Abstract: A process for making a non-zero dispersion shifted optical fiber having low splice loss and low attenuation and to an optical fiber produced by this process. A reduction of the splice loss is observed with decreasing drawing tension. The optical fiber has a core region that includes three segments and an inner cladding segment, each having a maximum refractive index percent difference, ?deltai %, i=0-3, the subscript i referring to a particular refractive index, the core segments being selected such that ?delta0%>?delta2%>?delta1%?0 and ?delta2%>?delta3%?0. Optical fibers exhibiting low splice loss were drawn at tensions not larger than 150 g, preferably not larger than 100 g.

Abstract: The present invention relates to a method as well as to a joint assembly (12) for splicing a first and a second eclectic cable (1, 2) by means of a tubular elastic sleeve (15) at a splicing zone (11) between such cables (1, 2), said tubular sleeve (15) being supported in an expanded condition on a removable hollow supporting element (16) detachable in a first supporting portion (17) and a second supporting portion (18).

Abstract: An induction furnace capable of drawing large diameter preforms of up to 130 mm is described. The induction furnace has top and bottom chimneys surrounding the entire preform during operation of the furnace with an inert conditioning gas which is introduced into the top chimney and flows downward through the furnace body and bottom chimney without significant turbulence. A distributor ring inside the top chimney redirects flow from a circumferential direction to a downward direction. The top chimney also includes a resilient seal to releasably hold the top of the preform. The bottom chimney has a smoothly decreasing cross-sectional area preventing turbulence at the furnace exit. The furnace insulation is preferably a rigid self-supporting graphite cylinder. A method of drawing large diameter preforms either to an optical fiber or to a preform of smaller diameter using such a furnace is also described.

Abstract: A process for manufacturing a multipolar cable having at least one pair of cores, each core having at least one conductive element and at least one layer of electrical insulation in a position which is radially external to the at least one conductive element. The process includes the steps of: a) assembling the at least one pair of cores so as to form an assembled element having a plurality of interstitial zones between the cores, and b) depositing by co-extrusion an expandable polymeric material in a position which is radially external to the cores so as to fill the interstitial zone and to form a filling layer of substantially circular transverse cross section, and at least one containment layer of polymeric material in a position radially external to the filling layer. The multipolar cable obtained from the process.

Abstract: A process for manufacturing a cable which includes a conductor; an inner semiconductive layer surrounding the conductor and having a thickness lower than or equal to 0.4 mm; and an insulating layer surrounding the inner semiconductive layer.

Abstract: A method and plant for the introduction of a liquid into a molten mass under pressure. Such a method and plant are particularly, but not exclusively, suitable for the formation of a coating layer on a cable element having at least one conductor, the layer having an extruded thermoplastic polymer forming a continuous phase incorporating a dielectric liquid, and are useful, for example, in the production of an electric cable for the transportation and/or distribution of electrical power. The method includes the steps of bringing the liquid to a predetermined pressure greater than the pressure of the molten mass; feeding the liquid into a plurality of storage tanks, and injecting the liquid into the molten mass at an injection pressure equal to the above-mentioned predetermined pressure by means of a plurality of injectors in respective fluid communication with the plurality of storage tanks.

Abstract: Optical cable having at least one tubular element of polymeric material and at least one transmission element housed within said tubular element. The polymeric material is made from a polymeric composition having (a) at least one olefin polymer; (b) at least one inorganic filler; and (c) at least one olefin polymer including at least one functional group. The at least one olefin polymer including at least one functional group (c) is present in the polymeric composition in an amount of about 3 parts by weight to about 10 parts by weight, preferably about 5 parts by weight to about 8 parts by weight, with respect to 100 parts by weight of the olefin polymer (a).

Abstract: An intermediate preform is formed in a process of manufacturing an optical fibre by forming a sol containing a glass precursor; pouring the sol in a mold containing a set of elongate elements; aging the sol to obtain a gel body; removing the set of elongate elements from the gel body to create a corresponding set of holes in the gel body; and removing the gel body from the mold. The method further provides imparting a motion of the set of elongate elements during aging of the sol to avoid adhesion of the gel to the elongate elements, the motion being preferably a rotation about the respective axes or an alternate translation along the respective axes. An apparatus with means for carrying out the method is also described.

Abstract: A method for producing a cable including at least one transmissive element, for example, an element transmitting electrical energy or optionally optical signals as well, and an expanded and cross-linked coating layer in a radially outer position with respect to the at least one transmissive element, the coating layer having a composition including an expandable and cross-linkable polymeric material. The method includes a) extruding the composition; b) forming a coating layer made of expandable and cross-linkable polymeric material with the composition thus extruded; c) expanding the coating layer made of expandable and cross-linkable polymeric material; and d) cross-linking the coating layer made of expandable and cross-linkable polymeric material. The expanding and cross-linking steps c) and d) are carried out by heating the coating layer made of expandable and cross-linkable polymeric material at atmospheric pressure by means of a suitable heating fluid.

