Method and a manufacturing apparatus for manufacturing a fiber preform

摘要

A method and manufacturing apparatus for forming one or several material layers inside a basic tube, which basic tube is used in the manufacture of an optical fiber preform. The surface inside the basic tube is electrically charged by guiding a first electrically charged gas flow inside the basic tube, whereafter a second electrically charged gas flow is guided into the basic tube. The gas flow contains material particles and the sequentially alternating first gas flow and second gas flow have opposite charges.