Marcos S. Gonçalves

Designing Novel Photonic Devices by Bio-Inspired Computing

Three bio-inspired optimization schemes, integrated into a robust frequency domain 2-D finite-element code, have been assessed by the design of two novel nonintuitive photonic crystal-type devices: an unbalanced power splitter and a micro-to-nano waveguide coupler. The bio-inspired schemes were taken from three biological-based classes of algorithms: genetic algorithm, evolution strategy, and artificial immune system. The results show that such schemes constitute valuable and powerful tools for the design of advanced and sophisticated photonic devices, where pixels concept was changed by photonic crytals structures to enable their future fabrication.

Time-domain full-band method using orthogonal edge basis functions

A new time-domain numerical approach for two-dimensional vectorial wave equation solutions based on slow wave variation is presented. The algorithm incorporates finite-element discretization and uses orthogonal edge basis functions to describe pulse propagation in optical waveguides.

Estudo do amortecimento do pêndulo simples: uma proposta para aplicação em laboratório de ensino

The pendula are largely used in teaching activities of physical introductory courses. Often, in these activities an ideal model is used to study the behavior of the pendulum. In this work a model that takes into account the oscillation damping is suggested. An experimental methodology is purposed aiming to detect the falling down of oscillation amplitude and to fit these data to a mathematical model. The results show that the simple pendulum, set up by a small volume sphere and oscillating on low speed, can be studied with simplified models. The methodology and the mathematical model are appropriated for the knowledge level of the students from physic introductory courses and offer a more realistic insight about the pendulum behavior.

The study of piezoelectric devices with Thévenin's Theorem

This work presents a study of the behavior of piezoelectric devices based on a modified Thévenins equivalent electric circuit. It aims to characterize piezoelectric devices using electric network theory and to complement the instruction of Thévenins Theorem in classes about electric circuits. The employed approach allows us to outline the most important concepts of operation of the piezoelectric transducers. The manner for obtaining the equivalent electric circuit and a simple experimental procedure are presented. The work shows that Thévenins Theorem, commonly taught in electric circuits classes, can be used for evaluating of piezoelectric devices. The methodology employed in this work facilitates the comprehension of the physical principles of the piezoelectric elements.

Experimental evaluation of the performance of a wireless sensor network in agricultural environments

Um estudo experimental, visando a avaliar a distância de operacao adequada entre os nos de uma rede de sensores sem fio disponivel no mercado, foi realizado para diferentes cultivos agricolas (milho, pinhao-paraguaio e eucalipto), buscando oferecer aos agricultores e pesquisadores dados experimentais do desempenho da rede, que possa good yield are environmental factors, which include high temperatures and high humidity within the facilities, causing stress to the animal and consequent decreased production (SOUSA, 2005).am ser uteis para ser considerados no dimensionamento e no projeto de redes de sensores sem fio em situacoes semelhantes as estudadas. A avaliacao mostrou que a distância de separacao dos nos depende do tipo de cultura e e um fator critico para garantir a viabilidade do uso da RSSF. Na configuracao usada, com envio de pacotes a cada 2 segundos, a autonomia da bateria foi de cerca de quatro dias. Portanto, a autonomia pode ser aumentada com um intervalo maior de tempo entre o envio de pacotes.

Evolutionary strategy algorithm applied to optimize micro-to-nano coupler devices

This work presents the integration of finite element method and artificial intelligence approaches to model and optimize non-intuitive micro-to-nano couplers. The non-intuitive term is related to the columns arrangements into the photonic couplers, which best optimized solution coupled 73.94%. Another important advantage is the possibility to fabricate this device into Unicamp facilities.

Design of photonic devices using bio-inspired algorithms

The design of photonic devices in computer simulators is a complex task and, in some cases, there are not analytical solutions to support. An alternative is the application of some optimizations techniques. For this reason, this work presents three different bio-inspired algorithms (GA, ES and AIS) to optimize three different photonic devices. The main objectives are providing a flexible and efficient computational optimization tool to design different photonic devices and benchmarking the efficiency of each one. In addition, the efficiency results compare the optimization convergence and computational efforts necessary for each optimization.

Towards an integrated evolutionary strategy and artificial neural network computational tool for designing photonic coupler devices

Abstract Photonics has been widely explored in computing and communications, mainly to rationalize the relationship between device size minimization and data processing/transmission maximization. Generally driven by optimization and modeling techniques, the design of photonic devices is often performed by bio-inspired algorithms integrated to electromagnetic solvers, which have achieved advances but is still time-consuming. As an alternative to a costly finite element method (FEM) solver, a multilayer perceptron (MLP) neural network is proposed for computing power coupling efficiency of photonic couplers, originally designed through an integrated evolutionary strategy (ES) and FEM routine. We address the ES-FEM design of two efficient couplers, present the MLP implementation and the MLP training and testing over the routine generated datasets, and measure MLP and FEM runtime. MLP suitably predicted the power coupling efficiency of a variety of unknown couplers on tests. The measured runtime showed MLP is ∼105 faster than FEM. In conclusion, MLP is a potential tool to be integrated to ES on the design of such photonic couplers.

Numerical Analysis of the Resonant Cavities in Series for Optical Filter Applications

This project presents the design of an integrated optical filter developed through the integration of Finite Element Method FEM and Genetic Algorithm AG. The filter was carried out by association of photonic crystals microcavities and optical couplers. Numerical results shows that the filter has features that make it suitable for DWDM systems.

Numerical Analysis of a Novel Optical Filter for DWDM Systems

The use of electromagnetic simulations has become an important methodology to design photonic devices. Associating these electromagnetic simulators with the optimization techniques it is possible to design complex structures. The aim of this work is a development of a new integrated optical filter for DWDM applications. This project was carried out by using the Finite Element Method associated with Genetic Algorithm and the numerical results show that the filter has high selectivity and low insertion losses and it is suitable to work in a DWDM system.