This paper presents a new sensor system for vibration and relative humidity measurements
based on its interaction with the evanescent field of a microwire. The interrogation of the
sensing head is carried out by monitoring the fast Fourier transform (FFT) phase of one of
the FFT peaks of the microwire transmission signal. This technique is not dependent of the
signal amplitude and also eludes the requisite of tracking the wavelength evolution in the
spectrum, which can be a handicap when there are multiple interference frequency ...This work was supported in part
by the Spanish Comisión Interministerial de Ciencia y Tecnología within
project TEC2013-47264-C2-2-R and SUDOE ECOAL-MGT and FEDER
funds from the European Union
