Various‐order soliton molecule evolution in a fiber laser with nonlinear polarization rotation effect

The generation and evolution of soliton molecules are investigated theoretically with the coupled nonlinear Schrodinger equations based on a vector field. The formation of second‐and third‐order soliton molecules is investigated. Besides this, various‐order soliton molecules from the 6th order to the 13th order have been observed by adjusting small‐signal gain and phase delay. Finally, we analyze the reason for the soliton molecule generation. Exploring soliton molecules is helpful for optical communication as well as for fiber laser design.