Radiation effects on fiber Bragg grating temperature sensors written in a Ge-doped core silica

We measured the Bragg wavelength shift (BWS) of a fiber Bragg grating (FBG), which was inscribed in four different commercial Ge-doped fibers exposed to gamma-radiation up to a dose of 16.3 kGy at the same Bragg wavelength and evaluated the change of full width at half maximum (FWHM) and FBG temperature sensitivity after irradiation. A radiation-induced shift of the Bragg wavelength was clearly observed during irradiation. Moreover, we confirmed that the FBG temperature sensitivity was distinctly decreased after irradiation.