Effect of grating length on the response of fiber bragg grating bonded with graphene on polymer plate

In this work, the sensing characteristics of FBG bonded with graphene on a polymer plate are demonstrated under various mechanical deflections within the tension and compression modes. The sensing elements utilized for this purpose were 5 mm, 15 mm, 25 mm, 35 mm and 45 mm FBG sensor bonded onto the surface of graphene with polymer plate. Results showed a linear relation between the sensitivity and deflection for the FBGs bonded onto plastic and deflected at stress locations of 1 cm and 2 cm. However, for the stress location of 3 cm and for the FBGs bonded onto graphene with plastic, the response curves were deviated from being linear. The sensitivity at 3 cm stress location for tension and compression modes was found to be larger than those for other applied stress locations. Besides, a linear relationship between the sensitivity and deflection was observed for the 5 mm, 15 mm, 25 mm and 35 mm grating lengths. It was found that the FBG sensitivity was increased upon the increment of grating length. Noticeably, the sensitivity and deflection correlation for the 45 mm FBG was found to be sinusoidal, by which a very sensitive sensor can be produced for environmental monitoring and alarm system applications.