Top Emitting VCSEL Array Heat Spreading Superstrate
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Solution Overview
Problem
Top emitting VCSEL arrays face significant thermal management challenges due to the poor thermal conductivity of GaAs substrates, leading to heat buildup, reduced performance, and limited operational characteristics, which restrict their use in high-power applications.
Innovation Solution
A top emitting VCSEL array design with a separate heat spreading superstrate positioned above the VCSEL devices, allowing for efficient heat dissipation through a thermally conductive material like SiC or Diamond, while maintaining light transmission, and incorporating a pattern of conductive elements for sectional control and improved frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If top emitting VCSEL arrays are used for high power applications, then power output can be increased, but heat buildup occurs due to poor thermal conductivity of GaAs substrates
Solution Approach 1:
A separate heat spreading superstrate is introduced as an intermediary component between the VCSEL array and the heat sink. This superstrate, made of materials with high thermal conductivity such as diamond or cubic silicon carbide, acts as a thermal mediator that efficiently conducts heat away from the VCSEL devices without interfering with their optical emission function
Solution Approach 2:
The system employs composite material structure combining GaAs substrate (for VCSEL fabrication) with a separate heat spreading superstrate made of diamond or cubic silicon carbide. This composite approach allows each material to perform its optimal function: GaAs for laser device integration and the superstrate for thermal management
2Temperature
If heat sinking is implemented around or covering the VCSEL devices, then heat removal can be improved, but light transmission is blocked
Solution Approach 1:
The heat sinking function is segmented from the VCSEL device structure itself and placed on a separate heat spreading superstrate. This spatial segmentation allows the heat sink to perform thermal management without interfering with the optical path of the top-emitting VCSELs
Solution Approach 2:
The heat spreading superstrate serves as a mediator that thermally connects to the VCSEL devices while being optically transparent to their emissions, thus enabling heat removal without blocking light transmission
3Ease of manufacture
If GaAs substrate is used for VCSEL fabrication, then device integration is achieved, but thermal conductivity is poor
Solution Approach 1:
The system uses a composite material architecture where GaAs substrate provides the platform for VCSEL fabrication and integration, while a separate heat spreading superstrate made of diamond or cubic silicon carbide provides high thermal conductivity for heat management
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 thermal management, increases power density, and improves frequency response, enabling top emitting VCSEL arrays to operate at higher outputs and maintain reliability, thus competing with edge emitting arrays in various applications.
Implementation Method 1
A top emitting VCSEL array design with a separate heat spreading superstrate positioned above the VCSEL devices, allowing for efficient heat dissipation through a thermally conductive material like SiC or Diamond
Implementation Method 2
an active region configured to generate light positioned between the lower mirror and the first region
Data Source
AI summary
A top emitting VCSEL array may be coupled to a separate heat spreading superstrate that may be positioned above the apertures of the array and that may be able to transmit the emitted beams through the heat spreading superstrate. The VCSEL devices in the array may be controlled by an electrical connection to a pattern of conductive elements positioned in close contact with, but electrically isolated from, the heat spreading superstrate. The conductive elements may electrically control one or more of the VCSEL devices to enable sectional control of the light output. The elements may also be arraigned in a ground-signal-ground or coplanar waveguide configuration to improve the frequency response of the array.