Improving slow light effect in photonic crystal line defect waveguide by using eye-shaped scatterers

Eye-shaped scatterers are adopted into a photonic crystal waveguide (PCW) in two ways: (1) slow light with wide bands and group index ng from 14.1 to 32.8 can be generated by simply replacing the first and second rows of air holes adjacent to the linear defect with eye-shaped scatterer and (2) slow light with wide bands of ng from 36.5 to 287.5 are achieved by substituting all air holes with eye-shaped scatterers. More simulation results show that the latter method can achieve slow light with low dispersion at large ng, and near zero dispersion structures by adjusting the lattice parameter a and parameter e (e is inversely related to the ratio of the radius of the minor axis c to that of the major axis b).