Properties of localization in silicon-based lattice periodicity breaking photonic crystal waveguides

Abstract

The light localization effects in silicon photonic crystal cavities at different disorder degrees have been studied using the finite difference time domain (FDTD) method in this paper. Numerical results showed that localization occurs and enhancement can be gained in the region of the cavity under certain conditions. The stabilities of the localization effects due to the structural perturbations have been investigated too. Detailed studies showed that when the degree of structural disorder is small(about 10%), the localization effects are stable, the maximum enhancement factor can reach 16.5 for incident wavelength of 785 nm and 23 for 850 nm in the cavity, with the degree of disorder about 8%. The equivalent diameter of the localized spot is almost constant at different disorder degrees, approximating to ${\lambda \mathord{/ {\vphantom {\lambda 7}} \kern-\nulldelimiterspace} 7}$λ/7, which turned out to be independent on the structural perturbation.