Tapered Optical Fiber Sensor for Discrimination of Strain and Temperature

Abstract

A simple Mach-Zehnder Interferometer \n(MZI) based on a standard single-mode fiber for simultaneous \nstrain and temperature sensing was proposed \nand demonstrated experimentally. The interferometer \nwas fabricated by electrical arc discharge method \nin which a part of the standard single-mode fiber was \nheated and stretched. Any special type of fiber or a particular \nsplicer was not required to form the MZI and it \nindicated high resolution. To find the modes that contributed \nto the interference spectrum, Fourier analysis \nwas done and the spatial frequency versus normalized \nintensity plot showed that LP02 was the excited dominant \nhigher order cladding mode. Coefficient matrix \nwas realized for simultaneous measurement of strain \nand temperature ability of such an MZI. For discrete \nmeasurements, a resolution of 0:79 C and 1:18 microstrain \ncan be achieved for 10 pm wavelength resolution. \nThis extremely simple, low-cost sensor easily fabricated \nwith good repeatability is a good candidate in diverse \nsensing applications.