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

Abstract

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 beseen that there are two absorption peaks, 915 nm and 975 nm, respectively. The absorption coefficientcorresponding to 915 nm absorption peak is smaller, but the absorption spectrum is wider. Theabsorption coefficient corresponding to the absorption peak at 975 nm is relatively large, but thespectrum width is very narrow. The advantages and disadvantages of Yb3+ doped laser materialscompared 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 innercladding of double cladding optical fibers and reduces the pump efficiency.