Development of superluminal pulse propagation in a serial array of high-Q ring resonators

We experimentally examined the development of superluminal pulse propagation through a serial array of high-Q ring resonators that provides a dynamic recurrent loop. As the propagation distance, i.e., the number of ring resonators that the pulses passed through increased, the pulse advancement increased linearly, largely maintaining its Gaussian shape. The sharp edge encoded at the front of the pulse was, however, neither advanced nor delayed,...