The disclosed embodiments generally relate to extruding multiple layers of micro- to nano-polymer layers in a tubular shape. In particular, the aspects of the disclosed embodiments are directed to a method for producing a Bragg reflector comprising co-extrusion of micro- to nano-polymer layers in a tubular shape.

A terahertz hollow core waveguide includes several successively cascaded waveguide units, and the waveguide units includes fiber core and cladding. The fiber core is composed of air, and the cladding is composed of dielectric rings, air rings, support strips, and an outer cladding. The medium rings and the air rings are successively surrounded on the outside of the fiber core, and the outer cladding is surrounded on the outside of the outermost air ring. All support strips in the same air ring of the same waveguide unit form a support strip group, and the support strips in the support strip group are arranged along the circumferential direction to connect two adjacent dielectric rings in the same waveguide unit or to connect the outermost dielectric ring and the outer cladding in the same waveguide unit.

A terahertz hollow core waveguide includes several successively cascaded waveguide units, and the waveguide units includes fiber core and cladding. The fiber core is composed of air, and the cladding is composed of dielectric rings, air rings, support strips, and an outer cladding. The medium rings and the air rings are successively surrounded on the outside of the fiber core, and the outer cladding is surrounded on the outside of the outermost air ring. All support strips in the same air ring of the same waveguide unit form a support strip group, and the support strips in the support strip group are arranged along the circumferential direction to connect two adjacent dielectric rings in the same waveguide unit or to connect the outermost dielectric ring and the outer cladding in the same waveguide unit.

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 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.

The present disclosure discloses a polarization-maintaining hollow-core antiresonant fiber. An inner layer of the polarization-maintaining hollow-core antiresonant fiber includes first thin walls, second thin walls, and third thin walls. The present disclosure introduces high birefringence through the wall thickness difference between the first thin wall and the second thin wall, and effectively amplifies a birefringence effect achieved by the wall thickness difference through quasi multi-symmetric structures of the first thin walls and the second thin walls. In addition, the present disclosure reduces the transmission loss and suppresses the leakage of light through the inner layer, particularly, the third thin walls of the inner layer, so that the fiber of the present disclosure realizes polarization maintaining, and meanwhile, reduce the loss as far as possible.

The present disclosure discloses a polarization-maintaining hollow-core antiresonant fiber. An inner layer of the polarization-maintaining hollow-core antiresonant fiber includes first thin walls, second thin walls, and third thin walls. The present disclosure introduces high birefringence through the wall thickness difference between the first thin wall and the second thin wall, and effectively amplifies a birefringence effect achieved by the wall thickness difference through quasi multi-symmetric structures of the first thin walls and the second thin walls. In addition, the present disclosure reduces the transmission loss and suppresses the leakage of light through the inner layer, particularly, the third thin walls of the inner layer, so that the fiber of the present disclosure realizes polarization maintaining, and meanwhile, reduce the loss as far as possible.

Methods, devices, and systems for welding optical fibers and perforated elements by pulsed laser beam are provided. In one aspect, a method includes focusing a pulsed laser beam onto a region of a joining surface formed by an outer circumference of an optical fiber and an inner circumference of a hole of a perforated element, a beam direction of the pulsed laser beam running in an axial direction of the joining surface, and moving a laser focus of the pulsed laser beam in the region axially in or counter to the beam direction to produce at least one weld seam in the region. The optical fiber and the perforated element are locally melted in the region by the pulsed laser beam focused into a material of the optical fiber and a material of the perforated element and are thereby welded to one another.

Methods, devices, and systems for welding optical fibers and perforated elements by pulsed laser beam are provided. In one aspect, a method includes focusing a pulsed laser beam onto a region of a joining surface formed by an outer circumference of an optical fiber and an inner circumference of a hole of a perforated element, a beam direction of the pulsed laser beam running in an axial direction of the joining surface, and moving a laser focus of the pulsed laser beam in the region axially in or counter to the beam direction to produce at least one weld seam in the region. The optical fiber and the perforated element are locally melted in the region by the pulsed laser beam focused into a material of the optical fiber and a material of the perforated element and are thereby welded to one another.

The disclosed embodiments generally relate to extruding multiple layers of micro- to nanopolymer layers in a tubular shape. In particular, the aspects of the disclosed embodiments are directed to a method for producing a Bragg reflector comprising co-extrusion of micro- to nanopolymer layers in a tubular shape.