Abstract: An optical cable is manufactured in a single continuous process starting directly from at least an optical preform, by means of a fiber/cable integrated manufacturing line including a fiber(s) drawing assembly for the production of one or more optical fibers from respective optical preforms, and a cabling assembly for producing the optical cable from the optical fiber(s), the cabling assembly comprising a fiber buffering assembly for the application of a loose or tight coating to the optical fiber(s), and a strengthening and sheathing sub-assembly for applying one or more reinforcing and protective layers to the buffered optical fiber(s).

Abstract: An optical cable is manufactured in a single continuous process starting directly from at least an optical perform, by means of a fiber/cable integrated manufacturing line (50) including a fiber(s) drawing assembly (100) for the production of one or more optical fibers from respective optical preforms, and a cabling assembly (200) for producing the optical cable from the optical fiber(s), the cabling assembly comprising a fiber buffering assembly (200a) for the application of a loose or tight coating to the optical fiber(s), and a strengthening and sheathing sub-assembly (200b) for applying one or more reinforcing and protective layers to the buffered optical fiber(s).

Abstract: An optical fiber having: a) a glass portion; and b) at least one protective coating layer disposed to surround the glass portion, the protective coating layer having a modulus of elasticity value between ?40° C. and +60° C. between 5 MPa and 600 MPa, preferably not higher than 500 MPa, more preferably not higher than 450 MPa and much more preferably not higher than 300. Preferably the protective coating layer is a single protective coating layer which is disposed in contact with the glass portion.

Abstract: Optical fiber capable of controlling attenuation losses caused by microbending on the signal transmitted thereby. The optical fiber comprises: a) an internal glass portion; b) a first coating layer of a first polymeric material surrounding said glass portion; and c) a second coating layer of a second polymeric material surrounding said first coating layer, wherein said first polymeric material has a hardening temperature lower than ?10° C., an equilibrium tensile modulus lower than 1.5 MPa, wherein said first coating layer has a thickness of from 18 ?m to 28 ?m and wherein said second coating layer has a thickness of from 10 ?m to 20 ?m.

Abstract: An apparatus for producing a low-PMD optical fiber having a furnace for melting a lower portion of an optical preform; a traction device for pulling an optical fiber from the lower portion of an optical preform; a spinning device for imparting a substantially constant and unidirectional spin to the optical fiber as it is pulled, which causes the fiber to undergo an elastic torsion; a winding device for winding the optical fiber onto a reel; and a twisting device for imparting to the spun optical fiber a unidirectional twist in a direction opposite the elastic torsion, so as to control the residual twist in the optical fiber. A process for producing the fiber, an optical fiber and a cable are also provided.

Abstract: Optical fiber having a glass portion; at least one protective coating of thermoplastic material having at least one thermoplastic elastomer; the thermoplastic material having the following characteristics: a modulus of elasticity value at +25° C. lower than 150 MPa, preferably at least 10 Mpa, more preferably higher than 20 Mpa, and a Vicat point higher than 85° C., preferably higher than 120° C., more preferably lower than 350° C. Preferably, the coating is a single protective coating directly positioned onto the glass portion.

Abstract: An optical fiber having an internal glass portion, a first coating layer surrounding the glass portion and a second coating layer surrounding the first coating layer. The first coating layer is formed from a cured polymeric material obtained by curing a radiation curable composition having a radiation curable oligomer having a backbone derived from polypropylene glycol and a dimer acid based polyester polyol. The cured polymeric material has: (a) a hardening temperature (Th) from ?10° C. to about ?20° C. and a modulus measured at the Th lower than 5.0 MPa; or (b) a hardening temperature (Th) from ?20° C. to about ?30° C. and a modulus measured at the Th lower than 20.0 MPa; or (c) a hardening temperature (Th) lower than about ?30° C. and a modulus measured at the Th lower than 70.0 MPa.

Abstract: A method and device for vaporizing a liquid reactant. A vaporizing plate having a top surface defines a liquid flow channel, the channel being laterally delimited by edges having a height greater than a minimum thickness of liquid reactant required to generate vapor under film or nucleate boiling regime. A heating system is associated to the vaporizing plate for heating the liquid reactant over a minimum temperature required to generate vapor under nucleate or, preferably, film boiling regime. A cap covers the vaporizing plate to collect the vapor at a predetermined pressure and provided with a vapor exit and a liquid feeder feeds the liquid reactant onto the vaporizing plate.

Abstract: The present invention relates to a radiation curable coating composition comprising a radiation curable oligomer comprising a backbone derived from polypropylene glycol and a dimer acid based polyester polyol, wherein said coating composition, when cured, is having: a) a hardening temperature (Th) of from ?10° C. to about ?20° C. and a modulus measured at said Th of lower than 5.0 MPa; or b) a hardening temperature (Th) of from ?20° C. to about ?30° C. and a modulus measured at said Th of lower than 20.0 MPa; or c) a hardening temperature (Th) of lower than about ?30° C. and a modulus measured at said Th of lower than 70.0 MPa.

