Orientation-dependent optic-fiber accelerometer based on excessively tilted fiber grating

Abstract

An orientation-dependent optic-fiber accelerometer based on the excessively tilted fiber grating (ExTFG) inscribed in SM28 fiber is demonstrated, which is based on the optical power demodulation scheme. Without any complicated processing, the cladding mode resonances of the bare ExTFG show high sensitivity to slight perturbation of bending. Due to its excellent azimuthrelated bending properties, such a bare ExTFG fixed on a simple cantilever beam has exhibited strong orientationdependent vibration properties. Experiment results show that TE mode of the sensor can provide a maximal acceleration sensitivity of 74.14 mV/g @72 Hz and maximal orientation sensitivity of 9.1 mV/deg, while for TM mode, a maximal acceleration sensitivity of 57.85 mV/g @72 Hz and maximal orientation sensitivity of 7.4 mV/deg could be achieved. These unique properties would enable the sensor acts as a vector accelerometer for the applications in many vibration measurement fields.

Excessively Tilted Fiber Grating Sensors

“…In 2020, Xie et al have proposed an 81-TFG based vector accelerometer sensor [47], in which the asymmetrical structure of the grating has shown a directionally dependent bend response. Based on its high axial strain sensitivities of -2.93 and -2.31pm/ for the TE and TM cladding mode, and combined with the good orthotropic orientational bending sensitivities of the TE and TM modes, the vector accelerometer sensor exhibits strong orientation-dependent vibration properties, which also shows a "figure-8-shape" distribution for the vibration measurements at a certain frequency (Fig.…”

Low Acoustic Frequency Sensing Based on Ghost Mode of Small Angle Tilted Fiber Bragg Grating

“…For TFBGs, micro-bending is easy to cause leakage of the cladding modes and changes to their coupling efficiencies. For example taking advantages of their bending sensitivity, scholars realized accelerometers based on TFBGs with excellent performance [23][24][25]. Even mode coupling method is easy to transfer when receiving an external perturbation, these enable TFBG a high potential in the field of diaphragm based acoustic detection.…”