We report statistical fluctuations for the transmissions of a series of photonic-crystal waveguides (PhCWs) that are supposedly identical and that only differ because of statistical structural fabrication-induced imperfections. For practical PhCW lengths offering tolerable −3dB attenuation with moderate group indices (ng≈60), the transmission spectra contains very narrow peaks (Q≈20,000) that vary from one waveguide to another. The physical origin of the peaks is explained by calculating the actual electromagnetic-field pattern inside the waveguide. The peaks that are observed in an intermediate regime between the ballistic and localization transports are responsible for a smearing of the local density of states, for a rapid broadening of the probability density function of the transmission, and bring a severe constraint on the effective use of slow light for on-chip optical information processing. The experimental results are quantitatively supported by theoretical results obtained with a coupled-Bloch-mode approach that takes into account multiple scattering and localization effects.

Opt. Express

Mazoyer, S., Lalanne, P., Rodier, J. C., Hugonin, J. P., Spasenović, M., Kuipers, K., … Krauss, T. F. (2010). Statistical fluctuations of transmission in slow light photonic-crystal waveguides. Opt. Express, 18(14), 14654–14663. doi:10.1364/OE.18.014654