Intrinsic evolution pathway connecting two quasi-steady dissipative soliton states in a pulsating Yb-doped fiber laser

The pulsating behavior of dissipative solitons is a typical manifestation of complex nonlinear dynamics in ultrafast fiber lasers. However, the intrinsic evolution of dissipative solitons within a single pulsation cycle remains largely unexplored. Here, we observe a pulsating state in an Yb-doped fiber laser and reveal an intrinsic evolution pathway connecting two quasi-steady dissipative soliton states. Within one pulsation cycle, the system evolves from an initial quasi-steady dissipative soliton state through a sequence of nonlinear regimes associated with period-doubling bifurcation signatures, a period-3 window, and chaotic behavior, and finally evolves into another quasi-steady dissipative soliton state. Real-time spectral measurements further reveal that the transition occurs through continuous spectral reshaping, indicating a gradual transformation between the two quasi-steady dissipative soliton states. These findings provide insights into the intrinsic evolution of dissipative solitons and the emergence of complex evolution pathways in nonequilibrium dissipative systems.