Instability limits to "fast light" optical pulse propagation

This work demonstrates a novel experimental configuration that uses two potassium vapor cells, each of which is pumped by a single monochromatic beam, to suppress modulation instability. The linear dispersive properties of the combined system gives rise to fast light (similar to dispersion management in optical telecommunication systems), but the induced modulation instability cannot occur because no atom experience the combined effect of both pump frequencies. Results also show the electronic power spectrum of the detected fluctuations in the transmitted bichromatic pump beam, optical pulse propagation through a cell of potassium atoms pumped by a bichromatic field, and a large fast-light pulse advancement using the two-zone setup.