US 2024/0271970 A1 · Fibre Optic Sensing

Abstract

This application describes methods and apparatus for fibre optic sensing. A receive unit includes an optical arrangement configured to receive coherent optical radiation that has propagated through a sensing optical fibre and to form first and second optical signals, wherein the second optical signal comprises optical radiation received from the sensing optical fibre later than the optical radiation of the first optical signal by a defined time period. A photodetector detects the first optical signal mixed with the second optical signal and a processor demodulates a derivative signal formed by interference of the first and second optical signals. First and second receive units may be located at opposite ends of a cable structure to provide respective measurement signals and a signal processor can process the two measurement signals to locate a disturbance.

Claims22

Dependent claims

A fibre optic sensing apparatus, comprising:

a first receive unit comprising:
an optical arrangement configured to receive coherent optical radiation that has propagated through a sensing optical fibre and to form first and second optical signals from the optical radiation received, wherein the second optical signal comprises optical radiation received from the sensing optical fibre later than the optical radiation of the first optical signal by a defined time period;
a photodetector configured to detect the first optical signal mixed with the second optical signal;
and
a processor configured to process an output of the photodetector to demodulate a derivative signal formed by interference of the first and second optical signals.

2 more elements

Dependencies are inferred from the claim text.

Fibre Optic Sensing

Life of this patent

Fibre Optic Sensing

Life of this patent

Abstract

Claims22