Investigating the Design and Simulation of a Tunable Optical Filter Based on Photonic Crystal Using Selective Optofluidic Infiltration

In this paper an optical filter based on 2D hexagonal photonic crystals that is suitable for the third window of optical communications is proposed. The structure consists of two waveguides including one L4 resonant cavity created by removing 4 holes between them, and one L1 resonant cavity by removing 1 hole near the output waveguide; moreover, 8 holes around the L4 cavity had been selected for optofluidic infiltration within them. This structure is very flexible, and different wavelengths in the third telecommunication window can be chosen using selective optofluidic infiltration with different refractive indices. Simplicity in design, no need to change the size of the holes and separating the desired wavelengths by selecting different optofluidic infiltration materials are the main features of this study. The plane-wave expansion method (PWE) and the finite-difference time-domain method (FDTD) have been used to extract the photonic bandgap and study the behavior of the photonic structure, respectively.