Vectorial distributed acoustic sensing based on a multicore fiber and phase-sensitive optical time-domain...

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Technology
• Vibration Analysis

Background:

• Distributed acoustic sensing (DAS) typically measures scalar vibrations.
• Existing methods often require specialized fiber configurations or complex algorithms for vector measurements.
• Accurate, high-resolution vector vibration sensing is crucial for various industrial applications.

Purpose of the Study:

• To propose and demonstrate a vectorial distributed acoustic sensing (vDAS) system.
• To achieve distributed two-dimensional vector vibration measurements.
• To enhance spatial resolution and suppress noise in vibration sensing.

Main Methods:

• Utilizing phase-sensitive optical time-domain reflectometry (ΦOTDR).
• Implementing an optical pulse compression (OPC) algorithm for high spatial resolution and noise suppression.
• Employing a Rayleigh-enhanced seven-core fiber (eSCF) to amplify Rayleigh backscattering (RBS) differentials.

Main Results:

• Achieved a spatial resolution of 1.1 m and strain resolution of 1.1 pε/√Hz.
• Demonstrated maximum acceleration sensitivity of 1.04 mrad/g at 60 Hz.
• Obtained an orientation reconstruction error of 1.92°.

Conclusions:

• The vDAS system enables full quantification of perturbations.
• Vectorial distributed vibration sensing is achieved without specialized fiber layouts or complex algorithms.
• The system shows significant potential for applications like vertical seismic profiling and pipeline inspection.