Fabrication and characterization of tellurite and germanate waveguides for optoelectronics applications. / Produção e caracterização de guias de onda de telureto e germanato para aplicações em optoeletrônica.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

The objective of this work is the production and characterization of GeO2-PbO and TeO2-ZnO waveguides. The waveguides were produced using thin films and glasses by means of different procedures. The films were produced using the RF magnetron sputtering method and characterized by a variety of techniques. In particular, scanning electron microscopy was essential to optimize the processes involved in producing the waveguides. This was one the fundamental challenge of this work since there are no reports in the literature describing these processes on such materials. The thin film waveguides were produced on top of a silicon substrate using conventional microelectronic procedures: chemical cleaning, thermal oxidation, sputtering deposition, optical lithography and wet chemical corrosion or plasma etching. Several tests performed using these processes enabled the determination of the best condition (SF6 etching, AZ-5214 resist and resist removal with microstripper 2001) for the implementation of rib waveguides with 1 to 10 m width and average depth of 70 nm for GeO2-PbO and 90 nm for TeO2-ZnO. For the rib waveguides of PbO-GeO2 and TeO2-ZnO the propagation losses were optically measured. Both systems presented a multimode (TE) guiding with attenuation values of 2.2 dB/cm for PbO-GeO2 and 1.5 dB/cm for TeO2-ZnO at 633 nm. These values depend heavily on the surface and lateral roughness, on the uniformity of the films and on the difference between the refractive index. We conducted computer simulations of optical guiding in planar and rib structures in order to estimate the guiding losses. The calculated values were compatible with the experimental results. Glasses waveguides of GeO2-PbO-Ga2O3 and TeO2-GeO2-PbO were produced using the direct writing technique with a femtosecond laser. The structures were analyzed optically in order to determine the overall propagation losses. The optimized writing parameters were 0.05 mm/s speed with 10 W laser power. Using these parameters we obtained for the propagation losses at 633 nm, 6.8 dB (for 0.75 cm length) and 7.0 dB (for 0.9 cm length) for TeO2-GeO2-PbO and GeO2-PbO-Ga2O3, respectively. This work presents the development of an adequate technology for the production of waveguides composed of new materials with promising applications for optoelectronics and photonics.

ASSUNTO(S)

laser microfabrication microfabricação laser sputtering germanato thin film germanate optoelectronic filmes finos guia de onda tellurite telureto optoeletrônica sputtering waveguide

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