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 method of evaluating the Polarization Mode Dispersion (PMD) of an optical fiber by arranging the optical fiber at substantially zero tension on a surface, propagating prescribed evaluation optical signals along the optical fiber, measuring fiber Differential Group Delay (DGD) values in response to the evaluation optical signals, repeating at least once the acts of propagating and measuring, each time preliminarily inducing a change in a mode coupling of the fiber, and determining the fiber PMD on the basis of a calculated DGD average value. Changes in the polarization mode coupling of the fiber are induced by, moving at least a section of the fiber substantially orthogonally to the surface.

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: A process for producing a cable, such as, for medium-tension or high-tension power transmission or distribution, having at least one coating layer made of a thermoplastic polymer material. The process includes at least the following steps: (a) extruding a thermoplastic material of at least one thermoplastic polymer and at least one dielectric liquid; (b) passing the thermoplastic material through at least one static mixer; and (c) depositing and shaping the thermoplastic material around a conductor belonging to the cable so as to obtain a layer of thermoplastic coating on the conductor.

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: A process for manufacturing a water-resistant telecommunication cable. The cable has a solid and compact element having a water-soluble polymer material having vinyl alcohol/vinyl acetate copolymer having a hydrolysis degree of 60-95% and a polymerisation degree higher than 1,800 and at least one solid low-melting and one solid high melting plasticizers. The process produces continuously the water-soluble polymer material by separately feeding, in sequence, a multi-screw extruder, in the flow direction, with the copolymer and the high melting plasticizer melting and mixing them while transporting them through the extruder, and with the low melting plasticizer, melting and mixing them with the copolymer and the high melting plasticizer, subsequently homogenizing the copolymer and the plasticizers and finally discharging the melt, at a temperature lower than or equal to 205° C. A process for extruding the above PVA based water-soluble polymer material.

Abstract: A telecommunication fiber optic cable for gas pipeline application has a built-in leakage detecting device. The cable has an optical core including a number of telecommunication optical fibers, an outer jacket covering the optical core, and one or more gas leakage detector optical fibers. One or more gas leakage detector optical fibers are enclosed within the outer jacket. Preferably, the cable has a linearly extending rod reinforcing system having strength rods that force the cable to bend in a preferential bending place. Preferably, the leakage detector optical fibers are located at, or close to, a plane that is substantially orthogonal to the preferential bending plane and passing through the cable neutral axis.

Abstract: A cable including at least one core having at least one transmissive element and at least one coating layer made from a coating material, wherein the coating material has at least a first polyethylene having a density not higher than 0.940 g/cm3, preferably not lower than 0.910 g/cm3, more preferably 0.915 g/cm3 to 0.938 g/cm3, and a Melt Flow Index (MFI), measured at 190° C. with a load of 2.16 Kg according to ASTM D1238-00 standard, of 0.05 g/10? to 2 g/10?, preferably 0.1 g/10? to 1 g/10?; the first polyethylene being obtained from a waste material; at least a second polyethylene having a density higher than 0.940 g/cm3, preferably not higher than 0.970 g/cm3, more preferably 0.942 g/cm3 to 0.965 g/cm3. Preferably, the coating layer is a cable external layer having a protective function.

Abstract: A process for manufacturing an elastomeric sleeve of a joint for electrical cables. The sleeve has an electric field-control element, an electrical insulating element surrounding the electric field-control element, and at least a semiconductive element having two stress control screens. The process includes providing the electric field-control element and the two stress control screens on a supporting element; introducing the supporting element into a mold provided for molding the electrical insulating element; filling with the electrical insulating material the space radially external to the electric field-control element and the stress control screens, the step of filling being carried out during the step of introducing; curing the electrical insulating material to obtain the electrical insulating element of the elastomeric sleeve. An apparatus for carrying out the process for manufacturing is also disclosed.

Abstract: An optical fiber includes an optical fiber axis; a core extending along the axis, the core being made of a first, undoped material having a first refractive index; and a cladding coextensive to and surrounding the core. The cladding includes a background matrix made of the first material and has a plurality of holes formed in the background matrix extending parallel to the fiber axis arranged around the core in substantially concentric rings, and filled with a second material having a second refractive index lower than the first refractive index. The number of the rings of holes is two or three, an average distance between the holes is at least about 6 ?m, a ratio between an effective radius of the core and the average distance between the holes is at most about 1, and a ratio between an average dimension of the holes and the average distance between the holes is at least about 0.5.

Abstract: A method and a related apparatus for monitoring an external surface of stranded cables, such as submarine cables for optical telecommunications, and electrical energy cables, provide for telemetrically acquiring a profile of the cable external surface by means of a laser optical triangulation technique, obtaining a spectrum of the telemetrically-acquired profile and comparing the obtained spectrum to a previously measured reference spectrum corresponding to a cable free of defects, thereby deducing the presence of defects by differences in the spectra.