Optically transparent Er³⁺/Tm³⁺/Yb³⁺ tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO₂-15ZnO-7ZnF₂-3YF₃-1.5YbF₃-0.3ErF₃-0.2TmF₃ (mol%) is prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nano-crystals in glass matrix appear to be smaller than 100 nm from the scanning electron microscope measurement. Visible up-conversion luminescence of the as melted glass and glass ceramics is investigated. The three-color up-conversion luminescence intensities by 980-nm pumping are increased significantly due to the heat treatment, and the blue intensity increases with a higher magnitude than other wavelengths after heat treatment.

The emission properties of 2 \mu m region fluorescence of Tm³⁺-Ho³⁺ co-doped tellurite glasses are investigated. Introducing F^- ions to the composition of tellurite glasses plays a positive effect on the 2 \mu m emission. A maximum intensity of 2 \mu m emission is achieved when 1.5-mol% Tm₂O₃ and 1-mol% Ho₂O₃ concentration are doped in the glasses. The emission cross section and gain coefficient of the ⁵I₈-⁵I₇ transition of Ho³⁺ are calculated. The emission cross section has a maximum of 1.29×10^-20 cm² at 2048 nm wavelength. The results indicate that Tm³⁺-Ho³⁺ co-doped tellurite glasses are suitable for 2 \mu m application.

为了研究锗酸盐玻璃中采用Yb³⁺/Tm³⁺/Ho³⁺三掺杂方式实现2 μm激光的可行性,研究了3种稀土离子的掺杂浓度对近2 μm发光的影响,从而对稀土离子掺杂浓度进行优化选择以确定理想的掺杂浓度。实验结果表明,在TmF3掺杂摩尔分数为1%时,随着Yb³⁺浓度的提高Ho³⁺的2 μm荧光强度增强[当TmF3掺杂摩尔分数为3%时,随着Yb³⁺浓度的提高Ho³⁺的2 μm荧光强度降低[随着Yb³⁺浓度的提高,Tm³⁺的近2 μm荧光发射会得到增强,且当Tm³⁺浓度较高时其发光更为明显,这相对削弱了Ho³⁺的2 μm荧光。Ho³⁺2 μm发光受Tm3＋/Ho³⁺的浓度比值影响很大,即用980 nm光抽运三掺杂样品,无论Tm³⁺浓度单一提高还是Ho³⁺浓度单一降低,对于Ho³⁺的2 μm荧光都是不利的。

Thermal stability and 2-\mu m fluorescence of high and low Al(PO₃)₃ content of fluorophosphate glasses are investigated. Thermal stability of high Al(PO₃)₃ content of fluorophosphate glass is better than low Al(PO₃)₃ content of fluorophosphate glass. However, 2.04-\mu m fluorescence intensity of high Al(PO₃)₃ content of fluorophosphate glass is only 48.2, lower than low Al(PO₃)₃ content of fluorophosphate glass. Raman spectroscopy is employed to investigate the difference in thermal stability and 2-\mu m fluorescence. Moreover, fluorescence peak intensity ratios of 2.04 to 1.81 \mu m and 2.04 to 1.57 \mu m are calculated, which indicate that Er-Tm-Ho doped fluorophosphate glasses are suitable materials in 2-\mu m applications.

Edge-cladding is a key factor in improving saturated small signal gain coefficient 'beta's of large laser disc glass. In this paper, the glasses were melted with traditional method. The influences of mixed alkali effect (MAE) on refractive index, thermal expansion coefficient 'alpha', glass transition temperature Tg, dilatometer softening temperature Td, and relative chemical durability of phosphate edge-cladding glasses were studied. The results reveal that when Li/(Na+Li)=0.5, Tg, Td, and dissolution rate (DR) reach a minimal value. These results are preferred in phosphate edge-cladding glasses.

The thermal properties of 68TeO2-15BaF2-5SrF2-10LaF3-2KF glass were measured by different temperature analysis (DTA). Up-conversion luminescence of Er3+ ion in the obtained glass was investigated. Mechanism of up-conversion emission was discussed. The result shows that the obtained oxyfluoride tellurite glass 68TeO2-15BaF2-5SrF2-10LaF3-2KF has a good thermal stability ('Delta'T = 153.6 Celsius degree) and strong up-conversion green emissions around 527 nm and 549 nm and red emission at 660 nm. This glass can be a promising host material for up-conversion fiber lasers.

Optically transparent Er3+-doped tellurite-based nanocrystallized glasses with the composition of 70TeO2-15Li2O-15Nb2O5-0.5Er2O3 (mol) have been prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nanocrystals in glass matrix appear to be 35-50 nm from the X-ray diffraction (XRD) measurement. The microhardness measurement shows that the Vickers hardness values of the nanocrystallized tellurite glasses are larger (33%-62%) than those in the base glass. The Raman spectra imply that the maximum phonon energy of the based glass decreases and shifts from 668 to 638 /cm after heat-treatment. Visible upconversion luminescence and infrared luminescence of the base glass and heat-treated glasses under 980-nm laser diode (LD) excitation are investigated. The 524-, 546- and 656-nm upconversion intensities by 980-nm pumping increase significantly.

A series of highly Er^(3+)/Yb^(3+) co-doped fluoroaluminate glasses have been investigated in order to develop a microchip laser at 1.54 μm under 980 nm excitation. Measurements of absorption, emission and up-conversion spectra have been performed to examine the effect of Er^(3+)/Yb^(3+) concentration quenching on spectroscopic properties. In the glasses with Er^(3+) concentrations below 10 mol%, concentration quenching is very low and the Er^(3+)/Yb^(3+) co-doped fluoroaluminate glasses have stronger fluorescence of 1.54 μm due to the ^(4)I_(13/2)-->^(4)I_(15/2) transition than that of Er^(3+) singly-doped glasses. As Er^(3+) concentrations above 10 mol% in the Er^(3+)/Yb^(3+) co-doped samples, concentration quenching of 1.54 μm does obviously occur as a result of the back energy transfer from Er^(3+) to Yb^(3+). To obtain the highest emission efficiency at 1.54 μm, the optimum doping-concentration ratio of Er^(3+)/Yb^(3+) was found to be approximately 1:1 in mol fraction when the Er^(3+) concentration is less than 10 mol%.

Nd3+-doped tellurite glass and a single mode tellurite glass fiber with a core diameter of 8 μm were prepared in this work. The 1.33-μm emission from the 4F_(3/2)-->4I_(13/2) transition of Nd3+ with a spectral bandwidth of 55 nm in tellurite glass fiber is observed. The lifetime of 164 $\mu $s of 4F_(3/2) level and quantum efficiency of about 100% are obtained.

Spectral characteristics of the amplified spontaneous emission (ASE) from a novel single mode Er3+ doped tellurite fiber with D-type cladding is reported in this letter. When pumped at 980 nm, an ASE source that has nearly a 100-nm flat FWHM bandwidth is obtained with a fiber length of 30-60 cm. Variation of ASE spectra with pump powers and fiber lengths are measured. Output power up to 2.0 mW is obtained with a launched pump power of 660 mW.