All-fiber high-power spatiotemporal mode-locked laser based on multimode interference filtering

Multimode interference (MMI) has been considered to be critical and investigated extensively in mode-locked laser based on single transverse mode systems, whereas there are few researches related to three-dimensional nonlinear dynamics within lasers. In this paper, we demonstrate all-fiber high-power spatiotemporal mode-locked (STML) laser by optimizing MMI filtering, where we find that the MMI filtering plays an important role in counteracting the coupling of high-order modes and improving output power of STML laser. The results under weak coupling condition when the length of graded-index multimode fiber (GIMF) is integral multiple of beat length show that the oscillator generates dissipative soliton pulses at 1036.86 nm with pulse width of 5.65 ps, and the slope efficiency of pump-signal is up to 10.3% with average power/energy of 215 mW/6 nJ, which is the highest among all-fiber STML lasers in normal dispersion regime. Besides, the multiple-soliton of STML, including multiple pulses and harmonic mode-locking can be observed in the experiment. Our work significantly broadens the dimensions of design for all-fiber high-power STML and makes them much more accessible for being put into applications. (C) 2022 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

In this paper, an all-fiber high-power spatiotemporal mode-locked (STML) laser is demonstrated by optimizing multimode interference (MMI) filtering. The experiment results show the generation of dissipative soliton pulses and the observation of multiple solitons. This work broadens the design dimensions of all-fiber high-power STML and has significant applications.