Open AccessEnhanced range of the dynamic strain measurement in phase-sensitive OTDR with tunable sensitivity
Author(s) -
Haijie He,
Lianshan Yan,
Heng Qian,
Xinpu Zhang,
Bin Luo,
Wei Pan
Publication year - 2019
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.378257
Subject(s) - optical time domain reflectometer , reflectometry , optics , sensitivity (control systems) , dynamic range , demodulation , materials science , wavelength , phase (matter) , high dynamic range , time domain , optical fiber , physics , fiber optic sensor , computer science , electronic engineering , polarization maintaining optical fiber , telecommunications , channel (broadcasting) , quantum mechanics , computer vision , engineering
Phase-sensitive optical time domain reflectometry (Φ-OTDR) realizes quantitative measurement of the dynamic strain employing phase demodulation. Unfortunately, it is difficult to measure the large dynamic strain with the conventional Φ-OTDR due to the restriction of the unwrapping algorithm. In this work, an approach based on two-wavelength probe is proposed and demonstrated to improve the measurable range of the dynamic strain in Φ-OTDR. By utilizing the difference between the two phases acquiring with two different lasers, the large dynamic strain can be recovered. In experiments, dynamic strains with peak values from 10.32 uɛ to 24.08 uɛ are retrieved accurately, which cannot be recovered with the conventional Φ-OTDR. Moreover, the tunable sensitivity is also demonstrated through adjusting the wavelengths of the probe. With the increment of the wavelength interval from 9.06 nm to 23.06 nm, the normalized sensitivity increases from 0.4 to 1 accordingly. That agrees well with the theoretical prediction. Foreseeably, the proposed method will extend the scope of application fields for Φ-OTDR, which requires large dynamic strain recognition.