2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/111941We analyze the propagation of fast-light pulses through a finite-length resonant gain medium both analytically and numerically. We find that intrinsic instabilities can be avoided in attaining a substantial peak advance with an ultra-short rather than a long or adiabatic probe.3 pages, 3 figures. Replaced with revised version submitted to Optics LettersQuantum Physicstext