Abstract
We propose and demonstrate an architecture of a 2 x 2 port optical cross-connect (OXC) using tuneable fibre Bragg gratings and optical circulators. The proposed OXC is scalable to N x N ports owing to the cascadability of individual routing modules, which perform routing of specific wavelength channels. The performance of the cross-connect is also experimentally evaluated.

Abstract
In 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 power is observed over all the tuning range.

Abstract
A multiplexer/demultiplexer for 100GHz 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.

Abstract
The 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/ demultiplexer based on Bragg grating technology, dispersion compensators, and optical cross-connects. Active photonic devices such as wavelength converters, fiber lasers, and fiber amplifiers have also been studied. New ideas are being continuously developed and tested.

Abstract
A new scheme is presented for simultaneous measurement of strain and temperature using a sampled fibre Bragg grating based on a long period structure written using the electric are technique. The temperature and strain measurement resolutions are estimated to be +/-0.50degreesC/rootHz and +/-3.38 muepsilon/rootHz, respectively.

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.