Nonlinear pulse propagation in InAs/InP quantum-dot optical amplifiers: Rabi-oscillations in the presence of non-resonant nonlinearities

摘要

We study the interplay between coherent light-matter interactions andnon-resonant pulse propagation effects when ultra-short pulses propagate inroom-temperature quantum-dot (QD) semiconductor optical amplifiers (SOAs). Thesignatures observed on a pulse envelope after propagating in a transparent SOA,when coherent Rabi-oscillations are absent, highlight the contribution oftwo-photon absorption (TPA), and its accompanying Kerr-like effect, as well asof linear dispersion, to the modification of the pulse complex electric fieldprofile. These effects are incorporated into our previously developedfinite-difference time-domain comprehensive model that describes theinteraction between the pulses and the QD SOA. The present, generalized, modelis used to investigate the combined effect of coherent and non-resonantphenomena in the gain and absorption regimes of the QD SOA. It confirms that inthe QD SOA we examined, linear dispersion in the presence of the Kerr-likeeffect causes pulse compression, which counteracts the pulse peak suppressiondue to TPA, and also modifies the patterns which the coherent Rabi-oscillationsimprint on the pulse envelope under both gain and absorption conditions. Theinclusion of these effects leads to a better fit with experiments and to abetter understanding of the interplay among the various mechanisms so as to beable to better analyze more complex future experiments of coherent light-matterinteraction induced by short pulses propagating along an SOA.