Passively mode-locked multi-mode fiber laser

Summary form only given. Fiber amplifiers and lasers based on multimode (MM) fibers have recently allowed a great increase in the pulse peak powers and pulse energies available from a fiber optic geometry. These advances are made possible due to the increase in mode-size of the fundamental mode feasible with MM fibers. To date, however, applications of MM fibers in the field of fiber optics were somewhat restricted due to the limitations in mode-quality achievable from a MM fiber amplifier. Here we overcome the spatial mode problem by precision splicing a single-mode mode-filter fiber to the MM fiber for fundamental mode excitation.