Guiding modes and field distribution are calculated by finite element method. For three kinds of etched cross-section
waveguide (rectangle, trapezoid, upside-down trapezoid) with 0.5μm and 1.0μm film thickness, mode characteristic,
percentage of core power at wavelength of 1.53μm and 0.98μm and overlap factor between signal and pump are
contrastively studied. For the same etched depth and mask width, trapezoid waveguide is superior to rectangle and then
upside-down trapezoid in the view of field confinement and overlap factor. Whereas rectangle waveguide is optimum
and upside-down trapezoid is the worst for the same core cross-section area. The gain of different etched cross-section
waveguide amplifier is numerically calculated by multi-theoretical model, which is founded by rate equations pumped
at 0.98μm, two-dimension waveguide finite element model, propagation equations with forward and backward direction
amplified spontaneous emission. Results also show rectangle waveguide is optimum for the same core cross-section area.
The gain of 1μm film thickness waveguide amplifier increases by more than 20% compared with 0.5μm thickness
waveguide. These simulation results provide a theoretical basis for the design of Yb-Er co-doped Al2O3
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.