Multilayer Waveguide Optical Gyroscope with Vertical Separation
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Solution Overview
Problem
Conventional Fiber Optic Gyroscopes (FOGs) face limitations in size, cost, reliability, and performance due to their complex architecture, numerous components, and susceptibility to temperature and mechanical gradients, which affect accuracy and stability.
Innovation Solution
A multilayer waveguide optical gyroscope with non-intersecting, spiraling coils vertically separated to reduce optical cross-coupling, integrated with a lithium niobate phase modulator chip and other components on a substrate, enabling a compact design with improved reliability and reduced polarization errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional FOG architecture with long fiber optic coils is used, then measurement precision is improved, but volume of stationary object increases
Solution Approach 1:
The patent transitions from planar fiber optic coils to three-dimensional waveguide structures with vertical layering. Multiple waveguide layers are stacked vertically with controlled spacing, allowing the optical path to extend in the vertical dimension while maintaining a compact horizontal footprint. This enables long effective optical paths necessary for high accuracy without requiring large device volume.
Solution Approach 2:
The patent implements nested waveguide structures where multiple waveguide layers are positioned within each other vertically. The waveguides are arranged in a compact stacked configuration with successive layers nested at different heights, maximizing the optical path length within a minimal volume envelope while maintaining structural integrity.
2Measurement precision
If conventional FOG architecture with multiple discrete components is used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple discrete FOG components into an integrated waveguide structure. The source, modulator, beam splitters, mirrors, and detector are combined into a single monolithic waveguide circuit where light propagates through integrated waveguide paths. This consolidation maintains the functional complexity needed for high accuracy measurement while eliminating the mechanical complexity of assembling and aligning multiple separate components.
Solution Approach 2:
The waveguide structure performs multiple functions simultaneously: it guides light, provides polarization control, implements beam splitting and combining, and enables phase modulation all through integrated waveguide elements. A single waveguide layer can serve multiple optical functions, reducing the total component count while maintaining measurement precision.
3Measurement precision
If conventional FOG architecture is used, then measurement precision is improved, but reliability decreases
Solution Approach 1:
By merging all optical components into a single integrated waveguide structure, the patent eliminates the numerous interfaces, splices, and mechanical connections present in conventional FOGs. Each waveguide is a monolithic structure with no moving parts or assembly points, dramatically reducing potential failure locations while preserving the optical path length necessary for high accuracy.
4Measurement precision
If conventional FOG architecture with fiber optic coils is used, then measurement precision is improved, but ease of manufacture decreases
Solution Approach 1:
The patent replaces the mechanical fiber optic coil winding process with a planar waveguide fabrication process. Instead of manually or mechanically winding meters of fiber optic cable into complex quadrupole patterns, the optical paths are defined by lithographically patterned waveguides that can be manufactured using standard semiconductor fabrication techniques, dramatically simplifying the manufacturing process and reducing packaging costs.
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 multilayer waveguide optical gyroscope achieves a higher coil density in a smaller volume, enhances reliability, and improves bias performance by eliminating channel crossovers and intrinsic polarization preserving waveguides, while reducing production costs and size constraints.
Implementation Method 1
The operation of a FOG is based on the Sagnac effect which produces a phase shift between the clockwise and counter clockwise propagating optical beams in a fiber ring interferometer.
Implementation Method 2
a phase modulator of the light propagating in the two beams that is accomplished by applying a voltage to the waveguides fabricated in the lithium niobate optical chip
Data Source
AI summary
A waveguide optical gyroscope includes a multilayer waveguide rotation sensor fabricated on a substrate. The multilayer waveguide rotation sensor includes one or more overlaying non-intersecting, spiraling coils that are vertically separated to reduce or eliminate optical cross coupling. The waveguides are optically coupled by a vertical waveguide and are optically coupled to the other components of the optical gyroscope, including a light source and detector, which may be integrated or fabricated on the substrate. A lithium niobate phase modulator chip may be disposed on the substrate and optically coupled to the waveguides in the multilayer waveguide rotation sensor. The multilayer waveguide rotation sensor enables a small cross section for the guiding channels thereby achieving a high coil density in a small volume.