Distributed optical fibre sensor

A distributed optical fiber sensor for determining an optical time domain reflectometry (OTDR) trace of an optical fiber that extends through an environment, comprising:

• a probe light source arranged to generate a subset of probe light pulses, wherein the subset of probe light pulses is launched into the optical fiber for backscatter within the optical fiber;
• an optical detector arranged to detect, from the optical fiber, a backscattered light corresponding to the subset of probe light pulses;
• a converter arranged to sample the detected backscattered light at a rate faster than a pulse duration of the subset of probe light pulses to generate backscatter samples arising from the subset of probe light pulses, the backscatter samples corresponding to different overlapping segments of the optical fiber that are proximal to a particular position on the optical fiber;
• and
• an OTDR trace calculator arranged to calculate an OTDR trace for the particular position on the optical fiber based on combining the backscatter samples that correspond to the different overlapping segments of the optical fiber that are proximal to the particular position.

A method of operating a distributed optical fiber sensor to determine an optical time domain reflectometry (OTDR) trace of an optical fiber that extends through an environment and to measure one or more parameters of the environment, the method comprising:

• launching, from a probe light source, a first subset and a second subset of probe light pulses into the optical fiber for backscatter within the optical fiber;
• receiving, from the optical fiber, a first backscattered light corresponding to the first subset of probe light pulses and a second backscattered light corresponding to the second subset of probe light pulses;
• sampling, by a converter, the received first backscattered light to provide first backscatter samples arising from the first subset of probe light pulses, wherein the first backscatter samples are used for parameter measurement;
• sampling, by the converter, the received second backscattered light at a rate faster than a pulse duration of the second subset of probe light pulses to provide second backscatter samples arising from the second subset of probe light pulses, the second backscatter samples corresponding to different overlapping segments of the optical fiber that are proximal to a particular position on the optical fiber, wherein the second backscatter samples are used for OTDR trace measurement;
• calculating, by a parameter calculator, the one or more parameters of the environment using the first backscatter samples arising from the first subset of probe light pulses;
• and
• calculating, by an OTDR trace calculator, an OTDR trace for the particular position on the optical fiber based on combining the second backscatter samples arising from the second subset of probe light pulses that correspond to the different overlapping segments of the optical fiber that are proximal to the particular position.