Study on Energy Level and Spectral Characteristics of High Power Yb Doped Fiber Laser

摘要

The energy level structure and spectral characteristics of Yb-doped fiber laser are analyzed, and the absorption and emission cross sections of ytterbium ions in quartz matrix are given. It can be seen that there are two absorption peaks, 915 nm and 975 nm, respectively. The absorption coefficient corresponding to 915 nm absorption peak is smaller, but the absorption spectrum is wider. The absorption coefficient corresponding to the absorption peak at 975 nm is relatively large, but the spectrum width is very narrow. The advantages and disadvantages of Yb~(3+) doped laser materials compared with other rare earth ions doped laser materials are analyzed. It is pointed out that Yb3+ itself, due to its strong absorption and emission at 980 nm, disperses the pump power in the inner cladding of double cladding optical fibers and reduces the pump efficiency.