PREPARATION METHOD OF OPTICAL FIBER PREFORM

摘要

In the production of a preform for an optical glass fibre a glass rod (1) is introduced into one end of a glass tube (2) while gas is supplied to the other end and exhausted through the annular gap between rod and tube. The assembly is then heated to collapse the tube onto the rod. The rod is introduced vertically into the upper end of the tube and the gas is nitrogen or clean dry air. The rod may have a conical end which engages a construction at the lower end of the tube.