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Optical fiber humidity sensor based on a tapered fiber with hydroxyethylcellulose/polyvinylidenefluoride composite
Author(s) -
Lokman Asiah,
Nodehi Somayeh,
Batumalay M.,
Arof H.,
Ahmad H.,
Harun Sulaiman Wadi
Publication year - 2014
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.28091
Subject(s) - cladding (metalworking) , materials science , relative humidity , humidity , refractive index , coating , optical fiber , composite number , fiber , fiber optic sensor , moisture , composite material , optoelectronics , optics , meteorology , physics
A simple relative humidity (RH) sensor is demonstrated using a tapered fiber with an hydrogel coating. Hydroxyethylcellulose/polyvinylidenefluoride polymers are used to form the hydrogel coating of the tapered fiber as they are sensitive to moisture and thus the humidity of the atmosphere. Changes in humidity level alter the refractive index of the fiber coating and this condition leads to variation in optical output power. A difference of up to 0.89 dB of the transmitted optical power is observed when RH changes from 50 to 80%. The proposed sensor has a sensitivity of about 0.0228 dB/%RH with a slope linearity of more than 99.91%. In summary, the hydrogel coating acts as an inner cladding whose refractive index decreases with the rise in humidity and thus allows more light to be transmitted in humid state. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:380–382, 2014