Yb-Doped Aluminophosphosilicate Triple-Clad Laser Fiber With High Efficiency and Excellent Laser Stability

摘要

We fully demonstrated an ytterbium (Yb) doped triple-clad laser fiber with intense pump absorption, high efficiency, and laser stability. P5+/Al3+. molar ratio in the central region of fiber core was specially designed to be similar to 1.08 for compensating P2O5 evaporation, while the ratio in the outer region was set as similar to 0.92 for obtaining a flattened refractive index profile. Applying a two-stage deposition process, one-time collapse technique, low-temperature multi-times sintering, and suitable flow of pure POCl3 during sintering and collapsing process were instrumental in decreasing and offsetting element evaporation. Measured in an all-fiber master oscillator power amplifier configuration, the 7-m-long fiber obtained 1.39 kW nearsingle-mode laser output at 1079.6 nm with a slope efficiency of 85.2% and a beam quality M-2 of 1.36. Output laser spectrum with no sign of nonlinear-related peaks and a narrow 3-dB-bandwidth of similar to 0.33 nm was obtained. The fiber-based laser setup was kept at the maximum power for 1 h with power degradation less than 0.21%. The results demonstrated Yb-doped aluminophosphosilicate triple-clad fiber is a highly competitive candidate for commercial high-power laser and high-power narrow-linewidth fiber laser.