Simultaneous Generation of Bright/Dark Cavity Soliton in the Spatial-Multiplexed Kerr Resonator

The bright and dark cavity solitons (CSs) are typical stable nonlinear states that can be preserved in Kerr resonators. However, due to the distinct forming mechanisms, the generation of the two kinds of CSs requires different dispersion conditions and thus they are difficult to be produced by individual resonator, simultaneously. In this paper, we overcome this limitation through the fiber Kerr resonator constructed by the few-mode fiber (FMF). We start by designing the FMF and optimizing the dispersion characteristics of the modes such that the fundamental mode (LP01) and the higher-order mode (LP11) exhibit anomalous and normal group velocity dispersion, respectively. Subsequently, by constructing a mode-division-multiplexing resonator based on the FMF, the simultaneously emitting various nonlinear states is numerically analyzed. In particular, we achieve the simultaneous emission of bright solitons on the fundamental mode and dark solitons on the higher-order modes. Our study not only deepens the understanding of the fundamental physics of mode-division-multiplexing resonators, but also provides a promising pathway for the generation of bright and dark solitons simultaneously.