Spatiotemporal mode-locked (STML) fiber lasers have become a new platform for investigating nonlinear phenomena. In this work, spatiotemporal dual-periodic soliton pulsation (SDSP) is firstly observed in an STML fiber laser. It is found that in the SDSP, the long-period pulsations (LPPs) of different transverse modes are synchronous, while the short-period pulsations (SPPs) exhibit asynchronous modulations. The numerical simulation confirms the experimental results and further reveals that the proportion of transverse mode components can manipulate the periods of the LPP and SPP but does not affect the synchronous and asynchronous pulsations of different transverse modes. The obtained results bring the study of spatiotemporal dissipative soliton pulsation into the multi-period modulation stage, which helps to understand the complex spatiotemporal dynamics in STML fiber lasers and discover new dynamics in high-dimensional nonlinear systems.

中文翻译：

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多模光纤激光器中的时空双周期孤子脉动

时空锁模（STML）光纤激光器已成为研究非线性现象的新平台。在这项工作中，首次在 STML 光纤激光器中观察到时空双周期孤子脉动（SDSP）。研究发现，在SDSP中，不同横模的长周期脉动（LPP）是同步的，而短周期脉动（SPP）则表现出异步调制。数值模拟证实了实验结果，并进一步揭示了横模分量的比例可以操纵LPP和SPP的周期，但不影响不同横模的同步和异步脉动。获得的结果将时空耗散孤子脉动的研究带入多周期调制阶段，有助于理解STML光纤激光器中复杂的时空动力学，发现高维非线性系统中的新动力学。