Optical fibre fracture detector - utilises laser to transmit pulse for reflection to time measuring circuit

摘要

The fracture in fibre optic is detected by a probe in which a laser transmits light for reflection by the fracture. A power supply (4) controlled by a driver circuit (6) causes diode laser (2) to emit linearly polarised pulse of incident light. This passes through an objective (8) to a coupler (10) for focussing (12) on the face of the optical fibre (16). Light reflected by the fracture returns via a focussing analyser (18) which allows selected light to pass to receiver (22) via another objective lens (20). Time measuring circuit (24) determines the required distance.