Nd3+:Er3+:Yb3+ codoped Al2O3 powder is prepared by the nonaqueous sol-gel method and pressed into a small wafer. The two-stage sensitization processes for energy transfer among Yb3+, Er3+, and Nd3+ are discussed. Under a 978-nm semiconductor laser excitation, the photoluminescence intensities at 813 and 887 nm, corresponding to the 4F5/2+2H9/24I9/2 and 4F3/24I9/2 transitions of Nd3+ ions, enhance monotonously with the increasing temperature, and the fluorescence intensity ratio of the near-IR emissions can be fitted the exponential function R=3.12 exp(−1150/T) in the temperature range of 375 to 889 K. The maximum sensitivity is 0.0015 K−1 at 574.3 K. The data are of undoubted repeatability, and the material is applicable for sensitive, high-temperature measurement.
Non-uniform designs for Erbium doped waveguide amplifiers (EDWA) and Yb: Er co-doped waveguide amplifiers (YEDWA) were presented based on the standard rate equations including six Er energy levels and two Yb energy levels. Numerical results were shown that the design of the non-uniform EDWA operated by gain value get a gain improvement of 110.3% than uniform one, and designs of non-uniform EDWA and YEDWA operated by pump efficiency get gain improvements of 21.03% and 10.17% than uniform ones, even get gain improvements of 2.25% and 7.26% than the absolute gain maximum of uniform EDWA and YEDWA, respectively. The optimization of population inversion in 4I11/2 could be demonstrated by the photoluminescence (PL) enhancement observed in cascaded Er doped glass measurement at room temperature.
High efficient coupling between waveguide amplifier and single mode fiber is an important aspect for component integration in the optical communication. Mode matching degree between waveguide and fiber straightly affects coupling loss and actual light intensity distribution in waveguide. In this paper, Bessel function field in step refractive index fiber excites erbium-doped Al2O3 rib waveguide amplifiers on silicon substrate with SiO2 buffers with large refractive index changes. Rib height is selected 0.8μm for 1μm film thickness and 3μm rib width waveguide amplifier for single mode operation at signal wavelength. Signal and pump guided modes are calculated by finite element method. Mode excitation fractions of signal and pump are obtained. The dependences of coupling loss and subsequent gain on fiber core radius and fiber-waveguide offset are analyzed in detail. The coupling losses between fiber and three different geometry structure waveguide amplifiers (rectangle, trapeze, trapeze upside down) with the same active core cross-section area are compared. The gains of corresponding waveguide amplifiers are compared as well as.
The large refractive index changes can provide a strong confinement of the electromagnetic field on the active region of erbium-doped Al2O3 rib waveguide amplifiers on silicon substrate with SiO2 buffers. The finite element technique is used to calculate the dispersion characteristics for different rib waveguide geometry. The propagation constants of the quasi-TE and quasi-TM mode and magnitude distributions of electromagnetic field components are presented at both signal and pump wavelengths. A suitable waveguide amplifier transverse cross-section sizes are determined in order to assure the single mode operate at least at the signal wavelength. Bessel distribution field in fiber excites the modes in waveguide amplifier considering fiber-waveguide coupling. The mode excitation fraction is given as a function of fiber core radius. Normalized pump and signal intensities are obtained.
Er3+-doped A1203 thin films are deposited on silicon substrates by reactive closed-field unbalanced magnetron sputtering(CFUBMS).The process parameters,such as target bias voltage, substrate bias voltage, 02 gas flows, sputtering gas pressure,are studied.The thin film properties of interest are Al/O ratio,thickness,refractive index,crystallographic
structure and surface roughness. 1.53μm photoluminescence(PL) characterization pumping at wavelength 980nm is measured.The relationship between PL peak intensity and different anneal temperature, and different pumping power is experimental investigated.