▎ 摘　　要

We propose for the first time a THz graphene-based electro-optical modulator. The novelty comes from working the device in modulation instability (MI) regime. Multiple embedded graphene layers inside an ionic gel enclosed by a Fabry-Perot resonator provide an enhanced nonlinearity required for starting MI process. Appeared as a pump wave, MI intensely amplifies the modulated wave. Consequently, the operational broad bandwidth and high modulation depth can be obtained. By using the double-gated electrodes' structure, the ultrafast generation rate of the charge carriers and lowly required driving voltage are attainable for a small footprint. The emerging high sensitivity of the device to the external electric field implies its applicability in non-intrusive electric field sensory tools. Finally, this graphene-based modulator introduces a feasible entity to control the chaotic wave propagation in THz optical communication.