Energy enhancements in the mode-locked laser cavities using multi-mode fiber lasers

The averaged mode-locking dynamics in a multi-mode fiber is studied. The transverse mode structures of the electric field are determined from a linear eigenvalue problem, and the co-propagation of the corresponding mode envelopes is governed by a system of coupled Ginzburg-Landau equations (CGLEs) which accounts explicitly for bandwidth-limited saturable gain as well as saturable absorption. Simulations show that stable and robust mode-locked pulses with high energy can be produced. The maximum pulse energy is simulated as a function of the linear coupling and coiling loss. The present work provides for an excellent tool for characterizing mode-locking performance.