Multi-core fiber enabled fading noise suppression in {\phi}-OFDR based quantitative distributed vibration sensing

TL;DR

This paper introduces a multi-core fiber approach to suppress fading noise in {}-OFDR, significantly improving vibration sensing sensitivity, resolution, and robustness over long distances.

Contribution

The novel use of multi-core fiber and weighted vectorial averaging effectively mitigates fading noise in {}-OFDR, enhancing its practical sensing capabilities.

Findings

Achieved 2.2 nm length precision and 2 cm sensing resolution over 500 m.

Demonstrated high sensitivity and robustness against fading noise.

Showed potential for practical applications in distributed vibration sensing.

Abstract

Coherent fading has been regarded as a critical issue in phase-sensitive optical frequency domain reflectometry ({\phi}-OFDR) based distributed fiber-optic sensing. Here, we report on an approach for fading noise suppression in {\phi}-OFDR with multi-core fiber. By exploiting the independent nature of the randomness in the distribution of reflective index in each of the cores, the drastic phase fluctuations due to the fading phenomina can be effectively alleviated by applying weighted vectorial averaging for the Rayleigh backscattering traces from each of the cores with distinct fading distributions. With the consistent linear response with respect to external excitation of interest for each of the cores, demonstration for the propsoed {\phi}-OFDR with a commercial seven-core fiber has achieved highly sensitive quantitative distributed vibration sensing with about 2.2 nm length precision and 2 cm sensing resolution along the 500 m fiber, corresponding to a range resolution factor as high as about about 4E-5. Featuring long distance, high sensitivity, high resolution, and fading robustness, this approach has shown promising potentials in various sensing techniques for a wide range of practical scenarios.