Thermal Isolation Element for Silicon Photonics
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Solution Overview
Problem
Thermal phase shifters in photonic integrated circuits are less energy efficient and slower to react due to thermal impedances, leading to fragile devices and increased complexity when efforts are made to improve energy efficiency or reaction time.
Innovation Solution
The fabrication of silicon photonic devices with thermal isolation elements, where a trench is formed on a photonic platform or substrate to create an airtight cavity filled with a predefined atmosphere, enhancing thermal impedance without making the devices brittle, allowing for localized control of thermal impedances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If thermal isolation elements are added to improve energy efficiency and reaction time, then thermal impedance is improved, but device complexity and fragility increase
Solution Approach 1:
The patent applies local quality by creating trenches only in specific regions where thermal isolation is needed, rather than uniformly across the entire device. This allows thermal impedance to be locally optimized in hotspots while maintaining structural integrity and minimizing added complexity in other regions.
Solution Approach 2:
The thermal isolation structure is segmented into discrete trenches rather than a continuous barrier. This segmentation provides thermal isolation where needed while maintaining mechanical continuity and reducing the overall complexity compared to a complete thermal barrier approach.
2Speed
If thermal isolation elements are added to improve reaction time, then thermal impedance is improved, but device fragility increases
Solution Approach 1:
Trenches are created only in regions where rapid thermal response is critical, such as near phase shifters or modulators. This localized approach improves reaction time in functional areas while avoiding the creation of fragile structures across the entire device substrate.
Solution Approach 2:
The trenches act as intermediary thermal isolation elements that mediate between the heat-generating components and the substrate. This intermediate structure provides thermal management without requiring direct modification of the substrate itself, thereby reducing fragility.
3Loss of energy
If thermal impedance is increased to improve energy efficiency, then energy consumption is reduced, but thermal management complexity increases
Solution Approach 1:
The patent implements thermal isolation with local quality by positioning trenches specifically around high-energy-consumption components. This allows energy efficiency to be improved where needed without creating a complex thermal management system across the entire device.
Solution Approach 2:
The trench structure provides self-service thermal management by passively isolating heat sources through its geometric configuration. The trenches themselves create the thermal isolation effect without requiring active control mechanisms, reducing thermal management complexity.
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
The solution results in mechanically stable and robust photonic integrated circuits with improved thermal impedance, enabling fine-tuned control of thermal properties for applications like wavelength division multiplexing and optical RF filtering, while maintaining device stability.
Implementation Method 1
bonding the first surface of the photonic platform to a second surface of a substrate to define an airtight cavity with the trench and the substrate, wherein the airtight cavity contains a predefined atmosphere at a predefined pressure
Data Source
AI summary
Thermal isolation elements are provided in wafer-bonded silicon photonics that include a photonic platform, including a heating element and an optical waveguide that are disposed between a first surface and a second surface (opposite to the first surface) of the photonic platform; a substrate, including a third surface and a fourth surface (opposite to the third surface); wherein the first surface of the photonic platform is bonded to the third surface of the substrate; and wherein a cavity is defined by a trench in one or more of: the first surface and extending towards, but not reaching, the second surface, and the third surface and extending towards, but not reaching, the fourth surface; wherein the cavity is filled with a gas of a known composition at a predefined pressure; and wherein the cavity is aligned with the optical waveguide and the heating element.