Vector pulsating solitons and soliton molecules under higher-order effects in passively mode-locked fiber lasers

We numerically study the transport dynamics of vector solitons in ytterbium-doped fiber lasers based on a coupled Ginzburg-Landau equation with higher-order effects. By adjusting the small signal gain coefficient and intracavity birefringence, the number of soliton molecules can be manipulated, the transmission of synchronous and asynchronous vector solitons and the generation of chaotic pulse sequences can be realized. Synchronous vector solitons can be generated when the intracavity birefringence is relatively low, the stable transmission of multi-soliton molecules and the interaction between soliton molecules can be achieved. By changing the value of the phase delay, periodic pulsating solitons can be produced. Furthermore, the phenomenon of the pulse train from the period-doubling to chaos can also be observed. With the enhancement of the intracavity birefringence, asynchronous vector solitons can also achieve stable transmission in the cavity, which the amplitudes and widths of two components are opposite with the different phases. The proposed model has universal application value and the numerical results have guiding significance for studying polarization tunable lasers and exploring the nonlinear mechanism in fiber lasers.