Combined Temperature and Photobleaching Effects on P-Doped Optical Fibers

In this paper, we investigate the combined effects of temperature and photobleaching (PB) on multimode phosphorus-doped (P-doped) optical fibers (OFs) response under irradiation. To achieve this purpose, we investigate the kinetics of the radiation-induced attenuation (RIA) in the visible spectral range (450–800 nm) under X-ray irradiation up to 5Gy(SiO₂) with a dose rate of 10 mGy(SiO₂)/s, varying the temperature of irradiation from −80°C to +80°C. This study is part of a recent series of investigations on the regeneration of these radiation-sensitive optical fibers after they have served as dosimeters. The spectral range investigated allows us to study absorbing defects such as the metastable and stable phosphorus oxygen hole centers (POHC) and the P2 point defects. Our data suggests that thermally-assisted bleaching has an impact during and after irradiation on the RIA. It is clear that thermal bleaching is relevant, especially for wavelengths below 580 nm; its contribution remains minor compared to that of the PB by 408 nm laser. Furthermore, thermal bleaching appears to be negligible for wavelengths above 580 nm. This work provides further understanding of the combined temperature and photobleaching effects on the regeneration of transmission capability of P-doped fiber dosimeters in the visible range.