Single shot picosecond optical pulse waveform measurement has been investigated by an electro-optic sampling technique. An optical gate driven by an ultrafast photoconductive switch is employed as an optical sampler. Discrete sampled signals are coupled into an optical fiber array consisting of different length fibers to control the time delay. The output of the optical fiber array is detected by a photodetector and displayed on an oscilloscope with an expanded time scale. For measurement of 100 ps duration optical pulse, the time resolution of the system was estimated to be 14 ps.