Optical comb generator as an efficient short-pulse source

We demonstrate a novel technique for converting a continuous-wave laser beam into a stable train of short pulses with a high repetition rate. The system, which is generally applicable, is based on a purely passive coupled-cavity optical frequency comb generator, which ensures a high overall efficiency. The repetition rate of the device is determined by the drive frequency of an electro-optic modulator and the pulse width by the rf power applied to the modulator. We have observed pulses down to 3.3 ps long at a 5.34-GHz repetition rate and an overall efficiency of 11%. The experimental results for pulse shape and width show excellent quantitative agreement with the results of a simple model.