Figure 4
From: Tunable pattern-free graphene nanoplasmonic waveguides on trenched silicon substrate
Fermi level dependence of the mode properties for the proposed GPWG and the application for a GPWG-based optical modulator.
(a) The effective mode width and the propagation loss as a function of EF2/EF1 for the present GPWG with different Fermi levels in graphene when w = 100 nm and d2 = 40 nm. (b) Real(neff) and the propagation loss of the proposed GPWG as a function of the Fermi level EF1 for the core (the gate voltage) when w = 100 nm, d1 = 60 nm and d2 = 40 nm. The position of the on-state (EF1 = 0.3 eV, VG = 7.2 V) and the-off state (EF1 = 0.16 eV, VG = 2 V) for the proposed optical modulator are marked with grey dashed lines. Insets: Mode profiles for the two states. (c) The normalized light intensity propagation profiles in the designed optical modulator for the on-state and the off-state, respectively.
