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Erbium-activated silica-zirconia planar waveguides prepared by sol-gel route

GONCALVES, Rogeria R.; MESSADDEQ, Younes; CHIASERA, Alessandro; JESTIN, Yoann; FERRARI, Maurizio; RIBEIRO, Sidney J. L.
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
698.4995%
Er(3+) doped (100-x)SiO(2)-xZrO(2) planar waveguides were prepared by the sol-gel route, with x ranging from 10 up to 30 mol%. Multilayer films doped with 0.3 mol% Er(3+) ions were deposited on fused quartz substrates by the dip-coating technique. The thickness and refractive index were measured by m-line spectroscopy at different wavelengths. The fabrication protocol was optimized in order to confine one propagating mode at 1.5 mu m. Photoluminescence in the near and visible region indicated a crystalline local environment for the Er(3+) ion. (c) 2007 Elsevier B.V. All rights reserved.

Er:YAl(3)(BO(3))(4) glassy thin films from polymeric precursor and sol-gel methods: Waveguides for integrated optics

MAIA, L. J. Q.; MASTELARO, Valmor Roberto; HERNANDES, Antonio Carlos; FICK, J.; IBANEZ, A.
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
605.77906%
This paper presents the characterization of single-mode waveguides for 980 and 1550 nm wavelengths. High quality planar waveguide structure was fabricated from Y(1-x)Er(x)Al(3)(BO(3))(4) multilayer thin films with x = 0.02, 0.05, 0.1, 0.3, and 0.5, prepared through the polymeric precursor and sol-gel methods using spin-coating. The propagation losses of the planar waveguides varying from 0.63 to 0.88 dB/cm were measured at 632.8 and 1550 nm. The photoluminescence spectra and radiative lifetimes of the Er(3+) (4)I(13/2) energy level were measured in waveguiding geometry. For most samples the photoluminescence decay was single exponential with lifetimes in between 640 mu s and 200 mu s, depending on the erbium concentration and synthesis method. These results indicate that Er doped YAl(3)(BO(3))(4) compounds are promising for low loss waveguides. (C) 2009 Elsevier B.V. All fights reserved.; FAPESP[02/13748-9]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CAPES[455/04]; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); CAPES-COFECUB Brazil-French international agreement; Comité Français d´Evaluation de la Coopération Universitaire avec le Brésil (COFECUB); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

NIR luminescent Er3+/Yb3+ co-doped SiO2-ZrO2 nanostructured planar and channel waveguides: Optical and structural properties

Cunha, Cesar dos Santos; Ferrari, Jefferson Luis; de Oliveira, Drielly Cristina; Queiroz Maia, Lauro June; Leonidas Gomes, Anderson Stevens; Lima Ribeiro, Sidney Jose; Gonçalves, Rogéria Rocha
Fonte: ELSEVIER SCIENCE SA; LAUSANNE Publicador: ELSEVIER SCIENCE SA; LAUSANNE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
616.52152%
Optical and structural properties of planar and channel waveguides based on sol gel Er3+ and Yb3+ co-doped SiO2-ZrO2 are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO2/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 degrees C after annealing from 23 up to 500 min, depending on the ZrO2 content Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO2 nanocrystals dispersed in a silica-based glassy host Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er3+ ions was observed for the Yb3+- codoped planar waveguides, denoting an efficient energy transfer from the Yb3+ to the Er3+ ion. (C) 2012 Elsevier B.V. All rights reserved.; FAPESP; FAPESP; CAPES; CAPES; CNPq; CNPq

Refratômetro por ondas evanescentes em guias de ondas planares; Refractometer by evanescent waves in planar waveguides

