Wideband, Efficient Optical Serrodyne Frequency Shifting with a Phase Modulator and a Nonlinear Transmission Line

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.