  We study theoretically nonlinear propagation of light in a graphene
monolayer. We show that the large intrinsic nonlinearity of graphene at optical
frequencies enables the formation of quasi one-dimensional self-guided beams
(spatial solitons) featuring subwavelength widths at moderate electric-field
peak intensities. We also demonstrate a novel class of nonlinear self-confined
modes resulting from the hybridization of surface plasmon polaritons with
graphene optical solitons.
