Controlling ultrashort pulses shape using one-dimensional graded index photonic crystals

In this study, we analyze the characteristics of a one dimensional coupled cavity-waveguide composed of SiO2/TiO2 layers in which three defects are located symmetrically in structure, using finite-time domain-method and transfer matrix method. Then we introduced a new structure based on mentioned one-dimensional structure in which the higher refractive index material is maintained constant, while lower refractive index slightly increases with a constant step value from the beginning to the end of the structure. Simulation results reveal that the graded structure represents unique features in comparison with the conventional structure.