Optical Sensing of Alkane and Gasoline Vapors Using Swelling Plastic Optical Fiber

Abstract

Optical fiber sensors for detecting vapor pressure of alkane and gasoline gases have been studied. The sensing mechanism is based on the swelling phenomena in the rubber-type cladding polymers. The POF-type sensor heads were prepared by coating the swelling polymer, on the plastic fiber core with slightly lower refractive index than that of the cladding polymers. When it was exposed to alkane vapor or gasoline gases, the refractive index of the cladding layer decreased by swelling and the sensor head changed its structure from leaky to guided-type. In the experiment, a large change in the light intensity through the sensor head was observed for a various kind of alkane vapors and gasoline gases with good sensitivity and reproducibility.