Patent ID: 8013986

Claim:
A method for measuring Brillouin backscattering from an optical fibre comprising: launching a probe pulse of coherent light with frequency f 0 into an optical fibre; receiving backscattered light from the optical fibre that includes at least one Brillouin spectral line at a frequency f B (t) shifted from f 0 by a Brillouin shift, the Brillouin spectral line varying with time and distance along the fibre; obtaining a signal representative of the received backscattered light; dividing the signal into a plurality of signal components each having a different frequency band and delivering each signal component to a detection channel; in each detection channel: detecting the signal component using a detector to generate an electrical signal; and digitising the electrical signal using an analog-to-digital converter to sample the electrical signal and generate a sequence of digital samples representing the electrical signal; and processing the digital samples from the detection channels to determine one or more properties of the Brillouin spectral line of the received backscattered light as a function of time/distance along the optical fibre.