摘要
While the performance of mode-locked fiber lasers has been improved significantly,the limited gain bandwidth restricts them from generating ultrashort pulses approaching a few cycles or even shorter.Here we present a novel method to achieve few-cycle pulses(~5 cycles)with an ultrabroad spectrum(~400 nm at-20 dB)from a Mamyshev oscillator configuration by inserting a highly nonlinear photonic crystal fiber and a dispersion delay line into the cavity.A dramatic intracavity spectral broadening can be stabilized by the unique nonlinear processes of a self-similar evolution as a nonlinear attractor in the gain fiber and a"perfect"saturable absorber action of the Mamyshev oscillator.To the best of our knowledge,this is the shortest pulse width and broadest spectrum directly generated from a fiber laser.
基金
National Science Foundation(1710914)
China Scholarship Council(201706170153)。
