Brigitte Boulard

Infrared to visible conversion in rare-earth-doped planar waveguides

The first observation of optical properties of new rare-earth-doped vitreous fluoride waveguides has been recently reported. These vitreous fluoride films have been deposited by a physical vapour deposition technique on fluoride substrates. Several PZG films and sandwiches deposited on various substrates have been prepared with thickness of a few μm and doped in the guiding layer by various amounts of erbium and other rare-earth ions. High δn/n (10−2) has been achieved as a result of the glass compositions. Infrared as well as green and blue upconversion pumped fluorescences have been recorded under side light injection.

Er3+ activated silica-hafnia glass-ceramics planar waveguides

Silica-hafnia glass-ceramics waveguides activated by Er3+ ions were fabricated by sol-gel route. X ray diffraction and optical spectroscopy showed that after an adapted heat treatment, the resulting materials showed a crystalline environment. Analysis of the luminescence properties has demonstrated that erbium ions are, at least partially, trapped in a crystalline phase. Losses measurements at different wavelength highlight a very low attenuation coefficient indicating that this nanostructured material is suitable for a single band waveguide amplifier in the C band of telecommunication.

Vapour-phase deposition of rare-earth-doped PZG glasses

Abstract Physical vapour deposition has been used in transition metal fluoride glasses (TMFG) systems to prepare fluoride glass films doped with various active ions (3d transition or rare-earth). Active planar waveguides have been realized with PZG doped films on flat ZBLAN or CaF 2 substrates.

Rare earth–activated glass-ceramic in planar format

Rare earth-activated glass-ceramic waveguides constitute a potential significant system to behave as an effective optical medium for light propagation and luminescence enhancement. We present a review on fabrication and optical, structural, and spectroscopic characterization of some kind of rare earth activated oxide glass-ceramic waveguides, obtained by sol-gel route with both bottom-up and top-down approaches, and fluoride glass-ceramic waveguides fabricated by physical vapor deposition.

Raman spectroscopy vibrational analysis of octahedrally coordinated fluorides: Application to transition metal fluoride glasses

Abstract An extensive Raman investigation of octahedrally coordinated single-crystal fluorides have been performed. The theoretical study of these phases, using group theory, gives the evidence of close relationship between metal oxidation number, connection schemes, and spectra features. The results of this study, when applied to the case of transition metal fluoride glasses, propose these glasses to be built up with octahedral entities predominantly linked by corners to form one-dimensional networks.

Physical vapour deposition of rare-earth fluorides

Abstract A systematic study of evaporation for single or binary mixtures of rare earth (RE) fluorides (LaF 3 , PrF 3 , NdF 3 , GdF 3 ErF 3 and YbF 3 ) has been performed. Single RE fluorides follow the physical evaporation laws, while for binary RE fluoride mixtures the role of crystal chemistry on the evaporation behaviour has been shown.

Viscosity matching of new PbF2-InF3-GaF3 based fluoride glasses and ZBLAN for high NA optical fiber

New multicomponent PbF2–InF3–GaF3 bulk glasses have been investigated. They show lower phonon energy (540 cm−1) in comparison with 580 cm−1 for ZBLAN. Large PbF2 concentration provided glasses with high refractive index up to 1.582 and the viscosity curves revealed an excellent thermal compatibility with ZBLAYN glass. A multimode fiber with a numerical aperture of 0.51, a loss of 0.85 dB/m at 1.3 μm was fabricated using the rotational casting method.

Improvement of Mach–Zehnder interferometry technique for third-order susceptibility measurement

Abstract We present in this paper an improved method to measure the third-order nonlinearity of poor optical quality samples. The principle is based on a pump/probe experiment using a Mach–Zehnder interferometer coupled to a CCD camera. The method first consists of recording the interference pattern in absence of pump beam thus allowing to characterize the linear properties of the sample. This acquisition is then compared to the interference pattern when the pump beam generates a nonlinear dephasing. From these data we can extract the nonlinear index coefficient. Therefore poor optical quality samples can be characterized because either inhomogeneities or surface defects induce linear amplitude or phase variations.

Optical investigation of fluoride glass planar waveguides made by vapour phase deposition

Abstract Fluoride glass waveguides fabricated by vapour phase deposition have been investigated. The refractive indices have been measured using the M-line technique. Birefringence is detected, probably originating from stress developed at the layer-substrate interface. The quality of the core-cladding interface has been inspected by phase stepping microscopy; the thickness of the layers and roughness of the interfaces have also been measured.

K2AlF5 · H2O: Location of hydrogen atoms by X-ray diffraction and Raman spectroscopy study

Abstract The complete structural determination of K 2 AlF 5 · H 2 O is achieved by X-ray diffraction on a single crystal. As previously described, the cell is orthorhombic ( Cmcm , a = 9.200(3), b = 8.119(4), c = 7.486(3) A, Z = 4). The structure is essentially characterized by very slightly kinked chains of AlF 6 octahedra, sharing opposite corners, running in the [001] direction. Hydrogen atoms are located by difference Fourier synthesis on 8f positions; their introduction in the structural model improved the final results significantly ( R = 0.0383, R w = 0.0283). The OH … F hydrogen bonding system is discussed with the help of Raman spectroscopy.