Highly Sensitive Optical Fiber Curvature and Acoustic Sensor Based on Thin Core Ultralong Period Fiber Grating

A novel fiber sensor for curvature and acoustic wave measurement, which is based on a thin core ultralong period fiber grating (TC-ULPFG), has been proposed and experimentally demonstrated. By tracking the power variation of different resonant wavelength caused by TC-ULPFG, high curvature sensitivit...

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Bibliographic Details
Main Authors: Wenjun Ni, Ping Lu, Xin Fu, Shun Wang, Yuan Sun, Deming Liu, Jiangshan Zhang
Format: Article
Language:English
Published: IEEE 2017-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/7847362/
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Summary:A novel fiber sensor for curvature and acoustic wave measurement, which is based on a thin core ultralong period fiber grating (TC-ULPFG), has been proposed and experimentally demonstrated. By tracking the power variation of different resonant wavelength caused by TC-ULPFG, high curvature sensitivity of 97.77&#x00A0;dB&#x002F;m<sup>&#x2013;1</sup> is achieved, to best of our knowledge, which is the highest than other structures at the same measurement range. Thus, the desired curvature property of the TC-ULPFG is used for acoustic measurement. The polyethylene terephthalate film is selected as a transducer, on which TC-ULPFG is tightly pasted. The acoustic pressure sensitivity of 1.89&#x00A0;V&#x002F;Pa is two orders higher than other structures based on the diaphragm transducer, and the noise-limited minimum detectable pressure is 1.94 mPa&#x002F;Hz<sup>1&#x002F;2</sup> at 200&#x00A0;Hz. In addition, the frequency fluctuations are nearly &#x00B1;0.4&#x00A0;dB from 70 to 200&#x00A0;Hz and &#x00B1;0.2&#x00A0;dB from 1 to 3&#x00A0;kHz. Therefore, the proposed optical fiber acoustic sensor has a flat frequency response at a relatively lower frequency. The TC-ULPFG shows many advantages, including high sensitivities of curvature, high acoustic pressure sensitivity, easy fabrication, simple structure, and low cost.
ISSN:1943-0655