Abstract: The present disclosure relates to an armoured AC cable comprising at least one core comprising an electric conductor, and an armour surrounding the at least one core and comprising ferromagnetic wires, wherein the ferromagnetic wires are permanently magnetized with a remanent magnetic field which is uniform or variable along the cable length L. The present disclosure also relates to a process for producing an armoured AC cable, a method for improving the performances of an armoured AC cable, and a method for reducing losses in an armoured AC cable.

Abstract: The present disclosure relates to an armoured AC cable comprising at least one core comprising an electric conductor, and an armour surrounding the at least one core and comprising ferromagnetic wires, wherein the ferromagnetic wires are permanently magnetized with a remanent magnetic field which is uniform or variable along the cable length L. The present disclosure also relates to a process for producing an armoured AC cable, a method for improving the performances of an armoured AC cable, and a method for reducing losses in an armoured AC cable.

Abstract: A microbundle optical cable such as, a riser cable, includes an outer jacket and a plurality of microbundles housed in the outer jacket. At least one of the microbundles includes an optical fiber ribbon enclosed in a microbundle coating. The at least one microbundle includes a longitudinal axis and a cross-section taken on a plane substantially perpendicular to the longitudinal axis. The cross-section may include a first dimension and a second dimension. The first dimension is higher than the second dimension. Therefore, the cross-section shape is an elongated cross shape.

Abstract: A method for detecting faulty laying down of an optical cable exhibiting a measured cut-off wavelength includes providing an optical cable for transmitting optical signals including at least one single-mode optical fiber having an attenuation equal to or larger than a first threshold value as measured when wound for one turn around a bending radius equal to or smaller than 5 mm at at least one predetermined test wavelength, the test wavelength being smaller than the measured cut-off wavelength, and an attenuation smaller than a second threshold value as measured when wound for one turn around a bending radius equal to at least a minimum bending radius at an operative wavelength equal to or larger than the measured cut-off wavelength; laying the optical cable; and measuring the attenuation in the at least one optical fiber at the predetermined test wavelength.

Abstract: A method for detecting faulty laying down of an optical cable exhibiting a measured cut-off wavelength includes providing an optical cable for transmitting optical signals including at least one single-mode optical fibre having an attenuation equal to or larger than a first threshold value as measured when wound for one turn around a bending radius equal to or smaller than 5 mm at at least one predetermined test wavelength, the test wavelength being smaller than the measured cut-off wavelength, and an attenuation smaller than a second threshold value as measured when wound for one turn around a bending radius equal to at least a minimum bending radius at an operative wavelength equal to or larger than the measured cut-off wavelength; laying the optical cable; and measuring the attenuation in the at least one optical fibre at the predetermined test wavelength.

Abstract: A method and device for manufacturing a preform for optical fibers through chemical deposition on a substrate for deposition arranged vertically is described, comprising a chemical deposition chamber including at least one gripping member rotatably mounted about an axis Z-Z and adapted to hold at least one end of at least one elongated element constituting a substrate for chemical deposition for the formation of a preform for optical fibers. The chamber includes, moreover, at least one burner which is mobile along a direction Z substantially parallel to said axis Z-Z and adapted to deposit, on said at least one elongated element, a chemical substance for the formation of a preform and at least one suction element for collecting exhaust chemical substances, said at least one suction element being arranged on the opposite side to said at least one burner with respect to said axis Z-Z and being mobile along said direction Z.

Abstract: A bend-insensitive optical cable for transmitting optical signals includes an optical cable having a length, extending from an input end adapted to receive the optical signals, to an output end and including at least one single-mode optical fiber having a cable cut-off wavelength, of 1290 nm to 1650 nm. The at least one optical fiber is helically twisted around a longitudinal axis with a twisting pitch, for a twisted length, extending along at least a portion of the length, of the optical cable, wherein the twisted length and the twisting pitch are selected such that the optical cable exhibits a measured cut-off wavelength equal to or lower than 1260 nm. Preferably, the at least one fiber has a mode-field diameter of 8.6 ?m to 9.5 ?m. According to a preferred embodiment, the optical cable includes two optical fibers twisted together along the longitudinal axis, each of the two optical fibers having a cable cut-off wavelength of 1290 nm to 1650 nm.

Abstract: A process for manufacturing an optical fiber, includes the steps of: a) producing a soot core preform by depositing a core material on a substrate; b) removing the substrate from the soot preform leaving an axial cavity along the longitudinal axis of the soot core preform; (c) drying and consolidating the soot core preform so as to obtain a glass core preform having an axial hole corresponding to the axial cavity; d) reducing a diameter of the axial hole; and e) stretching the glass core preform so as to substantially close the axial hole, wherein the process further includes the step of measuring at least one geometric characteristic of the axial hole of the glass core preform.

Abstract: A microbundle optical cable such as, a riser cable, includes an outer jacket and a plurality of microbundles housed in the outer jacket. At least one of the microbundles includes an optical fiber ribbon enclosed in a microbundle coating. The at least one microbundle includes a longitudinal axis and a cross-section taken on a plane substantially perpendicular to the longitudinal axis. The cross-section may include a first dimension and a second dimension. The first dimension is higher than the second dimension. Therefore, the cross-section shape is an elongated cross shape.

Abstract: A bend-insensitive optical cable for transmitting optical signals includes an optical cable having a length, extending from an input end adapted to receive the optical signals, to an output end and including at least one single-mode optical fiber having a cable cut-off wavelength, of 1290 nm to 1650 nm. The at least one optical fiber is helically twisted around a longitudinal axis with a twisting pitch, for a twisted length, extending along at least a portion of the length, of the optical cable, wherein the twisted length and the twisting pitch are selected such that the optical cable exhibits a measured cut-off wavelength equal to or lower than 1260 nm. Preferably, the at least one fiber has a mode-field diameter of 8.6 ?m to 9.5 ?m. According to a preferred embodiment, the optical cable includes two optical fibers twisted together along the longitudinal axis, each of the two optical fibers having a cable cut-off wavelength of 1290 nm to 1650 nm.

