Abstract
The theory of nonlinear systems based on frequency domain analysis using Volterra series is shown to provide an appropriate means of assessing laser distortion which includes the effects of laser resonance. Hence, it is an appropriate and tractable means of assessing the performance of optical subcarrier multiplexed (SCM) systems. Based on this analysis the performance of SCM systems is examined, with calculation of the carrier-to-intermodulation ratio for an eight-channel SCM system providing an illustrative example.

Abstract
Analytic techniques proposed for distortion analysis are shown not to predict adequately the higher order terms generated by a semiconductor laser diode of relevance to the design and dimensioning of subcarrier multiplexed optical communications systems. A modified analysis which avoids this deficiency is outlined and illustrative results are presented.

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.

Abstract
A new sensing configuration is proposed for simultaneous measurement of strain and temperature that relies on a single long period grating written by the electric arc technique. The underlying principle is the azimuthal asymmetry induced by the electric arc fabrication technique, which results in a device with polarization dependent insertion loss sensitive to both temperature and strain. With the proposed configuration, resolutions of +/- 2.8 degreesC/rootHz and +/- 13.9 muepsilon/rootHz are obtained for temperature and strain measurements, 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.

Abstract
Two different architectures of multiplexers/demultiplexers based on 4 x 1 and 1 x 4 configurations are discussed. These architectures are implemented using apodized fibre Bragg gratings as optical filters and optical circulators. The spectral characteristics of the devices for channel separations of 100 GHz and 50 GHz are analysed and their performance is evaluated. Optical switch and cross-connect configurations are also demonstrated.