Pierre François

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In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic(More)
A simple theoretical modeling of the static properties of a fiber laser that includes distributed losses and inhomogeneous pumping is presented. Closed-form expressions for both the output and the backward (at the input mirror) intensities are obtained. The model is based on an extended formulation of the Rigrod's theory. It is shown that the laser responds(More)
We present experimental evidence of antiphase dynamics in self-pulsing erbium-doped fiber lasers operating simultaneously at 1.536- and 1.55-microm wavelengths. Autonomous chaos is also observed for several ranges of pumping rates. The fractal dimension of the chaotic attractor, calculated from experimental data by use of the Procaccia method, is found to(More)
We study, both experimentally and theoretically, the threshold properties of the polarized modes in Nd(3+)-doped fiber lasers. We demonstrate the influence of the gain anisotropy induced by the pump polarization and of the loss anisotropy induced by the cavity mirror tilt. An understanding of these two phenomena reveals the microscopic anisotropies of the(More)
Collimators are used as lateral beam shaping devices in proton therapy with passive scattering beam lines. The dose contamination due to collimator scattering can be as high as 10% of the maximum dose and influences calculation of the output factor or monitor units (MU). To date, commercial treatment planning systems generally use a zero-thickness(More)
We demonstrate a switching effect between the two polarization eigenstates of a Nd-doped fiber laser when it is subjected to an optical feedback signal. Conditions for an optimization of this effect are recognized to depend on the relative orientation of the fiber eigenaxes and the polarization states of the pump and feedback beams.
Advanced 1-D models for Secondary Settling Tanks (SSTs) explicitly account for several phenomena that influence the settling process (such as hindered settling and compression settling). For each of these phenomena a valid mathematical expression needs to be selected and its parameters calibrated to obtain a model that can be used for operation and control.(More)
Wastewater regulation and treatment is still a major concern in planetary pollution management. Some pollutants, referred to as particulate matter, consist of very small particles just suspended in the water. Various techniques are used for the suspended particles survey. Few of them are able to provide real-time data. The development of new, real time(More)