Generation and Dynamics Behaviors of Various Soliton Phenomena in 1.5-μm Ultrafast Er-doped Fiber Lasers

In this work, systematic experimental research was conducted on the erbium-doped fiber lasers based on the nonlinear polarization rotation technology, achieving various types of soliton pulse lasers and discussing their output laser performance. Based on the NPR technology, a highly stable traditional soliton passive mode-locked fiber laser with a pulse width of 482 fs was achieved. The bound-state soliton phenomenon was achieved by adjusting the polarization state of the laser cavity. The modulation period of the spectrum was 1.80 nm, and the corresponding interval between adjacent two pulses within the bound-state soliton was 4.2 ps. Through cavity design, the net dispersion value of the laser resonator cavity was adjusted to be close to zero dispersion, thereby generating an output of stretched soliton mode-locked pulses, with a full width at half-maximum of optical spectral exceeding 45.14 nm. Based on the experimental device of stretched pulse soliton, by adding dispersion compensation fibers to adjust the net dispersion of the resonator to positive dispersion, dissipative soliton pulse laser output was achieved, with a full width half maximum spectral as high as 29.66 nm, and the 3-dB spectral range covering about 1540 nm to 1570 nm. These results highlight the multifunctionality of the 1.5 μm fiber laser in controlling soliton pulse patterns, compactness and stability. We further conducted numerical simulations to verify these experimental results. This work will enrich the research on nonlinear photonics and pulse dynamics, and provide valuable insights for the development of ultrafast fiber lasers. It holds significant value in promoting the advancement of ultrafast fiber lasers and the broader field of pulse nonlinear polarization dynamics.