A powerful light pulse propagation through an optical amplifier driven at saturation was studied theoretically and experimentally. It was shown that the maximum light pulse of aQ-switched laser propagates through amplifying medium with velocity much higher than the light velocity without any essential decrease of pulse duration. Conditions of reducing pulse duration by nonlinear amplification were found. It was found necessary to increase the leading edge rise time of the light pulse. "Superlight" velocity of propagation was measured in experiments. Appreciable reduction of pulse duration by nonlinear amplification was achieved experimentally when the leading edge of the input light pulse had been cut down by an additional Kerr cell.