Mode-Controllable and High-Pulse-Energy Spatiotemporally Mode-Locked Fiber Laser

Spatiotemporally mode-locked (STML) fiber lasers have been a remarkable platform for exploring multidimensional nonlinear optical dynamics and developing novel photonic devices. However, realizing high-selective transverse-mode control of STML fiber lasers is still very challenging. Here, we report transverse-mode selective operation of a 1-μm STML fiber laser by using a self-designed mode-coupling (MC) device, effectively tuning the mode-locked fiber laser across different transverse-mode states, lower-order modes, moderate-order modes and higher-order modes. In each mode state, various pulsing states including single pulse, pulse gr56oup, and multi-pulses are also achieved, with individual pulse duration tunable from 560 ps to 335 ps. What's more, STML pulses with record pulse energy of 531 nJ are realized by using large-mode-area gain fiber and highly chirping the laser pulse. Spectral width of the STML fiber laser is as narrow as 140 pm.