Abstract: An electrical pulse of predetermined waveform is generated to control an electro-optical shutter to cut out a portion of predetermined waveform from a laser pulse passing therethrough. The electrical pulse is generated across the plates of a capacitor. A DC source is connected directly to one of the plates and the other via a conductor and a semiconductor switch.The waveform is generated by illuminating the semiconductor switch with a series of short rapid light pulses from a mode-locked laser generator. A staircase waveform results with each step corresponding to a pulse from the mode-locked laser. The waveform can be matched to the predetermined model by adjusting the intensity and the spacing of the switching laser pulses.The falling portion of the waveform can be similarly produced using a second semiconductor switch connected between the capacitor plates together. For a very steep falling edge a single high intensity light pulse can be applied shorting the plates together via the second switch.