Abstract: The invention relates to the production of an anti-resonant hollow-core fiber consisting of a capillary blank and a sleeve tube. The capillary blank comprises an external capillary and a nested internal capillary, and is stretched to a maximum external diameter ODARE_cap and a maximum wall thickness WTARE_caP. The blank is mounted on the inside of the sleeve tube. In order to retain the advantages of the pre-produced capillary blank with respect to ease of assembly and precision, while keeping the associated drawbacks owing to ovality low and predictable, it is proposed that the geometric internal diameter and external diameter of the external capillary and of the internal capillary, as well as ODARE_cap and WTARE_caP, are aligned in relation to one another in such a way that the ARE-external capillary of the capillary blank has a degree of ovality of less than 1.025.

Abstract: The invention relates to microstructured optical fibers that are drawn through hollow channels and have a core region, which extends along a fiber longitudinal axis, and a jacket region surrounding the core region. The aim of the invention is to reduce a damping increase due to corrosion and to reduce the emission of chlorine on the basis of the microstructured optical fibers. This is achieved in that at least some of the hollow channels are delimited by a wall material made of synthetic quartz glass which has a chlorine concentration of less than 300 wt. ppm and oxygen deficiency centers in a concentration of at least 2×1015 cm-3.

Abstract: 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.

Abstract: The invention relates to an anti-resonance ele-ment preform for producing an anti-resonant hollow-core fiber, in an axial top view comprising a circular first cir-cle element with a first circle radius and a circular arc-shaped first circular arc element with a first circular arc radius. Furthermore, the invention relates to a method for producing an anti resonance element preform, a preform for producing an anti-resonant hollow-core fiber comprising at least one anti-resonance element preform and an anti-resonant hol-low-core fiber. According to the invention, it is provided that the first circle element and the first circular arc element are connected to one another at two contact points.

Abstract: A method for producing a preform of an anti-resonant hollow-core fiber, comprising the 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, each comprising an ARE outer tube and an ARE inner tube inserted therein, c) preparing a positioning template, having a number of passage openings passing through the positioning template, adapted for a longitudinal guidance of an anti-resonance element preform each, wherein the positioning template and the cladding tube are made of identical material, d) attaching the positioning template to a first end of the cladding tube, e) inserting at least parts of the anti-resonance element preforms through the passage openings.