High repetition frequency spatiotemporal mode-locked fiber laser based on cavity induced modulation instability

Intermodal dispersion and modal instability have been the primary challenges for achieving spatiotemporal mode-locked (STML) in multimode fiber. This paper utilizes the nonlinear multimode interference effect to redistribute the mode energy and suppress the intermodal dispersion. By building on this approach and combining it with cavity-induced modulation instability (CIMI), we experimentally demonstrate the STML pulse with a high repetition frequency of 1.116 GHz, corresponding to a harmonic order of 93. Our research not only significantly expands the application of spatiotemporal mode-locked lasers in high repetition frequency systems, but also provides valuable insights for further understanding the dynamics of spatiotemporal mode-locking.