Abstract
Fiber Bragg Gratings (FBG's) are nowadays widely used in various fields, including telecommunications. Since emergence, this component has found many applications due to its properties, versatility and variety of controllable parameters that can shape in various manners its spectral properties. These devices have the advantage of being built of fiber and they are widely used in mono and multichannel networks.

Abstract
This paper presents some aspects of the production, characterization and implementation of fibre Bragg grating as a key element for selective filtering in optical communications. Theory, fabrications and applications of the Fibre Bragg grating for a specific tuneable optical add-drop multiplexer (OADM) are presented. The OADM performance on a 2.48832 Gbit/s dense wavelength division multiplexing optical communications system with 95 km is reported. The power penalty for the removed channels was less than 0.1 dB. We obtain good agreement between the FBG behaviour the OADM performance with the numerical simulations results. Copyright SBMO.

Abstract
This paper presents a smart composite for structural monitorisation, based on fibre Bragg grating sensors. The sensor plate, a carbon fibre reinforced plastic laminate having an embedded optical strain gauge rosette, was designed, produced, and tested. These instrumented carbon fibre laminates can be used for monitoring of reinforcement and protection of structures, playing an important role in the control of repaired constructions. The smart structures developed are shown to have the ability of measuring temperature and strain.

Abstract
We 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.

Abstract

Abstract
We report, for the first time to our knowledge, the excellent optical performance of long-period gratings written in three standard libers and in two nonstandard fibers, namely, S-doped and N-doped fibers, using the flexible and low-cost electric are technique. The fundamental mechanism for their formation is proposed. The gratings thermal behavior and the effect of fiber preannealing prior to writing have been investigated. We have demonstrated a good stability of these gratings at high temperatures.