All-fibered high-quality low-duty cycle 20-GHz picosecond pulse source

The current bandwidth limitations of optoelectronic devices do not enable the direct generation of pulses with temporal width below a few ps and actively mode-locked fiber lasers were found to be an efficient, but onerous option to overcome this limitation. As an alternative issue to conventional mode-locking operation, we propose here a new, passive and cost-effective approach allowing the generation of picosecond optical pulse trains with very low duty-cycle (around 1/15) at a repetition rate of 20 GHz.