Ribeiro, Rafael Alves de Souza
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/12/2010 PT
Relevância na Pesquisa
706.0765%
Nesse trabalho, propomos uma modificação da técnica de caracterização de filmes conhecida por m-line para o desenvolvimento de um refratômetro para gases e líquidos. O principio dessa técnica consiste no acoplamento de ondas evanescentes em guias de ondas planares obtidos via o fenômeno da reflexão total interna frustrada através de dispositivos acopladores. Observa-se experimentalmente, após incidir um feixe de laser contínuo na base do acoplador óptico, uma grande atenuação da radiação refletida para determinados ângulos de incidência, que é justamente a radiação acoplada nos modos permitidos pelo guia de onda. Medindo-se os valores desses ângulos e usando a teoria de acoplamento, é possível determinar as características desconhecidas do sistema. Esse sistema consiste de um acoplador óptico semicircular de alto índice de refração em cuja base foram depositados, via evaporação, um filme de dióxido de silício (SiO2) e outro de dióxido de zircônio (ZrO2). Ou seja, o sistema resume-se a dois meios finitos (filmes) prensados entre dois meios semi-infinitos (prisma e amostra). Como a espessura dos filmes e os índices de refração complexos dos filmes e do prisma são conhecidos, a única variável é o índice de refração do quarto meio...

Erbium-activated silica-zirconia planar waveguides prepared by sol-gel route

Goncalves, Rogeria R.; Messaddeq, Younes; Chiasera, Alessandro; Jestin, Yoann; Ferrari, Maurizio; Ribeiro, Sidney J. L.
Fonte: Elsevier B.V. Sa Publicador: Elsevier B.V. Sa
Tipo: Artigo de Revista Científica Formato: 3094-3097
ENG
Relevância na Pesquisa
698.4995%
Er(3+) doped (100-x)SiO(2)-xZrO(2) planar waveguides were prepared by the sol-gel route, with x ranging from 10 up to 30 mol%. Multilayer films doped with 0.3 mol% Er(3+) ions were deposited on fused quartz substrates by the dip-coating technique. The thickness and refractive index were measured by m-line spectroscopy at different wavelengths. The fabrication protocol was optimized in order to confine one propagating mode at 1.5 mu m. Photoluminescence in the near and visible region indicated a crystalline local environment for the Er(3+) ion. (c) 2007 Elsevier B.V. All rights reserved.

NIR luminescent Er3+/Yb3+ co-doped SiO2-ZrO2 nanostructured planar and channel waveguides: Optical and structural properties

Cunha, Cesar dos Santos; Ferrari, Jefferson Luis; de Oliveira, Drielly Cristina; Queiroz Maia, Lauro June; Leonidas Gomes, Anderson Stevens; Lima Ribeiro, Sidney Jose; Goncalves, Rogeria Rocha
Fonte: Elsevier B.V. Sa Publicador: Elsevier B.V. Sa
Tipo: Artigo de Revista Científica Formato: 120-129
ENG
Relevância na Pesquisa
616.52152%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Optical and structural properties of planar and channel waveguides based on sol gel Er3+ and Yb3+ co-doped SiO2-ZrO2 are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO2/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 degrees C after annealing from 23 up to 500 min, depending on the ZrO2 content Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO2 nanocrystals dispersed in a silica-based glassy host Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er3+ ions was observed for the Yb3+- codoped planar waveguides, denoting an efficient energy transfer from the Yb3+ to the Er3+ ion. (C) 2012 Elsevier B.V. All rights reserved.

Erbium-activated HfO2-based waveguides for photonics

Gonçalves, Rogeria R.; Carturan, Giovanni; Montagna, Maurizio; Ferrari, Maurizio; Zampedri, Luca; Pelli, Stefano; Righini, Giancarlo C.; Ribeiro, Sidney J.L.; Messaddeq, Younes
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 131-139
ENG
Relevância na Pesquisa
600.51863%
Silica-based sol-gel waveguides activated by Er3+ ions are attractive materials for integrated optic devices. 70SiO(2)-30HfO(2) planar waveguides, doped with Er3+ concentrations ranging from 0.01 to 4 mol%, were prepared by sol-get route. The films were deposited on v-SiO2 and silica-on-silicon substrates, using dip-coating technique. The waveguides show a homogeneous surface morphology, high densification degree and uniform refractive index across the thickness. Emission in the C-telecommunication band was observed at room temperature for ill the samples upon excitation at 980 nm. The shape is found to be almost independent on erbium content, with a FWHM between 44 and 48 nm. The I-4(13/2) level decay curves presented a single-exponential profile, with a lifetime ranging between 1.1 and 6.7 ms, depending on the erbium concentration. The waveguide deposited on silica-on-silicon substrate supports one single propagation mode at 1.5 mum with a confinement coefficient of 0.85, and a losses of about 0.8 dB/cm at 632.8 nm. (C) 2003 Elsevier B.V. All rights reserved.

