Distributed optical fibre sensor

摘要

There is described a distributed optical fiber sensor for detecting one or more physical parameters indicative of an environmental influence on a sensor optical fiber, as a function of position along the sensor fiber. The sensor uses probe light pulses of different wavelengths. At least some of the probe light pulses may also be of different pulse lengths. The relative phase bias between interferometric signals in backscattered probe light of different wavelength pulses may also be controlled.

主权项

1. A distributed optical fibre sensor for determining at least one physical parameter as a function of position along a sensing fibre from properties of probe light backscattered within the sensing fibre, the sensor comprising:
a probe light source arranged to launch probe light pulses into the sensing fibre, the probe light pulses including successive groups each of two or more probe light pulses having different optical wavelengths to each other; a detector arranged to detect probe light backscattered in said sensing fibre, including separately detecting interference signals in the backscattered probe light arising from respective probe light pulses of said different wavelengths; and an analyser arranged to determine said parameter as a function of position along the sensing fibre from the detected interference signals of one or more of said wavelengths, wherein the probe light source is arranged such that the two or more different optical wavelengths of probe light pulses in a group provide one or more predetermined relative phase bias misalignments between the interference signals arising from the different wavelengths.