Stacked Bi-Directional VCSEL Layout for Dual-Facing Optics
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Solution Overview
Problem
Existing vertical cavity surface emitting lasers (VCSELs) require separate chips and modules for front-facing and world-facing operations, leading to increased complexity, thickness, and form factor, as they typically use either top-emitting or bottom-emitting configurations, which are difficult to integrate into a single device.
Innovation Solution
A VCSEL device is designed with both top-emitting and bottom-emitting VCSELs integrated on a single chip, where a first set of epitaxial layers for bottom-emitting VCSELs is disposed on a substrate, and a second set of epitaxial layers for top-emitting VCSELs is grown on top, allowing for bi-directional light emission without the need for separate chips and modules, by aligning emission areas with a housing aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate chips and modules are used for front-facing and world-facing VCSEL operations, then each VCSEL type can be optimized independently, but device complexity and form factor increase
Solution Approach 1:
The patent combines both front-facing VCSELs and world-facing VCSELs onto a single semiconductor chip, integrating two previously separate devices into one unified structure. This merging reduces device complexity and form factor while maintaining the operational reliability of both VCSEL types through shared substrate and epitaxial layer infrastructure
2Reliability
If separate chips and modules are used for front-facing and world-facing VCSEL operations, then each VCSEL type can be optimized independently, but thickness and form factor increase
Solution Approach 1:
The patent utilizes vertical stacking of VCSEL structures along the thickness dimension of the substrate, with first VCSELs positioned at a first thickness location and second VCSELs at a second thickness location. This dimensional arrangement allows both VCSEL types to coexist in a compact form factor while maintaining their respective optical paths and emission characteristics
3Device complexity
If top-emitting and bottom-emitting VCSELs are integrated on a single chip, then form factor and complexity are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements local quality by providing different epitaxial layer structures at different locations on the substrate: first VCSELs have first active regions with first composition ratios optimized for front-facing operation, while second VCSELs have second active regions with second composition ratios optimized for world-facing operation. This localized differentiation enables independent optimization of each VCSEL type while maintaining a unified chip structure
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 reduces the form factor and complexity by enabling bi-directional light emission, allowing for front-facing and world-facing operations without additional components, while maintaining independent control over each VCSEL type.
Implementation Method 1
vertical cavity surface emitting laser (VCSEL) device includes a substrate layer and a first set of epitaxial layers for a bottom-emitting VCSEL disposed on the substrate layer
Implementation Method 2
growing, on a substrate, a first set of epitaxial layers for a bottom-emitting VCSEL
Data Source
AI summary
In some implementations, a vertical cavity surface emitting laser (VCSEL) device includes a substrate layer and a first set of epitaxial layers for a bottom-emitting VCSEL disposed on the substrate layer. The first set of epitaxial layers may include a first set of mirrors and at least one first active layer. The VCSEL device may include a second set of epitaxial layers for a top-emitting VCSEL disposed on the first set of epitaxial layers for the bottom-emitting VCSEL. The second set of epitaxial layers may include a second set of mirrors and at least one second active layer. The top-emitting VCSEL and the bottom-emitting VCSEL may be configured to emit light in opposite light emission directions.