Intermodal interferometer for strain and temperature sensing fabricated in birefringent boron doped microstructured fiber
Intermodal interferometer for strain and temperature sensing fabricated in birefringent boron doped microstructured fiber
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Date
2011
Authors
P. Mergo
G. Statkiewicz-Barabach
Joel Pedro Carvalho
Orlando Frazão
J. Olszewski
W. Urbanczyk
José Luís Santos
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Journal ISSN
Volume Title
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Abstract
We present a compact in-line fiber interferometric sensor fabricated in a boron doped two-mode highly
birefringent microstructured fiber using a CO2 laser. The intermodal interference arises at the fiber output
due to coupling between the fundamental and the first order modes occurring at two fiber tapers
distant by a few millimeters. The visibility of intermodal interference fringes is modulated by a polarimetric
differential signal and varies in response to measurand changes. The proposed interferometer was
tested for measurements of the strain and temperature, respectively, in the range of 20-700 °C and
0-17 mstrain. The sensitivity coefficients corresponding to fringe displacement and contrast variations
are equal respectively for strain −2:51nm=mstrain and −0:0256 1=mstrain and for temperature
16:7pm=°C and 5:74 × 10−5 1=°C. This allows for simultaneous measurements of the two parameters
by interrogation of the visibility and the displacement of interference fringes.