Pure high-even-order dispersion pulsating dynamics in soliton fiber lasers

Soliton pulsation, an intriguing unstable pulse structure with periodic evolution, has consistently attracted the attention of researchers. Herein, we numerically demonstrate the generation of pulsating dynamics in a soliton fiber laser with pure high-even-order dispersion (PHEOD). Our findings primarily uncover two types of pulsations, creeping states and period bifurcations, which are mainly driven by the mismatch between the phase induced by self-phase modulation (SPM) and PHEOD. Furthermore, by observing the “bifurcation tree” pattern generated by increasing gain saturation energy (Es), we revealed a distinct pattern in PHEOD soliton lasers, characterized by alternating transitions between the single soliton state (encompassing both stable mode-locked and pulsating states) and the chaotic state. Ultimately, by analyzing the state distributions under different PHEOD and Es, we found that the phenomenon of period bifurcation is more likely to occur under higher-order dispersion conditions. These insights broaden the fundamental understanding of solitons and highlight the universal behavior of soliton pulsations in novel laser systems.