Guoy-effect optical distance and displacement sensor - has laser for providing beam to dual-mode optical fibre and detects phase difference change between modes due to transition from near to far field using interference pattern

摘要

The sensor contains an optical dual mode fibre (2) with an elliptical core and parameters selected to enable propagation of the fundamental mode LP01 and the LP11 mode. A laser (1) stimulates both modes at one end. The phase difference of both modes emanating from the other end is measured from an interference pattern formed from the two modes depending on distance from the fibre end according to the Guoy effect, i.e. the change in phase difference of both modes during transition from the near field (A) to the far field (B). USE/ADVANTAGE - For simple measurement of distances in millimetre range, without ambiguity of direction of distance change.