| In optical fiber communication system, wavelength range of 800nm to 1625nm in near infrared region has been widely applied into data transmission. At present, the investigations of erbium doped silica fibers whose main work window in 1530-1560nm C-band have already been quite mature, but the band only use a portion of the quartz single-mode optical fiber low loss window, limiting the full use of optical fiber channel. Nd3+possesses typical-1060nm and-1330nm near infrared fluorescent emissions, among which the-1330nm emission band belongs to the O-band, and is located in the second traditional communication window with minimal dispersion. Therefore, neodymium doped glass waveguide amplifier is the next promising optical amplifier since the development of the erbium doped fiber amplifier (EDFA), and semiconductor optical amplifier (SOA).Nd3+doped medium-low phonon energy germanate glasses were synthesized by optimizing the doping concentration of Nd2O3. The optical and spectral properties of germanate glasses were tested and analysesed with 2wt% Nd2O3 as the optimal doping concentration. Optical channel waveguides were prepared by K+-Na+ ion exchange method on the Nd3+ doped germanate glass surface, and the near infrared fluorescence spectra were characterized and investigated systematically, which layed the foundation for Pr3+, Er3+ and Ho3+ ions doped germanate glasses used for O-, S-and U- and other special band signal amplifier. The research results of this paper were as follows:1. Nd3+-doped NMAG glasses were prepared from high-purity Na2CO3, MgO, Al2O3, GeO2, and Nd2O3 powders according to the host molar composition 23Na2O-2MgO-22Al2O3-53GeO2, and 0.1,1,2,3 and 4wt% Nd2O3 based on the host weights for low- and high-concentration doping cases are adopted. According to the theory of Judd-Ofelt, the absorption spectrum of 2wt%Nd2O3 doped NMAG glass was fitted, and the intensity parameters Ωt (t= 2,4,6) of Nd3+were derived to be 5.45×10-20, 4.60×10-20, and 4.97×10-20cm2, respectively. The spontaneous oscillator strength, predicted spontaneous emission probabilities, radiative lifetime and branching ratios of Nd3+ ions were calculated. Fluorescence lifetimes, quantum efficiencies, and cross-relaxation rates for 4F3/2 level of Nd3+ in NMAG glasses were obtained. The maximum emission crosssections of the 1.065μm and 1.337μm emission bands were caculated to be 21.5×10-21 and 7.6×10-21cm2, respectively. The low phonon energy and large absorption and emission crosssections, help to absorb enough pump energy and contribute to efficient energy transfer, indicating that the Nd3+ oped germanate glasses are suggested being adopt for the infrared laser working material. Based on the theoretical study, the quantum efficiency of 4F3/2→4I11/2 transition was derived to be-71.3%.2. By introducing Al2O3 into germanate glass matrix, aluminium germanate glasses were prepared and synthesize, which were acid resistant, settling the problems that substrates were susceptible to acid corrosion during K+-Na+ion exchange process. The ion-exchange process was performed to fabricate the channel waveguide. The Nd3+ doped K+-Na+ ion exchange germanate glass channel waveguide surface structure was characterized using atomic force microscope (AFM), and the measured near field pattern diameter is ～8μm, and the numerical aperture 0.0755 and cut-off wavelength 0.569μm. The ASE emission spectra exhibit four transition emissions originating from 4F3/2 level and locating at 905,1060,1334 and 1816nm, respectively, and the efficient NIR fluorescence demonstrates Nd3+ doped NMAG glass ion-exchanged channel waveguides have promising potential for the development of optical amplifiers, broadband light sources, tunable lasers and high power waveguide lasers. |
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