Direct-diode-pumped 10-W-level all-fiber laser at 3003 nm

We report a high-power all-fiber laser generating 10.26 W at 3003 nm, representing the first, to the best of our knowledge, 10-W-level output via a direct laser-diode (LD) pumping. The resonator is constructed by inscribing a pair of fiber Bragg gratings (FBGs) directly into an 8-m heavily Er³⁺-doped (7 mol.%) fluoride fiber using the femtosecond laser direct writing technique. To optimize the laser performance at this extreme gain edge, an independent temperature-control strategy is employed to maintain precise spectral alignment between the FBGs. Experimental observations of significant power saturation and roll-off at high pump levels are further elucidated through numerical simulations, revealing the impact of FBG thermal instability. These findings provide critical insights into the development of a compact and robust high-power all-fiber laser at 3.0 μm.