Abstract
An optical fibre has been used as an intensity-based sensor for the monitoring of the fluid front infiltrating a reinforcing fibre mat in composites manufacturing. The sensor length comprised the fibre core, initially surrounded by air or vacuum and subsequently covered by the infiltrating fluid. Two configurations were tested where a step-change or a continual output signal was obtained, respectively. In the latter case, the sensor used in this study demonstrates an improvement of up to two orders of magnitude over conventional monitoring techniques used for this application. This performance is coupled with more obvious advantages of low cost, compatibility with composite fabrication, and ease of use.