Cselt-centro Studi E Laboratori Telecomunicazioni S.p.a.

Cselt- Centro Studi E Laboratori Telecommunicazioni Spa

Agilent Technologies, Inc.

Sip- Societa Italiana Per L'esercizio Delle Telecominicazioni P.a.

Giuseppe Cocito

Giorgio Grego

Marco Braglia

Eros Modone

Paolo Bielli

Salvatore Contu

Roberto De Franceschi

Daniele Bresciani

Leonardo Michetti

Giorgio Greco

To manufacture polarization-maintaining optical fibers, a fiber is directly and continuously irradiated with at least one beam of UV radiation during drawing and before application of external coatings.

Method of making polarization-maintaining optical fibers

A duct for housing cables for underground telecommunications networks has one or more tubular elements of a first plastic material, having helical ribs on their inner surface. The ribs may also be formed as inserts into the material of the tubular element.

Underground tubular ducts for telecommunications networks

Fluoride glass optical fibers 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 fiber and an internal layer of a second fluoride glass of composition suitable to form the core of the fiber is prepared 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 fiber, and the resulting tube is drawn.

Method for the fabrication of fluoride glass single mode optical fibers

Refractive index change in a glass substrate, necessary to obtain a guiding region, is obtained by bombarding the substrate surface with an electron beam. An electric field induced by negative charge accumulation is created under the surface, whereby sodium ions present in glass are made to migrate towards the inside of the substrate.

Method of fabricating integrated optical guides of glass

The system uses a monochromatic radiation source (1) and an acousto-optic modulator (2), which is driven by a periodically variable frequency. The modulator emits a first beam having the same wavelength as the source and a second beam, whose wavelength and emission direction vary with the modulating frequency. After the second beam has been collimated, radiations of both beams are sent towards the component under test and an electrical signal with varying frequency is generated representative of the beat between such radiations at the output from the component. A spectral analysis of the beat signal is carried out, and the refractive index value is derived from the position taken by the various frequencies of the beat signal on a detection plane.

System for measuring the refractive index profile of optical components

An expansible reel is provided having a plurality of rigid structural mems parallel to each other and to a central axis of the reel, joined at the ends to supports allowing small radial displacements of the members. Between contiguous rigid members there are placed inflatable members into which compressed air is introduced to space apart the rigid members when an optical fibre wound around the reel is to be submitted to tests under controlled tensile stress conditions.

Expansible reel for tests on filamentary material in particular optical

A method of manufacturing dichroic antenna structures, which makes use of a projector mounted on the mobile arm of a computer-controlled machine to project the shape of selective antenna elements on the surface of an insulating layer, clad with a metallic layer covered in turn with a photographic emulsion. Development and chemical etching of the excess conductive parts are then carried out.

Method of making a dichroic antenna structure

A method of making optical performs from which optical fibers are drawn after collapsing of the preform, which comprises depositing by a vapor-phase reaction a plurality of layers on the inner surface of a support tube and controlling the temperature profile around the perimeter of the support so that the thickness of the deposit varies between at least one maximum and at least one minimum. Upon collapse of the support this gives rise to a core having a noncircular cross section.

Method of producing optical fibers with noncircular core

The process employs solid-state halides heated at high temperature, under pressure conditions necessary to their vaporization, and obtains their condensation to a solid state on the internal surface of a glass tube, which, after collapsing, forms the preform.

Process and apparatus for producing optical-fiber preforms for

A method of and an apparatus for measuring the softening point of a vitreous specimen in which the viscosity variation as a temperature function is determined by applying torsion to the specimen and measuring the transmitted torque as a function of temperature.

Method of and apparatus for measuring the softening point of a vitreous

Optical-fiber trunks to be spliced are inserted into opposite ends of a downwardly converging longitudinal groove formed at the bottom of a channel member and are held in position by resilient tongues extending into that groove from an overlying retaining member. The latter, made of sheet metal, may be integral with the channel member but could also be a polygonal jacket enveloping an array of channel members accommodating individual fibers of an optical cable to be spliced. Instead of individual channel members so arrayed, an elongate body with several throughgoing channels and associated retaining elements may be used for cable splicing.

Devices for splicing optical fibres and cables

An elongate light conductor of circular or other cross-section is continuously produced by depositing, in a vacuum chamber, a powdered glassy (i.e. vitreous or vitrifiable) material upon the upper end of a descending rod of like material while training a stream of doping ions upon the same end. Vitrification may be assisted by an electron beam, also trained upon the powder-receiving rod end, and/or by thermal treatment of the rod leaving the vacuum chamber. The lower end of the rod is softened in a furnace from which a vitreous strand of reduced cross-section is continuously drawn through an orifice and wound upon a mandrel.

Process and apparatus for the continuous production of elongate light

One or more optical fibers, forming part of a cable for the transmission of luminous signals, are divided into sheathed sections spliced together inside a junction box having opposite walls provided with a pair of nipples in which the incoming and outgoing cable portions are resiliently clamped. Between these nipples the two sections of each fiber, partly stripped of their sheaths, are bent into a loop along which they are joined together by a sleeve. Adjacent fiber loops of the same cable can be separated within the box by interposed sheets. The loops not only relieve stresses on the bared fiber ends but also facilitate the equalization of ray paths in a multifiber optical cable.

Growing community of inventors

S. Giusto Canavese, Italy

Giuseppe Cocito