Abstract:
Des matériaux composites sont réalisés par dépôt de verre de fluorures en phase liquide ou vapeur sur des substrats généralement métalliques, préchauffés au voisinage de la température de ramolissement du verre. Ce dépôt est effectué par immersion, par coulage, par projection du verre fondu, par fusion de la poudre de verre, ou par évaporation sous vide. L'invention s'applique aux verres spéciaux à faible viscosité et principalement aux verres de fluorures. Les matériaux composites sont utilisables en génie chimique et en électronique.
Abstract:
Microstructured optical fibre is fabricated using extrusion. The main design of optical fibre has a core suspended in an outer wall by a plurality of struts. A specially designed extruder die is used which comprises a central feed channel, flow diversion channels arranged to divert material radially outwards into a welding chamber formed within the die, a core forming conduit arranged to receive material by direct onward passage from the central feed channel, and a nozzle having an outer part in flow communication with the welding chamber and an inner part in flow communication with the core forming conduit, to respectively define an outer wall and core of the preform. With this design a relatively thick outer wall can be combined with thin struts (to ensure extinction of the optical mode field) and a core of any desired diameter or other thickness dimension in the case of non-circular cores. As well as glass, the extrusion process is suitable for use with polymers. The microstructured optical fibre is considered to have many potential device applications, in particular for non-linear devices, lasers and amplifiers.
Abstract:
High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.
Abstract:
Fluoride glass optical fibres are fabricated by minimizing the number of high-temperature operations. A tube comprising an external layer of a first fluoride glass of composition suitable to form the cladding of the fibre and an internal layer of a second fluoride glass of composition suitable to form the core of the fibre is prepared from a melt by a conventional rotational casting technique. Then, the internal layer is thinned by means of chemical etching at ambient temperature until the attainment of a ratio between the volumes of the two layers that corresponds to the ratio between the core and cladding diameters required for a single mode fibre, and the resulting tube is drawn.
Abstract:
Process for the vapour-phase deposition of a fluoride glass on a substrate. The fluoride glass has the following composition (in mole %, the total being 100%): 30-50 PbF2, 30-50 GaF3, 0-30 ZnF2, 1-5 MF2 (M = Mn, Cd), 1-5 InF3, 0-10 AlF3, 0-10 additive. This process is characterised in that said substrate is contacted with the vapours generated by a molten bath of metallic flurides including a receiving bath with the following composition (in mole %, the total being 100%): 9-26 YF3, 19-28 BaF2, 35-40 InF3, 18-25 M'F2 (M' = Mn, Cd, Zn), 0-10 additive, and further comprising, in the relative proportions indicated above, the other ingredients of the fluoride glass to be deposited. The invention also relates to the vitreous compound deposited on a substrate thus obtained, which can be used as a waveguide in the infrared range.
Abstract:
La présente invention concerne un procédé de fabrication d'une pièce cylindrique, notamment en verre fluoré, caractérisé par le fait que :
- l'on met en oeuvre une cavité cylindrique verticale (1) tapissée de membranes poreuses (2,3), dont les dimensions internes sont supérieures de quelques dizaines de microns à celles de la pièce, et dans laquelle est susceptible de coulisser un piédestal cylindrique (5) constituant un support pour la pièce, - on prévoit sur le piédestal (5) une souche (101) originelle constituée du verre, - on chauffe la souche (101) jusqu'à la fusion et on injecte un gaz en permanence dans les membranes poreuses (2,3) pour maintenir entre elles et la souche (101) en fusion une couche de gaz de quelques dizaines de microns d'épaisseur évitant ainsi tout contact, - on alimente la souche (101) à l'état fondu par le haut de la cavité (1) par une distribution (30) continue d'une poudre des constituants du verre, - on descend (50) le piédestal (5) au fur et à mesure de la formation de la pièce à partir de la souche (101).
Abstract:
Provided is a process for preparing a homogenous fluoride glass containing high purity BaF₂ through the CVD process characterized in that the used gaseous mixture comprising: a barium β-diketonate complex serving as a first starting material and represented by the following general formula (1) of: wherein R is an alkyl group having 1 to 7 carbon atoms, R′ is a substituted alkyl group having fluorine atoms substituting hydrogen atoms and represented by C n F 2n+1 where n is an integer of from 1 to 3; and a gaseous or vaporizable compound of the matallic element constituting said fluoride glass, the gaseous or vaporizable compound serving as a second starting material; and a fluorine-containing gas serving as fluorinating agent. Further provided is a process for preparing a preform for a fluoride optical fiber which is low in trasmission loss, by depositing the fluoride glass over the interior wall of a cylindrical tube or the wall of rod-like glass substrate through the CVD process followed by collapsing.