Shape preserving atomic pulse amplifier

Propagation of a weak probe pulse through $\Lambda$ system in resonant gain configuration is investigated. We employ the control field intensity that permits amplification during propagation, without instability at two photon resonance. Posterior to amplification, broadened obtained, which retains its initial shape and travels speed light vacuum, experiencing any delay, absorption, dispersion. The salient feature this technique lies fact addition preserving shape, it also ensures stable propagation after amplification. It works for arbitrary shapes.