Abstract
An intensity-referenced temperature-independent curvature-measurement technique that uses a smart composite that comprises two chirped fiber Bragg gratings is demonstrated. The two gratings are embedded on opposite sides of the composite laminate and act simultaneously as curvature sensors and as wavelength discriminators, enabling a temperature-independent intensity-based scheme to measure radius of curvature. Also, the system's performance is independent of arbitrary power losses that are induced in the lead fibers to the sensing head. It is demonstrated that the measurement range depends on the relative positions of the chirped fiber Bragg gratings and on their spectral bandwidths. By using two chirped fiber Bragg gratings with bandwidths W-1 = 2.8 nm and W-2 = 3.7 nm and with central wavelengths at lambda(01) = 1560.3 nm and lambda(02) - 1563.7 nm, we obtained a resolution of 1.6 mm/(1)Hz for the measurement of the radius of curvature (similar to R = 350 mm) over the measurement range 190 mm < R < infinity. (c) 2005 Optical Society of America.

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 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 new scheme based on four-wave mixing is presented using a ring erbium-doped fibre laser and tuneable fibre Bragg gratings that can effectively perform wavelength conversion in a wide wavelength range. An application of this wavelength-conversion architecture to optical communications is also presented.

Abstract
All-optical switching devices based on fibre Bragg grating (FBG) structures written on a standard single-mode fibre and in an erbium-doped fibre have been experimentally demonstrated in the third telecommunication window. The switching devices work due to the thermal changes induced by a high-power continuous-wave laser diode. The filters tunability characteristics have been demonstrated for different pump powers (up to 900 mW) and different pump laser wavelengths (at 980 and 1480 nm), presenting different thermal absorption behaviour within different working regimes. (c) 2006 Wiley Periodicals, Inc.

Abstract
An intensity-referenced temperature-independent curvature measurement technique using a smart composite comprising two chirped fiber Bragg gratings is demonstrated. The two gratings are embedded on opposite sides of a composite laminate and act simultaneously as curvature sensors and as wavelength discriminators, enabling an unambiguous measurement of the composite radius of curvature.