Temperature insensitive bending sensor based on in-line Mach-Zehnder interferometer

Abstract

A simple and compact fiber bending sensor based on the Mach-Zehnder interferometer was proposed. A photonic crystal fiber (PCF) with a length of 10 mm was spliced by collapsing air holes with two conventional single mode fibers to consist of an all fiber bending sensor. The sensitivity of 0.53 nm/m−1 was obtained at 1586 nm for the curvature range from 0 to 8.514 m−1. The temperature sensitivity was very low. The measurement error due to the temperature effect was about 8.68×10−3 m−1/°c, and the temperature effect in the curvature measurement could be ignored. This device can avoid the cross sensitivity of the temperature in the curvature measurement.