Abstract
A passive all-fibre technique for fibre Bragg grating wavelength shift detection previously presented is used here for the demodulation of two Bragg sensors placed in a tree topology and addressed in time. The scheme involves a light source with particular spectral profile that allows the direct tracking of the Bragg wavelength shifts, providing satisfactory resolution over a large dynamic range and direct application in demultiplexing fibre sensing systems. Experimental results are presented relative to the measurement of static and dynamic strain, as well as temperature.

Abstract
A technique for the demodulation of fiber Bragg grating (FBG) sensors based on the use of a second wavelength-matched FBG receiver to track wavelength shifts from the FBG sensor is analyzed, particularly regarding its sensitivity as determined by primary noise sources. Numerical and experimental results show that there is an optimum Bragg wavelength difference between the two FBG's that maximizes the sensitivity for this demodulation technique. (C) 1997 Optical Society of America

Abstract
A new technique is described for the extraction of the intrinsic semiconductor laser parameters from intermodulation measurements of composite second-order (CSO) and composite third-order (CTB) distortion products. The effect of the parasitics elements are eliminated, by taking the distortion measurements at constant optical modulation depth, which enables one to obtain the laser parameters on packaged laser diodes. An optimization algorithm is then described that extracts the relevant laser parameters from the distortion data. This method was applied to a commercially available packaged laser diode and very good agreement was obtained between the measured and theoretical results.

Abstract
We report the experimental observation of up-conversion in an integrated silica-on-silicon waveguide. Blue light at 455 nm and 475 nm was observed. In addition to the strong blue emission near infrared (similar to 800 nm), visible (648 nm) and UV (366 nm) lines were also detected. We investigated the excitation mechanisms by using different pumping wavelengths. (C) 1997 Elsevier Science B.V.

Abstract
Flame hydrolysis deposited (FHD) silica waveguides are very important for use in planar lightwave circuits (PLC) because of their low loss and inherent compatibility with silica optical fibers. A low damage, anisotropic reactive ion etch process for the fabrication of single and multimode waveguides in silica for planar lightwave circuit applications is presented. The etch rate of the glass results in smooth sidewalls and deep anisotropic etching. Propagation losses and polarization sensitivity arising from the etch process are discussed.

Abstract
We report what is to our knowledge the first laser operation of Nd3+-doped LiNbO3 near 900 nm. An absorbed power threshold of 26 mW was obtained when the device was pumped at 814 nm. The design of the waveguide geometry to favor laser operation at this wavelength is demonstrated. (C) 1997 Optical Society of America.