摘要:
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.
摘要:
Method and burner for increasing the deposition rate of porous glass deposit in the manufacture of optical preforms, by modifying the cross-sectional shape of the flow of glass particles impacting onto a target preform. In particular, the cross-section of the flow of glass particles is modified by increasing the dimension of the flow from a circular cross-section to one having a major and minor axis in a direction substantially perpendicular to the longitudinal axis of the target preform.
摘要:
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.
摘要:
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. Said at least one suction element is advantageously positioned at a different height (preferably lower) with respect to that of said at least one burner to optimise the fluid dynamic conditions inside the chemical deposition chamber.
摘要:
Multi-flame burner wherein each flame is separated with respect to the neighboring flame by at least one separating tube made of a heat resistant material, for example, quartz glass or ceramic material. The burner also has a plurality of co-axial pipes, preferably made of a metallic material. The cross section of the upper end of the separating tube can be modified in order to increase the deposition rate of the burner. Methods for manufacturing optical fibre preforms by vapour deposition using the multi-flame deposition burners.
摘要:
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. Said at least one suction element is advantageously positioned at a different height (preferably lower) with respect to that of said at least one burner to optimise the fluid dynamic conditions inside the chemical deposition chamber.
摘要:
A method is disclosed for feeding a flow of gas to a burner for manufacturing an optical fibre preform, said burner comprising: a plurality of coaxial tubes, each two adjacent coaxial tubes defining an annular channel between themselves; an annular gas distribution chamber at one extremity of said annular channels and in fluid communication therewith, said annular distribution chamber being delimited in the radial direction by an inner and an outer surface; said method comprising introducing the flow of gas into the distribution chamber so that the direction of its radially outermost portion is tangential to the radially outer surface of the distribution chamber. The method allows obtaining a better gas velocity distribution in said annular channels. A burner for performing said method is also disclosed.
摘要:
A method for feeding a flow of gas to a burner for manufacturing an optical fiber preform. The burner has a plurality of coaxial tubes, each two adjacent coaxial tubes defining an annular channel between themselves; an annular gas distribution chamber at one extremity of the annular channels and in fluid communication therewith, the annular distribution chamber being delimited in the radial direction by an inner and an outer surface. The flow of gas is introduced into the distribution chamber so that the direction of its radially outermost portion is tangential to the radially outer surface of the distribution chamber. The method allows obtaining a better gas velocity distribution in the annular channels.
摘要:
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.
摘要:
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.