reduced beam quality and higher resistive losses.
Innovation Solution
Implementing multiple gain layers within a VCSEL cell, where each gain layer is separated by insulating layers and driven with the same voltage and current, to increase power output by utilizing the chip thickness rather than area, reducing DBR reflectivity and resistive losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple gain layers are implemented within a VCSEL cell, then power output increases linearly, but fabrication complexity increases due to integration of multiple electrodes through gain layers
Solution Approach 1:
The patent transitions from increasing power through lateral chip area expansion to increasing power through vertical stacking of multiple gain layers within a single cell. This dimensional shift from 2D (chip area) to 3D (chip thickness) allows power scaling without proportionally increasing fabrication complexity, as the vertical integration is achieved through systematic layer stacking rather than lateral expansion.
2Power
If conventional approaches use larger chips with more cells, then power output increases, but beam quality deteriorates due to constraints in transverse and longitudinal dimensions
Solution Approach 1:
The patent resolves the beam quality degradation by shifting the power scaling mechanism from lateral chip area expansion to vertical gain layer stacking. This maintains a compact lateral footprint that preserves beam quality while achieving power increase through the vertical dimension, avoiding the transverse and longitudinal dimension constraints that plague conventional approaches.
3Power
If conventional approaches use larger chips, then power output increases, but resistive losses increase
Solution Approach 1:
The patent reduces resistive losses by implementing multiple gain layers within a compact chip footprint rather than expanding chip area. The vertical stacking approach maintains shorter current paths and reduces the overall resistance compared to lateral expansion, thereby decreasing I²R losses while still achieving power scaling.
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 approach leads to a linear increase in power output, improved beam quality, and reduced thermal waste, while requiring a more complex fabrication process to integrate multiple electrodes through the gain layers.
Implementation Method 1
The cell structure consists of several gain layers between the DBR mirrors. The gain layers are in parallel electrically with each other, driven with the same voltage and current. The power of a cell is increased in proportion to the number of gain layers within a cell.
Implementation Method 2
The cell structure consists of several gain layers between the DBR mirrors.
Implementation Method 3
The cell structure consists of several gain layers between the DBR mirrors.
Data Source
AI summary
This invention opens up the chip thickness for increasing VCSEL power. It describes a method by using multiple gain layers 10, separated by insulating layers 11, powered in parallel electrically through embedded electrodes 13, 14 connected through via holes. The gain layers, as a whole, are bounded on top and bottom by DBR mirrors 12. The structure, compared to a standard VCSEL, leads to higher power, lower resistive loss, higher device speed, higher beam quality, and fewer number of DBR layers.