METHOD AND APPARATUS FOR DRYING AND CONSOLIDATING A PREFORM FOR OPTICAL FIBRES

A process and an apparatus for drying and consolidating an optical fibre preform in a furnace tube comprising a heating chamber, wherein an extension tube having an extension chamber configured to house at least a length portion of the preform is removably joined to the furnace tube and the drying process starts with the preform not completely inserted into the furnace tube, an upper length portion of the preform being surrounded by the extension tube joint to the furnace tube. 1. A method for manufacturing an optical fibre preform comprising:providing a furnace comprising a furnace tube having an elongated heating chamber configured to house a preform, the heating chamber having an upper entry opening for the insertion of the preform;providing an extension tube comprising an extension chamber having a lower opening and configured to house at least a length portion of a preform;inserting a lower length portion of an optical fibre preform, the preform being a porous preform, in the heating chamber in such a way that an upper length portion of the optical fibre preform lies outside of the furnace tube;enclosing the upper length portion of the optical fibre preform in the extension tube;joining the furnace tube with the extension tube so as the lower opening of the extension chamber is in communication with the upper entry opening of the heating chamber to form a single chamber;dehydrating the lower length portion of the preform by exposing said lower length portion to a first heating zone of the furnace tube set at a dehydration temperature, andgradually lowering the optical preform through the first heating zone so as to dehydrate the upper length portion of the optical fibre preform.2. The method of claim 1 , wherein the furnace tube has a second heating zone positioned below the first heating zone and set at a consolidation temperature claim 1 , wherein gradually lowering the optical fibre preform further comprises exposing successive length portions of the preform ...

Method for Manufacturing a Glass Preform for Optical Fibers

Methods for manufacturing fluorine-doped glass preforms for optical fibers are disclosed. An exemplary method includes exposing a soot preform to an atmosphere containing a fluorine-containing gas in a first elongated chamber of a first furnace. The first elongated chamber typically has a single isothermal hot zone, which may be maintained at a doping temperature of about 800° C. to 1200° C., to obtain a fluorine-doped soot preform. The exemplary method further includes dehydrating the fluorine-doped soot preform by exposing it to an atmosphere containing a chlorine-containing gas in a second elongated chamber of a second furnace. The second elongated chamber typically has an upper hot zone, which may be maintained at a dehydration temperature of about 1000° C. to 1350° C., and a lower hot zone, which may be maintained at a consolidation temperature of about 1500° C. to 1650° C. Dehydration of the fluorine-doped soot preform typically occurs in the upper hot zone of the second furnace. The exemplary method further includes consolidating the fluorine-doped soot preform within the lower hot zone of the second furnace to form a fluorine-doped glass preform.

Suspending device for optical fibre preforms

An optical fibre preform suspending device for vertically holding an optical fibre preform by a preform handle comprising a handle enlarged-width portion is provided. The preform suspending device having a substantially cylindrical shape and comprising a housing portion having a receiving space with a front top opening and a front bottom opening and a supporting surface between the front top opening and the front bottom opening. The preform suspending device also comprises a supporting member placed on the supporting surface, for holding the handle enlarged-width portion. The supporting member is radially independent from the housing portion.

Method of manufacturing preforms for optical fibres having low water peak

A method of manufacturing at least one optical fibre preform comprising: providing a plurality of partially porous intermediate preforms, each partially porous intermediate preform having a longitudinal axis and comprising a respective soot intermediate clad layer formed around a respective glass core rod comprising a central core region of radius a and an inner clad region of radius b to define a first core-to-clad ratio a/b; consolidating the formed soot intermediate clad layers to form a respective plurality of intermediate glass preforms, each of the plurality of intermediate glass preforms comprising an intermediate clad region having an external radius c to define a second core-to-clad ratio a/c of from 0.20 to 0.30, and overcladding at least one intermediate glass preform by forming an overclad region surrounding the intermediate clad region to form an optical fibre glass preform, wherein consolidating comprises exposing the plurality of intermediate preforms to a consolidation hot zone of a single furnace body while rotating each of the intermediate preforms about its respective longitudinal axis.

