Open AccessBrillouin optical time-domain analyzer based on orthogonally-polarized four-tone probe wave
Author(s) -
Xiaobin Hong,
Wenqiao Lin,
Zhisheng Yang,
Sheng Wang,
Jian Wu
Publication year - 2016
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.24.021046
Subject(s) - optics , spectrum analyzer , optical fiber , distortion (music) , physics , brillouin scattering , fiber optic sensor , materials science , acoustics , optoelectronics , amplifier , cmos
The tolerance of the non-local effect in the BOTDA method using a dual-tone probe wave with fixed frequency separation is theoretically and experimentally investigated in this paper. The presented analysis points out that when the sensing fiber consists of two long fiber segments with large BFS difference (> 100 MHz), there will always be only one probe tone interacting with the pump pulse in the front fiber segment. Therefore, although the pulse distortion problem can still be overcome in this case, the conventional non-local effect would impose systematic error on the estimated BFS of the hotspot located at the end of the front fiber segment. For the purpose of avoiding the impact of non-local effect and eliminating the pump distortion problem simultaneously when using high probe power, a novel method based on a four-tone probe wave is proposed, in which the probe light consists of two pairs of orthogonally-polarized dual-tone probe waves with opposite frequency scanning direction. The experimental results demonstrate that the proposed method is capable of realizing 2 m spatial resolution over 104-km-long sensing fiber without the impact of non-local effect.