Tapered core fibers are produced using tapered core rods that can be etched or ground so that a fiber cladding has a constant diameter. The tapered core can be an actively doped core, or a passive core. One or more sleeving tubes can be collapsed onto a tapered core rod and exterior portions of the collapsed sleeving tubes can be ground to provide a constant cladding diameter in a fiber drawn from the preform.

Methods for preform and tube draw based on controlling forming zone viscosity determined by calculating a holding force exerted by the glass component in the forming zone on the strand being drawn below. The holding force may be calculated by determining a gravitational force applied to the strand and a pulling force applied to the strand by a pulling device, where the holding force is equal to the opposite of the algebraic sum of the gravitational and pulling forces. The holding force may also be calculated by measuring a stress-induced birefringence in the strand at a point between the forming zone and the pulling device, determining an amount of force applied to the strand at the point corresponding to the birefringence, and calculating the holding force by correcting the amount of force for a gravitational effect of the weight of the strand between the forming zone and the point.

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 the step of providing and/or arranging the anti-resonant element preforms and/or the process of carrying out a hot-forming process includes a fixation measure and/or a sealing measure using an amorphous SiO.sub.2 particle-containing sealing or joining compound.

A multicore fiber-to-single core fiber adapting device, also referred a fan-in/fan-out (FIFO) device. More specifically, an optical fiber system comprising a multicore fiber, a tapered glass device that it is configured to connect a multicore fiber to a multiple single core fiber, and/or single mode fibers, advantageously having one or more protective layers to protect the tapered device. Associated methods of manufacture.

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 the step of providing the cladding tube includes a processing measure, in which the cladding tube wall is machined with a longitudinal structure extending in the direction of the cladding tube longitudinal axis in the region of the target positions.

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; forming a number of precursors for anti-resonant elements at target positions of the cladding tube wall; 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 from which the hollow-core fiber is drawn. 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 the formation of the anti-resonant element precursors includes the formation of elongated pressure chambers, each of which adjoins a wall that can be deformed under pressure and heat in the region of the target positions of the anti-resonant elements and which cause a section of the deformable wall to protrude in the direction of the cladding tube inner bore under the effect of pressure and heat, thereby forming an anti-resonant element or a precursor for same, while carrying out a process according to step (c).

The present disclosure relates to a method for forming a glass, ceramic or composite material. The method may involve initially forming a plurality of tubes and then performing a coating operation to coat the plurality of tubes with materials containing metal or metalloid elements, including inorganic compounds, organometallic compounds, or coordination complexes to form coated tubes. The method may further include performing at least one of a thermal operation or a thermochemical operation on the coated tubes to form a solid glass, ceramic, or composite structure with dimensions representing at least one of a rod or fiber.

A method for manufacturing a fan-in-fan-out device which does not require processing of a small-diameter hole and improves work efficiency of installation of an optical fiber, includes: arranging a first holding member in a hole of a second holding member, the hole being larger than an outer diameter of the first holding member, and holding a plurality of optical fibers between the first holding member and the second holding member respectively along a plurality of grooves formed on an outer periphery of the first holding member or an inner periphery of the hole of the second holding member; heating and integrally melting the arranged first holding member, the plurality of held optical fibers, and the second holding member in a portion including an axial end portion of the second holding member; and drawing the melted portion.

A system and methods are described herein for preheating a preform in a preheater furnace and then transferring the preheated preform to a consolidation furnace for chemical treatment and sintering the preform into a clear glass which can be drawn into optical fiber. In addition, the preheater furnace is described herein which is configured to heat the preform per a predetermined heat-profile until the preform is uniformly heated to a temperature above 1000° C.

The present disclosure relates to a method for forming a glass, ceramic or composite material. The method may involve initially forming a plurality of tubes and then performing a coating operation to coat the plurality of tubes with materials containing metal or metalloid elements, including inorganic compounds, organometallic compounds, or coordination complexes to form coated tubes. The method may further include performing at least one of a thermal operation or a thermochemical operation on the coated tubes to form a solid glass, ceramic, or composite structure with dimensions representing at least one of a rod or fiber.