We investigated the combined effects of temperature and X-rays exposures on the nature of point defects generated in Ge-doped multimode optical fibers. Electron paramagnetic resonance (EPR) results on samples X-ray irradiated at 5 kGy(SiO2), employing different temperatures and dose rates, are reported and discussed. The data highlight the generation of the Ge(1), Ge(2), E′Ge and E′Si defects. For the Ge(1) and Ge(2), we observed a decrease in the induced defect concentrations for irradiation temperatures higher than ~450 K, whereas the E′ defects feature an opposite tendency. The comparison with previous post-irradiation thermal treatments reveals peculiar effects of the temperature increase during the irradiation. Such difference, confirmed also by online radiation-induced attenuation measurements, has to be considered for practical use of these fibers in a mixed environment. Importantly, even if post-irradiation fading should be considered, the Ge(1) and Ge(2) concentrations measured by postmortem EPR experiments in room-temperature-irradiated samples are quite representative of the concentrations induced in the temperature range 230–450 K regardless of the investigated dose rate. The enhancement of the E′ content can be related to the simultaneous generation of this defect with non-bridging oxygen hole center from strained bonds implying a relevant modification of the defects generation/formation processes in the host glass matrix.

Alessi, A., Agnello, S., Girard, S., Di Francesca, D., Reghioua, I., Marcandella, C., et al. (2017). Coupled irradiation-temperature effects on induced point defects in germanosilicate optical fibers. JOURNAL OF MATERIALS SCIENCE, 52(18), 10697-10708 [10.1007/s10853-017-1244-x].

Coupled irradiation-temperature effects on induced point defects in germanosilicate optical fibers

Alessi, A.
;
Agnello, S.;Di Francesca, D.;Cannas, M.;
2017

Abstract

We investigated the combined effects of temperature and X-rays exposures on the nature of point defects generated in Ge-doped multimode optical fibers. Electron paramagnetic resonance (EPR) results on samples X-ray irradiated at 5 kGy(SiO2), employing different temperatures and dose rates, are reported and discussed. The data highlight the generation of the Ge(1), Ge(2), E′Ge and E′Si defects. For the Ge(1) and Ge(2), we observed a decrease in the induced defect concentrations for irradiation temperatures higher than ~450 K, whereas the E′ defects feature an opposite tendency. The comparison with previous post-irradiation thermal treatments reveals peculiar effects of the temperature increase during the irradiation. Such difference, confirmed also by online radiation-induced attenuation measurements, has to be considered for practical use of these fibers in a mixed environment. Importantly, even if post-irradiation fading should be considered, the Ge(1) and Ge(2) concentrations measured by postmortem EPR experiments in room-temperature-irradiated samples are quite representative of the concentrations induced in the temperature range 230–450 K regardless of the investigated dose rate. The enhancement of the E′ content can be related to the simultaneous generation of this defect with non-bridging oxygen hole center from strained bonds implying a relevant modification of the defects generation/formation processes in the host glass matrix.
Alessi, A., Agnello, S., Girard, S., Di Francesca, D., Reghioua, I., Marcandella, C., et al. (2017). Coupled irradiation-temperature effects on induced point defects in germanosilicate optical fibers. JOURNAL OF MATERIALS SCIENCE, 52(18), 10697-10708 [10.1007/s10853-017-1244-x].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/253467
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