Experimental studies of multiple pulses in a passively ytterbium-doped fiber laser based on graphene-oxide saturable absorber

Abstract

The different multiple pulse phenomena are experimentally studied in a passively mode-locked ytterbium-doped fiber laser based on graphene-oxide saturable absorber (GOSA) with net normal dispersion cavity. At the same pump power with different polarization orientations, we observe the multiple pulse phenomena, including harmonic mode-locking of rectangular pulses, dissipative solitons, quasi-harmonic mode-locking, periodical peak modulation, multipulse bunches, multipulse cluster, and chaotic multipulse. The inserted 2 nm narrow bandwidth filter is important for limiting the gain bandwidth and shaping pulses. Adjusting the polarization controller is equivalent to changing the gain in the laser cavity, which is the main reason for the formation of different multiple pulses states. This is the first time that different multiple pulses states have been observed in an-normal-dispersion Yb-doped fiber laser with graphene-oxide saturable absorber. These results could extend the understanding of multiple pulse dynamics in GOSA mode-locked fiber lasers.