Paramagnetic Germanium-related centers induced by energetic radiation in silica devices for optical transmissions.

Abstract : In the present work we investigated the creation processes of Ge-related paramagnetic point defects in silica fibers and preforms, doped with different amounts of germanium, and irradiated with various ionizing sources. Different paramagnetic defects species, like GeE', Ge(1) and Ge(2), were revealed by electron paramagnetic resonance measurements and their concentration was studied as a function of the irradiation dose. The comparison with the optical absorption spectra points out the main role of Ge(1) on the optical transmission loss of fibers in the UV region.