Ion-implanted waveguide formation in silica

The optimum processing parameters for the fabrication ef low-loss waveguides in fused silica by ion implantation and annealing have been determined through a comparison of implantation-induced physical and optical properties. The step height at an implanted/unimplanted boundary resulting from Si implantation tvas measuredd as a function of ion dose (2x10(12)-6x10(16)/cm(2)), post-implantation annealing temperature (200-900 degrees C) and time (0-2.5 hr), for a given ion energy (5 MeV), the compaction increased for doses <similar to(15)/cm(2) and thereafter, saturated, Isochronal and isothermal annealing both resulted in a non-linear reduction in compaction, typical of a thermally-induced process, In contrast to the continual seduction in compaction observed during isochronal; annealing, the loss coefficient exhibited a distinct minimum of similar to 0.15 dB/cm at an intermediate temperature of 500 degrees C, This feature was consistent with the removal of a specific defect or colour centre, Investigation of the annealing behaviour of the B-2-band indicated that this defect was not responsible for the observed loss behaviour nor was the decrease in refractive index, Surface cracking was observed for C, Si, and Ge-implantations at doses around 3x10(13)/cm(2), an effect exaggerated for the lighter ions.