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SNR improvement in time-expanded phase-sensitive OTDR using Nyquist zone averaging
Optics Letters
|January 16, 2025
Summary
This study introduces a new post-processing method for time-expanded phase-sensitive optical time-domain reflectometry (TE Φ-OTDR). The technique enhances signal-to-noise ratio (SNR) by averaging multiple Nyquist zones, improving distributed sensing capabilities.
Area of Science:
- Optoelectronics
- Distributed Sensing
- Signal Processing
Background:
- Time-expanded phase-sensitive optical time-domain reflectometry (TE Φ-OTDR) offers centimeter-scale resolution and MHz RF detection bandwidth.
- Current TE Φ-OTDR methods extract fiber response from the first Nyquist zone (NZ).
Purpose of the Study:
- To propose a novel post-processing strategy for TE Φ-OTDR to improve signal-to-noise ratio (SNR).
- To enhance the performance of distributed sensing systems without compromising spatial resolution or acoustic sampling.
Main Methods:
- A post-processing technique involving spectral averaging across multiple Nyquist zones (NZs) was developed.
- The proposed method was evaluated by analyzing 200 NZs.
Main Results:
- The spectral averaging strategy significantly improved the average SNR of TE Φ-OTDR traces by 23.56 dB.
- The enhancement in SNR was achieved without any degradation in acoustic sampling or spatial resolution.
Conclusions:
- The proposed post-processing method effectively enhances SNR in TE Φ-OTDR systems.
- This advancement offers a more robust and sensitive distributed sensing solution for various applications.
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