Light manipulation in resonant photonic devices

In recent years there has been an increasing research interest aimed at the development of slow and fast light techniques. Because of their spectral properties, integrated optical cavities can be effectively exploited either as slow or fast light structures. While several authors demonstrated that coupled-resonator optical waveguide structures realized by micro-rings or photonic crystal cavities enable slow light generation, to date, much research effort is needed to demonstrate fast light devices. Integrated optical resonant devices for group velocity manipulation are critically reviewed in this paper. Modelling, optimization and potentiality of a resonant structure including two vertically-stacked micro-rings, recently investigated by the authors, are also discussed.