Remotely addressed optical fibre curvature sensor using multicore photoniccrystal fibre

We demonstrate an all-fibre curvature sensor that uses two-core photonic cr ystal fibre (PCF) as the sensing element. The PCF acts as a two-beam interf erometer in which phase difference is a function of curvature in the plane containing the cores. A broadband source illuminates both cores, and the sp ectrum at a single point in the far-field interferogram is recorded. Applyi ng a three-wavelength phase recovery algorithm to the data provides an unam biguous measurement of the interferometer phase, and hence curvature. (C) 2 001 Published by Elsevier Science B.V.