Optical Fiber Acoustic Sensor with Focusing Member
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Solution Overview
Problem
Existing optical fiber acoustic sensors struggle to efficiently measure weak acoustic signals due to their simple structure, which limits their sensitivity.
Innovation Solution
The optical fiber acoustic sensor incorporates an acoustic focusing member, such as a conical or focusing antenna, where the sensing optical fiber is wound multiple times to focus external acoustic signals, enhancing the generation of Rayleigh scattered light and improving measurement sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing optical fiber is simply laid along the measurement target region, then the device complexity is low, but the measurement sensitivity is insufficient for weak acoustic signals
Solution Approach 1:
An acoustic focusing member is introduced as an intermediary component between the acoustic signal source and the sensing optical fiber. This mediator concentrates the acoustic energy onto the fiber, enabling weak acoustic signals to be detected without requiring complex sensor structures or multiple fibers.
Solution Approach 2:
The acoustic focusing member changes the spatial distribution parameter of acoustic energy by concentrating dispersed acoustic waves into a focused region where the optical fiber is positioned. This parameter change enhances the acoustic signal intensity at the measurement point, improving detection sensitivity.
2Measurement precision
If the sensing optical fiber is wound multiple times on the acoustic focusing member, then the measurement sensitivity is improved, but the device complexity increases
Solution Approach 1:
The optical fiber is wound multiple times around the acoustic focusing member, transitioning from a linear one-dimensional arrangement to a multi-turn three-dimensional configuration. This dimensional change increases the interaction length between the fiber and focused acoustic energy, enhancing measurement sensitivity.
3Measurement precision
If an acoustic focusing member is added to focus external acoustic signals, then the measurement sensitivity is significantly improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The acoustic focusing member is designed with self-focusing properties that automatically concentrate acoustic energy onto the optical fiber without requiring complex alignment mechanisms or active control systems. This self-service characteristic simplifies the manufacturing and assembly process while maintaining high measurement sensitivity.
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 configuration allows the sensing optical fiber to react more effectively to focused acoustic signals, significantly improving the measurement sensitivity of acoustic signals, including weak ones.
Implementation Method 1
at least one acoustic focusing member having the sensing optical fiber wound thereon multiple times, arranged in a measurement target region and configured to focus an external acoustic signal
Implementation Method 2
there is known an optical fiber acoustic sensor using Rayleigh scattering (DAS: Distributed Acoustic Sensor)
Data Source
AI summary
The present invention relates to an optical fiber acoustic sensor with improved acoustic signal measurement sensitivity, and includes: a light source unit that generates and outputs pulsed light; an optical circulator that outputs the pulsed light output from the light source unit and input to an input terminal through an output terminal, and outputs light incident reversely from the output terminal through a detection terminal; a sensing optical fiber connected to the output terminal of the optical circulator and installed to extend over a measurement target region; at least one acoustic focusing member having the sensing optical fiber wound thereon multiple times, arranged in a measurement target region and adapted to focus an external acoustic signal; a light detection unit that detects Rayleigh scattered light scattered in the sensing optical fiber and traveling reversely; and a signal processing unit that control generation of the pulsed light by the light source unit and measures a vibration frequency and an intensity of acoustic received through the sensing optical fiber from a signal detected by the light detection unit, based on an output time point of the pulsed light.