TÉCNICA DE INTERROGAÇÃO DE SENSORES ÓPTICOS BASEADOS EM LPGS POR ANÁLISE HARMÔNICA

This paper presents the development of the interrogation technique for fiber optic sensors based on Long Period Gratings (LPG). The technique is based on a simple and robust mathematical model in which the equations of the harmonic components of the electrical signal consider the variation in the width of the absorption spectrum of the LPG when interrogating different substances. The validation of the technique is based on experimental results on the measurements of the refractive index, when considering this variation in spectral absorption width.