METHOD OF MANUFACTURING PREFORMS FOR OPTICAL FIBRES HAVING LOW WATER PEAK

A method of manufacturing an optical fibre preform comprising: providing a glass core rod comprising a central core region of radius a and an inner clad region of external radius b to define a first core-to-clad ratio a/b; forming an intermediate glass preform comprising an intermediate clad region surrounding the inner clad region of the glass rod and having an external radius c to define a second core-to-clad ratio a/c, and overcladding the intermediate glass preform by forming an overclad region surrounding the intermediate clad region to form an optical fibre preform, wherein the first core-to-clad ratio a/b is equal to or less than 0.40 and the second core-to-clad ratio a/c is of from 0.20 to 0.25. 1. A method of manufacturing an optical fibre preform comprising:providing a glass core rod comprising a central core region of radius a and an inner clad region of external radius b to define a first core-to-clad ratio a/b;forming an intermediate glass preform comprising an intermediate clad region surrounding the inner clad region of the glass rod and having an external radius c to define a second core-to-clad ratio a/c, andovercladding the intermediate glass preform by forming an overclad region surrounding the intermediate clad region to form an optical fibre preform,wherein the first core-to-clad ratio a/b is equal to or less than 0.40 and the second core-to-clad ratio a/c is of from 0.20 to 0.25.2. The method of claim 1 , wherein a/b is of from 0.34 to 0.40.3. The method of claim 1 , wherein a/b is of from 0.38 to 0.40.4. The method of claim 1 , wherein forming an intermediate glass preform comprises:depositing soot material around the glass core rod by a flame hydrolysis process to form a soot intermediate clad layer, andheating to consolidate the deposited soot intermediate clad layer to form an intermediate glass preform.5. The method of claim 4 , wherein the soot material forming a soot intermediate clad layer is silica soot.6. The method of claim 4 , ...

Method for manufacturing silicon dioxide preforms employed in the production of optical fibers

The present invention relates to a method for manufacturing a preform of silica for optical fiber production, as well as to a method for the production of optical fibers comprising a step of drawing the optical fiber from such a preform of silica, the method comprising a step of vaporization of a siloxane feedstock added with a compound having the following formula (I): wherein R, R′ and R″, equal or different each other, are an alkyl group having from 1 to 5 carbon atoms, and A is a saturated or unsaturated chain of atoms selected from the group consisting of carbon atom, nitrogen atom, and oxygen atom, said chain A forming with the nitrogen atom linked thereto a saturated, unsaturated or aromatic heterocyclic moiety.

Apparatus and method for manufacturing glass preforms for optical fibers

An apparatus for manufacturing glass preforms for optical fibers includes a reaction chamber surrounding a deposition region, a holding device for holding a target rod within said deposition region, one or a plurality of deposition burners positioned below said deposition region and configured to direct a high temperature flow of forming glass particles toward said target rod, a hood positioned opposite to the deposition burners with respect to said holding device and configured for discharging soot of un-deposited glass particles, said hood including at least one exhaust port provided at a first end portion thereof and side panels extending from a second end portion thereof toward said first end portion. At least a portion of the side panels of the hood is gas permeable.

Method for vapour deposition on an elongated substrate

Device and method for chemical deposition on an elongated member of vitreous material in which a rotating gripping member causes a first end portion of the elongated member to rotate. The second end portion of the elongated member is borne by a pair of supporting members which are axially spaced apart (L 1 ) and are capable of permitting angular rotational movement and axial sliding of the second end portion. Each supporting member also applies a radial constraint preventing the second end portion from moving away from the axis of rotation, thus forcing the second portion and the elongated member to lie with a longitudinal axis coaxial with the axis of rotation. Any curvature of the elongated member is corrected and recovered in this way.

