Measuring a parameter in an optical fibre interferometric array via subtracting the cross-talk phasor of the array sensors from their measured phasors

摘要

A method of measuring a parameter in an optical fibre interferometric array 9; the method comprises the steps of: launching optical pulses into the array; creating an interference signal within n sensor elements in the array; detecting the phase of the interference signals; and processing the returned optical interference signal to remove a cross-talk term for each of the n sensor elements. The removal cross-talk terms is done by subtracting the cross-talk phasor for the nth sensor from the measured nth sensor phasor. The removal process of the cross-talk phasor terms begins with subtraction of the cross-talk phasor for the second sensor element from the measured second sensor element phasor. The cross-talk phasor for the first sensor element in the array is assumed to be zero. The sensor elements may be reflectors 20,21,...2n. being arrayed along the optical fibre 1. The optical path L between the reflectors is dependent on the selected parameter. This may be strain, pressure or temperature.