On the generation of high-quality Nyquist pulses in mode-locked fiber lasers

Nyquist pulses have wide applications in many areas, from electronics to optics. Mode-locked lasers are ideal platforms to generate such pulses. However, how to generate high-quality Nyquist pulses in mode-locked lasers remains elusive. We address this problem by managing different physical effects in mode-locked fiber lasers through extensive numerical simulations. We find that net dispersion, linear loss, gain and filter shaping can affect the quality of Nyquist pulses significantly. We also demonstrate that Nyquist pulses experience similariton shaping due to the nonlinear attractor effect in the gain medium. Our work may contribute to the design of Nyquist pulse sources and enrich the understanding of pulse shaping dynamics in mode-locked lasers.