Collisions of heteronuclear dichromatic soliton compounds in a passively mode-locked fiber laser

The complexity of multi-dimensional optical wave dynamics arises from the introduction of multiple degrees of freedom and their intricate interactions. In comparison to multimode spatiotemporal mode-locked solitons, expanding the wavelength dimension is also crucial for studying the dynamics of multi-dimensional solitons, with simpler characterization techniques. By inserting a section of zero-dispersion highly nonlinear fiber (HNLF) into a passively mode-locked fiber laser, two heteronuclear dichromatic soliton compounds with different group velocities (GVs) are formed within the resonant cavity of the laser. The cross-phase modulation effect leads to the formation of a robust fast-GV compound (FGC), consisting of a partially coherent dissipative soliton bunch (PCDSB) and dispersion waves (DWs), while a conventional soliton (CS) and a narrow spectral pulse (NSP) form a slow-GV compound (SGC). Multiple SGCs can further interact to form an SGC loosely bound complex. These two types of compounds with different GVs continuously collide and exchange energy through the four-wave mixing (FWM) effect in the HNLF, promoting the annihilation, survival, and regeneration of the SGC complex. This exploration of interactions between asynchronous compounds broadens the study of soliton dynamics in multi-dimensions and offers insights for potential applications in areas such as high-throughput optical communication and optical computing.