Abstract: The present invention relates to an optical fibre mainly consisting of silica glass, which fibre comprises: i) an inner core having a first refractive index n1 and a first diameter a; ii) an outer core surrounding the outer circumference of the inner core and having a second refractive index n2 and a second diameter b; and iii) a cladding surrounding the outer circumference of the outer core, which cladding has a third refractive index n3, wherein n1>n2>n3.

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 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 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 an optical fibre mainly consisting of silica glass, which fibre comprises:

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:

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.