IMPROVEMENTS IN AND RELATING TO FIBRE OPTIC SENSORS

摘要

An AE sensor comprising a fused-tapered optical fibre coupler (11) for receiving light from a light source (12) at the insertion end of the coupler and, via an interaction/coupling region, splitting the light to produce light signals at each exit end of the coupler, detector means (D1, 132) for detecting said light signals and comparator means (10) for comparing said signals to thereby indicate the occurrence of an acoustic emission event during a steady state condition characterise in that the coupler has a sharp taper angle and a short interaction/coupling region to maximise the stress concentration following an AE event in the interaction region, thereby increasing the sensitivity of the coupler, and hence the sensor, to stress.