Experimental study of a phase modulator using an active interferometric device

“Copyright © [2010] IEEE. Reprinted from 15th IEEE Mediterranean Electrotechnical Conference. ISBN: 978-1-4244-5793-9. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”A novel architecture for an optical phase modulator is presented and experimentally demonstrated. This approach relies on a commercially available integrated Mach- Zehnder interferometer structure with Semiconductor Optical Amplifiers (MZI-SOA) and it is based in cross-phase modulation effect (XPM). The feasibility of the proposed optical phase modulator is experimentally investigated using different scenarios of input power and bit rates

Redes de Bragg em fibra óptica

O presente trabalho tem por objectivo o estudo e desenvolvimento de Redes de Bragg em fibra óptica. As redes de Bragg em fibra óptica são componentes ópticos com capacidades de filtragem únicas, tornando-os bastante úteis no desenvolvimento de diversos dispositivos para as comunicações ópticas ou como sensores de alta precisão para a biomecânica, a aeronáutica, o ambiente ou a engenharia civil. Deste modo, foi efectuada uma abordagem teórica onde foram demonstrados e simulados os princípios de funcionamento das redes de Bragg. Para isso, utilizou-se a teoria dos modos acoplados em fibra óptica. Posteriormente, foi descrito o sistema de gravação implementado para a gravação de redes de Bragg. O sistema permite a gravação de redes de Bragg por quatro métodos distintos. Foi também desenvolvido um modelo teórico do sistema, que permite tornar o processo de gravação totalmente automatizado. Implementaram-se diferentes técnicas de caracterização de redes de Bragg. Entre elas, destaca-se a aplicação de pressão pontual, que permite obter informação espacial sobre estruturas complexas baseadas em redes de Bragg. Foram desenvolvidos e caracterizados diferentes dispositivos baseados em redes de Bragg com aplicações nas comunicações ópticas, tais como filtros, compensadores de dispersão e sensores biomecânicos. Foram também estudadas as redes de Bragg gravadas em fibra de elevada birrefringência. Devido às propriedades únicas de filtragem no comprimento de onda e na polarização, foi possível desenvolver diversos dispositivos com aplicações na compensação da dispersão dos modos de polarização, na conversão de comprimentos de onda e na geração de bombas ópticas. Com base nestas redes especiais, foram também desenvolvidos métodos de optimização de sistemas de comunicação óptica.The objective of this thesis is the study and development of fiber Bragg gratings, which have unique optical processing properties. Therefore, Bragg gratings are quite interesting for the development of devices for optical communications, biomechanics, environment or civil. The work started with a theoretical analysis of the coupled mode theory applied to fiber Bragg gratings. The theoretical study was completed with the study of some simulation techniques. The recording of fiber Bragg gratings was also addressed in this work, were an automated recording setup has been implemented, based on the theoretical model developed in this thesis. We proceeded with the study and implementation of different characterization techniques. One of them is based on the local pressure, which enable the characterization of complex structures based on fiber Bragg gratings. We have also studied and implemented different devices, based on Bragg gratings, for dispersion compensation, optical filtering and biomechanical sensing. Finally, we have studied fiber Bragg gratings written in highly birefringent fibers. These components have exceptional properties regarding the filtering in wavelength and polarization, which enabled the implementation of devices for polarization mode dispersion compensation, optical pumps and wavelength conversion. Some optimization techniques, based on these gratings, for optical communications, were also developed

Low cost color assessment of turbid liquids using supervised learning data analysis – proof of concept

This work reports the development of a low cost in-line color sensor for turbid liquids based on the transmission and scattering phenomena of light from RGB and IR LED sources, gathering multidimensional data. Three different methodologies to discriminate color from the turbidity influence are presented as a proof of concept approach. They are based in regression models, expectation maximization Gaussian mixtures and artificial neural networks applied to labeled measurements. Each methodology presents advantages and disadvantages which will depend on the intended implementation. Regression models revealed to be best suited for standard or occasional measurements, the EM Gaussian mixture will perform better for well-known controlled range of colors and turbidities and the neural networks have easy implementation and potential suited for real-time IoT platforms.publishe

