Fabrication and characterization of sol-gel planar waveguides doped with rare-earth ions

Orignac, Xavier; Barbier, D.; Du, Xin Min; Almeida, Rui M.

doi:10.1063/1.117980

Cited by 104 publications

(44 citation statements)

References 9 publications

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“…Figure 1͑a͒ shows a detail of the orthorhombic CrVO 4 -type structure proposed for TiSiO 4 , which belongs to space group Cmcm. The framework structure of this polymorph is comprised of nearly regular edge-sharing octahedra of TiO 6 . In addition, the silicon atoms occupy the tetrahedral interstitial sites constructed by cubic close-packed oxygen atom arrays.…”

Section: Selected Structuresmentioning

confidence: 99%

“…2,3 This precise control of the refractive index over such a wide range has been used for the fabrication of several optical devices such as passive or active waveguides, antireflective coatings, and notch filters. [4][5][6] On the other hand, titanium silicate or TiO 2 / SiO 2 mixed-oxide thin films offers the possibility to reach extremely high dielectric-constant values. [7][8][9][10] This fact is fundamental for achieving one of the semiconductor industry goals, the scaling of metal-oxide-semiconductor fieldeffect transistors ͑MOSFET͒ to smaller and smaller physical dimensions.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of theTiSiO4structure and its pressure-induced phase transformations: Density functional theory study

2009

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Theoretical investigations concerning the possible titanium silicate polymorphs have been performed using density functional theory at B3LYP level. Total-energy calculations and geometry optimizations have been carried out for all phases involved. The following sequence of pressure-driven structural transitions has been found: CrVO 4 -type, Cmcm ͑in parenthesis the transition pressure͒, → zircon-type, I4 1 / amd ͑0.8 GPa͒, → scheelite-type, I4 1 / a ͑3.8 GPa͒. At higher pressure the last phase is found to be stable at least up to 25 GPa. The equation of state of the different polymorphs is also reported. We found that the highest bulk modulus corresponds to the zircon and scheelite phases with values of 248 and 238 GPa, respectively. The orthorhombic Cmcm phase is the most compressible of all the studied structures with a bulk modulus of 124 GPa, being also the most stable phase at ambient pressure. Finally, calculations of the electronic structure, vibrational and dielectric properties of TiSiO 4 are also reported.

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Section: Selected Structuresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of theTiSiO4structure and its pressure-induced phase transformations: Density functional theory study

2009

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“…[1][2][3][4][5] One of the important reasons for that relies on the particle size control of the precursor material. In general, it is possible to produce particle sizes sufficiently small to keep Rayleigh scattering losses to an acceptable low level even for important volume fraction of nanoparticles.…”

Section: ͓S0003-6951͑00͒03348-9͔mentioning

confidence: 99%

Low optical loss planar waveguides prepared in an organic–inorganic hybrid system

Ribeiro

Messaddeq

Gonçalves

et al. 2000

Applied Physics Letters

107

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HfO 2 -(3-glycidoxipropil)trimethoxisilane (GPTS) planar waveguides were prepared by a sol–gel route. A stable sol of Hafnia nanocrystals was prepared and characterized by photon correlation spectroscopy and high resolution transmission electron microscopy. The suspension was incorporated in GPTS host and the resulting sol was deposited on borosilicate substrates by the spin coating technique. Optical properties such as refractive index, thickness, number of propagating modes, and attenuation coefficient were measured at 632.8, 543.5, and 1550 nm by the prism coupling technique as a function of the HfO2 content.

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“…Rare-earth doping of sol-gel monoliths and films has been studied by a number of groups, e.g., [12]- [14]. Relative gain in sol-gel based Er-doped waveguides was first achieved by the use of a strip loaded format [15], but high coupling and background propagation losses prevented net fiber-to-fiber gain from being reached.…”

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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Fabrication and characterization of sol-gel planar waveguides doped with rare-earth ions

Cited by 104 publications

References 9 publications

Characterization of theTiSiO4structure and its pressure-induced phase transformations: Density functional theory study

Characterization of theTiSiO4structure and its pressure-induced phase transformations: Density functional theory study

Low optical loss planar waveguides prepared in an organic–inorganic hybrid system

Molecular homogeneity in erbium-doped sol-gel waveguide amplifiers

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