Abstract: An apparatus for measuring the weight of a preform for optical fibers during a chemical deposition process for the formation of a preform is disclosed. The apparatus has at least one elastic constraint associated with at least one end portion of an elongated element made of a chemical deposition substrate for the formation of the preform, a device for inducing an oscillation, for example axial, on said elongated element, a device for detecting the frequency of oscillation of said elongated element, and a device for calculating the weight of the preform according to the detected frequency of oscillation. Advantageously, the device allows the realisation of a method for measuring the weight of the preform wherein the errors in measurement caused by thermal drift effects, by the axial distribution of the masses on the preform and by loads which are different from the mass of the preform in formation are reduced to below the required precision in measurement.

Abstract: The hydroxyl content in an optical fiber is stabilized by a manufacturing process involving exposure of the optical fiber to a mixture of deuterium and a predetermined amount of hydrogen.

Abstract: A process for manufacturing an optical fiber, includes the steps of: a) producing a soot core preform by depositing a core material on a substrate; b) removing the substrate from the soot preform leaving an axial cavity along the longitudinal axis of the soot core preform; (c) drying and consolidating the soot core preform so as to obtain a glass core preform having an axial hole corresponding to the axial cavity; d) reducing a diameter of the axial hole; and e) stretching the glass core preform so as to substantially close the axial hole, wherein the process further includes the step of measuring at least one geometric characteristic of the axial hole of the glass core preform.

Abstract: A method and device for manufacturing a preform for optical fibres through chemical deposition on a substrate for deposition arranged vertically is described, comprising a chemical deposition chamber including at least one gripping member rotatably mounted about an axis Z-Z and adapted to hold at least one end of at least one elongated element constituting a substrate for chemical deposition for the formation of a preform for optical fibres. The chamber includes, moreover, at least one burner which is mobile along a direction Z substantially parallel to said axis Z-Z and adapted to deposit, on said at least one elongated element, a chemical substance for the formation of a preform and at least one suction element for collecting exhaust chemical substances, said at least one suction element being arranged on the opposite side to said at least one burner with respect to said axis Z-Z and being mobile along said direction Z.

Abstract: A method and device for manufacturing a preform for optical fibres through chemical deposition on a substrate for deposition arranged vertically. A chemical deposition chamber includes at least one gripping member rotatably mounted about an axis Z-Z and adapted to hold at least one end of at least one elongated substrate for chemical deposition for the formation of a preform. The chamber includes at least one burner which is mobile along a direction Z substantially parallel to the axis Z-Z and adapted to deposit on the elongated substrate, a chemical substance for the formation of a preform and at least one suction element for collecting exhaust chemical substances. The suction element is arranged on the opposite side of the burner with respect to the axis Z-Z and is mobile along the direction Z and is positioned at a lower height than the burner.

Abstract: A process and apparatus for elongating an optical fibre preform includes heating the preform so as to soften one region thereof; elongating the preform by submitting the preform to a traction; determining, during the step of elongating, the preform diameter in at least one measuring point along the preform; and controlling the step of elongating on the basis of the determined diameter. During the step of elongating, at least a geometrical parameter of the preform is measured, and the position of said diameter measuring point is controlled according to the measured geometrical parameter. Measuring at least a geometrical parameter of the preform may be accomplished by determining the profile of at least a portion of the softened region, e.g., an image of the neck region profile.

Abstract: An apparatus for measuring the weight of a preform for optical fibres during a chemical deposition process for the formation of a preform is disclosed. The apparatus has at least one elastic constraint associated with at least one end portion of an elongated element made of a chemical deposition substrate for the formation of the preform, a device for inducing an oscillation, for example axial, on said elongated element, a device for detecting the frequency of oscillation of said elongated element, and a device for calculating the weight of the preform according to the detected frequency of oscillation. Advantageously, the device allows the realisation of a method for measuring the weight of the preform wherein the errors in measurement caused by thermal drift effects, by the axial distribution of the masses on the preform and by loads which are different from the mass of the preform in formation are reduced to below the required precision in measurement.

Abstract: A process and apparatus for elongating an optical fibre preform includes heating the preform so as to soften one region thereof; elongating the preform by submitting the preform to a traction; determining, during the step of elongating, the preform diameter in at least one measuring point along the preform; and controlling the step of elongating on the basis of the determined diameter. During the step of elongating, at least a geometrical parameter of the preform is measured, and the position of said diameter measuring point is controlled according to the measured geometrical parameter. Measuring at least a geometrical parameter of the preform may be accomplished by determining the profile of at least a portion of the softened region, e.g., an image of the neck region profile.

Abstract: A method and device for manufacturing a preform for optical fibres through chemical deposition on a substrate for deposition arranged vertically. A chemical deposition chamber includes at least one gripping member rotatably mounted about an axis Z-Z and adapted to hold at least one end of at least one elongated substrate for chemical deposition for the formation of a preform. The chamber includes at least one burner which is mobile along a direction Z substantially parallel to the axis Z-Z and adapted to deposit on the elongated substrate, a chemical substance for the formation of a preform and at least one suction element for collecting exhaust chemical substances. The suction element is arranged on the opposite side of the burner with respect to the axis Z-Z and is mobile along the direction Z and is positioned at a lower height than the burner.