Ultra-low sampling resolution technique for heterodyne phase-OTDR based distributed acoustic sensing

Area of Science:

• Photonics and Optical Sensing
• Signal Processing

Background:

• Phase-sensitive optical time-domain reflectometry (Φ-OTDR) using heterodyne detection offers high signal-to-noise ratio (SNR) and a simple setup.
• However, the substantial raw data generated by Φ-OTDR poses challenges for storage and data transfer.

Purpose of the Study:

• To address the data storage burden in heterodyne Φ-OTDR systems.
• To propose and validate an ultra-low sampling resolution technique for data reduction.

Main Methods:

• Implementation of an ultra-low sampling resolution (1-bit) data acquisition technique.
• Demodulation of optical phase variations from reduced-resolution raw data.
• Experimental validation of the proposed technique in a heterodyne Φ-OTDR system.

Main Results:

• Successful demodulation of optical phase variations caused by external vibrations from 1-bit resolution data.
• Achieved a high vibration signal-to-noise ratio (SNR) of 58.03 dB.
• Demonstrated that extremely low sampling resolution data acquisition devices are adequate for heterodyne Φ-OTDR.

Conclusions:

• The proposed ultra-low sampling resolution technique effectively solves the data storage problem in heterodyne Φ-OTDR.
• This method enables significant cost reduction for Φ-OTDR systems by allowing the use of less demanding data acquisition hardware.
• High-performance vibration sensing is achievable even with highly compressed data.