Tapered Polymer Fiber Inclinometers

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.

A Temperature Independent Inclinometer Based on a Tapered Fiber Bragg Grating in a Fiber Ring Laser

“…q is the attenuation coefficient of the Gaussian curve in Equation (3). According to Equation (3), θ can be easily determined as follows [18]: FRL sensor to regulate the polarization state. 1% port of output coupler is used to extract the light to OSA or optical power meter from the ring cavity for further analysis.…”

“…q is the attenuation coefficient of the Gaussian curve in Equation (3). According to Equation (3), θ can be easily determined as follows [18]: When the inclinometer bends, the reflection attenuates strongly at the waist of the tFBG. The bend leaks the laser intensity.…”

“…q is the attenuation coefficient of the Gaussian curve in Equation (3). According to Equation (3), θ can be easily determined as follows [18]:…”

“…The bend leaks the laser intensity. The relationship between normalized reflectance coefficient (H) and β can be simply expressed as follows [ 18 ]: …”

“…Liu et al reported a tapered polymer fiber used as an inclinometer to measure tilt angles [ 18 ]. The detection sensitivity is as high as 4.23 dB/°.…”