Abstract: A method for controlling attenuation losses caused by microbending on the signal transmitted by an optical fiber having an internal glass portion. A first coating layer of a first polymeric material surrounds the glass portion and a second coating layer of a second polymeric material surrounds the first coating layer. The first polymeric material has a hardening temperature lower than 10° and an equilibrium modulus lower than 1.5 MPa.

Abstract: A network for distributing signals to a plurality of user having a distribution unit and a plurality of optical cables adapted to make the distribution unit communicate with the plurality of user equipment. In turn, each optical cable has an optical fibre having a core, a cladding and a predetermined simple refractive index profile ?n(r). Each optical fibre is adapted to guarantee a single-mode propagation at higher wavelengths than about 1260 nm and a few-mode propagation at about 850 nm, and each optical fibre has such refractive index profile ?n(r) as to guarantee macro-bending losses at 1550 nm that are less than about 0.5 dB and an intermodal delay ?? at 850 nm that is less than or equal to, about 1 ns/Km.

Abstract: In a process for manufacturing a micro-structured optical fibre, an intermediate preform is made by forming a sol; pouring the sol in a cylindrical mould including a set of structural generating elements defining internal structural elements of the intermediate preform; transforming the sol into a gel so as to obtain a cylindrical gel body defining the intermediate preform; and removing the cylindrical intermediate preform from the mould.

Abstract: A network for distributing signals to a plurality of user equipment having a distribution unit and a plurality of optical cables adapted to make the distribution unit communicate with the plurality of user equipment. In turn, each optical cable has an optical fibre having a core, a cladding and a predetermined simple refractive index profile &Dgr;n(r). Each optical fibre is adapted to guarantee a single-mode propagation at higher wavelengths than about 1260 nm and a few-mode propagation at about 850 nm, and each optical fibre has such refractive index profile &Dgr;n(r) as to guarantee macro-bending losses at 1550 nm that are less than about 0.5 dB and an intermodal delay &Dgr;&tgr; at 850 nm that is less than or equal to, about 1 ns/Km.

Abstract: In producing a preform for an optical fiber by MCVD technology, involving the buildup of a core matrix of doped silica layers inside a glass tube with subsequent thermal collapse of the structure, a layer of dopant is deposited on the inner surface of the finished core matrix before the collapse. The thickness of this dopant layer, which advantageously is in a colloidal state, progressively diminishes along the tube axis in a direction away from an end of the tube at which the collapse begins. The law of thickness variation is chosen to maintain an internal gas pressure of vaporized dopant equal to the vapor pressure of the dopant in the core material at the collapsing temperature, in order to prevent the appearance of a paraxial dip in the refractive-index profile of an optical fiber subsequently drawn from the collapsed preform.

Abstract: In order to prevent an uncontrolled collapse of a quartz tube whose inner surface is being coated with a vitrifiable substance in making a preform or parison of an optical fiber, one or more streams of carrier gas entraining the ingredients of the coating substance through the quartz tube are supplemented by a stream of supplemental carrier gas whose flow is being continuously controlled to keep the overall mass-flow rate substantially constant. The outer tube diameter is photoelectrically monitored and incipient changes thereof are compensated by controlling a flow of additional carrier or inert gas which does not pass through the tube but joins the traversing gas flow at the tube outlet, inside a solids separator with a restricted exit aperture, to modify the pressure differential across the tube wall.

Abstract: The method allows the production of silica and dopant with reactions among gaseous chemical compounds. The optical fibers produced do not present dip and exhibit low attenuation. Carbon dioxide is used as the oxidizer and organometallic aluminum compounds are used to obtain the dopant; silica is obtained from organometallic silicon compounds or silicon tetrachloride.

Abstract: The method of surfacing the heater of a furnace for optical fiber drawing allows elimination of defects in the inner heater surface, which defects give rise to particle emission towards the preform. This is achieved by depositing a thin layer of a mixture of oxides compatible with the material composing the heater.

Abstract: The process for manufacturing halide glasses uses a reaction between organometallic and inter-halide or halide-derived compounds, started at a temperature ranging from the highest melting temperature and the lowest boiling temperature of the compounds used.

Abstract: The method allows surface defect reduction in silica optical-fibres by enriching the external layer by silica bonded carbon atoms within the silica network: SiC.SiO.sub.2. Carbon is obtained from chemical reaction directly during the drawing step.Volume defects are reduced by rapidly cooling the fibre structure heated up to vitrous transition temperature.The apparatus allows the method to be carried out during drawing step.

Abstract: The method uses a raw-material and dopant-deposition technique, which requires vapor-state reactants and thermal sources for producing a temperature gradient suited to obtain a circularly and radially varying refractive-index profile in the supporting tube.