Optical and laser properties of Yb3+-doped Al2O3–P2O5–SiO2 large-mode-area photonic crystal fiber prepared by the sol–gel method

Yb3+, Al3+ and P5+ co-doped silica glass with the composition of 0.05Yb2O3–2.0Al2O3– 1.0P2O5–96.95SiO2 (mol%) was prepared by the sol–gel method. Using this glass as the fiber core, the corresponding large-mode-area (LMA) photonic crystal fiber (PCF) was drawn by the stack-capillary-draw technique. Spectral properties of the silica glass chip and LMA PCF are discussed. Pumped with a 976 nm laser diode, the PCF fiber achieved the highest laser output power of 34.6 W at ∼1040 nm, with a slope efficiency of 62%. To the best of our knowledge, this is the highest laser output power report on Yb3+-doped silica LMA PCF prepared by the sol–gel method. (letter)