Planar waveguides

摘要

A cladding layer on the core of an optical waveguide is subjected to a rapid thermal annealing process preferably either: in a multi-stage furnace in which the waveguide substrate can be transported rapidly on a carriage between stages at different temperatures; or in a quartz chamber adjacent a bank of quartz halogen lamps of low thermal inertia and easily switched rapidly between different intensities of thermal radiation through the chamber.