Q-switched noise-like pulses with rogue waves in a Yb-doped fiber laser

Q-switched noise-like pulses (NLPs) with rogue waves in a Yb-doped fiber laser is reported. It is demonstrated that the fiber laser can operate in the mode-locked NLP state or Q-switched NLP state via adjustments to the spectral filter and pump power. To the best of our knowledge, this is the first demonstration of Q-switched NLP operation in the Yb-doped fiber laser. By increasing the period of the spectral filter, the high-energy events are observed among the Q-switched NLPs. Statistical analysis confirms the occurrence of rogue waves. The energy of a single-shot giant pulse is measured similar to 15.1 times that of the mode-locked NLP. The single-shot spectra measured by the dispersive Fourier transformation (DFT) system reveal a new type of rogue wave phenomenon. The rogue wave manifests as bound complexes consisting of an NLP and its amplified spontaneous Raman radiation, and 85 % of the pulse energy is contributed by the Raman component. We believe that the occurrence of the rogue wave is induced by sporadic Raman noise in the NLP, which is wavelength-selected by periodic transmittance of a Lyotfilter, and is rapidly amplified by Yb-doped fiber as well as the Raman effect in a few roundtrips.