[1] [1] Yeatman E M, Ahmad M M, McCarthy O et al.. Optical gain in Er-doped SiO2-TiO2 waveguides fabricated by the sol-gel technique. Opt. Commun., 1999, 164(1～3):19～25

[2] [2] Polman A. Exciting erbium-doped planar optical amplifier materials. Proc. SPIE, 2000, 3942:2～11

[3] [3] Almeida R M. Sol-gel planar waveguids for integrated optics. J. Non-Cryst, Solids, 1999, 259(1～3):176～181

[5] [5] Tanabe S, Ohyagi T, Soga N et al.. Copositional dependence of Judd-Ofelt parameters of Er3+ ions in alkali-metal borate glasses. Phys. Rev. (B), 1992, 46(6):3305～3310

[6] [6] Ofelt G S. Intensity of crystal spectra rare-earth ions. J. Chem. Phys., 1962, 37(3):511～518

[7] [7] Tanabe S. Optical transitions of rare earth ions for amplifiers: how the local structure works in glass. J. Non-Cryst. Solids, 1999, 259(1～3):1～9

[8] [8] Helen M P, Cockroft N J, Gosnell T R et al.. Uniform upconversion inhigh-concentration Er3+-doped soda lime silicate and aluminosilicate glasses. Opt. Lett., 1997, 22(11):772～774

[9] [9] Yong Gyu Choi, Kyong Hon Kim. Spectroscopic properties of and energy transfer in PbO-Bi2-Ga2O3 glass doped with Er2O3. J. Am. Ceram. Soc., 1999, 82(10):2762～2768

[10] [10] Ponnusamy Nachimuthu, Ranga Jagannathan. Judd-Ofelt parameters, and emission characteristics of Ln3+(Nd3+,Ho3+,Er3+) ions in PbO-PbF2 glasses. J. Am. Ceram. Soc., 1999, 82(2):387～392

[12] [12] Chen Xiaobo, Chen Jinhai. Up-conversion luminescence phenomenon of Er3+ ions in ErP5O14- noncrystal glass. Chinese J. Lasers, 1992, B1(5):389～393

[13] [13] Hehlen M P, Cockfoft N J, Gosnell T R et al.. Uniform upconversion in high-concentration Er3+-doped soda lime silicate and aluminosilicate glasses. Opt. Lett., 1997, 22(11):772～774