• We have successfully implemented in our labs the generation, transmission, detection and routing of optical packets for next generation all-optical networks .. IDtrafast switching function (!ls time base) is demonstrated using a RF frequency tone as header, combined with a highcapacity digital payload, both inserted in the optical packet. The packet may propagate kilometers in the network, without degrading. At node input the optical packet header is detected and a switching control mechanism directs the packet to a prescribed output, without further opto-electric conversion. Tlte optical circuit is noise-free, with BER results better than 10"12 .This system is applicable to metropolitan and access WDM optical networks. style.Keywords: Optical Packets, Photonic Switching, Optical networks, digital communications.Resumo -lmplementamos com sucesso em nossos laborat6rios, a gera~ao transmissao detec~iio e roteamento de pacotes 6pticos para Redes Todas-6pticas de Pr6xima Gera~iio. Chavearnento ultra-nipido ( base de tempo llS) e demonstrado usando urn tom RF como cabes:alho, que e inserido no pacote 6ptico combinado com uma carga uti! digital de alta capacidade. 0 pacote carregado propaga-se pela rede 6ptica e e detectado na entrada do n6 segninte, distante do local de gera~iio ate varies kilometres, sem degrada~iio. Na entrada do n6, urn mecanisme de controle de chavearnento direciona o pacote 6ptico a uma porta de safda, sem conversiio eletro-6ptica. 0 circuito 6ptico e livre de rufdo, com medidas de taxa de erro ate melhores do que 10· 12 • Este sistema pode ser aplicado em redes 6pticas WDM metropolitanas e acesso.

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We have undertaken electrochemical C-V measurements of Ga0.94Al0.06As:Ga0.57Al0.43As isotype n-n heterojunctions in order to determine the conduction band offset ΔEc. Samples were grown by liquid-phase epitaxy; carrier concentrations were determined to be, respectively, 1016 cm−3 for the small band-gap layer and 1016 cm−3 or 1017 cm−3 for the large band-gap layer. From results obtained with various different samples, we determine ΔEc/ΔEg≊0.54–0.64, quite close to the new accepted value of the GaAs:GaAlAs interface. Moreover, the density of fixed interface charges are estimated and found to be related to the monolayer doping density of the large band-gap layer.

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