Tapered Polymer Fiber Inclinometers

Cheng-Ling Lee,Chi-Feng Lin,Chao-Tsung Ma,Rui-Cheng Zeng,Wen-Fung Liu,Chun-Ren Yang

doi:10.1109/jphot.2020.2974796

Cheng-Ling Lee, Chi-Feng Lin + Show 4 more

Open Access

https://doi.org/10.1109/jphot.2020.2974796

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Abstract

This work proposes a novel, highly sensitive, and simple structure based on a tapered polymer as a tilt fiber sensor to sensitively measure tilt angles (θ).The fiber-optic tilt sensor consists of a tapered polymer and single-mode fibers (SMF), into which the tapered polymer to generate a bent in the sensor that is strongly correlated with θ. The used tapered polymer in the tilt sensing is the temperature (T) insensitive. It is further combined with a general fiber Bragg grating (FBG) as a temperature indicator for achieving simultaneous measurement of inclination (θ) and ambient T. The endface of the fiber is coated with a gold film to increase the light reflectivity and improve the measurement range. Experimental results show that when the sensor tilts, the reflective optical power changes significantly with high sensitivity, and the peak wavelength of FBG shifts when T varies. Both parameters can be measured simultaneously with good discrimination. An average tilt angle sensitivity of approximately 4.23 dB/deg. and a high resolution of 0.009 deg. are achieved in a θ variation from −6 to +6 deg. Simulations were performed and the numerical results were in good agreement with the experimental measurement.

Highlights

With the number and size of civil engineering projects being constructed continuing to increase, such as high-rise buildings, bridges, and dams, the use of inclinometers to detect variations in the tilt angle (θ ) within structures is significant and urgent
This work proposes a novel, highly sensitive, and simple structure based on a tapered polymer as a tilt fiber sensor to sensitively measure tilt angles (θ).The fiber-optic tilt sensor consists of a tapered polymer and single-mode fibers (SMF), into which the tapered polymer to generate a bent in the sensor that is strongly correlated with θ
This work proposes a simple fiber-optic tilt angle sensor based on a taper-shaped polymer combined with an fiber Bragg grating (FBG) as a tilt fiber sensor that can measure T simultaneously

Summary

Introduction

With the number and size of civil engineering projects being constructed continuing to increase, such as high-rise buildings, bridges, and dams, the use of inclinometers to detect variations in the tilt angle (θ ) within structures is significant and urgent. An optical fiber interferometer based on an abrupt fiber taper, cascading peanut-shaped fiber was proposed for tilt angle measurements with high sensitivity in the range of 0–6.66 deg. A taper section and lateral-offset fusion splicing fiber was proposed to achieve fiber-optic interferometric-type tilt angle sensors with high sensitivity from –5 to 5 deg. We propose a novel tapered polymer fiber tilt sensor (TPFTS) with simple structure to sensitively measure θ. This is for the first time the polymer materials of NOA series were utilized in the fibers to be found the good bonding with fiber as well as high sensitivity of tilt angle variation [14]. The results reveal that the highest sensitivity of 5.76 dB/deg. at ± 2.5 deg. by the sensor have been presented

Sensor Fabrication and Principle

Experimental Results and Discussion

Conclusion