Ultraviolet optical properties of silica controlled by hydrogen trapping at Ge-related defects

International audienceWe studied the effects induced by the ultraviolet-laser and -lamp exposure sequences on the twofold coordinated germanium (=Ge··) and the H(II) center (=Ge·-H) in silica. The H(II) centers, generated after the first laser irradiation stage by the trapping of atomic hydrogen H0 at the (=Ge··), are destroyed by the subsequent lamp exposure with efficiency depending on photon energy. The H(II) photodestruction is activated from ~4 eV, and its cross section is here quantitatively measured, so giving the absorption profile of this center. Consistent with the observed correlated recovering of (=Ge··), the photodestruction is mainly due to the photolysis of the G-H bond leading to hydrogen detrapping

Ultraviolet optical properties of silica controlled by hydrogen trapping at Ge-related defects

International audienceWe studied the effects induced by the ultraviolet-laser and -lamp exposure sequences on the twofold coordinated germanium (=Ge··) and the H(II) center (=Ge·-H) in silica. The H(II) centers, generated after the first laser irradiation stage by the trapping of atomic hydrogen H0 at the (=Ge··), are destroyed by the subsequent lamp exposure with efficiency depending on photon energy. The H(II) photodestruction is activated from ~4 eV, and its cross section is here quantitatively measured, so giving the absorption profile of this center. Consistent with the observed correlated recovering of (=Ge··), the photodestruction is mainly due to the photolysis of the G-H bond leading to hydrogen detrapping

Optical and photonic material hardness for energetic environments

We studied the effects of dielectric change in the chemical composition and in the realization procedures under radiation exposure. We have compared the radiation effects on Ge-doped and F-doped fibers and preforms: the first play a crucial role in the photosensitivity property, the second improves the dielectric radiation hardness even at low concentrations. The use of different spectroscopic techniques (RIA, OA, EPR) allow the identification of the point defect formation mechanisms at the origin of the optical degradation properties

Optical and photonic material hardness for energetic environments

We studied the effects of dielectric change in the chemical composition and in the realization procedures under radiation exposure. We have compared the radiation effects on Ge-doped and F-doped fibers and preforms: the first play a crucial role in the photosensitivity property, the second improves the dielectric radiation hardness even at low concentrations. The use of different spectroscopic techniques (RIA, OA, EPR) allow the identification of the point defect formation mechanisms at the origin of the optical degradation properties

Radiation-Induced Defects in Fluorine-doped Silica-Based Optical Fibers: Influence of the H2-Loading

International audienceWe investigated the effects of 10-keV X-ray radiation on the transmission properties of F-doped optical fibers in the 200-850 nm range of wavelengths (1.5 – 6 eV). The influence of a H2-loading of the fiber on its radiation sensitivity is also presented

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

International audienceIn 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

Radiation-Induced Defects in Fluorine-doped Silica-Based Optical Fibers: Influence of the H2-Loading

International audienceWe investigated the effects of 10-keV X-ray radiation on the transmission properties of F-doped optical fibers in the 200-850 nm range of wavelengths (1.5 – 6 eV). The influence of a H2-loading of the fiber on its radiation sensitivity is also presented

Photoluminescence properties of point defects in Ge-doped fibers and preforms

International audienceThe optical properties of Ge-related point defects are often the most important parameter for the performances of silica based optical fibers. On one side their presence is often detrimental for the light transmission, on the other side some defect typologies exhibit modifications under radiation exposure thus offering the peculiar property of photosensitivity that is exploited to build technologically relevant devices such as fiber Bragg gratings