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Chirp-pulse pair φOTDR.

Pengbai Xu, Jinhui Lian, Zhigeng Ye

|May 1, 2025

Summary

A new chirp-pulse pair phase-sensitive optical time-domain reflectometry (CPP-φOTDR) uses adaptive filtering to enhance vibration measurements. This technique improves dynamic range and sensitivity for applications in marine science and geophysics.

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Area of Science:

Photonics and Sensing Technologies
Optical Metrology

Background:

Phase-sensitive optical time-domain reflectometry (φOTDR) is crucial for distributed sensing.
Existing φOTDR methods face trade-offs between measurement range and sensitivity.

Purpose of the Study:

To introduce a novel chirp-pulse pair phase-sensitive optical time-domain reflectometry (CPP-φOTDR) technique.
To enhance vibration measurement capabilities using adaptive filtering.

Main Methods:

Utilized a pair of chirp pulses with differing chirp rates (low and high).
Applied an adaptive filtering algorithm to process Rayleigh backscattering (RBS).
Employed receiver bandwidth of 500 MHz for signal retrieval.

Main Results:

Achieved enhanced sensitivity and extended measurement range simultaneously.
Demonstrated a 25.1 dB improvement in dynamic range with adaptive filtering.
Successfully retrieved vibrational signals using the proposed CPP-φOTDR.

Conclusions:

The CPP-φOTDR technique offers wide dynamic range and broad frequency bandwidth for vibration measurements.
This method provides a cost-effective solution without additional acquisition costs.
Potential applications include ocean monitoring in marine science and seismic wave analysis in geophysics.