Fiber curvature sensor based on Mach-Zehnder interferometer using up-taper cascaded long-period grating

Abstract

A novel fiber curvature sensor based on Mach–Zehnder interferometer using up-taper cascaded long-period grating is proposed. The variation of the sensor's curvature will change the phase difference of core mode and cladding mode in the sensor, and will finally induce a wavelength shift in the transmission spectrum. By monitoring the wavelength shift, a sensor for bending measurement is achieved. Experimental results show that the curvature sensitivity of the proposed sensor is as high as −12.555 nm/m−1 in the curvature range of 0.706–3.444 m−1. As the curvature increases, the dip wavelength has a blue shift. The curvature resolution of the proposed sensor is about 1.59 × 10−3 m−1. And the temperature effect is also investigated. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:246–248, 2016