Early days of VAD method

Early history of the development of VAD method for mass-production of optical fibers for telecommunications is presented. Today, more than 300milion km fibers are made in the world every year, and 60% of the fibers are made by VAD method. There were many difficulties in the development of the method, the biggest hurdle was the consolidation process, and it was solved by the introduction of helium gas in zone-heating furnace.