Open AccessDynamic strain measurement with kHz-level repetition rate and centimeter-level spatial resolution based on Brillouin optical correlation domain analysis
Author(s) -
Bin Wang,
Xinyu Fan,
Yuanxiu Fu,
Zuyuan He
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.006916
Subject(s) - optics , brillouin zone , brillouin scattering , image resolution , frequency domain , amplifier , physics , domain analysis , time domain , spatial frequency , materials science , optical fiber , computer science , optoelectronics , cmos , computer vision , software construction , software , software system , programming language
In this paper, we propose and demonstrate an ultrahigh-speed Brillouin optical correlation domain analysis (BOCDA) with a single-position sampling rate of 200 kS/s and a spatial resolution of 8 cm. The Brillouin gain spectrum (BGS) is obtained by using a data subtraction scheme rather than the conventional lock-in amplifier (LIA) detection configuration, thus removing the limitation of measurement speed imposed by the LIA. Meanwhile, a voltage controlled oscillator (VCO) is used to sweep the frequency interval between the pump and the probe rapidly. As a proof of concept, we implement measurements of various dynamic strains with frequencies up to 20 kHz at arbitrary position. Moreover, to implement high-speed distributed measurements of Brillouin frequency shift (BFS) along the whole fiber under test (FUT), we propose a novel measuring method which moves the correlation peak and sweeps the pump-probe frequency interval simultaneously. A repetition rate of 1 kHz is verified by measuring dynamic strains with frequencies up to 200 Hz, for distributed measurements performed with 200 points.