Abstract: An apparatus and method is disclosed for producing arbitrary optical and electrical waveforms. The apparatus includes a means for accepting or generating a comb-like optical spectrum, and an optical pulse shaper. The optical pulse shaper includes a spatial dispersion means, and a spatial modulating means having the capability to substantially independently modulate a characteristic of each of a pair of optical spectral lines. The apparatus and method may be used to generate a variety of waveform types, and convert between waveform types such as RZ and NRZ.