Low temperature food product

A low temperature confectionery product comprising the following ingredients: a) 0 to 8 wt.% of cocoa solids non fat; b) 3.5 to 15wt.% of milk fat; c) from 15 to 25 wt.% of cocoa butter, hard fat cocoa butter equivalents or substitutes and combinations thereof; d) from 35 to 55 wt.% of water; e) from 5 to 30 wt.% of sugar; f) from 9 to 20 wt.% of milk solids non fat; providing that (b) + (f) is greater than or equal to 14 %. This confectionary product is stored at low temperatures, i.e. in a refrigerator or freezer, but may be consumed either directly from the freezer/refrigerator or at ambient temperatures.

Method of manufacturing preforms for optical fibres having low water peak

CHOCOLATE PRODUCTS FOR LOW TEMPERATURE

Low temperature food product

A low temperature confectionery product comprising the following ingredients : a) 0 to 8 wt.% of cocoa solids non fat; b) 3.5 to 15wt.% of milk fat; c) from 15 to 25 wt.% of cocoa butter, hard fat cocoa butter equivalents or substitutes and combinations thereof; d) from 35 to 55 wt.% of water; e) from 5 to 30 wt.% of sugar; f) from 9 to 20 wt.% of milk solids non fat; providing that (b) + (f) is greater than or equal to 14 %. This confectionary product is stored at low temperatures, i.e. in a refrigerator or freezer, but may be consumed either directly from the freezer/refrigerator or at ambient temperatures.</S DOAB>

Process for producing a low-attenuation optical fiber

A process for producing a low-attenuation optical fiber comprises producing a soot core preform (23) by chemical deposition on a substrate; removing the substrate from the soot core preform (23), thereby forming a central hole (26) along the soot preform (23); drying and consolidating the soot core preform (23) in a consolidation furnace (20) to form a glass core preform (23); heating the glass preform (23) in the consolidation furnace (20) over a glass melting temperature to produce a reduction of the diameter of the central hole (26); and stretching the glass core preform (23) to completely close the central hole.

Manufacturing process of preforms for optical fibers with low water peak

Un procedimiento de fabricación de una preforma de fibra óptica, que comprende: - proporcionar una barra (1) de núcleo de vidrio que comprende una región (11) del núcleo central de radio a y una región (12) de revestimiento interior de radio externo b para definir una primera relación de núcleo a revestimiento a/b; - formar una preforma (10) intermedia de vidrio que comprende una región (13) de revestimiento intermedio que rodea la región (12) de revestimiento interior de la barra del núcleo de vidrio y que tiene un radio exterior c para definir una segunda relación de núcleo a revestimiento a/c, y - revestir la preforma (10) intermedia de vidrio mediante la formación de una región (14) revestida que rodea la región (13) de revestimiento intermedio para formar una preforma de fibra óptica, caracterizado porque la primera relación de núcleo a revestimiento a/b es de al menos 0,34 e igual a o menor que 0,40 y la segunda relación de núcleo a revestimiento a/c es desde 0,20 a 0,25. A method of manufacturing a fiber optic preform, comprising: - providing a glass core bar (1) comprising a region (11) of the central radius core a and a region (12) of inner lining of external radius b to define a first core to coating ratio a / b; - forming an intermediate glass preform (10) comprising an intermediate coating region (13) surrounding the inner coating region (12) of the glass core bar and having an outer radius c to define a second ratio of core to a / c coating, and - coating the intermediate glass preform (10) by forming a coated region (14) surrounding the intermediate coating region (13) to form a fiber optic preform, characterized in that the first core to coating ratio a / b is at least 0.34 and equal to or less than 0.40 and the second core to shell ratio a / c is from 0.20 to 0.25.

