Dispersion and light transport characteristics of large-scale photonic-crystal coupled nanocavity arrays.

We investigate the dispersion and transmission properties of slow-light coupled-resonator optical waveguides that consist of more than 100 ultrahigh-Q photonic crystal cavities. We show that experimental group-delay spectra exhibited good agreement with numerically calculated dispersions obtained with the three-dimensional plane wave expansion method. Furthermore, a statistical analysis of the transmission property indicated that fabrication fluctuations in individual cavities are less relevant than in the localized regime. These behaviors are observed for a chain of up to 400 cavities in a bandwidth of 0.44 THz.