Single-photon detector based long-distance Brillouin optical time domain reflectometry

Abstract

We present a long-range Brillouin optical time domain reflectometer (BOTDR) based on photon counting technology using single-mode fibres. We use the slope of a fiber Bragg grating (FBG) as a frequency discriminator, in order to convert count rate variation into a frequency shift. We demonstrate experimentally the ability to perform a distributed temperature measurement, by detecting a hot spot in a thermal bath and the possibility to achieve measurement above 100 km with a spatial resolution of 10 m. A performance study of our distributed sensor as a function of the photon counter efficiency is also presented.