Enhancing slow and fast light effects in quantum dot semiconductor waveguides through ultrafast dynamics

We show that ultrafast carrier dynamics plays an important role on slow and fast light effects based on coherent population oscillations in quantum dot semiconductor waveguides. Fast light in the gain regime and slow light in the absorption regime are found to be enhanced at frequencies beyond the usual limits of the carrier lifetime. The effects are investigated by a comprehensive model and shown to originate from non-equilibrium dynamics within the quantum dot carrier populations.