PROJECT TITLE :

Long-Range Distributed Vibration Sensing Based on Phase Extraction From Phase-Sensitive OTDR

ABSTRACT:

Distributed fiber-optic vibration sensors based mostly on section-sensitive optical time-domain reflectometry ( $phi$-OTDR) have found several applications in various fields. During this paper, we tend to analyze the phase noise of $phi$-OTDR, which is the most limiting factor of the measurement vary. We have a tendency to found that the laser part noise and phase extraction error caused by the intensity noise in photodetection contribute to the full section noise. By introducing a series of auxiliary weak reflection points along the fiber, we tend to develop a phase-noise-compensated $phi$-OTDR and notice a long-vary distributed vibration sensing based mostly on the section extraction. Furthermore, a statistical analysis was proposed to take care of the vibration measurement sensitivity along the whole fiber. In the experiment, vibrations at thirty km were measured with a linear response, which confirmed the validity of our proposed system.