The evolution of soliton pulses into noise-like pulses in a nonlinear fiber externally to the laser oscillator is demonstrated at 1.9 µm, for the first time. Soliton collapse based mechanisms induce noise-like pulses with varying properties as a function of nonlinear fiber length without requiring any laser cavity feedback. The proposed method allows the generation of noise-like pulses with a sub-300 fs spike and sub-40 ps pedestal duration. Power scaling of the noise-like pulses is demonstrated in a double-clad thulium-doped fiber amplifier with amplification up to an average power of 5.19 W, corresponding to a pulse energy of 244 nJ. This method provides an alternative route for generating fully synchronized noise-like pulses and solitons in the same system, without relying on the conventionally used mechanism of changing the intracavity nonlinearity within the laser cavity.

Laser cavities which can generate different types of ultrashort pulses are attractive for practical applications and the study of pulse dynamics. Here, we report the first experimental observation of both conventional solitons (CS) and dissipative solitons (DS) generated from a single all-fiber laser with net-anomalous dispersion. A birefringence-related intracavity Lyot filter with an adjustable extinction ratio enables the switching between the two types of ultrashort pulses. Depending on the polarization controller settings and the pump power, either chirp-free CS with a pulse energy of 406 pJ and a spectral bandwidth of 5.1 nm or up-chirped DS with a pulse energy of 5.1 nJ and an optical bandwidth of 9.6 nm can be generated. Similar polarization features are observed when the laser switches between different soliton operations as both CS and DS are group-velocity-locked vector solitons. Our work paves a novel way to generate dissipative solitons with a relatively high pulse energy (one order of magnitude larger than for CS) and a large chirp directly from an all-fiber net-anomalous-dispersion cavity through birefringent filter management.

We demonstrate that soliton pulses centered at 1.9 μm can evolve into noise-like pulses in a high numerical aperture fiber. The amplified pulses have an energy of 56 nJ and a duration of 210 fs after compression.

We report a thulium-doped all-fiber mode-locked laser that can be switched between stable conventional and dissipative soliton regimes. Periodic soliton explosions with oscillatory recovery dynamics are observed in the transition between the two stable regimes.

We investigate the nonlinear pulse evolution dynamics in a Tm-doped fiber laser in real-time with a modified dispersive Fourier transform technique. Coherence degradation and recovery processes are analyzed with spectral intensity correlation maps.