Sensitivity enhancement of FBG sensor for portlandite monitoring

In this paper, a cladding etched fiber Bragg grating (FBG) sensor is proposed to monitor chemicals (Ca(OH)2 and Mg(OH)2) which produces in civil structures. Further, to enhance the sensitivity, an indium tin oxide is coated on cladding etched FBG sensor. It is observed that the indium tin oxide coated sensor is highly sensitive in terms of chemical detection and inducing wavelength shift of 12 nm and 10 nm with Ca(OH)2 and Mg(OH)2 respectively. On the other hand, cladding etched FBG sensor produces a wavelength shift of 8 nm and 6 nm for Ca(OH)2 and Mg(OH)2 respectively.