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Abstract: Ho3+/Yb3+ codoped lanthanum–tungsten–tellurite (TWL) glasses are prepared by melt-quenching method. The Judd–Ofelt intensity parameters (Ωt t =2, 4, 6), radiative transition rates, radiative lifetimes, and branching ratios of Ho3+ are calculated based on the absorption spectrum to evaluate the spectroscopic properties of Ho3+ in TWL glass. The mid-infrared emission of the samples are investigated under the excitation of 980nm LD. The absorption, emission cross-sections and gain coefficient of Ho3+:5I7 → 5I8 are calculated. The energy transfer processes of Yb3+–Yb3+ and Yb3+–Ho3+ are analyzed, the results show that the Yb3+ ions can transfer their energy to Ho3+ ions with large energy transfer coefficient, and a maximum efficiency of 84%. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we report the infrared emission properties of Tm3+/Ho3+ co-doped TeO2–WO3–La2O3 (TWL) glass under 808 nm laser excitation. A broad and flat emission from 1600 to 2200 nm corresponding to the Tm3+ (3F4→3H6) and Ho3+ (5I7→5I8) emissions is observed. The full width at half maximum (FWHM) of this broadband increases up to a value of ∼370 nm with an optimal [Tm3+]/[Ho3+] concentration ratio. The energy transfer processes of Tm3+↔Ho3+ are analyzed and the results show that energy transfer between Tm3+ and Ho3+ plays an important role in the luminescence mechanism. The OH− influence on the broadband emission is also discussed. These results indicate that Tm3+–Ho3+ co-doped TWL glass could be a promising material for widely tunable laser or broadband amplifier applications. [Copyright &y& Elsevier]

A Ho 3+ -doped silica glass, 0.08Ho 2 O 3 –1.6Al 2 O 3 –98.32SiO 2 (mol%), was prepared by the sol–gel method combined with high temperature sintering. The 2 μm luminescence properties of the Al 3+ /Ho 3+ co-doped silica core glass were investigated. A single-mode double cladding Al 3+ /Ho 3+ co-doped silica fiber with a 15 μm core diameter and 0.08 core numerical apertures was prepared. Pumped with a 1.95 μm Tm 3+ fiber laser, 320 mw laser output centered at 2040 nm with M 2 factor of 1.14 was obtained from a 150-cm-long double-cladding fiber. The laser has a threshold of 850 mw launched power with a slope efficiency of 48.46%. For the first time a robust single-mode 2 μm fiber laser was realized in a fiber with Al 3+ /Ho 3+ co-doped silica core glass prepared by the sol–gel method. [ABSTRACT FROM AUTHOR]

Abstract: In a three-components fluorophosphate glass system, the introduction of H3BO3 brings some valuable influence to the spectroscopic and thermal properties of the glasses. With H3BO3 increases from 2 to 20mol%, , S ed4I13/2, FWHM, T g and fluorescence lifetime change from 3.21×10−20 cm2, 1.77×10−20 cm2, 45nm, 480°C and 8.8ms to 4.66×10−20 cm2, 2.11×10−20 cm2, 50nm, 541°C and 7.4ms, respectively. , , has a maximum when H3BO3 is 11mol%. T g and Tx −T g increases with H3BO3 introduction. Results showed that in fluorophosphate glasses, proper amount of B2O3 can be used as a modifier to suppress upconversion and improve spectroscopic properties, broadband property and crystallization stability of the glasses while keeps the fluorescence lifetime relatively high. [Copyright &y& Elsevier]

Abstract: Broadband and upconversion properties were studied in Er3+/Yb3+ co-doped fluorophosphate glasses. Large Ω 6 and S ed/(S ed+S md) values and the flat gain profile over 1530–1585nm indicate the good broadband properties of the glass system. And a premise of using Ω 6 as a parameter to estimate the broadband properties of the glasses is proposed for the first time to our knowledge. Results showed that fluorescence intensity, upconversion luminescence intensity, the intensity ratio of red/green light (656nm/545nm) are closely related to the Yb3+:Er3+ ratio and Er3+ concentration, and the corresponding calculated lifetime of 4F9/2 and 4S3/2 states for red and green upconversion samples proves this conclusion. The upconversion mechanism is also discussed. [Copyright &y& Elsevier]

Abstract: A novel Tm3+-doped lead silicate glass with good thermal stability was prepared in this work. Through thorough investigation of 2µm luminescent properties of the glasses, optimal Tm2O3 doping concentration was checked to be 3wt%. Double cladding fiber was prepared by stacking method. As a result, 2µm laser output was realized in a 40cm fiber and the maximum output power reached 70mw. [Copyright &y& Elsevier]