  We report shifting of the frequency of an 850 nm laser with an instantaneous
bandwidth of (350-1650), MHz and an efficiency between 35% (minimum) to 80%
(best at frequencies around 600 and 1500, MHz) by phase modulation with a
sawtooth waveform ("serrodyne frequency shifting"). We use a fiber-coupled
traveling wave electro-optical modulator driven by a nonlinear transmission
line.