MINERJUS: solução de apoio à classificação processual com uso de Inteligência Artificial

The electronic court case is a reality in Brazil, where 70% of new cases in all judiciary are virtual. Making proper use of this reality and improving it is paramount to meet the demand for approximately 25 million new processes per year. This project proposes an improvement in the speed and correctness of the electronic process classification through the use of Artificial Intelligence. Thus, it is conjectured to assist legal operators responsible for the registration of the initial petition document (creation of the process), as well as those responsible for its analysis, by means of automatic and assertive suggestion on the subject matter of the process, providing greater agility of processing and quality to the information contained in the Brazilian court records. During the development of the solution several machine learning algorithms were tested identifying the best performing, in this case Support Vector Machine, accuracy and precision as well as the response time and training for efficient process classification.O processo judicial eletrônico é uma realidade no Brasil, onde 70% dos casos novos em todo poder judiciário são virtuais. Fazer uso adequado desta realidade e aprimorá-la é primordial para dar vazão à demanda de aproximadamente 25 milhões de processos novos por ano. Este projeto propõe uma melhoria na celeridade e corretude da classificação dos processos eletrônicos, por meio da utilização de Inteligência Artificial. Com isso, conjectura-se auxiliar operadores do direito responsáveis pelo cadastro do documento petição inicial (criação do processo), bem como os responsáveis pela sua análise, por meio de sugestão automática e assertiva quanto ao assunto do processo, imprimindo maior agilidade de tramitação e qualidade nas informações contidas nos autos judicias brasileiros. Durante o desenvolvimento da solução foram testados diversos algoritmos de aprendizado de máquina identificando o de melhor performance, no caso o Suporte Vector Machine, com relação a acurácia e precisão, bem como o tempo resposta e treinamento, para uma eficiente classificação processual

Inscription of narrow bandwidth bragg gratings in polymer optical fibers

We report on the production and characterization of narrow bandwidth fiber Bragg gratings (FBGs) in two spectral regions using polymer optical fibers (POFs). Narrow bandwidth FBGs are increasingly important for POF transmission systems, WDM technology and sensing applications. Long FBGs with resonance wavelength around 850 nm and 1550 nm were fabricated in several types of polymer optical fibers. The 3 dB FBG bandwidth varies from 0.22 nm down to 0.045 nm considering a Bragg grating length of 10 mm and 25 mm, respectively

UV inscription and pressure induced long-period gratings through 3D printed amplitude masks

In this work, we demonstrate for the first time the capability to inscribe long-period gratings (LPGs) with UV radiation using simple and low cost amplitude masks fabricated with a consumer grade 3D printer. The spectrum obtained for a grating with 690 µm period and 38 mm length presented good quality, showing sharp resonances (i.e., 3 dB bandwidth < 3 nm), low out-of-band loss (~0.2 dB), and dip losses up to 18 dB. Furthermore, the capability to select the resonance wavelength has been demonstrated using different amplitude mask periods. The customization of the masks makes it possible to fabricate gratings with complex structures. Additionally, the simplicity in 3D printing an amplitude mask solves the problem of the lack of amplitude masks on the market and avoids the use of high resolution motorized stages, as is the case of the point-by-point technique. Finally, the 3D printed masks were also used to induce LPGs using the mechanical pressing method. Due to the better resolution of these masks compared to ones described on the state of the art, we were able to induce gratings with higher quality, such as low out-of-band loss (0.6 dB), reduced spectral ripples, and narrow bandwidths (~3 nm).publishe

Gestão de Associações no Brasil: desafios e tendências

O documento apresenta os resultados da Pesquisa Gestão de Associações no Brasil: Desafios e Tendências. Seu objetivo é de entender quais são as práticas de gestão associativa mais utilizadas por associações brasileiras e como elas variam em função de seu de tipo de membro -- pessoa física ou jurídica