Optical attenuation in ion-implanted silicon waveguide racetrack resonators.

The optical absorption at wavelengths near 1550 nm has been quantified as a function of annealing temperature in ion-implanted silicon-on-insulator racetrack resonators. The variation of the output characteristics of the bus waveguide versus the concentration of implantation-induced lattice disorder in the ring is used to develop a novel method for the determination of the coupling and round-trip loss of the resonator, independently. This experimental procedure has general applicability for the determination of these parameters. Significant propagation loss is found to persist following annealing at temperatures previously observed to remove the majority of ion implantation damage. It is suggested that these annealing characteristics are a consequence of an ion implantation range which is greater than the silicon waveguide layer thickness.