Modeling of gain and phase dynamics in quantum dot amplifiers

By means of an electron hole rate equationmodelwe explain the phase dynamicsof a quantum dot semiconductor optical amplifier and the appearance of different decay timesobserved in pump and probe experiments. The ultrafast hole relaxation leads to a first ultrafastrecovery of the gain, followed by electron relaxation and, in the nanosecond timescale,radiative and non-radiative recombinations. The phase dynamics is slower and is affected bythermal redistribution of carriers within the dot. We explain the ultrafast response of quantumdot amplifiers as an effect of hole escape and recombination without the need to assumeAuger processes