Apparatus for drying and/or consolidating a preform for optical fibres

An apparatus (10) for drying and/or consolidating an at least partially porous optical fibre preform, comprising:- a furnace (9) comprising a muffle tube (11) extending along a vertical axis (Z) and forming a hollow muffle chamber configured to house a preform (16), the muffle tube (11) having a muffle opening (15) at its top side, which is configured to allow passage of the preform (16);- an extension tube (19) forming a hollow extension chamber (21) configured to house at least a length portion of the preform (16) and having a central axis aligned in the vertical axis (Z), wherein the extension tube (19) has a lower opening (24) and upper opening (23) placed at the top side of the extension tube (19) and opposite to the lower opening (24), and wherein the extension tube (19) is removably attached to the muffle tube (11) at the lower opening (24) so as to close the muffle opening (15) when the extension tube (19) is joined to the muffle tube (11) to form a single chamber,- a hood (30) placed on a top side of the extension tube (19) and removably fixed to the same, the hood (30) defining an inner space (37) when fixed to the extension tube (19) and including a discharge port (46) and a hood cap (33) with a hood through-hole (34) which is substantially axially aligned to the upper opening (23), the hood through-hole (34) and the upper opening (23) being configured for the passage of a cylindrical supporting rod (18a) of a supporting handle (18) for the suspension of the preform (16), and- a flow control assembly (90; 91) including a sealing assembly (80) operatively connected with the hood (30) and substantially centred about the vertical axis (Z), wherein the sealing assembly (80) includes a ring-shaped seal (82) and an expansible member (83) having a generally tubular shape configured to allow passage of the supporting rod (18a) and to expand and contract in a vertical direction (L), wherein the ring-shaped seal (82) is located radially inward of the expansible ...

Method and apparatus for drying and consolidating a preform for optical fibres

Vorrichtung und verfahren zur abscheidung aus der gasphase auf einem langgestreckten substrat

Método para la fabricación de preformas de dióxido de silicio empleadas en la producción de fibras ópticas

Un procedimiento para fabricar una preforma de sílice para la producción de fibra óptica, donde el procedimiento comprende una etapa de vaporización de una materia prima de siloxano agregada con un compuesto que tiene la siguiente fórmula (I): **(Ver fórmula)** donde R, R' y R", iguales o diferentes entre sí, son un grupo alquilo que tiene de 1 a 5 átomos de carbono, y A es una cadena saturada o insaturada de átomos que se selecciona del grupo que consiste en átomo de carbono, átomo de nitrógeno y átomo de oxígeno, donde dicha cadena A forma con el átomo de nitrógeno unido a este un resto heterocíclico saturado, insaturado o aromático.

Method of manufacturing preforms for optical fibres having low water peak

A method of manufacturing at least one optical fibre preform comprising: providing a plurality of partially porous intermediate preforms, each partially porous intermediate preform having a longitudinal axis and comprising a respective soot intermediate clad layer formed around a respective glass core rod comprising a central core region of radius a and an inner clad region of radius b to define a first core-to-clad ratio a/b; consolidating the formed soot intermediate clad layers to form a respective plurality of intermediate glass preforms, each of the plurality of intermediate glass preforms comprising an intermediate clad region having an external radius c to define a second core-to-clad ratio a/c of from 0.20 to 0.30, and overcladding at least one intermediate glass preform by forming an overclad region surrounding the intermediate clad region to form an optical fibre glass preform, wherein consolidating comprises exposing the plurality of intermediate preforms to a consolidation hot zone of a single furnace body while rotating each of the intermediate preforms about its respective longitudinal axis.

Apparatus for drying and/or consolidating a preform for optical fibres

An apparatus for drying and/or consolidating an at least partially porous optical fibre preform.

