Method and preform for producing a hollow core fiber and method for producing a preform for a hollow core fiber

A method for producing a hollow core fiber by thermally drawing a preform that comprises a hollow core region and a jacket region which is traversed by hollow channels that extend between a first preform end and a second preform end, wherein the preform, starting with the first end, is fed to a heating device at a feed rate, is softened therein in part, and the hollow core fiber is continuously drawn off from the softened part while a remaining preform length is shortened, wherein the core region and/or the hollow channels are subjected to pressure, wherein at least one means for applying pressure is arranged at the second preform end, and in that the thermal drawing is terminated as soon as the means for applying pressure and/or the second preform end has reached a predetermined limit temperature and/or the remaining preform length has fallen below a predetermined minimum length.