Methods for producing hollow-core optical fibers

A method for producing a hollow-core optical fiber, the method comprising:

• drawing a hollow-core optical fiber from a hollow-core preform, the hollow-core preform comprising an annular support structure with an inner surface defining an interior cavity, the interior cavity comprising a sealed tube in contact with the inner surface, the sealed tube comprising a wall defining an internal opening, the internal opening having a sealed end opposite a draw end, the drawing comprising regulating a pressure of the interior cavity to a predetermined pressure from 0.5 psig to 3.0 psig, the regulating the pressure of the interior cavity carried out by a manifold disposed proximate to the sealed end of the sealed tube and configured to supply a gas to the interior cavity without introducing gas into the sealed end of the sealed tube.