High Sensitivity Hollow-Core Fiber Strain Sensor Based on Signal Processing Assisted Vernier Effect

A fiber strain sensor with improved sensitivity is proposed and experimentally demonstrated, based on a single Fabry-Perot interferometer (FPI) using a signal processing assisted Vernier effect. The FPI structure is simply fabricated by splicing a segment of hollow-core fiber (HCF) between two piece...

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Bibliographic Details
Published in:IEEE photonics technology letters 2022-10, Vol.34 (19), p.1050-1053
Main Authors: Zhang, Fan, Qi, Beibei, Su, Baijin, Xu, Ou, Qin, Yuwen
Format: Article
Language:English
Subjects:
Capacitive sensors
Data processing
Fabry–Perot interferometer
fiber optics sensors
Interference
Interferometers
Optical fiber sensors
Optical interferometry
Sagnac interferometers
Sensitivity
Sensitivity enhancement
Sensors
Signal processing
Spectra
Splicing
Strain
Strain sensor
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Summary:A fiber strain sensor with improved sensitivity is proposed and experimentally demonstrated, based on a single Fabry-Perot interferometer (FPI) using a signal processing assisted Vernier effect. The FPI structure is simply fabricated by splicing a segment of hollow-core fiber (HCF) between two pieces of single-mode fiber (SMF) with a commercial fusion splicer. Through data processing, we do not need to precisely manufacture two interferometers with very small detuning between their optical path differences (OPDs), as in the traditional schemes based on Vernier effect, since it is difficult to control the detuning strictly. The optical spectra of the reference interferometer (RIM) are replaced by an artificial reference spectrum (ARS), which is produced by spatial frequency down-conversion of the interference spectra of the sensing interferometer (SIM) in the initial state. Then, the optical spectrum envelope of Vernier-effect can be obtained by multiplying the SIM intensity with the constructed ARS intensity. When the length of HCF is 1201\mu \text{m} , the sensitivity can reach 315pm/ \mu \varepsilon with the modulation length of 5 \mu m. Compared with the sensitivity without signal processing, the sensitivity magnification is 188.6 times. The proposed scheme to realize sensitivity-enhancement using a single FPI based on the HCF, could simplify the sensor structure and device fabrication.
ISSN:1041-1135
1941-0174
DOI:10.1109/LPT.2022.3199576