[1] [1] F. E. Auzel. Materials and devices using double-pumped phosphors with energy transfer. Proc. IEEE, 1973, 61(6):758～786

[2] [2] D. C. Hanna, R. M. Percival, I. R. Perry et al.. Frequency upconversion in Tm- and Yb:Tm-doped silica fibers. Opt. Comm., 1990, 78(2):187～194

[3] [3] M. P. Le Flohic, J. Y. Allain, G. M. Stephan et al.. Room-temperature continuous-wave upconversion laser at 455 nm in a Tm3+ fluorozirconate fiber. Opt. Lett., 1994, 19(23):1982～1984

[4] [4] H. Zellmer, S. Buteau, A. Tünnermann et al.. All fibre laser system with 0.1 W output power in blue spectral range. Electron. Lett., 1997, 33(16):1383～1384

[5] [5] O. A. Lopez, J. Mckittrick, L. E. Shea. Fluorescence properties of polycrystalline Tm3+-activated Y3AlO12 and Tm3+-Li+ co-activated Y3AlO12 in the visible and near IR ranges. J. Luminescence, 1997, 71(1):1～11

[6] [6] Gan Fuxi, Deng Peizheng. Laser Material. Shanghai: Shanghai Science and Technology Publishing, 1994. 392～401 (in Chinese)

[7] [7] M. Naftaly, A. Jha, B. N. Samson et al.. Spectroscopic properties of Nd in fluoroaluminate glasses for 1.3 μm optical amplifier. 11th IS(NOG)2, Sheffield, September 1998:143～148

[8] [8] R. S. Quimby, M. G. Drexhage, M. J. Suscavage. Efficient frequency up-conversion via energy transfer in fluoride glasses. Electron. Lett., 1987, 23(1):32～34

[9] [9] A. Shikida, H. Yanagita, H. Toratani. Al-Zr fluoride glass for Ho3+-Yb3+ green upconversion. J. Opt. Soc. Am. B, 1994, 11(5):928～932

[10] [10] P. M. Peters, S. N. Houde-Walter. Local structure of Er3+ in multicomponent glass. J. Non-Cryst. Solid, 1998, 239:162～169

[11] [11] J. C. Wright. Up-conversion and excited state energy tranefer in rare earth doped materials. Top. Appl. Phys., 1976, 15:239～255

[12] [12] T. Kushida. Energy transfer and cooperative optical transitions in rare-earth doped inorganic materials. Ⅰ. Transition probability calculation. J. Phys. Soc. Jpn., 1973, 34(5):1318～1326