Microwave Heating of Fused Quartz to High Temperatures in the Fabrication Process of Optical Fibers

Microwave heating in the fabrication process of high quality quartz fibers for telecommunication is described. In this process tubes and rods of ultrapure quartz with low dielectric loss factor are heated to temperatures above 2000 °C by means of a high Q tunable cavity. High quality fibers, referring to both optical attenuation and geometrical properties, have been manufactured. The homogeneous nature of microwave heating results in a significantly decreased production time per fiberkilometer. Measurements of the most important materials parameter, the dielecric loss factor of quartz as function of temperature and frequency, are presented.