Completely Capturing Light Pulses in a Few Dynamically Tuned Microcavities

We describe a dynamically tuned system capable of capturing light pulses incident from a waveguide in a pair of microcavities. We use coupled mode theory to design a method for determining how to tune the microcavity resonant frequencies. The results show that pulses can be captured almost completely, with arbitrarily small reflected power. We optimize the pulse capture bandwidth by varying the cavity coupling constants and show that the maximum bandwidth is comparable to the resonant-frequency tuning range. Our system may be implemented using refractive-index tuning in a 2-D silicon photonic crystal slab. Current technology would allow for capture of pulses with widths as low as ~100 ps, with a holding time limited only by cavity loss rates.