Tapered Plastic Optical Fiber Coated With HEC/PVDF for Measurement of Relative Humidity
Document Type
Article
Publication Date
7-3-2013
Abstract
A simple humidity sensor is proposed and demonstrated using a tapered plastic optical fiber (POF) as a probe. Its operation is based on intensity modulation technique using a tapered POF probe coated with a polymer blend of hydroxyethylcellulose/polyvinylidenefluoride (HEC/PVDF) composite that acts as the humidity sensitive cladding. The sensor is fabricated using an etching method and has a waist diameter of 0.45 mm and tapering length of 10 mm. As the relative humidity varies from 50% to 85%, the output voltage of the sensor increases linearly from 0.32 to 1.25 mV. The HEC/PVDF composite-coated sensor exhibits a sensitivity of 0.023 mV/% with a slope linearity of . The sensitivity of HEC/PVDF composite-coated cladding toward humidity stems from its ability to swell as humidity increases in the atmosphere resulting in a drop in its refractive index below that of the core and thus allowing more light to be transmitted through the tapered fiber.
Keywords
Fiber optic sensor, Tapered plastic optical fiber, Humidity sensor, Relative humidity (RH), Hydroxyethylcellu- lose/polyvinylidenefluoride (HEC/PVDF)
Divisions
fac_eng
Publication Title
IEEE Sensors Journal
Volume
13
Issue
12
Publisher
Institute of Electrical and Electronics Engineers (IEEE)