2.8μm high-repetition-rate fiber laser based on hybrid mode-locking

2.8 μm band mid-infrared fiber laser has attracted much attention because of its important application value in the field of laser medicine. In this study, a high repetition rate fiber laser system based on Er:ZBLAN fiber was successfully developed. The system adopts a short-cavity hybrid mode-locked structure as the seed source, and achieves for the first time a stable mode-locked pulse output of 176 MHz in the mid-infrared band, with an average output power of 442 mW, a pulse width of 285 fs, and a central wavelength of 2789 nm, which, to the best of our knowledge, is the highest pulse repetition rate ever generated directly by femtosecond fluoride-based fiber lasers. This research result not only expands the operating parameter range of mid-infrared mode-locked fluoride fiber lasers, but also provides a reliable technological solution to achieve longer wavelengths for high-precision ultrafast laser applications.