Fabry-Perot Interferometric Fibre Optic Temperature Sensor with Polyvinylidene Fluoride (PVDF) Coating

摘要

A novel polyvinylidene fluoride (PVDF) coated fiber-optic Fabry–Perot interferometric (FFPI) sensor for temperaturemeasurement is proposed and experimentally validated. The sensor head consists of a PVDF thin film formed by thephase inversion process via immersion precipitation at the freshly cleaved endface of a single mode telecommunicationsoptical fibre. The resin polyvinyl butryl (butvar) was used as a cross-linker to promote good adhesion between theoptical fibre glass and PVDF in order to reduce operational coupling loss. Sensor operation is demonstrated by shifts ofthe FFPI reflection spectra and its performance was analysed through measurement of optical thickness or pathdifference with temperature variation. Experimental data shows that the thermal expansion effect of the PVDF coating ismore dominant than its thermo-optic effect. The proposed sensor exhibits an exponential response over 21 to 160 °Cinside a tube furnace with a sensitivity that spans between 1.6 nm/°C and 7.5 nm/°C.