Large polarization response of planarized optical waveguide functionalized with 2D material overlays

We propose a planarized optical waveguide structure functionalized with 2D materials that exhibits strong polarization dependent light interaction. Numerical study on both TE–and TM-polarized lights propagation in the 2D material coated optical waveguide is carried out. The effective index, n_eff of optical waveguide increases with the increase of refractive index of the 2D material overlay but decreases when its extinction coefficient is increased. On the other hand, the effective extinction coefficient, k_eff of 2D material coated waveguide increases with the increase of both the real and imaginary parts of 2D material refractive index. It is found that TE-mode has a stronger interaction with 2D material overlay compared to TM-mode, giving rise to potential application like waveguide polarizer. By optimizing the coating thickness, TM-pass waveguide polarizer with high polarization extinction ratio of 78.5 and 97.7 dB can be produced using black phosphorus and graphene oxide, respectively, with a coating length of only 1 mm.