Opt. Lett. 39, 3484–3487 (2014)

Optical solitons are localized wave packets that retain their shape during propagation in an optical fibre due to the interplay of competing nonlinear and dispersive effects. Those with a peak intensity larger than the background are called 'bright' and those with a lower intensity than the background are called 'dark'. The latter are less sensitive to noise and fibre losses than the bright type and hence are promising for robust optical communication. Now, Y. F. Song and colleagues from the Jiangsu Normal University in China and the Nanyang Technological University in Singapore have demonstrated a dark soliton fibre laser around 1580 nm that operates at repetition rates as high as 280 GHz. The researchers took advantage of the modulation instability induced in a fibre loop cavity to increase the repetition rate of the dark solitons that naturally form. The repetition rate was then externally controlled by adjusting the power of the pump laser.