Error analysis of two-wavelength absorption-based fibre-optic sensors

An error analysis of two-wavelength absorption-based fibre-optic sensors is presented in this paper. A general formulation to express the measurement error and the error induced by the instability of the light power input int o the absorbing sample to be measured is derived. Using this formulation, t wo common and important errors in this type of sensor, temperature fluctuat ion of light sources and bending optical fibres, are numerically discussed as illustrative examples. The analyses can be applied to both transmission- type and reflection-type absorption-based fibre-optic sensors. (C) 2001 Els evier Science Ltd. All rights reserved.