Ultra-compact and broadband tunable mid-infrared tapered multimode interference splitter based on graphene plasmonic waveguide

Abstract

We propose and design an ultra-compact and broadband tunable multimode interference (MMI) splitter in mid-infrared based on graphene plasmonic waveguides. The size of the device is only 0.56μm×1.2μm, which corresponds to device area of only about 0.014λ 2 , where λ is the vacuum wavelength. And the center wavelength of the device can be tuned in a broad band from 7μm to 9μm with the Fermi level of graphene varied from 0.5eV to 1eV. Furthermore, the device is easy to be fabricated on chip.