Investigation on switchable operation states in a Tm/Ho co-doped fiber laser based on nonlinear optical loop mirror

Abstract

The nonlinear pulse dynamics have been studied in a thulium/holmium co-doped passively mode-locked fiber laser based on nonlinear optical loop mirror (NOLM). By enhancing the nonlinear effect of the cavity and without changing the polarization state of the cavity, four types of operation states that switch between each other, including the basic mode-locking pulse, the two solitons pulse, the bright-dark pulse, and the harmonic mode-locking pulse, can be obtained. Compared with the laser of single mode-locking state, passively mode-locked fiber lasers (PMLFLs) with switchable operation states can be used in a wide range of applications, such as optical communication, material processing and optical fiber sensing technology.