Generation of soliton rain in a passive mode-locked Tm-doped fiber laser at 2 µm

Abstract

In this paper, the experimental investigation and theoretical analysis on the soliton rain generated in the Tm-doped fiber laser have been carried out. On the basis of nonlinear polarization rotation technology, the fundamental and harmonic soliton rain pulses were obtained, the influence of net negative dispersion cavity length on the output performances of soliton rain pulse were studied, and the spectral sideband characteristics of soliton rain were numerically analyzed. By comparing the spectra of continuous wave mode-locking and soliton rain states, it can be found that the quasi-periodic modulation exists for the spectral sideband of soliton rain resulted from the complex interaction between the dispersive wave and the soliton wave. The interaction is one of the major factors for the formation of soliton rain. The research results are helpful for the better understanding of the soliton rain dynamics and mechanism in passive mode-locked fiber lasers.