REDUCTION OF PROPAGATION LOSS IN SILICA-ON-SILICON CHANNEL WAVE-GUIDES FORMED BY ELECTRON-BEAM IRRADIATION

Low loss is demonstrated at infrared wavelengths in channel guides for med by electron beam irradiation of SiO2 layers on Si substrates. By c omparing materials from different PECVD processes, it is shown that su bstrate losses may largely be eliminated by using a suitable SiO2 thic kness, and that extrinsic absorption caused by hydrogen contamination may be reduced by annealing before irradiation. The effectiveness of a nnealing depends strongly on the original material composition.