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.

This study proposes and experimentally demonstrates a NOA61-polymer fiber Fizeau interferometer (PFFI) connected to a flexible NOA65-polymer taper (PT) for simultaneous measurement of tilt angle and temperature (T). The PT/PFFI fiber sensor consists of a taper-shaped flexible NOA65 polymer and single-mode fiber with an endface that is attached to a NOA61-polymer. The NOA61-polymer of PFFI is highly sensitive to variations of T with high repeatability and enables the simultaneous measurement of tilt angle by connecting with the highly flexible NOA65-PT. the interference fringe visibility of optical spectra in the PFFI can be highly controlled by the tilt angle of the PT and is thus capable of measuring tilt angles with high sensitivity. On the other hand, wavelength shifts of the spectra in the PFFI only occur when T varies. The proposed PT/PFFI can simultaneously detect the tilt state and the variation of surrounding T by measuring the optical spectral responses and eliminating cross sensitivity. Experimental results demonstrate the PT/PFFI can simultaneously measure tilt angles and T with good sensitivities and obtain averages of 0.4 dB/° and 0.17 nm/°C, respectively.