Monolithic Single-Mode Nd-Doped Fiber Laser Operated at 915-nm With 37% Slope Efficiency

We report a highly efficient, Nd-doped all-fiber laser operating based on the three-level transition at 915 nm. A key feature of the laser is a novel active fiber with cladding-embedded absorbing rods that suppress parasitic amplified spontaneous emission (ASE) at 1060 nm. The laser demonstrates 37% slope efficiency, which is, to the best of our knowledge, the highest reported value among all-fiber lasers with near-diffraction-limited beam quality (M² < 1.2). Strong ASE suppression with a signal-to-ASE ratio exceeding 50 dB was achieved. Further output power and efficiency scaling can be reached by optimization of fiber components used in the laser cavity.