Figure 3
From: Ultracompact Graphene-Assisted Tunable Waveguide Couplers with High Directivity and Mode Selectivity
Single group TM antenna coupler. (a) Schematic of the device for coupling x-polarized incident light into left-propagating fundamental TM mode around 1.55 μm. (b) Distribution of electric field component Ey along the middle waveguide plane. (c) and (d) Electric field norm distribution for the left and right port respectively at 1.55 μm. (e) and (f) Directivity as a function of antenna center-to-center interval and graphene chemical potential respectively. (g) and (h) Corresponding operation wavelength variations for (e) and (f) respectively. (i) Normalized transmission curve for the two waveguide ports under different excitation polarization states. (j) \(|{\bf{E}}|\) distribution details along graphene plane. (k) Corresponding vector map for (c).
