Bend and refractive index sensing based on the tuning fork fiber

A fiber-optic based on the tuning fork structure is investigated for bend and refractive index (RI). The new bend/RI sensor based on the tuning fork structure is ease of fabrication, low cost, and simple signal acquisition. The operation principle relies on the power coupling of two cores inputted into light simultaneously. The beam-propagation method (BPM) is employed for modeling the propagation of light along the optical fiber sensing device proposed. The simulation results show that it exhibits very high sensitivity, accuracy and wide dynamic range in making curvature and RI measurements. The bending sensitivity is about 0.01184 W/m−1 at curvatures ranging from 0 to 50 m−1, the RI sensitivity is about −1.5557, −22.3031 and −102.44878 W/RIU at refractive indexes ranging from 1.33-1.418, 1.418-1.45 and 1.45-1.456, respectively.