Real-time observation of soliton pulsation in net normal-dispersion dissipative soliton fiber laser

We present experimental observations of soliton pulsations in the net normal-dispersion fiber laser by using the dispersive Fourier transform(DFT) technique. According to the pulsating characteristics, the soliton pulsations are classified as visible and invisible soliton pulsations. The visible soliton pulsation is converted from single-into dual-soliton pulsation with the common characteristics of energy oscillation and bandwidth breathing. The invisible soliton pulsation undergoes periodic variation in the spectral profile and peak power but remains invariable in pulse energy. The reason for invisible soliton pulsation behavior is periodic oscillation of the pulse inside the soliton molecule. These results could be helpful in deepening our understanding of the soliton pulsation phenomena.

Spatio-spectral dynamics of soliton pulsation with breathing behavior in the anomalous dispersion fiber laser

We have numerically and experimentally observed the soliton pulsation with obvious breathing behavior in the anomalous fiber laser mode-locked by a nonlinear polarization rotation technique.The numerical study of the soliton pulsation with breathing behavior was analyzed through the split-step Fourier method at first,and it was found that the phase difference caused by the polarization controller would affect the breathing characteristics.Then,taking advantage of the dispersive Fourier transform technique,we confirmed the breathing characteristic of soliton pulsation in the same fiber laser as the simulation model experimentally.These results complement the research on the breathing characteristic of soliton pulsation.

Comprehensive analysis of pure-quartic soliton dynamics in a passively mode-locked fiber laser

The understanding of soliton dynamics promotes the development of ultrafast laser technology. High-energy purequartic solitons(PQSs) have gradually become a hotspot in recent years. Herein, we numerically study the influence of the gain bandwidth, saturation power, small-signal gain, and output coupler on PQS dynamics in passively mode-locked fiber lasers. The results show that the above four parameters can affect PQS dynamics. Pulsating PQSs occur as we alter the other three parameters when the gain bandwidth is 50 nm. Meanwhile, PQSs evolve from pulsating to erupting and then to splitting as the other three parameters are altered when the gain bandwidth is 10 nm, which can be attributed to the existence of the spectral filtering effect and intra-cavity fourth-order dispersion. These findings provide new insights into PQS dynamics in passively mode-locked fiber lasers.

Interactions of adjacent pulsating, erupting and creeping solitons

This paper investigates the adjacent interactions of three novel solitons for the quintic complex Ginzburg-Landau equation, which are plain pulsating, erupting and creeping solitons. It is found that different performances are presented for different solitons due to isolated regions of the parameter space where they exist. For example, plain pulsating and erupting solitons exhibit mutual annihilation during collisions with the decrease of total energy, but for creeping soliton, the two adjacent pulses present soliton fusion without any loss of energy. Otherwise, the method for restraining the interactions is also found and it can suppress interactions between these two adjacent pulses effectively.

Properties of pulsating solitons in dissipative systems

In this paper, a set of detailed numerical simulations of pulsating solitons in certain regions, where the pulsating solitons exist, have been carried out. The results show that the transformation between pulsating soliton and fronts can be realised through a series of period-doubling bifurcations, while there exist many kinds of special solutions. The complete transformation diagram has been obtained when the value of nonlinear gain varies within a definite range. The detailed analysis of the diagram reveals that the pulsating soliton experiences period-doubling bifurcations for smaller values of the nonlinear gain. For larger values of it, the pulsating solitons show chaotic behaviour and complex pulse splitting except for some special bifurcations. With the value of nonlinear gain increasing further, the pulse profiles resume pulsating, but the pulse energy are much higher than before and the pulse centre may move along the propagation direction.