Symmetric and Asymmetric Core-Offset Mach–Zehnder Interferometer Torsion Sensors

In this letter, symmetric and asymmetric core-offset Mach-Zehnder interferometer (MZI) torsion sensors based on a single mode fiber (SMF) are presented. Here, three different MZIs were implemented and their interference patterns and torsion characteristics have been experimentally investigated. In our devices, the maximum torsion sensitivities are 6x10
^-3
, 12x10
^-3
, and 23x10
^-3
nm/°, with the possibility to discriminate between clockwise and anticlockwise rotation. Finally, these interferometers only employ SMF and can be fabricated at low cost.