Distributed Vibration Sensing Based on Optical Vector Network Analysis
Year: 2024
Type: article
Abstract: We introduce a novel method for distributed vibration sensing based on extracting the time-domain Rayleigh impulse response of an optical fiber from optical vector network analysis measurements. The optical-frequency-domain transfer function of the fiber is first measured, and then inverse Fourier transformed to provide the bandpass optical time-domain impulse response. Another relevant feature of the technique is that it enables excitation demodulation using the optical frequency dependence of the Rayleigh backscatter signal from the optical fiber, the so-called Rayleigh signature. This is the simplest method to obtain fully linear quantitative measurements of local changes in the strain or temperature experienced by the fiber and it is inherently free from signal fading impairments. Furthermore, the implementation of the technique uses a simple setup based on double-sideband modulation of a laser, self-homodyne detection with an optical hybrid, and narrow-bandwidth electrical signal acquisition and processing. We present proof-of-concept experiments to demonstrate the operation of the method with the measurement of dynamic strain and temperature perturbations in a 115-m optical sensing fiber with 16-cm spatial resolution and a sensitivity of 59$\text{n}\epsilon /\sqrt{\text{Hz}}$. This sensing technique has the potential to provide high-sensitivity distributed measurements of tens-of-hertz excitations in hundreds-of-meters fibers, with centimeter spatial resolution. Therefore, it can become a valuable tool for structural health monitoring in application fields such as aerospace, marine, or civil engineering.
Source: Journal of Lightwave Technology
Authors: Alayn Loayssa, Raffaele Vallifuoco, Rizwan Zahoor, Luigi Zeni, Mikel Sagues, Aldo Minardo
Language: English
Topic: Advanced Fiber Optic Sensors
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,495
OpenAlex ID: W4403827015