Fiber Mach-Zehnder interferometer based on multi-mode fiber and up-taper for curvature sensing applications

A novel curvature sensor comprize a section of multi-mode fiber and a up-taper is proposed and demonstrated experimentally. The whole fabrication process is quite simple and the sensor head is cost effective. Measurement results show that it has a maximum curvature sensitivity of -61.877nm/m-1 at 1.1718m-1 and -9.2115nm/m-1 from 1.1718m-1 to 1.6583m-1. Temperature sensitivity of 89.01 pm/°C within the range of 20~80 °C has also been achieved, which implies the possibility for measurement of temperature. High sensitivity and low-cost make it a preferable candidate for curvature sensing in practical applications.