Factors that reduce the duration of picosecond stimulated emission of the Al<sub>x</sub>Ga<sub>1–x</sub>As–GaAs–Al<sub>x</sub>Ga<sub>1–x</sub&amp

New experimental data have been obtained indicating the following two reasons for the previously discovered significant decrease in the duration of the intrinsic picosecond emission of the AlxGa1–xAs–GaAs–AlxGa1–xAs heterostructure emerging from its end in a preferred direction: 1) the emission reflected from the end returning to the active region takes up a significant portion of the population inversion energy that would otherwise be spent on generating emission moving toward the end; 2) the resulting inhomogeneities in the reflected emission caused such a switching of the states of the multistable photonic crystal induced in the heterostructure by its emission that the forbidden zone for the emission emerging from the end in a preferred direction grew, and the emission trajectories changed in the heterostructure and, as a consequence, in the air space.