Micro-Raman investigation of X or γ irradiated Ge doped fibers

Micro-Raman spectra have been recorded on Ge doped optical fibers before and after 10 keV-X or γ-ray irradiation up to doses of 1 MGy (X-ray) or 7.8 MGy (γ-ray). Our data provide evidence that, at such dose levels, the glass matrix is not modified in a detectable way. We observed that varying the Ge doping levels from 0 to about 11 wt.%, X or γ radiation sensitivity of the overall matrix remains unchanged. Such results are observed for fibers obtained with drawing conditions within the usual range used for the fabrication of specialty fibers as radiation-tolerant waveguides. Our data support the potentiality of fiber-based sensors using glass properties, e.g. Raman scattering, for applications in harsh environments as those encountered in nuclear power plants.