VCSEL Array Layout for Tighter Emitter Spacing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The spacing between adjacent emitters in a vertical cavity surface emitting laser (VCSEL) cannot be further reduced due to structural limitations.
Innovation Solution
The first ohmic metal layer is positioned in a non-overlapping manner relative to the connecting lines between emitters, allowing for reduced spacing between adjacent emitters in the same row and column, and the first and second pads are designed to avoid blocking the emission window, enhancing light output efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the spacing between adjacent emitters is reduced to achieve a smaller VCSEL dimension, then the overall device size is reduced, but the structural arrangement prevents further spacing reduction
Solution Approach 1:
The ohmic metal layer is positioned in the lateral dimension (in-plane direction) rather than extending vertically or radially, allowing emitters to be placed closer together without vertical interference. This dimensional repositioning resolves the spatial conflict between adjacent emitters and the metal layer, enabling further miniaturization of the VCSEL array while maintaining structural integrity.
2Reliability
If pads are positioned to collect current from emitters, then electrical connection is achieved, but pads may block the emission window and reduce light output efficiency
Solution Approach 1:
The ohmic metal layer is positioned locally in the non-light-emitting region rather than covering the entire emitter structure. This localized placement ensures electrical connection is maintained where needed while avoiding the light emission path, thus resolving the conflict between electrical connectivity and optical performance through spatial differentiation of functional zones.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided VCSEL including substrate, emitters arranged in m×n array, and first ohmic metal layer. Surface of substrate includes light-emitting regions in array of m rows and n columns and non-light-emitting region surrounding each light-emitting region, m×n≥2. Each emitter includes first DBR on surface of substrate, active layer on side of first DBR away from substrate, and second DBR on side of active layer away from substrate, at least part of first DBR disposed in respective light-emitting region, active layer and second DBR disposed in respective light-emitting region. First ohmic metal layer disposed on surface of first DBR away from substrate and disposed in non-light-emitting region, projection of first ohmic metal layer on substrate doesn't overlap projections of first and second connecting lines on substrate, first and second connecting lines respectively connects centers of emitters in same row, connects centers of emitters in same column.