Open AccessSuppressing non-local effects due to Doppler frequency shifts in dynamic Brillouin fiber sensors
Author(s) -
Joseph Murray,
Brandon Redding
Publication year - 2020
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.387859
Subject(s) - brillouin scattering , brillouin zone , optics , signal (programming language) , fiber optic sensor , doppler effect , sensitivity (control systems) , materials science , noise (video) , optical fiber , acoustics , computer science , physics , electronic engineering , engineering , astronomy , artificial intelligence , image (mathematics) , programming language
Brillouin fiber sensors have traditionally been limited to low-speed or static strain measurements due to the time-consuming frequency scans required. In the past decade, a number of novel high-speed measurement techniques have been proposed to enable Brillouin-based dynamic strain sensors. In this work, we present a new mechanism, which can limit the performance of high-speed dynamic Brillouin sensors. Specifically, we show that dynamic strain induced Doppler shifts can corrupt a distributed Brillouin strain measurement by introducing non-local signals throughout the fiber. We present a model showing that these non-local signals can introduce unacceptable levels of cross-talk or even exceed the local signal strength in reasonable operating conditions and experimentally observe these signals in a standard slope-assisted BOTDA sensor. Finally, we present a modified sensor architecture to address this issue and experimentally demonstrate low-noise (2.6 nε/Hz 1/2 ), dynamic strain measurements with significantly reduced sensitivity to this type of non-local signal.