Low-temperature crosstalk and surrounding refractive index insensitive vector bending sensor based on hole-assistant dual-core fiber

摘要

A low-temperature crosstalk and surrounding refractive index insensitive vector bending sensor based on resonance coupling is proposed and experimentally demonstrated. The sensor is constructed by directly sandwich-splicing a segment of single eccentric hole-assisted dual-core fiber between two single-mode fibers. The transmission characteristics of the sensor are theoretically analyzed by combining coupled-mode theory and full-vector finite-element method. The bending responses of the sensor are experimentally measured in the curvature range of 0-3.6651 m(-1). The bending sensitivities are-15.95 nm/m(-1) and 14.87 nm/m(-1) at 0 degrees and 180 degrees bending orientation, respectively, which are higher than that of most long-period fiber-grating-based and interferometer-based vector bending sensors. Moreover, the temperature and surrounding refractive index responses of the sensor are investigated. The measured results show that the proposed sensor has a low temperature sensitivity of 21.7 pm/degrees C in the range of 15 degrees C-55 degrees C and is insensitive to the surrounding refractive index in the range of 1.335-1.425, which reduces the cross-sensitivity from temperature and surrounding refractive index. (C) 2019 Optical Society of America