Optical Gyroscope Chip Wedge Resonator Coupling

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Solution Overview

Problem

The performance of conventional Resonant Micro-photonic Gyroscopes (RMGs) is limited by the quality factor Q of its resonator, which is often decreased due to fabrication constraints.

Innovation Solution

The development of a gyroscope chip with an integrated coupling element, featuring a ring resonator and a waveguide immovably attached to a substrate, with wedge-shaped cores to reduce electromagnetic mode losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional RMGs are made using crystalline-based whispering gallery mode resonators with external coupling elements, then the device can be made smaller and cheaper, but the quality factor Q of the resonator decreases due to fabrication constraints and coupling losses

Engineering Contradiction:

Improvequality factor QVSAvoidfabrication constraints

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the resonator and waveguide into a single integrated structure where the waveguide is formed as an extension of the resonator cavity. This integration eliminates separate coupling elements and reduces fabrication steps, thereby maintaining high quality factor while improving ease of manufacture.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the external coupling elements (prisms, tapered fibers) from the system and replaces them with an integrated waveguide structure. This removal of external components eliminates coupling losses and simplifies fabrication while preserving the resonator's high Q-factor.

Inventive Principle:

Principle #2Taking out (Extraction)

2Volume of moving object

If the resonator size is reduced to improve device compactness, then the gyroscope becomes smaller and more integrated, but the measurable angular velocity precision deteriorates

Engineering Contradiction:

Improveresonator sizeVSAvoidmeasurable angular velocity

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent changes the geometric parameters of the resonator, specifically introducing a wedge shape with a small angle (e.g., 5 degrees) at the coupling region. This parameter change optimizes the mode confinement and reduces radiation losses, allowing compact resonators to maintain high Q-factors and measurement precision.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If external coupling elements are used to couple light in and out of the resonator, then the device can be assembled with standard components, but the overall Q-factor decreases due to coupling losses

Engineering Contradiction:

Improvecomponent compatibilityVSAvoidcoupling losses

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent replaces mechanical coupling elements (prisms, fibers) with an integrated photonic waveguide structure. This substitution eliminates mechanical alignment requirements while minimizing optical coupling losses through optimized mode matching and evanescent field coupling.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 achieves high Q-factor values (greater than 10^6) and low measurable angular velocity (less than 0.2 deg/h), enhancing the precision and reliability of the gyroscope.

Implementation Method 1

a ring resonator core immovably attached to the first ring cladding layer and having a side wall, the side wall of the ring resonator core forming an obtuse angle with the upper surface of the substrate

Methodology Applied

Scientific EffectWedge shape electromagnetic mode confinement:

Implementation Method 2

Fiber optics gyroscopes (FOGs) are known to be used for sensing changes in a device's orientation based on Sagnac effect

Methodology Applied

Scientific EffectSagnac effect: Sagnac Effect

Implementation Method 3

a waveguide on the upper surface of the substrate, the waveguide comprising: a first waveguide cladding layer immovably attached to the substrate; and a waveguide core immovably attached to the first waveguide cladding layer

Methodology Applied

Scientific EffectImmovable attachment:

Data Source

PatentUS20250172750A1Chips for optical gyroscopes

Publication Date: 2025.05.29 OSCPS MOTION SENSING INC

AI summary

A chip for an optical gyroscope and an optical gyroscope including the chip. The chip includes a substrate having a substrate body with an upper surface; a waveguide on the upper surface of the substrate, the waveguide comprising a waveguide core immovably attached to the substrate; a pair of waveguide recesses formed in the substrate body and opening through the upper surface, the waveguide core being disposed between the pair of waveguide recesses; a ring resonator on the upper surface of the substrate and spaced from the waveguide, the ring resonator comprising a ring resonator core immovably attached to the substrate; and a pair of ring recesses formed in the substrate body and opening through the upper surface, the ring resonator core being disposed between the pair of ring recesses.