title: Strain sensor based on a pair of single-mode-multimode-single-mode fiber structures in a ratiometric power measurement scheme.
abstract: The strain and temperature dependencies of a step-index single-mode-multimode-single-mode (SMS) fiber structure are investigated numerically and experimentally. For intensity-based strain measurement using a single SMS fiber structure, at a selected wavelength, it is found that there is a high strain dependence, but also a temperature dependence that will induce strain measurement error. To minimize the temperature-induced strain measurement error, two SMS fiber structures are proposed and demonstrated in a ratiometric power measurement scheme; one SMS structure acts as the strain sensor, and the other SMS structure acts as the temperature monitor. The extracted temperature information is used to determine a strain value based on a suitable calibration of strain responses with temperature variations. It is demonstrated that for strain measurement from 0 to 1000 microepsilon within the temperature range from 10 degrees C to 40 degrees C, the proposed configuration can provide a strain and temperature resolution of 0.34 microepsilon and 0.14 degrees C, respectively, with a temperature-induced strain measurement error as low as 0.39 microepsilon.
authors.affiliation: Photonics Research Center, School of Electronic and Communications Engineering, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland. ahatta@dit.ie
authors.forename: Agus Muhamad
authors.initials: AM
authors.lastname: Hatta
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Semenova
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wu
authors.forename: Gerald
authors.initials: G
authors.lastname: Farrell