Micrometer Wire Assisted Inline Mach–Zehnder Interferometric Curvature Sensor

A highly sensitive curvature sensor based on the inline Mach-Zehnder interferometer (MZI) adjoined with a micrometer wire taper is realized using all single mode fiber (SMF). Experimental results suggest that the addition of the SMF micrometer wire with MZI reduces the period of the interference pattern from 39.27 to 1.76 nm and increases the amplitude sensitivity by twofold. The sensitivity of the proposed sensor is -11.92 dB/m^-1 and has a resolution of 8.4×10-5 m-1 in the curvature range of 0-1 m^-1. The sensing setup is highly stable and shows negligible hysteresis. The proposed sensor shows the negligible temperature sensitivity less than 0.0008 dB/°C. All the SMF structure and intensity-based interrogation method makes the sensor an economical alternative to the existing curvature sensors.