The possibility of slowing down or storing light holds interests in classical or quantum optical communications. Different schemes have been proposed; among them, active resonator-based devices seem to provide a scalable and low loss solution for this purpose. This paper will be devoted to the theoretical and experimental studies of active coupled resonator delay lines. High-quality (Q) factor resonators are strongly dispersive systems which can be used to control the group velocity of light. As it is the case for atomic systems the dispersion properties of these artificial media is dependent on their absorption or optical gain. Moreover by coupling several resonators it is also possible to tailor their transmission or high dispersion orders . For these two reasons, active coupled resonators may be of high interest for optical dispersion or delay lines. In the aim of practical applications, the first step consists in defining an experimental protocol allowing a resonator complete description to be obtained. Cavity ring down spectroscopy method can be adapted to obtain the essential parameters such as gain/absorption and dispersion. The method has been validated using a model system made of Er3+ doped optical fiber resonators and applied to various high-Q whispering gallery mode resonators including resonators under modal coupling. It is possible to find coupling configurations allowing the dispersion of coupled active resonator systems to be tailored by changing the optical losses or gain of each resonator. In particular these systems may be used as tunable transparent delay lines or for dispersion compensation. This last configuration can be used to enhanced or actively control the quality factor of passive cavities. Finally the dynamic control of dispersion or resonance properties via the gain control of active coupled microresonators could find some applications in optical buffering.