Creation of arbitrary spectra with an electro-optic modulator

We use a waveguide-based electro-optic phase modulator, driven by a nanosecond-timescale arbitrary waveform generator, to produce an optical spectrum with an arbitrary pattern of sidebands. A programmed sequence of linear voltage ramps, with various slopes, is applied to the modulator. The resulting phase ramps give rise to sidebands whose frequency offsets relative to the carrier are equal to the slopes of the corresponding linear phase ramps. This extension of the serrodyne technique provides multi-line spectra with sideband spacings in the 100 MHz range.