| 摘要 |
<p>An optical fibre coil assembly for use in systems for the detection of acoustic pressure, temperature etc comprises a coil of optical fibre 1 supported by means of a hollow encapsulating structure 2 and force adjustment means 4 for substantially reducing the overall force which would otherwise act on the coil structure to produce a change of length of the coil when the coil is subjected to acoustic pressure etc. The plates 4,5 seal the ends of the hollow support 2, removing from the central region 3 any influence of external pressure and amplifying axial forces on support from pressures Pe. Outward radial pressure is produced by the axial pressures Pe, the magnitude determined by the size of the central hole and Poisson's ratio of the material. This outward pressure balances the inward acoustic pressure, counteracting any change in the coil diameter and thus its overall length. <IMAGE></p> |
