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Polarization Mode Dispersion Measurements using Low-Coherence Interferometry
Luís M. N. Amaral; O. Frazão; M. B. Marques; Mário Lima; António TeixeiraAn interferometric setup for measuring Polarization Mode Dispersion (PMD), was tested. It uses a low-coherence technique in a Michelson interferometer to determine the PMD values in two reels, measuring the Differential Group Delay (DGD). The low-coherence source bounds the minimum value of DGD detected to 0,13 ps, leading to a minimum value detected around 0,14 ps. The measured PMD mean value for one reel, in ...
Thermally Tunable Bragg Grating Filtrers for Wavelength-Multiplexed Systems
M. J. N. Lima; O. Frazão; A. L. J. Teixeira; P. S. B. André; J. R. Ferreira da RochaIn this contribution we compare the thermal tuning capabilities of two type I gratings, considering an unloaded and a hydrogen-loaded fiber, and a type IIa grating. We further study their responses stability with temperature, analyzing their potential as optical filters in wavelength division multiplexing systems. We conclude that all of them have similar tuning efficiencies, howev...
Chirped Fibre Bragg Grating Based Multiplexer and Demultiplexer for DWDM applic...
R. Romero; O. Frazão; F. Floreani; L. Zhang; P. V. S. Marques; H. M. SalgadoA multiplexer/demultiplexer for 100 GHz channel spacing based on chirped fibre Bragg gratings with different bandwidths and optical circulators is presented. The spectral characteristics, specifications and operation of these passive devices are described, showing its potential use in dense wavelength division multiplexing (DWDM) applications.
Optical Fiber Communications: Recent Contributions in Photonic Device Technology
J. Carvalho; R. Romero; M. Melo; L. Gomes; O. Frazão; M. Marques; H. M. SalgadoThe current status of the research and development as well as the recent contributions in optical communications at INESC Porto is reviewed. This review includes all the work carried out in the last few years in optical fiber communications, namely the development of passive and active optical devices. Some of the passive structures that have been studied and developed are: add-drop multiplexers, multiplexer/de...
Tunable L-band erbium-doped fibre ring laser by means of induced cavity loss us...
M. Melo; O. Frazão; A. L. J. Teixeira; L. A. Gomes; J.R. Ferreira da Rocha; H. M. SalgadoIn this paper, we present a continuous-wave tunable fibre ring laser operating in the L-band. A bi-directional pumped L-band erbium-doped fibre amplifier provides gain to the loop. Tunability is achieved by bending a single-mode fibre taper using a micrometer drive, controlling in this way the spectral cavity losses. Laser emission is achieved between 1587 and 1606 nm, and low variation of the output laser powe...
A novel architecture of an optical cross-connect based on tuneable fibre bragg ...
O. Frazão; J. P. Carvalho; I. Terroso; V. Barbosa; Henrique Manuel de Castro Faria SalgadoOptical networks have evolved to sustain the growing need for bandwidth in communication networks. Wavelength switched networks using Dense Wavelength Division Multiplexing (DWDM), are a solution to this problem. Development of these networks demands the use of Optical Cross-connects (OXCs), optical devices that are able to control the communications channels and route them correctly. In this paper, a novel swi...
EDFA Gain Flattening Using Long-Period Fibre Gratings Based on the Electric Arc...
O. Frazão; G. Rego; M. Lima; A. Teixeira; F. M. Araújo; P. André; J. F. da Rocha; Henrique SalgadoWe have flattened the gain spectrum of a commercial Erbium-doped fibre amplifier, obtaining a curve with approximately 3 dB of ripple, from 1524 nm to 1551 nm, using long-period fibre gratings as equalising optical filters. The fabrication principle of the long-period fibre grating is based on the electric arc technique.
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