Titania-based organic-inorganic hybrid planar waveguides

Nassar, E. J.; Goncalves, R. R.; Ferrari, M.; Messaddeq, Y.; Ribeiro, SJL
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 221-225
ENG
Relevância na Pesquisa
702.8393%
Eu3+ -doped titania-silica planar waveguides were prepared from tetraethylorthotitanate (TEOT) and modified silane 3-amino-propyltriethoxysilane (APTS). Films were deposited on borosilicate glass substrates by a dip-coating technique. The refractive index, the thickness and the total attenuation coefficient of the waveguides were measured at 632.8 and 1550 nm by prism coupling technique. Starting from pure titania films, the addition of modified silane leads to a decrease in the refractive index and an increase in thickness. Squared electric field simulation has shown that the light confinement in the waveguide increases with the silane content of the so]. Emission spectra present a broad emission band due to the modified silane and EU emission transitions arising mainly from the D-5(0) level to the F-7(J) (J = 0-4) manifolds. The dependence of transition intensities and excited state lifetimes on the initial composition and also on the heat treatment performed was interpreted in terms of structural changes occurring during the preparation process. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Er3+-doped germanate glasses for active waveguides prepared by Ag+/K+ <-> Na+ ion-exchange

Barbosa, A. J.; Maia, L. J. Q.; Nascimento, A. M.; Goncalves, R. R.; Poirier, G.; Messaddeq, Y.; Ribeiro, S. J. L.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 4743-4748
ENG
Relevância na Pesquisa
609.01625%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Planar waveguides were prepared by Ag+/K+ <-> Na+ ion-exchange on Er+3 -doped GeO2-ZnO-Na2O-Li2O glasses obtained by a melting-casting method. Optical parameters of the waveguides were measured at 543.5, 632.8, and 1550 nm by m-line technique as a function of the Ag+ ion-exchange time. The optimized planar waveguides show an effective diffusion depth (d) of 2.95 mu m and well confined propagating TE0 and TM0 modes at 1550 nm. Spectroscopic properties as photoluminescence emission and emission decay time were evaluated for the erbium-doped planar waveguide, indicating that Ag+ <-> Na+ ion-exchange enhance the photoluminescence emissions in the green and infrared regions from erbium ions. The glass system studied is promising to be applied as optical amplifiers in the C-telecom band. Green emission sensitized by Ag+ was also observed. (c) 2008 Elsevier B.V. All rights reserved.

Active planar waveguides based on sol-gel Er3+-doped SiO2-ZrO2 for photonic applications: Morphological, structural and optical properties

Goncalves, R. R.; Guimaraes, J. J.; Ferrari, J. L.; Maia, L. J. Q.; Ribeiro, S. J. L.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 4846-4851
ENG
Relevância na Pesquisa
706.0765%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Er3+-doped glass-ceramic SiO2-ZrO2 Optical Planar waveguides were prepared by the sol-gel route using different SiO2:ZrO2 molar ratios (90:10, 85:15, 80:20 and 75:25). Multilayered films were deposited onto Si(100) substrates by the dip-coating technique. Structural characterization was performed using vibrational spectroscopy and X-ray diffraction. Some optical properties, densification and surface morphology of these films were investigated as a function of the SiO2:ZrO2 ratio. annealing temperature and time. Optical properties such as refractive index, number of propagating modes and attenuation coefficient were measured at 632.8, 543.5 and 1550 nm, by the prism coupling technique. Uniform surface morphology with roughness less than 0.5 nm. Low losses, less than 0.9 dB/cm at 612.8 nm in the TE0 mode, were measured for the planar waveguides containing up to 25 mol% zirconium oxide. Luminescence of Er3+ in the near infrared was observed for the active nanocomposite. (C) 2008 Elsevier B.V. All rights reserved.

