Local order around Er3+ ions in SiO2–TiO2–Al2O3 glassy films studied by EXAFS

d’Acapito, Francesco; Mobilio, Settimio; Gastaldo, P.; Barbier, D.; Santos, Luı́s F.; Martins, Orlando; Almeida, Rui M.

doi:10.1016/s0022-3093(01)00663-9

Cited by 35 publications

(36 citation statements)

References 16 publications

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“…In sample A the rare earth is linked to O atoms in the first coordination shell and to Si(P) atoms in the second shell in a way similar to that already observed in silicate glasses [17,30], phosphate glasses [31,32] and in the oxide formed at purpose in crystalline Si [12]. Also the structural parameters (about seven O atoms at 2.26 A and Si(P) atoms at 3.6 A corresponding to a Er-O-Si(P) bond angle of ≈140°) are in good agreement with the cited literature.…”

Section: Discussionsupporting

confidence: 62%

Role of CaO addition in the local order around Erbium in SiO2–GeO2–P2O5 fiber preforms

d’Acapito¹,

Maurizio²,

Paul³

et al. 2008

Materials Science and Engineering: B

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The development of materials for optical signal processing represents a major issue in present technology. In this contribution we present a study on Er-doped fiber preforms where particular attention is devoted on how the addition of CaO in the glass modifies the local environment of the rare earth. The results from photoluminescence and Extended X-ray Absorption Fine Structure (EXAFS) are compared and a clear link between the width of the emission line at 1.5 µm and the amorphous/crystalline local structure around the Er3+ ion is evidenced.Keywords: Optic fibers; EXAFS; Erbium; Nanoparticles 1. Introduction Knowledge of the environment of rare earth ions in glasses is essential for the understanding of the spectral properties of these glasses and the design of new glass compositions for photonics applications. Among the rare earths, erbium is especially interesting because the 4I13/2 − 4I15/2 transition at ≈1.54 µm coincides with the lowest attenuation window of silica glass fiber; hence, erbium doped glasses can be used to amplify attenuated signals in optical fiber telecommunication systems. While Erbium-Doped Fiber Amplifier (EDFA) was developed 20 years ago, extensive studies are still carried out to improve its properties. In particular, linear dimensions should be reduced although the severe limitations imposed by the poor rare earth solubility into silica matrix. Moreover, spectral bandwidth should be increased to improve the Wavelength Division Multiplexing (WDM) applications. To solve these problems, various approaches have been proposed namely Er-Tm co-doping [1] or Er incorporation in nanoparticles (NP). However, to be compatible with optical waveguide applications, Rayleigh scattering must be kept at a minimum. For this purpose, Tick proposed that the particles size must be less than 15 nm with a narrow distribution size and high density [2]. There are reports on thin films containing semiconductor and metal nanoparticles acting as sensitizers, absorbing the incident light with a high crosssection and exciting erbium co-doped ions in the nanoparticle vicinity through energy transfer [3][4][5][6][7][8]. Here we propose for the first time to incorporate Er into oxide nanoparticles in optical fibers to improve the spectroscopic properties of erbium ions. To our knowledge only few studies on nano-structured silica fibers were dedicated to metal ions properties [9]. In our samples, oxide nano-structures are prepared by adjusting the composition of usual modifiers in the core of the fiber. A glass with an immiscibility gap is obtained and two phases are then formed with high and low silica content. The nanoparticles are preserved when the perform is drawn into a fiber. An effective method to study the incorporation of Er in a matrix is by Extended X-ray Absorption Fine Structure (EXAFS) [10] as this technique provides quantitative information on the geometry and chemical composition of the environment of the element under study. The Er site has been successfully studied by this technique in a var...

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Section: Discussionsupporting

confidence: 62%

Role of CaO addition in the local order around Erbium in SiO2–GeO2–P2O5 fiber preforms

d’Acapito¹,

Maurizio²,

Paul³

et al. 2008

Materials Science and Engineering: B

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“…On the basis of results presented above and in [17,18], we can conclude that the local environments of Er 3+ , Eu 3+ and Ho 3+ luminescence centres in the Ca 3 Ga 2 Ge 3 O 12 glass network are the same and that the first coordination sphere around rare-earth impurity ions consists of six O 2À anions. This result is in good agreement with results obtained for Er 3+ (N = 6 Ä 7) [32] and Eu 3+ (N = 6) [33] ions in other oxide glasses.…”

Section: Peculiarities Of the Er 3+ Luminescence Kinetics In Ca 3 Ga supporting

confidence: 92%

Optical spectroscopy and local structure of Er3+ luminescence centres in СaO–Ga2O3–GeO2 glasses

Padlyak

Ryba‐Romanowski

Lisiecki

2008

Journal of Non-Crystalline Solids

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“…Direct physical measurement of the clusters in thin films is very challenging. One method that has been investigated is extended X-ray absorption fine structure (EXAFS) [18], allowing the neighboring atoms to Er ions to be determined. The first coordination shell was found to consist of 6-7 oxygen atoms, and Er ions were also not detected in the second nearest neighbor (SNN) positions, even for the highest Er concentrations (1.75 mol%).…”

Section: Formats For Edwasmentioning

confidence: 99%

Molecular homogeneity in erbium-doped sol-gel waveguide amplifiers

Laliotis

Yeatman

Ahmad

et al. 2004

IEEE J. Quantum Electron.

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Abstract-High net gain levels have recently been reported in silica-on-silicon waveguide amplifiers, using the sol-gel method of glass deposition. Spectroscopic measurements indicate that high inversion levels are achieved at high erbium concentrations, suggesting a high uniformity in the erbium distribution. Here we show that high inversion and low scattering losses are only achieved in sol-gel waveguides which have had restricted heat treatment and that both degrade upon additional annealing. Evolution of scattering loss spectra are presented, and these are included in a model of the ytterbium-sensitized waveguide amplifiers to show that the gain reduction with heat treatment is not wholly due to pump and signal excess losses, but also to changes in the spectroscopic properties of the erbium ions. In particular, the formation of clusters in which inversion is rapidly quenched is indicated. Thus, we show that the superior performance of the sol-gel method for rare-earth doping of silica waveguides, for amplifier and laser applications, results from its ability to form homogenous molecular structures which are meta-stable and which consequently cannot be formed in glasses that require high-temperature consolidation or annealing.

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Local order around Er3+ ions in SiO2–TiO2–Al2O3 glassy films studied by EXAFS

Cited by 35 publications

References 16 publications

Role of CaO addition in the local order around Erbium in SiO2–GeO2–P2O5 fiber preforms

Role of CaO addition in the local order around Erbium in SiO2–GeO2–P2O5 fiber preforms

Optical spectroscopy and local structure of Er3+ luminescence centres in СaO–Ga2O3–GeO2 glasses

Molecular homogeneity in erbium-doped sol-gel waveguide amplifiers

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