Electronically tunable mid-infrared mode-locked dysprosium fiber laser with over 330 nm tunability

Mode-locked fiber lasers are currently limited to sub-3-mu m wavelengths, despite application-driven demand for longer wavelength mid-IR pulse sources. Erbium- and holmium-doped fluoride fiber lasers are emerging for 2.7-2.9 mu m emission, yet further extending this coverage is challenging. Here, we propose a new approach using dysprosium-doped fiber with frequency shifted feedback (FSF), achieving 33 ps pulses with up to 2.7 nJ energy, tunable from 2.97 to 3.30 mu m. Notably, this is the longest wavelength mode-locked fiber laser and the most broadly tunable pulsed fiber source to date. Simulations are also performed, offering insights into the dynamics of FSF pulse generation.