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A Random-displacement Measurement by Combining a Magnetic Scale and Two Fiber Bragg Gratings
Published on: September 30, 2019
Interrogation technique for a fiber Bragg grating sensing array based on a Sagnac interferometer and an acousto-optic
Bin Zhou1, Zuguang Guan, Chunsheng Yan
1Centre for Optical and Electromagnetic Research, State Key Laboratory for Modern Optical Instrumentation, Zhejiang University, Hangzhou, China.
Optics Letters
|November 4, 2008
Summary
This study introduces a new real-time method for interrogating fiber Bragg grating (FBG) sensors using a frequency-shifted Sagnac interferometer. The technique enables cost-effective environmental monitoring with FBG sensors.
Area of Science:
- Optoelectronics
- Fiber optic sensing technology
- Interferometry
Background:
- Fiber Bragg grating (FBG) sensors are widely used for various sensing applications.
- Existing interrogation techniques can be complex or costly.
- Real-time monitoring is crucial for many dynamic environmental sensing scenarios.
Purpose of the Study:
- To develop and demonstrate a novel, low-cost, real-time interrogation technique for FBG sensing systems.
- To utilize a frequency-shifted asymmetric Sagnac interferometer for enhanced FBG sensing.
- To enable accurate measurement of environmental variations impacting FBG sensors.
Main Methods:
- A frequency-shifted asymmetric Sagnac interferometer was designed and implemented.
- Fiber Bragg grating sensors were integrated into the Sagnac loop via an optical coupler.
- An acousto-optic modulator (AOM) was asymmetrically placed within the loop.
- Linear sweeping of the AOM's driving frequency allowed for spectral analysis of interference signals.
Main Results:
- The proposed technique successfully demonstrated real-time interrogation of FBG sensors.
- The system accurately determined environmental variations by analyzing the spectrum of interference signals.
- Experimental validation confirmed the feasibility of the frequency-shifted asymmetric Sagnac interferometer approach.
Conclusions:
- The developed FBG interrogation technique offers a cost-effective and real-time sensing solution.
- The frequency-shifted asymmetric Sagnac interferometer provides a robust platform for FBG-based environmental monitoring.
- This method advances the capabilities of fiber optic sensing systems.
