In this work, we demonstrate the generation of high-performance tunable Raman solitons beyond 3 μm in a 10 cm, large-core (40 μm) fluorotellurite fiber. The pump source is a high-peak-power Raman soliton generated through soliton fission in a silica fiber. By further cascading the 10 cm highly nonlinear fluorotellurite fiber, this Raman soliton undergoes successive high-order soliton fission and soliton self-frequency shift with a tunable range of 2.7–3.3 μm. Such an ultra-short-length and ultra-large-core fiber significantly reduces the pulse width of the 3.3 μm Raman soliton to 55 fs, doubling the peak power to 2.3 MW compared to previous studies. Furthermore, owing to the seed’s high-repetition-frequency feature, the 3.3 μm Raman soliton’s power exceeds 2 W. These performance metrics represent the highest levels achieved for Raman solitons at wavelengths above 3 μm, offering a simple and effective new approach for generating high-peak-power femtosecond pulses in the mid-infrared spectral region.
