The chirping characteristics of traveling-wave semiconductor laser amplifiers (TW-SLAs) are analyzed in detail. The chirping compensation of light source chirping and fiber dispersion, using self-phase modulation (SPM) induced by gain saturation in a TW-SLA, is demonstrated theoretically. The possibility of phase compensation is shown in all the cases of different input pulse widths (much shorter, comparable, and far longer than the amplifier carrier lifetime). This feature can be used to achieve energy amplification with phase compensation of weak chirped pulses in long-haul optical communication systems.