Intense green upconversion emission in Tb3+/Yb3+ co-doped alumino-germano-silicate optical fibers

Tb/Yb共掺的石英光纤的上转换绿光发光研究，研究了最佳浓度配比和发光机理。

Multistage etching process for microscopically smooth tellurite glass surfaces in optical fibers

Bulk samples of tellurite glass with composition 75TeO(2)-20ZnO-5Na(2)O (TZN) were fabricated by melting and quenching techniques. In order to improve the surface quality of optical fiber preform made with this tellurite glass, the authors developed a multistage etching process. The relationship between successive etching treatments and roughness of the TZN glass surface was probed by using an atomic force microscope. The results demonstrate that this multistage etching method effectively improves this tellurite glass surface smoothness to a level comparable with that of a reference silica glass slide, and the corresponding chemical micromechanisms and fundamentals are discussed and confirmed by atomic force microscopy, potentially contributing to the development of multicomponent soft glass fibers and devices. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3437017]

Determination of dispersion and nonlinear coefficients of photonic crystal fibers by degenerated FWM method

使用四波混频测试光子晶体光纤的色散和非线性参数

Numerical analysis of four-wave-mixing based multichannel wavelength conversion techniques in fibers

We numerically investigate four-wave-mixing (FWM) based multichannel wavelength conversion for amplitude-modulated signals, phase-modulated signals, together with mixed amplitude and phase modulated signals. This paper also discusses the influence of stimulated Brillouin scattering (SBS) effects on high-efficiency FWM-based wavelength conversion applications. Our simulation results show that DPSK signals are more suitable for FWM-based multichannel wavelength conversion because the OOK signals will suffer from the inevitable datapattern-dependent pump depletion. In future applications, when the modulation format is partially upgraded from OOK to DPSK, the influence of OOK signals on the updated DPSK signals must be considered when using multichannel wavelength conversion. This influence becomes severe with the increase of OOK channel number. It can be concluded that DPSK signals are more appropriate for both transmission and multichannel wavelength conversion,especially in long haul and high bit-rate system.

High birefringent rhombic-hole photonic crystal fibers

High birefringence induced by rhombic air-hole photonic crystal fibers (PCFs) is numerically analyzed by using the finite-element method. The birefringence of a few kinds of PCFs was investigated with different parameters related to rhombic holes, including the rhombic-hole shape, size, and spacing. It was found that the birefringence of the proposed rhombic-hole PCF in this study is relatively larger than that of an elliptical-hole PCF with the same air-filling fraction (f = 0.0375) when the ratio of the rhombic-hole diagonal length is equal to the elliptical-hole ellipticity. (C) 2010 Optical Society of America

Explanation for Micromorphologies Around Broken Fibers in Fiber-Reinforced Composites

Experimental observations on micromorphologies around broken fibers in glass-fiber-reinforced epoxy matrix composites reveal different kinds of highly oriented patches at the circumambience of broken fibers, whereas the bulk of the matrix has been observed to be largely isotropic. These patches are interpreted to correlated areas where the stress gradients of the matrix are formed after fiber breaking, but the underlying cause for the orientation is still unknown. The authors have modified an embedded cell model to explain the experimental phenomena. The finite element simulation indicates that the surfaces around broken fibers display a change from an extension micromorphology to a mixed tension and shear micromorphology with the increase of applied strain.

Hollow fibers of yttria-stabilized zirconia (8YSZ) prepared by calcination of electrospun composite fibers

8YSZ fibers were synthesized by calcination of PVP/zirconium oxychloride/yttrium nitrate composite fibers (PVP-Precursor) obtained by electrospinning. Scanning electron microscopy (SEM) indicated that the 8YSZ fibers are hollow and the gas released during organic binder decomposition resulted in the formation of hollow center in fibers

The immobilization of proteins on biodegradable polymer fibers via click chemistry

A facile and efficient method to immobilize bioactive proteins onto polymeric substrate was established. Testis-specific protease 50 (TSP50) was immobilized on ultrafine biodegradable polymer fibers, i.e., (1) to prepare a propargyl-containing polymer P(LA90-co-MPCIO) by introducing propargyl group into a cyclic carbonate monomer (5-methyl-5-propargyloxycarbonyl-1,3-dioxan2-one, MPC) and copolymerizing it with L-lactide; (2) to electrospin the functionalized polymer into ultrafine fibers; (3) to azidize the TSP50, and (4) to perform the click reaction between the propargyl groups on the fibers and the azido groups on the protein.

The release behavior of doxorubicin hydrochloride from medicated fibers prepared by emulsion-electrospinning

The release behavior of a water-soluble small molecule drug from the drug-loaded nanofibers prepared by emulsion-electrospinning was investigated. Doxorubicin hydrochloride (Dox), a water-soluble anticancer agent, was used as the model drug. The laser scanning confocal microscopic images indicated that the drug was well incorporated into amphiphilic poly(ethylene glycol)-poly(L-lactic acid) (PEG-PLA) diblock copolymer nanofibers, forming "core-sheath" structured drug-loaded nanofibers.

Sintering-resistant hollow fibers of LaMgAl11O19 prepared by electrospinning

Lanthanum magnesium hexaaluminate (LMA) is very important ceramic material for catalytic combustion of natural gas. The sintering-resistant hollow fibers of LMA with diameters ranging from 1 to 3 mu m were fabricated from alcoholic solutions containing polyvinyl pyrrolidone (PVP) and aqueous solution of lanthanum, magnesium and aluminum nitrates. The interaction between PVP and nitrates were studied by X-ray diffraction and Fourier transmission-infrared spectroscopy. The forming mechanism of hollow fibers and the sintering ability of hollow LaMgAl11O19 fibers were discussed.

Preparation of Hollow Carbon and Silicon Carbide Fibers with Different Cross-Sections by using Electrospun Fibers as Templates

Hollow carbon nanofibers with circular and rectangular opening were prepared by using electrospun silica fibers as templates. Silica fibers were synthesized by electrospinning, and they were coated with a carbon layer formed by thermal decomposition and carbonization of polystyrene under a nitrogen atmosphere. Hollow carbon nanofibers with circular and rectangular openings were then obtained after the silica core was etched by hydrofluoric acid. The carbon nanofibers with different morphologies also could be used as templates to fabricate silicon carbide fibers. The silicon carbide fibers with circular and rectangular openings could be obtained by using hollow carbon nanofibers and carbon belts as templates, respectively.