Abstract
A theoretical and experimental investigation, which allows the quantification of the general error function relative to the synthetic-heterodyne signal processing in interferometric fibre-optic sensors, is performed. The implications on the performance of interferometric sensing arrays are addressed. Considering the decrease of the readout phase errors, potentially more favourable implementations of this processing technique are proposed and compared.

Abstract
An all-optical fibre referencing scheme for intensity based sensors which uses two identical fibre Bragg gratings is described. It provides a general and simple miniature sensor design with referencing effectiveness against system power fluctuations. The concept is demonstrated for a reflective-type displacement sensing cavity, and its potential for simultaneous measurand and temperature evaluation is evaluated.

Abstract
The electrocatalytic oxidation of D-sorbitol on a polycrystalline platinum electrode, in perchloric aqueous medium, was studied by cyclic voltammetry under varying sweep rate, potential limits, stirring, temperature, pH and concentration of D-sorbitol. A value of about 50 kJ mol(-1) was obtained for the apparent activation enthalpy of the oxidation reaction at 0.1 V vs. sme. The experimental rate equation is i = kC(D-sorb)(0.4) C-H+(-0.3).exp[0.4 FE/RT], valid for [D-sorbitol] < 0.1 mol dm(-3) and pH < 1.

Abstract
Interferometric sensors based on source coherence synthesis have been reported for measurement of quasistatic parameters. An absolute sensing technique has been demonstrated based on fringe visibility modulation using a frequency modulated laser. In this Letter, a technique is described which allows to perform absolute displacement measurements in the range from tens to several hundreds of micrometers. It is based on dynamical spectral filtering of a superluminescent source which provides frequency modulation amplitudes up to 3000 GHz. The principle is described and experimentally verified for displacement measurement

Abstract
Interferometric systems consisting of two tandem interferometers with white-light illumination have been used as optical-fibre remote-sensing systems. Recently, it has been shown that both phase and amplitude of the output signal are significantly affected by externally induced birefringence in the fibre linking the interferometers; in some cases, this may cause total fading of the interference signal. In this letter, a new scheme is proposed to overcome this problem in white-light fibre-optic interferometric sensors. The approach is based on birefringence compensation using Faraday rotator mirror elements. The principle is experimentally verified, and the results confirm the theoretical expectation.

Abstract
An investigation is performed of the characteristics of the self-referencing intensity based Q-type fibre optic sensor using a recirculation loop structure. Both transmissive and reflective configurations are analysed. Via the definition of the measurement parameter (the R parameter) the linearity and sensitivity of the sensor are addressed. Theoretical and experimental results are compared, considering the problem of sensor design and optimization.