Abstract: A mode-locked cavity-dumped laser in which the dumping is phase-coherently synchronized with the mode locking. An acousto-optic modulator is employed in the cavity for dumping. On two passes through the modulator, an envelope pulse of light has two portions deflected to a common output path, one of the portions being shifted upward in frequency and the other downward, by an amount equal to the acoustic excitation frequency. The ability of the modulator to provide output power is therefore envelope-modulated at twice the acoustic frequency. The power of successive output pulses is maintained uniform by synchronizing the phase of the circulating mode-locked pulses with respect to the phase of the envelope modulation.