Distributed sensor physical magnitude variations measurement method

摘要

Identical Bragg reflection gratings (4) are formed by periodic variations of the refractive index of the core of an optical fibre (1) over a length of e.g. 1 to 2 mm. The gratings are spaced e.g. 1 m apart and addressed by optical pulses (7) emitted from a laser source (5) into one end (1A) of the fibre via a coupler (6).The reflections are delivered to a receiver (8) linked to an oscilloscope (9). Any variation of the physical quantity in the vicinity of a grating is betrayed by consequential change in the time-varying intensity of the reflected energy.