All-Optical Graphene-Based Modulation of Surface Plasmon Polaritons via Modulation Instability for Secure Optical Communication

In this paper, an all optical graphene-based modulation approach is proposed induced by Modulation Instability (MI). The device structure is based on graphene sheets transferred on the both arms of a Mach- Zehnder interferometer to support amplified Surface Plasmon Polaritons (SPPs). Due to the nonlinear nature of MI to interfere in the modulation process, the proposed approach leads to an enhanced performance in comparison to the conventional Mach-Zehnder modulators; using a low power cw driving beam (~20 μW at λ=50 μm), a high speed modulation rate (~2 Tpps) and subsequently, a high depth (89%), wideband modulation (~81 GHz) can be resulted. Since the MI is a pre-state to the chaotic regime, the modulator can be also used for secure optical communication.