Directional torsion and temperature discrimination based on a multicore fiber with a helical structure

We propose and experimentally demonstrate a directional torsion sensor based on a Mach-Zehnder interferometer formed in a multicore fiber (MCF) with a similar to 570-mu m-long helical structure (HS). The HS was fabricated into the MCF by simply pre-twisting and then heating with a CO2 laser splicing system. This device shows the capability of directional torsion measurement from -17.094 rad/m to 15.669 rad/m with the sensitivity of similar to 0.118 nm/(rad/m). Moreover, since the multiple interferences respond differently to torsion and temperature simultaneously, the temperature cross-sensitivity of the proposed sensor can be eliminated effectively. Besides, the sensor owns other merits such as easy fabrication and good mechanical robustness. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement