▎ 摘　　要

We study the multimode interference (MMI) effect in a dielectric-loaded graphene waveguide (DLGW) numerically by the finite element method. By conducting the dispersion relation of graphene plasmon (GP) modes, a 1 x 2 splitter of GPs is proposed. Structure parameters are designed on the basis of the self-imaging principle, and the calculation of electrical field distributions illustrates two-wavelength splitting. Owing to the tunable permittivity of graphene by bias voltages, the active control of wavelength routing is achieved. High extinction ratios can also be obtained, which proves good splitting performance. It is considered that our findings provide a smart way of designing a tunable plasmonic splitter in the infrared region. (C) 2016 The Japan Society of Applied Physics