Envelope Extraction for Vibration Locating in Coherent Φ-OTDR
1Key Laboratory of Advanced Transducers and Intelligent Control Systems (Ministry of Education and Shanxi Province), College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China.
Sensors (Basel, Switzerland)
|February 15, 2022
Summary
This study introduces envelope extraction for phase-sensitive optical time-domain reflectometry (Φ-OTDR) systems. This method simplifies vibration locating and reduces hardware demands by lowering the required sampling rate.
Area of Science:
- Optical sensing
- Photonics
- Signal processing
Background:
- Coherent phase-sensitive optical time-domain reflectometry (Φ-OTDR) systems typically require high-frequency signal acquisition due to high central frequencies in beating signal spectra.
- High-performance hardware for signal acquisition increases system cost and complexity.
Purpose of the Study:
- To propose and validate a novel coherent Φ-OTDR system based on envelope extraction.
- To reduce the hardware requirements for signal acquisition in Φ-OTDR systems.
- To simplify the data demodulation process for vibration locating.
Main Methods:
- Development of a theoretical model for the quasi-sinusoidal amplitude-modulated beating signal between local oscillator light and Rayleigh backward scattering light.
- Utilization of an envelope detector for efficient envelope extraction of the beating signals.
- Direct application of the extracted envelope for vibration locating, bypassing conventional orthogonal demodulation.
Main Results:
- Successful implementation of envelope extraction for vibration locating in a coherent Φ-OTDR system.
- Demonstration of reduced sampling rate capability down to 10 MHz.
- Validation of the system's performance with a spatial resolution of 10 m and a sensing distance of 31 km.
Conclusions:
- Envelope extraction is a reliable and effective technique for vibration locating in coherent Φ-OTDR systems.
- The proposed method significantly reduces the necessary sampling rate, simplifying hardware requirements.
- The envelope extraction approach offers a simplified data demodulation pathway for Φ-OTDR sensing applications.
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