Graphene based multimode interference coupler as an optical refractive index sensor based on nonlinear modal propagation analysis

The objective of this study is to propose and introduce nonlinear modal propagation analysis (NMPA) method being a viable way to study the application of graphene based multimode interference (MMI) coupler as an optical refractive index sensor. The purpose of using graphene in this study is because of its high optical nonlinearity as well as having a small bandgap due to its thin layer. The graphene based sensor can be tuned for highest sensitivity in wavelength and refractive index to detect the clad material. Graphene will act as the core of the sensor which will be placed on top of the sample. The clad refractive index value can be obtained by observing and analyzing the change in the output facet intensity of the sensor. The result also shows that the sensor has high sensitivity due to the usage of graphene and nonlinear region.