Integrated Photonics Optical Gyroscope for Autonomous Vehicles
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Solution Overview
Problem
Existing optical gyroscopes, such as fiber optical gyroscopes, are large, expensive, and difficult to assemble due to the need for precise alignment of discrete optical components, making them unsuitable for mass production and integration into autonomous vehicles.
Innovation Solution
The development of small-footprint integrated optical gyroscopes based on silicon photonics or compound semiconductors, which utilize a front-end chip with integrated photonics to launch and receive light from a rotation sensing element, such as a fiber loop or waveguide chip, to measure angular velocity with high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fiber optical gyroscopes are used to achieve high measurement precision, then angular velocity measurement accuracy is improved, but device size and cost increase significantly
Solution Approach 1:
The patent merges multiple discrete optical components (light source, modulator, beam splitter, detectors) into a single integrated photonic chip. This integration maintains the interferometric measurement capability for high precision angular velocity sensing while dramatically reducing the device footprint from large-scale fiber optic coils to a compact chip-scale platform.
Solution Approach 2:
The patent replaces traditional mechanical gyroscopes with an optical-based integrated photonic gyroscope. This substitution eliminates moving parts while achieving superior measurement precision, and further replaces discrete optical components with integrated photonic circuits to reduce size.
2Measurement precision
If fiber optical gyroscopes are used to achieve high measurement precision, then angular velocity measurement accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple discrete optical components into a single integrated photonic chip, enabling mass production through standard semiconductor fabrication processes. This integration eliminates the need for precise manual alignment of discrete components, significantly reducing manufacturing cost while maintaining high measurement precision.
Solution Approach 2:
The patent transitions from discrete optical components requiring manual alignment to integrated photonic circuits fabricated using standard semiconductor processes. This parameter change in the manufacturing approach enables volume production at lower cost while preserving the interferometric measurement capability.
3Measurement precision
If fiber optical gyroscopes are used to achieve high measurement precision, then angular velocity measurement accuracy is improved, but assembly difficulty increases
Solution Approach 1:
The patent merges all optical components onto a single photonic chip, eliminating the need for complex assembly and precise alignment of discrete components. The integrated chip can be directly mounted on a circuit board, dramatically simplifying the assembly process while maintaining high measurement precision through the preserved interferometric measurement principle.
4Ease of manufacture
If mechanical gyroscopes are used to reduce cost, then manufacturing cost decreases, but measurement precision and reliability deteriorate
Solution Approach 1:
The patent replaces mechanical gyroscopes with an integrated photonic gyroscope that uses optical interferometry based on the Sagnac effect. This substitution eliminates moving parts, improving reliability and measurement precision while achieving cost reduction through integration and mass production capability.
Solution Approach 2:
The patent integrates all optical components onto a single chip, creating a compact, reliable device with no moving parts. This integration maintains high measurement precision through the interferometric measurement principle while enabling mass production at lower cost compared to traditional fiber optical gyroscopes.
5Ease of manufacture
If mechanical gyroscopes are used to reduce cost, then manufacturing cost decreases, but reliability under vibration and temperature variation worsens
Solution Approach 1:
The patent replaces mechanical gyroscopes with an integrated photonic gyroscope that has no moving parts. This substitution fundamentally improves reliability by eliminating mechanical components that are susceptible to vibration and temperature effects, while the integrated photonic structure provides inherent environmental stability.
Solution Approach 2:
The patent integrates all optical components onto a single chip, creating a compact system with no moving parts. This integration improves reliability by eliminating mechanical assemblies that are vulnerable to vibration and temperature variation, while the photonic integration provides structural stability against environmental disturbances.
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
These integrated optical gyroscopes achieve bias stability below 0.5°/Hr and Angle Random Walk (ARW) in the range of 0.05°/√Hr or below, comparable to fiber optical gyroscopes but at a significantly lower cost, making them suitable for mass market applications in autonomous vehicles.
Implementation Method 1
Optical gyroscopes typically have the highest performance and rely on interferometric measurements based on the Sagnac effect (a phenomenon encountered in interferometry that is elicited by rotation)
Implementation Method 2
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 coil
Data Source
AI summary
Novel small-footprint integrated photonics optical gyroscopes disclosed herein can provide ARW in the range of 0.05°/√Hr or below (e.g. as low as 0.02°/√Hr), which makes them comparable to fiber optic gyroscopes (FOGs) in terms of performance, at a much lower cost. The low bias stability value in the integrated photonics optical gyroscope corresponds to a low bias estimation error (in the range of 1.5°/Hr or even lower) that is crucial for safety-critical applications, such as calculating heading for autonomous vehicles, drones, aircrafts etc. The integrated photonics optical gyroscopes may be co-packaged with mechanical gyroscopes into a hybrid inertial measurement unit (IMU) to provide high-precision angular measurement for one or more axes.