Characteristics of fiber grating sensors and their relation to manufacturing techniques

This work examines the effects of different manufacturing techniques of fiber optic intracore Bragg gratings on their sensing and system parameters. Specifically, we have looked at tolerance with respect to center wavelength, strain, and temperature sensitivity. Our test results indicate a slight variation in the strain and temperature sensitivity of different gratings. In an attempt to quantify the effect of transverse loading on fiber gratings, three differently manufactured sensors were diametrically loaded and their spectrums studied. Our experimental results indicate a splitting of the grating spectrum with small loads for an optical fiber grating manufactured in either boron doped fiber or hydrogen loaded fibers. On the other hand, very small transverse sensitivity was observed for a fiber optic grating formed in a bend insensitive fiber suggesting some degree of control on the transverse sensitivity of these sensors.