A new technique has been developed for the generation and shaping of KrF laser pulses on a picosecond time scale using a fast electro-optic modulator. Subnanosecond electrical pulses with an amplitude much greater than the half-wave voltage are applied to the Pockels cell, which generates a train of short ultraviolet pulses. The first pulse in this train is then isolated and shortened to 30 psec by the combined effect of propagation through a saturated amplifier and optical breakdown in xenon.