Abstract: A method of manufacturing an optical fiber and related devices using an apparatus having an elongated microwave guide coupled to a resonant cavity formed of an outer cylindrical wall and inner cylindrical wall having a slit with a width W and configured to deliver microwave energy having a vacuum wavelength ? to a resonant cavity thereof to satisfy the relationship: W??/10 where a substrate tube is located within the resonant cavity and plasma chemical vapor deposition deposits layers of doped silica thereon followed by thermal collapsing the substrate and drawing an optical fiber therefrom.

Abstract: A method of manufacturing an optical fiber and related devices using an apparatus having an elongated microwave guide coupled to a resonant cavity formed of an outer cylindrical wall and inner cylindrical wall having a slit with a width W and configured to deliver microwave energy having a vacuum wavelength &lgr; to a resonant cavity thereof to satisfy the relationship: W≦&lgr;/10 where a substrate tube is located within the resonant cavity and plasma chemical vapor deposition deposits layers of doped silica thereon followed by thermal collapsing the substrate and drawing an optical fiber therefrom.

Abstract: The invention relates to a method of applying a protective organic coating to an optical glass fiber, said glass fiber is drawn from a preform and passed through a liquid which contains the material for forming said organic coating, once the amount of liquid coating material to be applied to the fiber has been adjusted, said coating matrial is hardened, while a gas is passed along the liquid wherein nitrous oxide (an N2O-containing gas) is used as said gas. The invention also relates to the coated optical glass fiber, produced by that method.

Abstract: The present invention relates to a method for producing a preform, which is substantially free of OH impurities, for an optical fiber, wherein one or more quartz layers, which may or may not be doped, are deposited on the internal surface of a quartz glass support tube, in which method a furnace is moved axially with respect to the support tube, and after the quartz layers have been deposited the support tube is contracted into a bar-shaped preform while being heated, wherein the furnace comprises an electrical resistance furnace, in which furnace the support tube is rotated, with the space between the rotating support tube and the furnace being washed with an inert gas.

Abstract: The invention relates to an apparatus for performing Plasma Chemical Vapor Deposition (PCVD), whereby one or more layers of silica can be deposited on an elongated vitreous substrate. The apparatus includes an elongated microwave guide which emerges into a resonant cavity which is substantially cylindrically symmetric about a cylindrical axis, along which axis the substrate can be positioned. Aspects of the apparatus include the cavity being substantially annular in form, with an inner cylindrical wall and an outer cylindrical wall and the inner cylindrical wall having a slit which extends in a full circle around the cylindrical axis: Additional aspects include the guide having a longitudinal axis which is substantially perpendicular to the cylindrical axis and which does not intercept the slit. The invention also relates to a method of manufacturing an optical fiber, a preform rod and a jacket tube as well as to the thus obtained optical fiber.

Abstract: The present invention relates to a method for producing a perform, which is substantially free of PH impurities, for an optical fibre, wherein one or more quartz layers, which may or may not be doped, are deposited on the internal surface of a quartz glass support tube, in which method a furnace is move axially with respect to the support tube, and after the quartz layers have been deposited the support tube is contracted into a bar-shaped perform while being heated, wherein the furnace comprises an electrical resistance furnace, in which furnace the support tube is rotated, with the space between the rotating support tube and the furnace being washed with an inert gas.

Abstract: The present invention relates to a method of applying glass layers, which may or may not be doped, to the interior of a substrate tube by means of a chemical vapor deposition (CVD) technique, using a reactive gas mixture, in order to obtain a preform that exhibits a precisely defined refractive index profile, which method comprises a number of steps.

Abstract: The invention relates to a device for drawing optical fibers from a preform, comprising: a furnace comprising a tube for heating one end of said preform to the drawing temperature thereof, which tube comprises: i) a central tube, ii) an upper extension tube connected to the lower part of said central tube so as to obtain a gas tight seal against an ambient atmosphere exterior said furnace, wherein the upper extension tube comprises an inlet for an inert gas in the top region of the upper extension tube, as a result of which the preform and the fiber to be drawn therefrom are surrounded by an inert gas, iii) a lower extension tube connected to said upper extension tube in such a manner that a gas tight seal against an ambient atmosphere exterior said furnace is obtained, iv) a tube outlet connected to said lower extension tube, means for drawing the fiber, means for supporting the preform in the furnace.

Abstract: The invention relates to an apparatus for performing Plasma Chemical Vapor Deposition (PCVD), whereby one or more layers of silica can be deposited on an elongated vitreous substrate, the apparatus comprising an elongated microwave guide which emerges into a resonant cavity which is substantially cylindrically symmetric about a cylindrical axis, along which axis the substrate can be positioned, in which apparatus: the cavity is substantially annular in form, with an inner cylindrical wall and an outer cylindrical wall; the inner cylindrical wall comprises a slit which extends in a full circle around the cylindrical axis; the guide has a longitudinal axis which is substantially perpendicular to the cylindrical axis and which does not intercept the slit. The invention also relates to a method of manufacturing an optical fiber, a preform rod and a jacket tube using said apparatus as well as to the thus obtained optical fiber.

Abstract: The invention relates to an apparatus for performing Plasma Chemical Vapor Deposition (PCVD), whereby one or more layers of silica can be deposited on an elongated vitreous substrate, the apparatus comprising an elongated microwave guide which emerges into a resonant cavity which is substantially cylindrically symmetric about a cylindrical axis, along which axis the substrate can be positioned, in which apparatus: the cavity is substantially annular in form, with an inner cylindrical wall and an outer cylindrical wall; the inner cylindrical wall comprises a slit which extends in a full circle around the cylindrical axis; the guide has a longitudinal axis which is substantially perpendicular to the cylindrical axis and which does not intercept the slit. The invention also relates to a method of manufacturing an optical fiber, a preform rod and a jacket tube using said apparatus as well as to the thus obtained optical fiber.

Abstract: A method of manufacturing an optical fiber, whereby a fiber is drawn from a molten extremity of a preform and is subsequently subjected to a torque, thereby causing a portion of the fiber to be twisted about its longitudinal axis and to be endowed with a spin. The torque is applied by running the fiber between a pair of wheels which rotate in mutually opposite senses about two different rotational axes, each wheel having a peripheral curved surface, the wheels being thus arranged that the fiber runs substantially tangential to their curved surfaces and is pressed therebetween, the wheels being moved back and forth relative to one another in a direction substantially perpendicular to the fiber so as to cause the fiber to be rolled back and forth between their curved surfaces.

Abstract: A method of manufacturing an optical fiber having a core portion doped with a dopant and a surrounding optical cladding portion is disclosed. The method comprises the steps of drawing a fiber from a molten extremity of a silica preform and moving the fiber along towards a device for coating it with a protective sheath. Prior to the coating step, the moving fiber is irradiated with irregularly modulated actinic radiation, thereby causing corresponding irregular variations in the refractive index of its core portion as a function of longitudinal position. The resulting fiber demonstrates a significantly reduced polarisation mode dispersion.

Abstract: A method of manufacturing an optical fiber, whereby a fiber is drawn from a molten extremity of a preform and is subsequently subjected to a torque, thereby causing a portion of the fiber to be twisted about its longitudinal axis and to be endowed with a spin. The torque is applied by running the fiber between a pair of wheels which rotate in mutually opposite senses about two different rotational axes, each wheel having a peripheral curved surface, the wheels being thus arranged that the fiber runs substantially tangential to their curved surfaces and is pressed therebetween, the wheels being moved back and forth relative to one another in a direction substantially perpendicular to the fiber so as to cause the fiber to be rolled back and forth between their curved surfaces.