Open AccessLarge pulse delay and small group velocity achieved using ultrahigh-Q photonic crystal nanocavities
Author(s) -
Takasumi Tanabe,
Masaya Notomi,
Eiichi Kuramochi,
Hideaki Taniyama
Publication year - 2007
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.007826
Subject(s) - optics , photonic crystal , slow light , group velocity , coupling (piping) , resonance (particle physics) , materials science , photon , wavelength , photonics , waveguide , pulse (music) , group delay and phase delay , optoelectronics , physics , atomic physics , detector , computer network , bandwidth (computing) , computer science , metallurgy
We systematically studied the spectral and temporal characteristics of wavelength-sized ultrahigh-Q photonic crystal nanocavities based on width-modulated line defects. By employing accurate measurements, we confirmed that the cavity exhibits an ultra-sharp resonance width (1.23 pm), an ultrahigh-Q (1.28x 10(6)), and an ultra-long photon lifetime (1.12 ns).We discussed the correlation between the spectral and temporal measurements for various cavities, and obtained extremely good agreement. In addition, we demonstrated photon trapping for the side-coupling configuration by employing ring-down measurement, which sheds light on another interesting aspect of this phenomenon. Finally, we performed pulse propagation experiments for samples with different waveguide-cavity coupling configurations, and achieved a smallest group velocity of about 4.6 km/s for a novel configuration. These results show that we can effectively trap and delay light by using ultra-small cavities, which can potentially increase the packing density of optical buffers and bit-shifters if applied to coupled-cavity waveguides.