Ultra-sensitive curvature sensor based on liquid crystal-infiltrated fiber interferometer

Abstract

All-fiber curvature sensors based on a liquid crystal-filled fiber Mach–Zehnder interferometer (LCF-MZI) are proposed and experimentally demonstrated for high performance measurements of very small curvatures from 0 to 0.0667 m−1, which is usually hard to be precisely monitored by well-known methods. Such a curvature sensor can be easily fabricated by splicing a section of an LC-filled hollow core fiber between two single mode fibers. Our experimental results show that the maximum curvature sensitivity of the proposed sensor is −724.3 nm/m−1 for a wavelength shift and 632 dB/m−1 for peak intensity. These results are at least 10 times better than those of previously reported fiber interferometer sensors.