▎ 摘　　要

We study saturable absorption in graphene-comprising nanophotonic waveguides taking into account the finite relaxation time as well as the carrier diffusion due to the nonuniform, tightly confined spatial profile of the guided modes. We discuss various details of graphene SA and comment on the necessary conditions that allow for directly comparing our model with available experimental. The mathematical framework is based on the nonlinear Schrodinger equation which provides a strict framework for our analysis and is developed for two optical channels. We explore the propagation of cw, long and short pulsed signals in a silicon slot waveguide and show the importance of our model in order to capture the ultrafast dynamics of graphene and the spatial distribution of guided modes. Finally, we demonstrate how cross absorption modulation can be exploited in order to imprint data from a high power optical channel to a low power channel.