High total dose radiation effects on temperature sensing fiber Bragg gratings

Fiber Bragg gratings (FBG's) written in a 10 mol.% Ge-doped core silica fiber using a phase mask were exposed to gamma-radiation. The transmission and reflection spectra were recorded during irradiation up to doses in excess of I MGy. There,vas no detectable change of the Bragg peak amplitude and the grating temperature sensitivity. The radiation-induced shift of the Bragg wavelength saturated at a dose of 0.1 MGy at a level less than 25 pm, which could still be decreased by optimization of the grating parameters, Our results confirm that FBG's are good candidates for sensing applications in radiation environments.