Grooved Suspended Waveguide Ring Resonator for Broadband Acoustic Sensing
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Solution Overview
Problem
Existing electroacoustic and fiber-optic sensors face limitations in achieving high-sensitivity and broadband acoustic sensing due to electromagnetic interference, narrow bandwidth, resonance-induced ringing, and size constraints, particularly in applications like structural health monitoring and underwater acoustic sensing.
Innovation Solution
A sensitivity-enhanced broadband acoustic sensor utilizing a grooved suspended waveguide ring resonator with a specific coupling distance and micro air grooves to enhance light localization and mechanical vibration effects, allowing for high-sensitivity and broadband acoustic sensing through evanescent wave interaction and micro-cavity optical force mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional piezoelectric transducers are designed to be highly resonant to achieve required sensitivity, then sensitivity is improved, but bandwidth becomes narrow and resonance-induced ringing occurs
Solution Approach 1:
The patent utilizes mechanical vibration of the ring resonator structure in response to acoustic waves. The ring resonator is designed to vibrate mechanically when exposed to acoustic signals, converting acoustic energy into mechanical motion that can be detected optically through the evanescent wave interaction, thereby achieving high sensitivity without being limited to a narrow resonant bandwidth
Solution Approach 2:
The patent replaces conventional piezoelectric transduction with an optical detection system. Instead of using piezoelectric materials that convert mechanical vibration to electrical signals, the invention uses optical evanescent waves to detect mechanical vibrations of the ring resonator, substituting the piezoelectric mechanism with an optical detection mechanism that enables broadband operation
2Volume of moving object
If diaphragm size is decreased for miniaturization, then device size is reduced, but sensitivity decreases rapidly
Solution Approach 1:
The patent transitions from a two-dimensional diaphragm structure to a three-dimensional ring resonator structure suspended in air. This dimensional change allows the sensing element to be positioned in a different spatial configuration where acoustic waves can directly interact with the ring structure through evanescent wave coupling, maintaining sensitivity while achieving miniaturization
Solution Approach 2:
The patent changes the physical parameters of the sensing structure by creating a suspended ring resonator with specific dimensions (inner radius 50-200 μm, outer radius 100-300 μm) and material properties. By optimizing these parameters, the structure achieves high sensitivity despite the reduced size compared to conventional diaphragms
3Volume of moving object
If fiber-optic acoustic sensors use thin film or deformable material for miniaturization, then device size is reduced, but achieving high-sensitivity and broadband sensing simultaneously becomes difficult
Solution Approach 1:
The patent employs composite material structures combining silicon nitride and silicon oxide layers to form the ring resonator. This composite structure provides both mechanical flexibility for acoustic response and optical properties for evanescent wave interaction, enabling miniaturized sensors to achieve high sensitivity and broadband operation simultaneously
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 sensor achieves enhanced detection accuracy and resolution of weak acoustic signals by localizing light energy in the cavity and utilizing mechanical vibrations, maintaining broadband sensitivity without affecting frequency band, and improving sensitivity through evanescent wave and acoustic wave interaction.
Implementation Method 1
a part of the light is coupled into a ring resonator formed by the ring waveguide core layer, and is transmitted around the ring resonator
Implementation Method 2
The interaction between the evanescent wave and the acoustic wave can change the effective refractive index of the ring waveguide core layer, thereby causing a resonance frequency shift of the ring resonator
Implementation Method 3
the response of a micro-cavity to acoustic waves can be enhanced by utilizing the mechanical vibration effect generated by acoustic acting on the suspended waveguide in the ring resonator
Data Source
AI summary
Disclosed is a sensitivity-enhanced broadband acoustic sensor based on a grooved suspended waveguide ring resonator, including a lower cladding layer and an upper cladding layer. A single straight waveguide core layer and a ring waveguide core layer are arranged between the upper cladding layer and the lower cladding layer. A coupling distance is arranged between the single straight waveguide core layer and the ring waveguide core layer; the other end face of the lower cladding layer opposite to the ring waveguide core layer is arranged with a suspended waveguide air groove, and the suspended waveguide air groove is located directly below the ring waveguide core layer. In the ring resonator, the response of a micro-cavity to acoustic waves can be enhanced by utilizing the mechanical vibration effect generated by an acoustically suspended waveguide, further enhancing the sensitivity of acoustic sensing.