Optical coupling between two nanobelts

In this study, we have investigated effective refractive index (ERI) and power confinement factor (PCF) in single nanobelt and coupling between two parallel nanobelts using finite-difference time-domain (FDTD) method. As the width of nanobelt increases, both the effective refractive index (ERI) and power confinement factor (PCF) are increased till the saturation values. The ERI changes linearly with refractive index in our simulation range, while the PCF shows nonlinear characteristic. The coupling length (LTLT) between two nanobelts is much shorter than that in weakly coupled waveguide, which may find applications in solving the cross talk problem. Nanobelt behaves like slab waveguide when the width becomes big enough.