Youcef Ouerdane

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Laser-induced self-organization of regular nanoscale layered patterns in fused silica is investigated using spectroscopy and microscopy methods, revealing a high presence of stable broken oxygen bonds. Longitudinal traces are then generated by replicating static irradiation structures where the nanoscale modulation can cover partially or completely the(More)
We present a new structure for erbium-doped optical fibers [hole-assisted carbon-coated, (HACC)] that, combined with an appropriate choice of codopants in the core, strongly enhances their radiation tolerance. We built an erbium-doped fiber amplifier based on this HACC fiber and characterize its degradation under γ-ray doses up to 315 krad (SiO2) in the ON(More)
The use of distributed strain and temperature in optical fiber sensors based on Brillouin scattering for the monitoring of nuclear waste repository requires investigation of their performance changes under irradiation. For this purpose, we irradiated various fiber types at high gamma doses which represented the harsh environment constraints associated with(More)
Vulnerability of Optical Frequency Domain Reflectometry (OFDR) based sensors to high γ-ray doses (up to 10 MGy) is evaluated with a specific issue of a radiation-hardened temperature and strain monitoring system for nuclear industry. For this, we characterize the main radiation effects that are expected to degrade the sensor performances in such applicative(More)
We investigated the laser-energy-density dependence of absorption changes and paramagnetic centers induced by a cw Ar(+)laser operating at 5.1 eV, in both unloaded and H(2)-loaded singlemode Ge-doped optical fibers. The induced absorption is measured in the blue and near ultraviolet spectral range by using the 3.1 eV photoluminescence, ascribed to Ge lone(More)
We investigated the efficiencies of two different approaches to increase the radiation hardness of optical amplifiers through development of improved rare-earth (RE) doped optical fibers. We demonstrated the efficiency of codoping with Cerium the core of Erbium/Ytterbium doped optical fibers to improve their radiation tolerance. We compared the γ-rays(More)
We investigate the radiation effects on germanosilicate optical fiber acting as the sensing element of optical frequency domain reflectometry devices. Thanks to a new setup permitting to control temperature during irradiation, we evaluate the changes induced by 10 keV x rays on their Rayleigh response up to 1 MGy in a temperature range from -40°C up to(More)
We report a method for fabricating fiber Bragg gratings (FBG) resistant to very severe environments mixing high radiation doses (up to 3 MGy) and high temperatures (up to 230°C). Such FBGs have been written in two types of radiation resistant optical fibers (pure-silica and fluorine-doped cores) by exposures to a 800 nm femtosecond IR laser at power(More)