Combined Temperature Radiation Effects and Influence of Drawing Conditions on Phosphorous-Doped Optical Fibers

This work focuses on the effects of high dose ionizing radiation, up to 10 MGy(SiO₂), on P-doped multimode optical fibers (OF) at different irradiation temperatures. The investigation is based on two complementary experimental techniques: radiation-induced attenuation (RIA) measurements and electron paramagnetic resonance (EPR). The latter technique allows measuring the P1, P2, metastable-POHC and stable-POHC defects. Three OF samples are drawn from the same preform to evaluate the influence of changing their drawing conditions of the OFs on the radiation responses. This first study is performed under X-rays at room temperature. The results are compared with the ones of γ-rays irradiation. The latter allows to highlight a linear correlation between the NIR absorption band at 1.6 µm and the EPR signal of P1 defects, which supports D. Griscom's assignment of this absorption band to the P1 defect. The combined effect of ionizing radiation and irradiation temperature is also investigated extensively: online RIA measurements as well as post-mortem EPR measurements for irradiation temperatures ranging from 25 to 280 °C and doses up to 3 MGy are performed. Both RIA and EPR data show that increasing the irradiation temperature can lead to an increased production of point defects and associated absorption bands. This result is of great importance for the employment of P-doped OFs in radiation environment.