Multi-pulse dynamic patterns in a mode-locked erbium-doped fiber laser based on an Sb₂S₃-PVA saturable absorber

Abstract

Multi-pulse dynamic patterns have been experimentally documented in a passively mode-locked (PML) erbium-doped fiber (EDF) laser using an Sb2S3-PVA saturable absorber (SA). The fundamental mode-locking operation with a repetition rate of ~3.22 MHz, a pulse width of ~2 ns, an SNR of ~50 dB and a peak power over 200 W, was achieved under pump power from 280 to 360 mW with appropriate polarization states introduced by the polarization controllers (PCs). By rotating the orientation of intra-cavity PCs carefully and slowly at a pump power of 350 mW, it was found that a multi-pulse bunch was transformed gradually from a single-pulse to a twelve-pulse bunch, with several intermediate transition states of multi-pulse bunches being observed. In addition, other characteristic modes including disordered multi-pulses and soliton rains have been experimentally observed by meticulously adjusting polarization of PCs at a pump power of 350 mW. Our systematic study clearly demonstrated that Sb2S3 has promising potential as an effective SA for generating different operation states of multi-pulses in PML anomalous-dispersion EDF lasers.