Optical Sub-Assembly Packaging for Lower Diode Thermal Impedance
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Solution Overview
Problem
Conventional optical sub-assemblies for laser diodes suffer from inefficient heat dissipation, which reduces efficiency and increases electrical power consumption due to limited directional heat dissipation through the submount structure and TEC device.
Innovation Solution
The optical sub-assembly design positions the diode between a silicon photonics (SiPho) die submount structure and a thermoelectric cooler (TEC), with the SiPho die overhanging the TEC to prevent underfill material from covering the waveguide, using thermally conductive and electrically insulating materials for enhanced cooling, and incorporating integrated circuits for direct thermal communication with the TEC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the diode is mounted on the submount structure with TEC cooling from below, then the structure is simple and easy to manufacture, but heat dissipation is limited to one direction reducing cooling efficiency
Solution Approach 1:
The patent transitions from single-direction (vertical) heat dissipation to multi-directional heat dissipation by adding lateral thermal pathways through heat sinks attached to the submount structure's sides, enabling heat to escape in multiple dimensions simultaneously
Solution Approach 2:
The cooling system is segmented into multiple independent heat dissipation pathways: vertical cooling through TEC and lateral cooling through heat sinks, allowing each segment to function independently and contribute to overall thermal management
2Device complexity
If conventional mounting is used with TEC below submount, then device complexity is low, but heat dissipation efficiency is insufficient
Solution Approach 1:
The patent adds lateral heat dissipation pathways perpendicular to the conventional vertical cooling path, creating a three-dimensional thermal management architecture that significantly improves heat removal efficiency without substantially increasing device complexity
Solution Approach 2:
The patent merges multiple cooling mechanisms (TEC active cooling and heat sink passive convection) into a unified thermal management system, combining their effects to achieve superior heat dissipation performance
3Temperature
If more directional heat dissipation pathways are added, then cooling efficiency improves, but device complexity increases
Solution Approach 1:
The submount structure is designed to serve multiple functions simultaneously: mechanical support for the diode, electrical connection pathway, and thermal conduction path to lateral heat sinks, reducing the need for separate dedicated components
Solution Approach 2:
The heat sink arrangement employs asymmetric design with heat sinks positioned on specific sides of the submount structure, optimizing thermal pathways based on the actual heat generation distribution and flow patterns rather than uniform symmetric placement
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 significantly improves thermal dissipation and optical power output while reducing total electrical energy consumption, achieving lower thermal impedance and cooler diode temperatures compared to conventional methods.
Implementation Method 1
a thermoelectric cooler (TEC) in thermal contact with the diode, wherein the diode is positioned between the diode submount structure and the TEC
Implementation Method 2
cooling the diode with a thermoelectric cooler (TEC)
Implementation Method 3
the SiPho die includes a waveguide, wherein light from the diode can exit the optical sub-assembly via the waveguide
Implementation Method 4
the underfill material is a thermally conductive and electrically insulating material
Data Source
AI summary
A method of cooling an optical sub-assembly includes operating a diode mounted to a diode submount structure and cooling the diode with a thermoelectric cooler (TEC) in thermal contact with the diode, wherein the diode is positioned between the diode submount structure and the TEC.