Organic-inorganic hybrids prepared by carboxylic acid solvolysis: Planar waveguides

Molina, C.; Maia, L. J. Q.; Messaddeq, Y.; Ribeiro, S. J. L.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 910-914
ENG
Relevância na Pesquisa
597.57883%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Organic-inorganic hybrid planar waveguides based on the UV sensitive methacryloxypropyltrimethoxysilane (MAPTMS) were prepared through non-hydrolytic sol-gel process by carboxylic acid solvolysis and also containing the fluormonomer precursor 2,2,3,3-tetrafluorpropylmethacrylate (TFPM) and methacrylic acid (MA) modified zirconium alkoxide (ZPO). The absence of water and the incorporation of C-F bonding containing precursor contributed to obtain low optical loss in the final material. Characterization techniques included Si-29-NMR, vibrational spectroscopy and optical characterization of the, waveguides with measurements of refractive index, thickness, propagating modes and attenuation coefficient by m-lines prism coupling technique at 632.8, 543.5 and, 1550 nm were performed. The surface of the films was investigated by roughness (RMS) and contact angle measurements. (c) 2011 Elsevier B.V. All rights reserved.

Inorganic nanoparticles in organic-inorganic hybrid hosts for planar waveguides

Gonçalves, R. R.; Carturan, G.; Scarpari, S.; Oliveira, D. C.; Bueno, L. A.; Ribeiro, S. J L; Messaddeq, Y.; Ferrari, M.; Montagna, M.; Rainho, J. P.; Carlos, L. D.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 134-139
ENG
Relevância na Pesquisa
711.13945%
Planar waveguides have been prepared on the ZrO2-(3-glycidiloxypropyl)trimethoxysilane (GPTS) system. Stable sols containing ZrO2 nanoparticles have been prepared and characterized by Photon Correlation Spectroscopy. The nanosized sol was embedded in (3-glycidoxipropyl)trimethoxisilane (GPTS) used as a hybrid host for posterior deposition. The opticalparameters of the waveguides such as refractive index, thickness and 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 Zr02 content. The planar waveguides present thickness of a few microns and support well confined propagating modes. Er doped samples display weak and broad (δλ≈96nm) emission at 1.5 μm.

Rare earth doped HfO2 nanoparticles embedded in SiO2-HfO2 planar waveguides. Preparation, optical, structural and spectroscopic characterization

Ribeiro, Sidney J L; Goncalves, Rogeria R.; Messaddeq, Younes; Aegerter, Michel A.; Montagna, Maurizio; Duverger, Claire; Ferrari, Maurizio
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 10-18
ENG
Relevância na Pesquisa
605.77906%
In this work we present results on the preparation of planar waveguides based on HfO2 and HfO2-SiO2. Stable sols containing europium and erbium doped HfO2 nanoparticles have been prepared and characterized. The nanosized sol was either deposited (spin-coating) on quartz substrates or embedded in (3-glycidoxipropil)trimethoxisilane (GPTS) used as a hybrid host for posterior deposition. The refractive index dispersion and luminescence characteristics were determined for the resulting HfO2 films. The optical parameters of the waveguides such as refractive index, thickness and propagation losses were measured for the hybrid composite. The planar waveguides present thickness of a few micra and support well confined propagating modes.

Sol-Gel Erbium-Doped Silica-Hafnia Planar and Channel Waveguides

Gonçalves, Rogéria R.; Carturan, Giovanni; Zampedri, Luca; Ferrari, Maurizio; Armellini, Cristina; Chiasera, Alessandro; Mattarelli, M.; Moser, Enrico; Montagna, Maurizio; Righini, Giancarlo C.; Pelli, Stefano; Nunzi Conti, Gualtiero; Ribeiro, Sidney J.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 111-120
ENG
Relevância na Pesquisa
612.74477%
Erbium activated SiO2 -HfO2 planar waveguides, doped with Er3+ concentrations ranging from 0.01 to 4 mol%, were prepared by sol-gel method. The films were deposited on v-SiO2 and silica-on-silicon substrates using dip-coating technique. The waveguides show high densification degree, effective intermingling of the two film components, and uniform surface morphology. The waveguide deposited on silica-on-silicon substrates shows one single propagation mode at 1.5μm, with a confinement coefficient of 0.81 and an attenuation coefficient of 0.8 dB/cm at 632.8nm. Emission in the C-telecommunication band was observed at room temperature for all the samples upon continuouswave excitation at 980 nm or 514.5 nm. The shape of the emission band corresponding to the 4I13/2 → 4I15/2 transition is found to be almost independent both on erbium content and excitation wavelength, with a FWHM between 44 and 48 nm. The 4I13/2 level decay curves presented a single-exponential profile, with a lifetime ranging between 1.1 - 6.6 ms, depending on the erbium concentration. Infrared to visible upconversion luminescence upon continuous-wave excitation at 980 nm was observed for all the samples. Channel waveguide in rib configuration was obtained by etching the active film in order to have a well confined mode at 1.5 μm.

