Dual-Wavelength 2- $\mu \text{m}$  Fiber Laser With Coupled Fiber Bragg Grating Cavities
We develop dual-wavelength 2-μm fiber lasers with coupled cavity configurations based on fiber Bragg gratings and study their output performance and emission dynamics. Efficient cavity-coupling management leads to different dual-wavelength operation regimes. Over 3 W of output power is realized at both 1942 and 2020 nm, and a power ratio of the 1942 nm to the 2020 nm laser emissions can be tuned from 24.9% to 237.6%. This first achieved 2-μm fiber laser system with binary-wavelength emission and flexible power ratios can find applications in various areas.