Comparison between PMMA and PVAC coated fiber Bragg grating sensors for relative humidity measurements

摘要

The paper reports some preliminary results obtained on two polymer-coated fiber Bragg grating based humidity sensors fabricated using poly(methyl methacrylate) (PMMA) or poly(vinyl acetate) (PVAc) as sensing material. The calibration of the two sensors has been carried out in the 20 - 70 %RH range at three different temperatures (15, 30 and 45°C) using a two-pressure humidity generator. Repeatability and time response were assessed by means of multiple reversible RH step inputs. The PMMA-coated sensor prototype displayed overall much better performance when compared to the PVAc-coated one, although it manifested a somewhat higher temperature sensitivity.