Erbium-activated HfO2-based waveguides for photonics

Gonçalves, Rogeria R.; Carturan, Giovanni; Zampedri, Luca; Ferrari, Maurizio; Montagna, Maurizio; Righini, Giancarlo C.; Pelli, Stefano; Ribeiro, Sidney J.L.; Messaddeq, Younes
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 89-90
ENG
Relevância na Pesquisa
602.64184%
70SiO2 - 30HfO2 planar waveguides, activated by Er3+ concentration ranging from 0.3 to 1 mol%, were prepared by solgel route, using dip-coating deposition on silica glass substrates. The waveguides showed high densification degree, effective intermingling of the two components of the film, and uniform surface morphology. Propagation losses of about 1 dB/cm were measured at 632.8 nm. When pumped with 987 nm or 514.5 nm continuous-wave laser light, the waveguides showed the 4I 13/2→4I15/2 emission band with a bandwidth of 48 nm. The spectral features were found independent both on erbium content and excitation wavelength. The 4I13/2 level decay curves presented a single exponential profile, with a lifetime between 2.9-5.0 ms, depending on the erbium concentration.

Nucleation and crystallization of titania nanoparticles in silica titania planar waveguides: A study by low frequency Raman scattering

Montagna, M.; Chiasera, A.; Moser, E.; Visintainer, F.; Ferrari, M.; Zampedri, L.; Gonçalves, R. R.; Ribeiro, S. J. L.; Martucci, A.; Guglielmi, M.; Ivanda, M.; Almeida, R. M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 520-526
ENG
Relevância na Pesquisa
597.57883%
SiO2 (1-x) - TiO2 (x) waveguides, with the mole fraction x in the range 0.07 - 0.20 and thickness of about 0.4 μm, were deposited on silica substrates by a dip-coating technique. The thermal treatments at 700-900°C, used to fully densify the xerogels, produce nucleation of TiO2 nanocrystals even for the lowest TiO2 content. The nucleation of TiO2 nanocrystals and their growth by thermal annealing up to 1300°C were studied by waveguide Raman spectroscopy, for the SiO2 (0.8) - TiO2 (0.2) composition. By increasing the annealing temperature, the Raman spectrum evolves from that typical of the silica-titania glass to that of anatase, but brookite phase is dominant at intermediate temperatures. In the low. frequency region (5-50 cm-1) of the Raman spectra, acoustic vibrations of the nanocrystals are observed. From the measured line shapes, we can deduce the size distribution of the particles. The results are compared with those obtained from the line widths in the X-ray diffraction patterns. Nanocrystals with a mean size in the range 4-20 nm are obtained, by thermal annealing in a corresponding range of 800-1300°C.

Broadband NIR emission in novel sol-gel Er3+-doped SiO 2-Nb2O5 glass ceramic planar waveguides for photonic applications

