Pulsating Soliton Dynamics in an All-Normal Dispersion Fiber Laser Based on MZI-Lyot Composite Filter

We experimentally and numerically demonstrate the controllable manipulation and dynamic switching among single-period pulsating soliton, period-doubled pulsating soliton, and asymmetric-spectral period-doubled pulsating soliton (ASPD-PS) in all-normal dispersion Yb-doped mode-locked fiber laser based on semiconductor saturable absorber mirror and Mach-Zehnder interferometer (MZI)-Lyot composite filter. The multiscale tunable filtering properties and asymmetric MZI structure provide a key regulating dimension and implementation pathway for generating diverse pulsating solitons. By utilizing the time-stretched dispersive Fourier transform technique, we observe that the ASPD-PS features an asymmetric profile between consecutive round trips, along with alternating red and blue shifts of the central wavelength and periodic intensity oscillations. Numerical simulations further verify that the generation of these pulsation behaviors are related to the spectral filtering effect and cross-phase modulation. Our findings deepen the understanding of nonlinear dynamics and present potential application value in high-capacity information processing.