Real‐Time Observation of Double‐Hopf Bifurcation in an Ultrafast All‐PM Fiber Laser

Hopf‐type bifurcation dynamics, a universal phenomenon existing in numerous physical systems, has recently been observed in mode‐locked erbium‐doped fiber lasers with anomalous or normal net dispersion. This study demonstrates the real‐time experimental observation of double‐Hopf‐type breathers in an all‐normal dispersion all‐polarization maintaining ytterbium‐doped fiber laser instead. It is shown that the breather frequency can be modulated periodically by the additional oscillation with increasing amplitude in response to increased pump power until a stationary dissipative soliton is formed. The possible explanation of the observed double‐Hopf‐like bifurcation dynamics is discussed by exploring the numerical approach that combines the interplay of the population inversion in the laser medium with the pulses energy. The results provide additional building blocks for further understanding laser physics and can help in optimizing fiber cavity designs. Hopf‐type bifurcation dynamics is a universal phenomenon existing in numerous physical systems. This study demonstrates the real‐time experimental observation of double‐Hopf‐type breathers in ultrafast fiber lasers, where the breather frequency is modulated by an additional oscillation. These results may significantly contribute to a more profound understanding of laser physics, and bring attractive perspectives for several cutting‐edge technological applications.