Zuowen Jiang

Theoretical study and experimental fabrication of high negative dispersion photonic crystal fiber with large area mode field

We present a systematic process of theoretical design and experimental fabrication of the large mode area and large negative dispersion photonic crystal fiber. An easily fabricated fiber structure is proposed. The influence of structure parameters deviations from the design on the chromatic dispersion are evaluated and a design rule is given. Finally our fabricated fiber and test results are demonstrated. The measured effective area of inner core mode is 40.7 mum(2) which is the largest effective area of high negative dispersion photonic crystal fibers that have been experimentally fabricated. The measured peak dispersion is -666.2ps/(nm.km) and the bandwidth is 40nm.

Ce-Tb-Mn co-doped white light emitting glasses suitable for long-wavelength UV excitation

We report on a new kind of white light emitting glass suitable for long-wavelength ultraviolet excitation by simultaneously emitting blue, green and red fluorescence, which is fabricated by melting of Ce(3+)-Tb(3+)-Mn(2+) co-doped borosilicate glass. The spectroscopic properties of singly, doubly and triply doped glasses have been reported and the energy transfer from Ce(3+) to Tb(3+) and Mn(2+) has also been investigated. By adjusting the concentration of different co-dopants, we obtained the ideal white light emitting borosilicate glass with the color coordinate (x = 0.318, y = 0.333).

Tailoring of clusters of active ions in sintered nanoporous silica glass for white light luminescence

To tailor clusters of active ions in glasses is laborious but critical for obtaining high efficient luminescence. Here, we present a facile method to tailor clusters of active ions by using one kind of porous host, the nanoporous silica glass. The white light-emitting glasses were prepared by sintering of nanoporous silica glasses impregnated with Ce3+, Tb3+, Mn2+ and Al3+ ions. The combination of blue, green and red emissions of Ce3+, Tb3+ and Mn2+ ions in the glasses under ultraviolet light excitation create white light emissions. The fluorescence of the glasses under long-wavelength ultraviolet excitation are dependent on energy transfer processes between the active ions; and the Al3+ plays a key role in adjusting of the energy transfer processes.

Enhanced green luminescence in Ce-Tb-Ca codoped sintered porous glass.

We report on a new kind of green-emitting high silica luminous glass, which is fabricated by sintering of Ce(3+)-Tb(3+) co-doped porous glass. The spectra show that there are energy transfer between Ce(3+) and Tb(3+), and cross-relaxation between (5)D(3) and (5)D(4) energy level of Tb(3+). The energy transfer process can be adjusted by addition of Ca(2+) into the Ce(3+)-Tb(3+) co-doped porous glass, and the transfer rate can be enhanced about four times than that of Ce(3+)-Tb(3+) co-doped porous glass. The role of Ca(2+) has been discussed, and the fluorescence decay curve reveals that the Ca(2+) play an important role in energy transfer.

Effect of Yb 3+ concentration on the broadband emission intensity and peak wavelength shift in Yb/Bi ions co-doped silica-based glasses

The effect of Yb(3+) concentration on the broadband emission intensity and peak wavelength shift in Yb/Bi ions co-doped silicate glasses is investigated. The optimal Bi(2)O(3) concentration range is about 2.0-2.5 mol% in 65SiO(2)-10Al(2)O(3)-25CaO matrix (SAC glasses). For Yb/Bi codoped SAC glasses, the maximum emission intensity excited by 980 nm LD is ~30 times and 1.5 times higher than that of single Bi-doped SAC glasses excited by 980 nm and 808 nm LD, respectively, the peak emission shows obvious red-shift from 1185 nm to 1235 nm band with the Yb(2)O(3) concentration change from 0 to 3.0 mol%. For the same Yb(2)O(3) concentration in SAC glasses, the measured fluorescence lifetime near 1020 nm of single Yb(3+)-doped glasses is longer than that of Yb/Bi codoping glasses, which implyes the efficient energy transfer from Yb(3+) to Bi(n+) in SAC glasses. The results indicate Yb(2)O(3) can be induced into the bismuth-doped silicate glasses to enhance the emission intensity and control the peak wavelength.

Investigation on radiation resistance of Er/Ce co-doped silicate glasses under 5 kGy gamma-ray irradiation

Various Er/Ce co-doped SiO2-Al2O3-CaO glasses are prepared by the melt-quenching method. The radiation resistance of Er/Ce co-doped glasses is investigated under 5 kGy gamma-ray irradiation. The absorption spectra, up-conversion spectra, fluorescence intensity and lifetime of Er/Ce co-doped glasses before and after irradiation are measured and analyzed in details. The radiation induced absorption (RIA) of the Er/Ce co-doped silicate glasses can be suppressed due to Ce ions co-doping. The fluorescence intensity and lifetime of Er/Ce co-doped glasses have no apparent change after irradiation. Furthermore, the possible mechanism of Ce effect on the radiation resistance improvement is discussed. The result indicates that Er doped glasses with an optimal Ce concentration introduction can be used as active medias for radiation-resistant materials in harsh radiation environments.

Experimental demonstration of very high negative chromatic dispersion dual-core photonic crystal fiber

This paper reports the experimental drawing fabrication of very large negative chromatic dispersion dual-core photonic crystal fiber. The fabricated fiber has a peak chromatic dispersion value of -820 ps/(nm km).

Efficient generation of blue light in high-delta microstructure fibers

By coupling femtosecond laser pulses at a wavelength of ~0.8 μm in high-delta microstructure fiber, efficient blueshifted radiation with a central wavelength near 0.4 μm was observed. The blue light can take 15% of output power. The mechanism for its generation is analyzed to be a degenerate parametric process 2ωp=ωs+ωi, where the frequency of the signal light ωs is nearly twice the pump frequency ωp, and the frequency of the idler light ωi can lie in the terahertz region.

Self-bleaching phenomenon observed in the Ce/Yb Co-doped silica fiber

We report on a self-bleaching phenomenon observed in the Ce Yb co-doped silica fiber. The excess loss of the Ce/Yb fiber reduces about 1.5 dB/m at 633 nm after the pump laser was turned off for an hour; recovered about 10% of its pristine condition.

Spectrum properties of Erbium with other rare-earth ions co-doped optical fiber

Erbium doped fiber amplifier have been demonstrated at several wavelengths. The exceptionally broad and intense absorption spectrum of erbium with other rare-earth co-doped fiber is advantage in high power amplifiers and fiber lasers. In order to broaden amplifying band, it is important to modify spectrum properties of erbium doped optical fiber. In this dissertation, erbium with ytterbium, thulium and Lanthanum co-doped fibers were fabricated by MCVD. This paper focus on the influence of concentration and ratio of rare-earth on spectrum properties of fiber. It was found that absorption of the EDFs was affected by erbium concentration and ratio of erbium and other rare-earth. Absorption band were broadened by adding dopant of other rare-earth.