▎ 摘　　要

NOVELTY - The switch has a bimodal resonance optical fractal structure provided in a composite structure. Four graphene layers are located at strongest position of a local electric field corresponding to the bimodal resonance optical fractal structure respectively, where nonlinear effect of the graphene layers is enhanced. The composite structure realizes multiple optical bistable state. USE - Period-double (PD) photonic crystal and graphene composite structure-based multi-value all-optical communication switch. ADVANTAGE - The switch has reduced trigger threshold values so as to enhance a nonlinear effect of the graphene layers. The composite structure can realize the optical bistable state, so that interval between turn-on and turn-off threshold values of the switch is adjusted flexibly by chemical potential and incident wavelength of the graphene layers. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a PD photonic crystal and graphene composite structure-based multi-value all-optical communication switch.