Comparison of pre and post-dispersion compensation schemes with RZ, NRZ and Gaussian modulations for 10 GBPS and 40 GBPS transmission rates / Comparação de esquemas de compensação pré e pós-dispersão com modulações RZ, NRZ e Gaussina para as taxas de transmissão de 10 GBPS e 40 GBPS

In this paper, we investigate two dispersion compensation methods: post-compensation, and pre-compensation for transmission rates from 10Gbps to 40Gbps with return to zero (RZ), non-return to zero (NRZ) and Guassian modulations using single fiber mode-fiber (SMF) and dispersion compensating fiber (DCF). The influence of the DCF compensator dispersion with different transmission rates was studied in order to evaluate the performance of the proposed systems. The simulation results were validated through the analysis of the quality factor (Q-factor) and the bit error rate (BER), where it was verified that the post-compensation system with Gaussian modulation offered better performance results in function of the transmission rate variation.

Analysis of the behavior of an all-optical not logic gate in a photonic crystal directional coupler / Análise do comportamento de uma porta lógica not totalmente óptica em um acoplador direcional de cristal fotônico

In the present work, an optical directional coupler (ODC) based on two-dimensional (2-D) photonic crystal (PhC) was analyzed and proposed, through the methods of plane wave expansion (PWE) and finite-difference time-domain (FDTD), which were used with the purpose of analyzing the behavior of a new all-optical NOT logic gate and the electric field distribution in the coupler for linear (bar), non-linear (cross) states and the control signal. The simulation results in OptiFDTD software show that the proposed crystal structure is a strong candidate for use in ultrafast photonic integrated circuits (PICs), being highly advantageous with excellent transmission performance and simple design