Generation of a noise-like pulse from an erbium-doped fiber laser based on nonlinear multimode interference

A noise-like pulse (NLP) is generated in an anomalous-dispersion passively mode-locked erbium-doped fiber laser using graded-index multimode fiber (GIMF) as the all-fiber saturable absorber (SA) for the first time. By splicing two sections of bending GIMF at both ends of a single mode fiber and optimizing the birefringence and nonlinear parameters, stable NLP mode-locking operation can be achieved within a wide pump power range. Meanwhile, the performances of NLP mode-locking have been analyzed experimentally by changing the length of the GIMF.