NEAR-INFRARED CHANNEL WAVE-GUIDES FORMED BY ELECTRON-BEAM IRRADIATION OF SILICA LAYERS ON SILICON SUBSTRATES

Results are presented for channel guides formed by electron beam irradiation of silica layers formed on Si substrates by plasma-enhanced chemical vapor deposition. Electroplating is shown to be a simple method of fabricating the required surface mask. Optical insertion loss measurements performed at 1.525 mu m wavelength show a strong dependence on the irradiation mask width, charge dose, and electron energy, and parameters for low propagation and coupling loss are identified. Optimum propagation losses are 0.4 dB/cm (TE), 0.75 dB/cm (TM). Spectral loss measurements are also presented for as-deposited and thermally annealed material, and it is shown that beneficial results are obtained by annealing before irradiation. The stability of irradiation-induced changes is also described.