It is estimated that, between the year 2000 and 2003, thenumber of online Internet users will grow from 250 millions to500 millions. This growth results in rapidly increasing demandfor fibre-optic communication bandwidth, occurring at alllevels: from access and local area networks (LANs) tometro-area networks (MANs). A now established solution for manyapplications such as interconnects and Gigabit Ethernet is thevertical cavity surface emitting laser (VCSEL). The advantagesof VCSELs are numerous: low fabrication and coupling costs,large modulation bandwidth, array integration and tunability.VCSEL-based modules, with speed up to 2.5 Gbit/s are nowcommercially available for multimode fibre (MMF) basedapplications. However, devices operating at long wavelength andhigher transmission rates (10Gbit/s and more) will be needed inthe near future. The purpose of the work presented in this thesis was toobtain an understanding of the high-speed properties of VCSELs,in order to extend the modulation frequency at which they canbe used in fibre optical communication systems. An approach forsystematic high-speed characterisation of VCSELs is presentedand both its potential benefits and problems are discussed. Itis shown that the VCSEL dynamics, under certain conditions, canbe well described by a small number of parameters that can beextracted from small signal measurements and used forfurtheroptimisation. The calibrated small-signal modulation responsesof VCSELs have been measured and fitted to an analyticaltransfer function allowing the estimation of the resonancefrequency, damping factor and parasitic cut-off at differentbias points. This data can be used to determine the relativeimportance of different bandwidth limiting effects due todamping, thermal heating and parasitics. Small signal analysis and transmission experiments wereperformed with a large sample of VCSELs covering the variousranges of applications. Visible VCSELs and resonant cavitylight emitting diodes (RCLEDs) for very short reach plasticoptical fibre (POF) applications, 850nm datacom VCSELs forshort distance multimode fibre networks, and long wavelengthVCSELs for long haul single mode fibre transmission. <b>Keywords:</b>Semiconductor lasers, VCSEL, high-speedmodulation, fibre optic networks, datacom, RCLED, plasticoptical fibre

<p>It is estimated that, between the year 2000 and 2003, thenumber of online Internet users will grow from 250 millions to500 millions. This growth results in rapidly increasing demandfor fibre-optic communication bandwidth, occurring at alllevels: from access and local area networks (LANs) tometro-area networks (MANs). A now established solution for manyapplications such as interconnects and Gigabit Ethernet is thevertical cavity surface emitting laser (VCSEL). The advantagesof VCSELs are numerous: low fabrication and coupling costs,large modulation bandwidth, array integration and tunability.VCSEL-based modules, with speed up to 2.5 Gbit/s are nowcommercially available for multimode fibre (MMF) basedapplications. However, devices operating at long wavelength andhigher transmission rates (10Gbit/s and more) will be needed inthe near future.</p><p>The purpose of the work presented in this thesis was toobtain an understanding of the high-speed properties of VCSELs,in order to extend the modulation frequency at which they canbe used in fibre optical communication systems. An approach forsystematic high-speed characterisation of VCSELs is presentedand both its potential benefits and problems are discussed. Itis shown that the VCSEL dynamics, under certain conditions, canbe well described by a small number of parameters that can beextracted from small signal measurements and used forfurtheroptimisation. The calibrated small-signal modulation responsesof VCSELs have been measured and fitted to an analyticaltransfer function allowing the estimation of the resonancefrequency, damping factor and parasitic cut-off at differentbias points. This data can be used to determine the relativeimportance of different bandwidth limiting effects due todamping, thermal heating and parasitics.</p><p>Small signal analysis and transmission experiments wereperformed with a large sample of VCSELs covering the variousranges of applications. Visible VCSELs and resonant cavitylight emitting diodes (RCLEDs) for very short reach plasticoptical fibre (POF) applications, 850nm datacom VCSELs forshort distance multimode fibre networks, and long wavelengthVCSELs for long haul single mode fibre transmission.</p><p><b>Keywords:</b>Semiconductor lasers, VCSEL, high-speedmodulation, fibre optic networks, datacom, RCLED, plasticoptical fibre</p>

El objetivo general del presente trabajo de título es compartir la experiencia real de un proyecto de conversión de bases de datos dentro de una entidad y organización bancaria, en un esquema de procesamiento de datos basado en computadores centrales mainframe IBM y con un administrador de base datos DB2. El proyecto se desarrolló en la entidad financiera BBVA banco BHIF en el año 2001. Para tal efecto se realizó el análisis, construcción, pruebas de sistema, pruebas de usuario, puesta en producción y seguimiento post-producción. Se determinó el uso de una metodología de desarrollo de software y una metodología de conversión de datos. El objetivo del proyecto era asegurar la conversión del 100% de la información para dar continuidad operacional al producto-negocio de Cobranza de Letras y Pagarés. De tal forma de garantizar un impacto mínimo en los servicios entregados a los clientes del banco y a los procedimientos realizados por los usuarios internos del banco. El resultado final fue el término exitoso del proyecto logrando realizar la conversión de la base de datos en ambiente real de producción y explotación de sistemas. Se alcanzó en primer término el objetivo de convertir la totalidad de registros de la base de datos a la nueva plataforma. En segundo lugar no se impactaron las actividades de negocio de los usuarios internos de las sucursales y fue trasparente para los clientes del banco. Las conclusiones más relevantes de esta experiencia son que los conocimientos adquiridos durante la carrera permiten enfrentar el desarrollo de proyectos de gran complejidad técnica, facilitando el aprendizaje de nuevas tecnologías para resolver los problemas que surgen en los proyectos informáticos. Otro aspecto relevante de esta experiencia es el de formar equipos de trabajo y establecer dinámicas de colaboración con profesionales extranjeros.