▎ 摘　　要

NOVELTY - The all-optical digital encoder comprises first uniform dielectric thin sheets (H), second uniform dielectric thin sheets (L) and two graphene single layers (G), forming composite structure HLH1GH2HHH2GH1LH, where H1GH2 and H2GH1 are layered structures formed by graphene single layer embedded in uniform dielectric thin sheet. The thickness of first uniform dielectric thin sheet and second uniform dielectric thin sheet is one-fourth of optical wavelength. The composite structure has optical component having local effect to electric field. The two graphene single layers are located at strongest local electric field position corresponding to one of optical component. USE - All-optical digital encoder used in all-optical communication. ADVANTAGE - The structure reduces the coding threshold of the encoder, and enhances the third-order nonlinear optical effect of graphene so as to realize optical bistable low threshold value, and can make the uniform dielectric thin sheet with low refractive index material cryolite, so that the thickness of the graphene single layer can be reduced, and increases the chemical potential and incident wavelength of graphene, thus increasing the optical bistable state of graphene. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of centrosymmetric period-doubling (PD) photonic crystal and graphene composite structure. Graphene single layer (G) First uniform dielectric thin sheet (H) Uniform dielectric thin sheet (H1, H2) Second uniform dielectric thin sheet (L)