An optical fiber may include a cladding structure extending along a fiber length providing a hollow interior fiber region, and anti-resonant (AR) elements formed as walled structures with walls extending along the fiber length. At least one of the AR elements surrounds an interior region and further includes one or more support structures in the interior region and formed as at least a portion of at least one of the walls, where the one or more support structures have a non-uniform thickness profile, and where the plurality AR elements is configured to guide light along the fiber length in a central portion of the hollow interior fiber region based on optical anti-resonance.

A method of manufacturing an optical fiber with a hole from a preform having a through hole is disclosed. The manufacturing method includes placing a preform in a drawing furnace, forming an optical fiber by melting and drawing the preform in the drawing furnace while a gas is introduced into the through hole, capturing an image of the optical fiber drawn from the preform, and measuring a hole diameter of the optical fiber based on an image captured in the capturing of the image and controlling a pressure of the gas introduced into the through hole based on a measurement result. In the capturing of the image, when the optical fiber deviates, a predetermined countermeasure is taken to make the image clear, and the image is maintained in a clear state.

A preform for an anti-resonant hollow core fiber which comprises a hollow core extending along a fiber longitudinal axis and a jacket surrounding the hollow core and traversed by hollow channels, wherein the preform has an outer diameter OD and a length L, wherein OD is at least 25 mm, and the ratio L/OD is greater than 71.5. A method for producing a preform for an anti-resonant hollow core fiber as described above, comprising thermally drawing a cylindrical preliminary product having a length of less than 3000 mm.

A method may include fabricating an anti-reflective hollow-core optical fiber (AR-HCF) and coupling light into the AR-HCF. The AR-HCF may include a cladding structure extending along a fiber length and providing a hollow interior fiber region, and also one or more nested AR elements. At least one of the nested AR elements may include a first AR element formed as a wall extending along the fiber length and located entirely within the hollow interior fiber region. The wall of the first AR element, in a cross-sectional plane orthogonal to the fiber length, may fully surround an interior region and further have a non-uniform thickness profile that forms one or more support structures. At least one of the one or more nested AR elements may include a second AR element located within the interior region of the first AR element and exclusively in contact with the one or more support structures.

A method of manufacturing a hollow core optical fiber from a hollow core optical fiber preform is disclosed, the method including measuring a first dimension of the hollow core optical fiber while drawing the hollow core optical fiber from the hollow core optical fiber preform, comparing the measured first dimension with a predetermined target range, and adjusting a first preform property of the hollow core optical fiber preform if the measured first dimension is outside of the predetermined target range while drawing the hollow core optical fiber from the hollow core optical fiber preform.

A method for producing a hollow-core preform may include rolling a glass sheet to form a rolled-glass structure; and attaching one or more of the rolled-glass structures to an inner surface of an annular support structure to form a hollow-core preform, wherein the inner surface of the annular support structure defines an interior cavity and the one or more of the rolled-glass structures are positioned within the interior cavity. The hollow-core preform may be drawn into a hollow-core optical fiber.