The curvature sensor based on fiber-optic spindle arrays

Abstract

Three curvature optical fiber sensors inserted with different spindle arrays have been proposed and experimentally demonstrated. The spindle structure is fabricated by a fusion splicer after that prestress was applied to a complete single-mode-fiber (SMF) with coating peeled off, where cladding modes are excited and couple with the core mode. The experimental results show that the curvature sensitivities of these sensors are respectively 24.08 dB/m−1, 28.79 dB/m−1 and −38.40 dB/m−1. With inserted spindles in the array increasing in the same length, the curvature sensitivity is improved by 14.32 dB/m−1. In addition to the advantages of low cost and easy fabrication, the sensors have great value in improving curvature sensitivity.