Dynamics of a radiation spectrum of the DFDL, excited by radiation of nanosecond duration

In this paper we showed, that the minimal width of a radiation spectrum of the DFDL is determined by change of population density of the upper laser level. Sharp falling of the population density of the upper laser level, corresponding to the generation of a single ultra-short pulse, causes a change of a refraction index of the active medium, resulting to the presence of a spectrum broadening of the radiation. The increase of a pumping level conducts to the increasing of the spectrum width, besides broadening in the short-wave side is more, than in the longwave one.