A miniature fiber-optic temperature sensor based on a Fabry–Perot interferometer

Abstract

A miniature fiber Fabry–Perot interferometer (FFPI) for temperature measurement is proposed and demonstrated. The sensor consists of a section of single-mode fiber (SMF) tip coated with a thin film of polyvinyl alcohol (PVA) at the end of the fiber tip. A well-defined interference pattern is obtained as the result of the FFPI based on Fresnel reflection. The sensing head is extremely sensitive to ambient temperature, and provides a stable temperature sensitivity with a maximum value up to 173.5 pm °C−1 above 80 °C. This proposed sensor has advantages of low cost, ultra-compactness, a small degree of hysteresis and high stability.