US 12,215,048 B2Granted

Methods for producing a hollow-core fiber and for producing a preform for a hollow-core fiber

AssigneeHeraeus Quarzglas GmbH & Co. KG

InventorsManuel Rosenberger, Michael Hünermann, Martin Trommer, Kay Schuster, Steffen Weimann

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Abstract

Methods are known for producing an anti-resonant hollow-core fiber which has a hollow core extending along a fiber longitudinal axis and an inner jacket region that surrounds the hollow core, said jacket region comprising multiple anti-resonant elements. The known methods have the steps of: providing a cladding tube that has a cladding tube inner bore and a cladding tube longitudinal axis along which a cladding tube wall extends that is delimited by an interior and an exterior; providing a number of tubular anti-resonant element preforms; arranging the anti-resonant element preforms at target positions of the interior of the cladding tube wall, thereby forming a primary preform which has a hollow core region and an inner jacket region; and elongating the primary preform in order to form the hollow-core fiber or further processing the primary preform in order to form a secondary preform. The aim of the invention is to achieve a high degree of precision and an exact positioning of the anti-resonant elements in a sufficiently stable and reproducible manner on the basis of the aforementioned methods. This is achieved in that while carrying out a process according to step (c), components of the primary preform made of quartz glass and/or parts surrounding the primary preform made of quartz glass are heated and softened together, wherein the quartz glass of at least one of the preform components and/or the quartz glass of at least one of the parts surrounding the preform contains at least one dopant which decreases or increases the viscosity of quartz glass.

Claims14

Dependent claims

A method for producing an anti-resonant hollow-core fiber comprising a hollow core extending along a longitudinal axis of the fiber and an inner sheath region surrounding the hollow core, which sheath region comprises several anti-resonance elements (AREs), comprising the method steps of:

(a) providing a primary preform for the hollow-core fiber which comprises at least one cladding tube having an inner bore of the cladding tube and a longitudinal axis of the cladding tube along which a cladding tube wall delimited by an inner side and an outer side extends,
(b) forming a number of precursors or preforms for AREs at desired positions of the cladding tube wall, and
(c) elongating the primary preform to form the hollow-core fiber or further processing the primary preform into a secondary preform from which the hollow-core fiber is drawn, wherein the further processing comprises a single or repeated performance of one or more of the following hot-forming processes:
(i) elongation,
(ii) collapse,
(iii) collapse and simultaneous elongation,
(iv) collapse of additional sheath material,
(v) collapse of additional sheath material and subsequent elongation,
(vi) collapse of additional sheath material and simultaneous elongation,
wherein, when performing a process in accordance with method step (c), components of the primary preform made of quartz glass and/or components made of quartz glass surrounding the primary preform are heated and softened together, wherein the quartz glass of at least one of the preform components and/or the quartz glass of at least one of the components surrounding the preform contains at least one dopant that lowers or increases the viscosity of quartz glass, and
wherein at least a portion of the precursors for AREs is present as tubular ARE preforms, which are composed of multiple nested structural elements, comprising an anti-resonance outer tube and an ARE inner tube inserted therein, and the ARE preforms include quartz glass which at a measured temperature of 1250° C. has a viscosity higher by at least 0.4 dPa·s than the quartz glass of the cladding tube.

8 more elements

A method for producing a preform for an anti-resonant hollow-core fiber comprising a hollow core extending along a longitudinal axis of the fiber and an inner sheath region surrounding the hollow core, which sheath region comprises several anti-resonance elements (AREs), comprising the method steps of:

(a) providing a primary preform for the hollow-core fiber which comprises at least one cladding tube having an inner bore of the cladding tube and a longitudinal axis of the cladding tube along which a cladding tube wall delimited by an inner side and an outer side extends,
(b) forming a number of precursors or preforms for AREs at desired positions of the cladding tube wall, and
(c) further processing the primary preform to form a secondary preform for the hollow-core fiber, wherein the further processing comprises a single or repeated performance of one or more of the following hot-forming processes:
(i) elongation,
(ii) collapse,
(iii) collapse and simultaneous elongation,
(iv) collapse of additional sheath material,
(v) collapse of additional sheath material and subsequent elongation,
(vi) collapse of additional sheath material and simultaneous elongation,
wherein, when performing a process in accordance with method step (c), components of the primary preform made of quartz glass and/or components made of quartz glass surrounding the primary preform are heated and softened together, wherein the quartz glass of at least one of the preform components and/or the quartz glass of at least one of the components surrounding the preform contains at least one dopant that lowers or increases the viscosity of quartz glass, and
wherein at least a portion of the precursors for AREs is present as tubular ARE preforms, which are composed of multiple nested structural elements, comprising an anti-resonance outer tube and an ARE inner tube inserted therein, and the ARE preforms include quartz glass which at a measured temperature of 1250° C. has a viscosity higher by at least 0.4 dPa·s than the quartz glass of the cladding tube.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/625,175Filed 15 Jul 2020
Priority: EP 1918686317 Jul 2019
Published: US 2022/0267193 A125 Aug 2022
Granted: 4 Feb 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

C03B 37/0122
By inserting one or more rods or tubes into a tube: for making preforms of photonic crystal, microstructured or holey optical fibres
C03B 37/02781
Fibres composed of different sorts of glass, e.g. glass optical fibres: hollow fibres, e.g. holey fibres
G02B 6/032
Optical fibres with cladding with or without a coating: with non solid core or cladding
C03B 2201/12
Doped with boron or fluorine or other refractive index decreasing dopant: doped with fluorine