A tapered‐stripe, traveling‐wave semiconductor optical amplifier was seeded with 3.3 mW of gain‐switched diode laser light to obtain over 200 mW average power with pulse widths≊105 ps full width at half‐maximum (FWHM) and a pulse repetition rate of 499 MHz corresponding to a peak power of 3.8 W. Shorter pulse widths were obtained when the amplifier was driven with less current at the expense of reduced output power. Pulse widths as short as 31 ps FWHM and an average power of 98 mW corresponding to a peak power of 6.3 W were obtained when a different, lower power seed laser was used. ©1995 American Institute of Physics.