A High-Resolution Tilt Sensor Utilizing Grooved Arch Beam-Assisted EFPI for Large Angle Measurement

In this article, a high-resolution fiber-optic tilt sensor assisted with grooved arch beam structure for large angle measurement is demonstrated. The grooved arch beam structure serves as a tilt transducer, which is composed of an arch beam, a copper bead placed inside the grooved channel and a reflection mirror attached at the center of beam and pointed perpendicular to a fixed optical fiber endface. As such, an extrinsic Fabry-Perot interferometer (EFPI) is formed by the optical fiber endface and the mirror. After tilting, copper bead remains at the bottom of grooved arch beam, while the deflection at grooved arch beam center varies, which leads to EFPI cavity length change. Experimental results indicate that tilt measurement sensitivity and resolution are up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 0.6565~\mu $ </tex-math></inline-formula>m/Deg and 0.0172°, respectively. The tilt sensor offers a wide measurement range of 40° with temperature dependence as low as −0.00534 Deg/°C. In addition, sensor stability is experimentally studied with measurement precision of 0.0027°. With the advantages of high sensitivity and resolution, large angle measurement range, the tilt sensor is considered to be an excellent candidate for tilt angle monitoring in the field of power industry, mining, petroleum exploration, and other energy sectors.