Suppression of Continuous-Wave-Induced Resonant Sidebands in Soliton Molecule Spectra

Abstract

In ultrafast lasers, soliton molecules display behaviors similar to those of molecular substances, making them a significant research focus due to their scientific value and potential applications. This paper explores the complex spectral sidebands of soliton molecules in erbium-doped fiber lasers. During the experiments, we observed one or two continuous waves along with their associated complex sidebands in the spectra of soliton molecules. To obtain purer soliton molecule spectra, we investigated the generation mechanisms of these continuous waves and their induced sidebands. Our research indicates that the sidebands arise from phase matching between dispersive waves and continuous waves, leading to resonant interference. By carefully disrupting this phase matching, we successfully suppressed the continuous waves and their induced sidebands. Consequently, we achieved soliton molecule pulses with higher spectral purity and greater stability. These findings provide new insights into the design of more stable soliton molecules and demonstrate significant potential for the exploration and optimization of mode-locked fiber lasers.

Keywords: Soliton molecules, mode-locked fiber laser, continuous-wave, phase-matching