Vector features of pulsating soliton in an ultrafast fiber laser.

Pulsating soliton in ultrafast fiber lasers has interesting non-stationary dynamics, which is one of the hot topics in field of nonlinear soliton. So far, most researchers only focused on the spectral and temporal characteristics of pulsating soliton. However, the vector features of pulsating soliton were rarely studied. In this work, we experimentally studied the pulsating vector solitons in an ultrafast fiber laser. Three categories of vector solitons with different polarization evolution characteristics could be obtained by adjusting the pump power and polarization controller, such as pulsating polarization-locked vector soliton (PLVS), pulsating polarization-rotation vector soliton (PRVS) and progressive pulsating PRVS. Interestingly, besides the basic polarization rotation with a period of 2 roundtrips, the polarization angle also evolves with progressive mode in the progressive pulsating PRVS state. The abundant results of pulsating vector solitons demonstrate that investigating vector features of nonlinear soliton dynamics is necessary and significant and would greatly enrich the research of soliton dynamics.