A simulation approach is presented that permits an accurate description of the behavior of a traveling-wave semiconductor laser amplifier fed by a multicarrier signal. It is shown to be equivalent to an exact solution of the discretized rate equation governing the amplifier behavior. The method is general enough to handle realistic input signal carriers as in a numerical FDM (frequency division multiplexing) environment. Comparisons with previously proposed models confirm the accuracy and flexibility of the approach.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>