Abstract
A fibre Bragg grating interrogation technique with tunable sensitivity is reported. It relies on the utilization of the edge filtering concept applied to a chirped fibre Bragg grating (CFBG) written in an erbium-doped fibre as the processing element. Through the combination of the optical gain properties of the erbium-doped fibre and of the distributed wavelength reflection characteristics of the CFBG, it is possible to achieve different reading sensitivities and amplification of the remote sensing signal.

Abstract
A full characterization of reversible long-period fibre gratings produced through the wind of a string around a fibre/grooved tube set is presented. This technique enables a good control over the gratings isolation loss-peaks and has high repeatability. The tunability of the resonant wavelengths through the etching of the fibres cladding, prior to perform the gratings, have been investigated. These mechanically induced long-period fibre gratings have shown high sensitivity to loads.

Abstract
The underlying formation mechanisms and the properties of long-period gratings produced through arc discharges are intrinsically related to the temperature reached by the fibre during arc exposure. In this work, the determination of the fibre temperature was based on Plank's blackbody radiation law. The radiation emitted by the optical fibre during heating due to an electric arc discharge, detected using a Cronin spectrometer, was fitted to the emission spectrum of the blackbody radiation, allowing the estimation of the temperature range attained by the fibre. A peak temperature of 1400 +/- 50 degrees C was obtained.

Abstract
A dynamic dispersion compensation device using a chirped fibre Bragg grating with a ring geometry embedded in a composite laminated is proposed. A numerical model is presented and compared with the experimental setup. It is shown that the theoretical and experimental results are in good agreement. The tunability of the device is obtained by applying different radius of curvature to the ring structure, and thus producing non-linear variations in the spatial period of the chirped fibre Bragg grating, without changing the usable bandwidth.

Abstract
A compact sensor able to discriminate between temperature and strain related effects was implemented. The proposed sensing head comprises a single long-period grating with two sections written consecutively in the SMF-28 fiber, by the electric arc discharge technique, using different fabrication parameters. The sensor performance is based on the distinct temperature and strain sensitivity values presented by two neighbor resonances belonging to each grating section. The temperature and strain resolutions are +/- 0.1 degrees C and +/- 40 mu epsilon, respectively.

Abstract
The radiation emitted by an optical fiber during heating due to an electric arc discharge was detected using a Cronin spectrometer. The fitting of the emission spectrum to the blackbody radiation, allowed the estimation of the temperature range attained by the fiber.