Fast all-optical switching using ion-implanted silicon photonic crystal nanocavities

On-chip all-optical switching based on the carrier plasma dispersion in an argon ion $(Ar+)$ implanted photonic crystal (PhC) nanocavity that is connected to input/output waveguides is described. A high dose of $Ar+$ is introduced, and annealing is used to recrystallize the silicon and thus create dislocation loops at the center of the PhC slab. Dislocation loops enable the fast recombination of the carriers, which allows a fast switching recovery time for PhC switches. The switching window $(∼70ps)$ is three times smaller than that without ion implantation, while the required operating energy remains almost the same $(<100fJ)$⁠.