Multi-Layer SiN Waveguide Optical Gyroscope Chip
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Solution Overview
Problem
Conventional fiber optical gyroscopes (FOGs) are large, expensive, and difficult to assemble due to the need for precise alignment of discrete optical components, making them challenging for volume production and integration into compact systems.
Innovation Solution
An integrated photonics optical gyroscope is fabricated on a silicon nitride (SiN) waveguide platform with a multi-layer configuration, where a first layer of SiN waveguides serves as a rotation sensing element and a second layer includes additional SiN waveguide-based optical components, allowing for hybrid integration of external elements like phase shifters and detectors, and enabling evanescent coupling between layers to minimize size and increase manufacturing scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete optical components are used to construct fiber optical gyroscopes, then measurement precision is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The patent integrates multiple discrete optical components (waveguides, phase shifters, detectors, lasers) onto a single silicon nitride chip platform. This merging eliminates the need for precise manual alignment of separate components while maintaining the interferometric measurement capability, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent transitions from a one-dimensional assembly of discrete components to a two-dimensional integrated chip layout. By arranging optical paths, phase shifters, and detectors in a planar configuration on the silicon nitride substrate, the system achieves compact integration without sacrificing measurement precision
2Measurement precision
If discrete optical components with precise alignment are used, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
By combining all optical components into a single integrated chip, the patent eliminates complex alignment procedures required for discrete components. The unified structure allows for standardized fabrication processes and simplifies assembly, directly improving ease of manufacture while preserving measurement precision
Solution Approach 2:
The patent replaces mechanical alignment of discrete components with monolithic integration on a silicon nitride chip. This substitution eliminates the need for manual positioning and mechanical adjustment, enabling scalable manufacturing through standard semiconductor fabrication techniques
3Device complexity
If multi-layer waveguide configuration is used, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes vertical layering of waveguides to achieve three-dimensional optical path routing on a two-dimensional chip. This approach reduces lateral complexity while the precise control of layer thickness and positioning during fabrication addresses manufacturing precision requirements through standardized semiconductor processes
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 multi-layer silicon nitride waveguide-based optical gyroscope achieves compactness, reduced weight, and lower production costs, facilitating mass production while maintaining high precision, essential for applications like autonomous vehicles and inertial measurement units.
Implementation Method 1
an integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first layer of silicon nitride (SiN) waveguides that constitute a rotation sensing element
Implementation Method 2
The two portions can be stacked together to have a multi-layer configuration coupled with each other
Implementation Method 3
Phase shifters can be of electro-optic materials such as lithium niobate or other polymers
Implementation Method 4
By setting up an interferometric system, one can measure the small path length difference that is proportional to the area of the enclosed loop and the angular velocity of the rotating fiber coil
Implementation Method 5
Optical gyroscopes typically have the highest performance and are based on interferometric measurements and the Sagnac effect
Data Source
AI summary
An integrated photonics optical gyroscope fabricated on a silicon nitride (SiN) waveguide platform comprises a first silicon nitride (SiN) waveguide layer that constitute a rotation sensing element; and, a second SiN waveguide layer with additional silicon nitride (SiN) waveguide-based optical components that constitute a front-end chip to launch light into and receive light from the rotation sensing element. The two SiN waveguide layers can be stacked together to have a multi-layer configuration vertically coupled with each other. External elements (e.g., laser, detectors, phase shifter) may be made of different material platform than SiN and can be hybridly integrated to the SiN waveguide platform. The phase shifters can be made of lithium niobate or other electro optic material.