Aquino, Felipe Thomaz; Ferrari, Jefferson Luis; Ribeiro, Sidney José Lima; Ferrier, Alban; Goldner, Philippe; Gonçalves, Rogéria Rocha
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 387-396
ENG
Relevância na Pesquisa
710.764%
This paper reports on the sol-gel preparation and structural and optical characterization of new Er3+-doped SiO2-Nb 2O5 nanocomposite planar waveguides. Erbium-doped (100-x)SiO2-xNb2O5 waveguides were deposited on silica-on-silicon substrates and Si(1 0 0) by the dip-coating technique. The waveguides exhibited uniform refractive index distribution across the thickness, efficient light injection at 1538 nm, and low losses at 632 and 1538 nm. The band-gap values lied between 4.12 eV and 3.55 eV for W1-W5, respectively, showing an excellent transparency in the visible and near infrared region for the waveguides. Fourier Transform Infrared (FTIR) Spectroscopy analysis evidenced SiO2-Nb2O5 nanocomposite formation with controlled phase separation in the films. The HRTEM and XRD analyses revealed Nb2O5 orthorhombic T-phase nanocrystals dispersed in a silica-based host. Photoluminescence (PL) analysis showed a broad band emission at 1531 nm, assigned to the 4I13/2 → 4I15/2 transition of the Er3+ ions present in the nanocomposite, with a full-width at half medium of 48-68 nm, depending on the niobium content and annealing. Hence, these waveguides are excellent candidates for application in integrated optics, especially in EDWA and WDM devices. © 2012 Elsevier B.V. All rights reserved.

Multi-objective genetic algorithm applied to spectroscopic ellipsometry of organic-inorganic hybrid planar waveguides

Fernandes, Vasco R.; Vicente, Carlos; Wada, Naoya; Andre, Paulo; Ferreira, Maria R.
Fonte: Optical Society of America Publicador: Optical Society of America
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
598.49957%
The applicably of multi-objective optimization to ellipsometric data analysis is presented and a method to handle complex ellipsometric problems such as multi sample or multi angle analysis using multi-objective optimization is described. The performance of a multi-objective genetic algorithm (MOGA) is tested against a single objective common genetic algorithm (CGA). The procedure is applied to the characterization (refractive index and thickness) of planar waveguides intended for the production of optical components prepared sol-gel derived organic-inorganic hybrids, so-called di-ureasils, modified with zirconium tetrapropoxide, Zr(OPr(n))(4) deposited on silica on silicon substrates. The results show that for the same initial conditions, MOGA performs better than the CGA, showing a higher success rate in the task of finding the best final solution. (C) 2010 Optical Society of America; FCT; FEDER; PTDC/CTM/72093/2006; SFRH/BD/41943/2007; MP0702

Optical Signal Processing in Highly-Nonlinear Chalcogenide Planar Waveguides

Pelusi, Mark; Ta'eed, Vahid G; Lamont, Michael R E; Eggleton, Benjamin J; Madden, Steve; Choi, Duk-Yong; Bulla, Douglas; Luther-Davies, Barry
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Conference paper
Relevância na Pesquisa
702.8393%
Bit-error rate performance of newly developed As2S3 planar waveguides in applications of high-speed all-optical time-division demultiplexing and wavelength conversion of 40-160 Gb/s optical signals through the use of four-wave mixing and cross-phase modul

Optical gain in nanocrystalline silicon: comparison of planar waveguide geometry with a non-waveguiding ensemble of nanocrystals

Luterova, K; Cazzaneli, M; Likforman, J-P; Navarro, D; Valenta, Jan; Ostatnicky, T; Dohnalova, K; Cheylan, S; Gilliot, P; Honerlage, B; Pavesi, L; Pelant, I
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
608.26938%
Stimulated emission from nanocrystalline silicon in the visible has become a hot topic during the past years. Various forms of silicon nanostructures are being exploited, among them planar optical waveguides made of silicon nanocrystals, silicon superlattices and tiny silicon nanoparticles. We report on optical gain measurements using the variable-stripe-length and the shifting-excitation-spot methods in two different types of nanocrystalline samples: a planar nanocrystalline waveguide prepared by silicon-ion implantation (400 keV, 4 × 1017 cm-2) into a silica substrate and a layer of porous silicon grains embedded in a sol-gel derived SiO 2 matrix. The latter does not exhibit any waveguiding. At a first sight one would expect much more favorable conditions for the stimulated emission occurrence in the former type of samples. We observed in fact small optical gain in both types (modal gain of 12 cm-1 at ∼760 nm in ion implanted sample and of 25 cm-1 at ∼650 nm in sol-gel embedded sample, respectively), however, under different pumping conditions. We discuss advantages and disadvantages of both nanostructures, referring in particular to leaky-mode emission that may occur in planar waveguides on transparent substrates.