Heraeus Quarzglas Gmbh & Co Kg

Steffen Weimann

Martin Trommer

Michael Hünermann

Oliver Ganz

Manuel Rosenberger

Kay Schuster

Enrico Ehrentraut

David Kostka

Yusuf Tansel

Michael HÜNERMANN

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.

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

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 a secondary preform is formed which has an outer diameter ranging from 30 to 90 mm, and at least one of the end faces of the anti-resonant element preforms is closed prior to drawing the fiber.

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 further processing the primary preform in order to form a secondary preform, including a process of elongating the primary preform in order to directly form the hollow-core fiber or to form the 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 a primary preform with an outer diameter ranging from 20 to 70 mm is used for the elongation process.

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 further processing the primary preform according to step (c), an external layer cylinder is used which has a radial viscosity profile such that the viscosity increases towards the interior of the external layer cylinder.

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; further processing the primary preform in order to form a secondary preform, including an elongation process; and drawing the secondary preform in order to form the hollow-core fiber. 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 after the primary preform is elongated, at least some of the formerly tubular anti-resonant element preforms of the primary preform have an oval outer cross-sectional shape with a longest cross-sectional axis Aand a shortest cross-sectional axis A, wherein the ratio A/Aof the length of the axes ranges from 1.01 to 1.27, and the shortest cross-sectional axis Aruns in a radial direction when viewed from the cladding tube longitudinal axis.

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Hanau, Germany

Steffen Weimann