Apparatus for drying and/or consolidating a preform for optical fibres

Apparatus and method for manufacturing glass preforms for optical fibers

Sposób i urządzenie do suszenia i konsolidacji preformy dla światłowodów

Method and apparatus for drying and consolidating a preform for optical fibres

Apparatus and method for manufacturing glass preforms for optical fibers

An apparatus (10) for manufacturing glass preforms for optical fibers comprises a reaction chamber (15) surrounding a deposition region (15a), a holding device (12) for holding a target rod (100) within said deposition region (15a), one or a plurality of deposition burners (11) positioned below said deposition region (15a) and configured to direct a high temperature flow of forming glass particles toward said target rod (100), a hood (16) positioned opposite to the deposition burners (11) with respect to said holding device (12) and configured for discharging soot of un-deposited glass particles, said hood (16) comprising at least one exhaust port (17) provided at a first end portion (19) thereof and side panels (24) extending from a second end portion (20) thereof toward said first end portion (19). At least a portion (24a) of the side panels (24) of the hood (16) is gas permeable.

Dispositivo y procedimiento para la deposicion de vapor de un sustrato alargado.

Procedimiento para la deposición química de material sintético sobre un miembro de substrato alargado con un eje longitudinal (18) que comprende las etapas de: - fijar un extremo (2a) de dicho medio alargado a un medio de sujeción, - impartir rotación alrededor de dicho eje longitudinal (18) a dicho miembro alargado por medio de dicho elemento de sujeción (5), y - depositar material sintético sobre dicho miembro alargado (2), caracterizado por el hecho de que comprende la etapa de restringir radialmente por lo menos un extremo (2a; 2b) de dicho miembro alargado (2) respecto a dicho eje longitudinal (18) en dos posiciones separadas axialmente.

Vorrichtung und verfahren zur abscheidung aus der gasphase auf einem langgestreckten substrat

Method for manufacturing silicon dioxide preforms employed in the production of optical fibers

The present invention relates to a method for manufacturing a preform of silica for optical fiber production, as well as to a method for the production of optical fibers comprising a step of drawing the optical fiber from such a preform of silica, the method comprising a step of vaporization of a siloxane feedstock added with a compound having the following formula (I): wherein R, R' and R'', equal or different each other, are an alkyl group having from 1 to 5 carbon atoms, and A is a saturated or unsaturated chain of atoms selected from the group consisting of carbon atom, nitrogen atom, and oxygen atom, said chain A forming with the nitrogen atom linked thereto a saturated, unsaturated or aromatic heterocyclic moiety.

Urządzenie i sposób wytwarzania szklanych preform do światłowodów

Sposób wytwarzania preform dla włókien optycznych mających niski pik wodny

Schokoladenprodukte fuer niedrige temperatur

Process for producing a low-attenuation optical fiber

A process for producing a low-attenuation optical fiber comprises producing a soot core preform (23) by chemical deposition on a substrate; removing the substrate from the soot core preform (23), thereby forming a central hole (26) along the soot preform (23); drying and consolidating the soot core preform (23) in a consolidation furnace (20) to form a glass core preform (23); heating the glass preform (23) in the consolidation furnace (20) over a glass melting temperature to produce a reduction of the diameter of the central hole (26); and stretching the glass core preform (23) to completely close the central hole.

Method of manufacturing preforms for optical fibres having low water peak

A method of manufacturing at least one optical fibre preform comprising: providing a plurality of partially porous intermediate preforms, each partially porous intermediate preform having a longitudinal axis and comprising a respective soot intermediate clad layer formed around a respective glass core rod comprising a central core region of radius a and an inner clad region of radius b to define a first core-to-clad ratio a/b; consolidating the formed soot intermediate clad layers to form a respective plurality of intermediate glass preforms, each of the plurality of intermediate glass preforms comprising an intermediate clad region having an external radius c to define a second core-to-clad ratio a/c of from 0.20 to 0.30 , and overcladding at least one intermediate glass preform by forming an overclad region surrounding the intermediate clad region to form an optical fibre glass preform, wherein consolidating comprises exposing the plurality of intermediate preforms to a consolidation hot zone of a single furnace body while rotating each of the intermediate preforms about its respective longitudinal axis.