There is provided a method for producing a multicore optical fiber while depressurizing holes in a common cladding tube. A production method for a multicore optical fiber includes a preform forming step of forming a common cladding tube having a plurality of holes extending between a first end and a second end, an end-face working step of digging the common cladding tube from the second end to a predetermined depth to forming a third end, a connection step of connecting a glass tube to the second end, an insertion step of inserting core rods into the holes to the third end, a sealing step of sealing the first end, and a drawing step of spinning the multicore optical fiber while depressurizing the holes through the glass tube and combining the common cladding tube and the core rods from the first end.

A method of forming an optical fiber includes the steps of forming a silica-based soot blank with at least one silica-based soot core cane at least partially embedded in the soot blank. The soot blank with the soot core cane positioned therein is consolidated to form a preform. The preform is then drawn to form an optical fiber. The soot core cane preferably has an average bulk density within 10% of the bulk density of the soot blank, and more preferably within 5% of the bulk density of the soot blank.

A method for fabricating a multicore fiber comprised of an elongate base body containing a glass cladding material and having at least two through-holes, inserting a core rod into the through-holes so as to form a component ensemble, drawing the component ensemble to form the multicore fiber, wherein the component ensemble is held from above by a holder made of glass, which is connected to the base body so as to form a welding contact surface. The fitting of the base body with core rods is not limited by the layout of the holder, and which in particular allows placement of all core rods from above even after the holder has been welded on, a holder with an elongate hollow part is used, having a hollow channel with an inner contour that is larger than a hole area circumference within which the through-holes lie at least 90% of their diameter.

A method of producing an optical fiber preform includes: an alkali-metal-doped silica glass body forming step of forming an alkali-metal-doped silica glass body doped with an alkali metal; a silica glass body forming step of forming a silica glass body to be at least a portion of a core portion around the alkali-metal-doped silica glass body such that the silica glass body contacts the alkali-metal-doped silica glass body; and a diffusing step of diffusing the alkali metal from the alkali-metal-doped silica glass body to the silica glass body by a heat treatment.

A preform manufacturing method of the present invention has a hole forming step of forming a plurality of holes in a glass body to produce a glass pipe, and a heating integration step of heating the glass pipe with core rods including core portions being inserted in the respective holes, thereby to implement integration of the core rods and the glass pipe. In the hole forming step, a peripheral hole out of the holes to be formed in the glass body is formed at a position determined in consideration of positional variation of the core portion before and after the integration.

Methods for producing a multicore fiber comprise a method step in which a component group is reshaped to form the multicore fiber or a pre-form for the multicore fiber, which comprises a hollow cylinder comprising a central bore and a hollow cylinder longitudinal axis, which hollow cylinder comprises a cladding glass region made of cladding glass and a plurality of core glass regions occupied by a core glass, wherein at least part of the central bore is occupied by a glass filling material. In order to provide a method for producing multicore fibers without central signal core, in which the risk of rejects during the completion of the hollow glass cladding cylinder is reduced, a marker element made of marker glass adjacent to the glass filling material is used, which extends along the longitudinal axis of the central bore.

A method of forming a multicore fiber comprises the steps of drilling a plurality of holes in a soot blank, inserting a plurality of graphite rods into the plurality of holes to form a soot preform assembly, consolidating the soot preform assembly in a high temperature furnace to form a glass preform assembly, removing the plurality of graphite rods from the glass preform assembly to form a solid glass preform containing multiple holes, inserting a plurality of glass core canes into the holes to form a multicore preform, placing the multicore preform in a draw furnace, and drawing multicore fiber from the multicore preform.

A method of manufacturing an optical fiber, the method including mounting a glass sleeve in a selective etching apparatus. The sleeve comprising one or more axial through-holes, and the etching apparatus comprising a first end cap with a central aperture disposed therethrough, the first end cap being attached to a first surface of the sleeve. The method further including exposing the sleeve to an acid solution such that a first portion of the first surface is exposed to the acid solution and a second portion of the first surface is not exposed to the acid solution. The first portion being adjacent to the central aperture when the sleeve is mounted in the selective etching apparatus, and the second portion being covered by the first end cap when the sleeve is mounted in the selective etching apparatus.

A method determines a position of a light wave guiding core body of an optical waveguide for machining on a numerically controlled machine tool. The waveguide includes the core body and a shell body enclosing it, both extending from a first end face to a second end face of the waveguide. The method includes providing an optical measurement system, including a light source device and a detection device, and measuring the first end face by the optical measurement system, including irradiating the waveguide by the light source, detecting radiation emitted by the first end face, and determining a position of a center point of the core body on the first end face based on the detected radiation. The optical measurement system is arranged on the machine tool. The measurement of the first end face is performed on the waveguide clamped on the machine table by the optical measurement system.

A method for producing a preform of an anti-resonant hollow-core fiber, comprising the method steps of a) providing a cladding tube, which has a cladding tube inner bore and a cladding tube longitudinal axis, along which a cladding tube wall extends, which is limited by an inner side and an outer side b) preparing a number of anti-resonance element preforms, which consist of several nested tubular structural elements, comprising an ARE outer tube and an ARE inner tube inserted therein, wherein the structural elements have a structural element longitudinal axis, c) arranging the anti-resonance element preforms on the inner side of the cladding tube wall, and d) thermal fixing of the anti-resonance element preforms to the cladding tube wall by means of heat input.