Channel waveguides formed in fused silica and silica-on-silicon by Si, P and Ge ion implantation

Low-loss channel waveguides have been formed in substrates of fused silica and silica-on-silicon by the implantation of 5 MeV Si, P and Ge ions. The silica-on-silicon substrates comprised an upper core layer which was doped with either 3 or 7% Ge. Annealing of the silica-on-silicon waveguides has defined a narrow range of temperature (500-600°C) over which the loss coefficient α was at a minimum of 0.10-0.20 dB/cm at wavelengths of λ=1300 and 1550 nm. For the fused-silica substrates a similar minimum loss (0.10-0.20 dB/cm) was measured at 1300 nm. However, at λ=1550 nm the value of α was significantly greater because of an absorption edge in the fused silica (Suprasil-2) at 1500 nm. The results show that the optical loss characteristics of the waveguides were essentially independent of the ion species