Thulium-doped silica-based optical fibers for cladding-pumped fiber amplifiers

Abstract

We present preparation and spectroscopic characterization of thulium-doped fibers with enhanced 3 H 4 fluorescence lifetime obtained by codoping with alumina. With an alumina content of 10 mol%, a fluorescence lifetime of 58 ls is achieved. For the first time we study and optimize the thulium-doped fiber amplifier (TDFA) with a dual-wavelength (800 + 1400 nm) pumping scheme, where the pump at 800 nm propagates in the cladding and the pump at 1400 nm propagates in the core. In the study we use numerical simulations and experimentally obtained fiber characteristics. The results are compared with those obtained for numerical simulation of a TDFA pumped at a single wavelength in the 1050 nm band.

Thulium-doped fibre broadband source for spectral region near 2 micrometers

“…For predicting the performance of various thulium doped fibre devices and their optimization, we developed a com− prehensive, spectrally and spatially resolved numerical model, which is described in detail elsewhere [37][38][39]. For numerical simulations we set thulium ion concentration not higher than 1000 ppm mol.…”

“…The pump source at 1611 nm is assumed because this wavelength is the closest wavelength to the Tm peak absorption 3 H 6 ® 3 F 4 at around 1630 nm and in the same time it falls within the amplification range of commercially available L−band EDFAs. In the case of in− −band pumping at 1611 nm and neglecting the cooperative up−conversion processes thanks to the limited concentration of thulium, the numerical model of TDF with a rich energy level structure [37,38] is simplified to a system with two energy levels. Evolution of pump and ASE optical powers and relative population of the metastable 3 F 4 level along the fibre is shown in Fig.…”

The spectroscopic and energy transfer characteristics of the rare earth ions used for silicate glass fibre lasers operating in the shortwave infrared

“…Value from [28] Value from [29] Value from [30,31] Value from [32] Value from [33] Value from [34] Value from [35] Value from [ "SD" represents solution doped 2 "MCVD" represents modified chemical vapour deposition 3 "m" represents measured lifetime the effects from energy transfer processes discussed below are minimal. The radiative lifetime of each energy level was determined using…”

“…The calculated lifetime of 335 μs [33] which takes into account nonradiative decay due to phonon (or perhaps clustron in the case of glasses) emission is midway between these values. A number of reports [35,36] have measured the 3 F 4 level lifetime to be in the range 420 μs to 430 μs; if we use the recently calculated radiative 3 F 4 level lifetime of 4.56 ms which relates to modern silicate glasses used for fibre laser applications, the quantum efficiency of the 3 F 4 → 3 H 6 transition is 9.4%; a lower bound to the quantum efficiency is 4.4% when the radiative lifetime of the 3 F 4 level of 6.3 ms is used. The narrow energy gap of ∼ 4900 cm −1 between the 3 F 4 and 3 H 6 levels of Tm 3+ means that the rates of radiative and nonradiative relaxation from the 3 F 4 level are of a similar magnitude.…”

Estudos preliminares da preparação de fibras ópticas plásticas e híbridos orgânicos-inorgânicos luminescentes a partir de poli(metacrilato de metila) comercial

“…A menor atenuação é observada na região de 1,5 μm e a tecnologia de purificação dos materiais de partida e de puxamento permitem que o valor observado desde os anos 70, de 0,2 dB/km, seja bastante próximo ao mínimo calculado (SAVAGE, 1987;GLAESEMANN, 1999). A dopagem relativamente simples permite que o material do núcleo possa ter sua composição alterada, visando simplesmente a variação no índice de refração que vai definir as propriedades de guiamento da luz, ou mesmo pela dopagem por íons ativos opticamente como os lantanídeos para a confecção de amplificadores ópticos (PETERKAA et al, 2007;INABA, 2000).O preço e o processamento otimizados definiram a sílica como principal material de escolha na confecção da grande maioria das fibras utilizadas principalmente em telecomunicações nos últimos 30 anos. Essa escolha definiu a faixa de comprimentos de onda utilizados em telecomunicações (1550 nm).…”