Abstract
The spatial resolution of strain/temperature measurements using Brillouin scattering in an optical fiber is proportional to the pulse width of a pump laser light. However, because the phonon spectrum is broadened and the signal-to-noise ratio (SNR) decreases if the pulse width is narrowed to improve resolution, it was widely assumed that there existed a practical lower limit for pulse width about 10 ns, resulting in resolution of 1 m. In a previous paper, we proposed a spectral broadening suppression method called pulse-prepump Brillouin optical time-domain analysis (PPP-BOTDA), which was verified to attain a 2 cm resolution. In this paper, we apply the pulse compression techniques used in high-resolution radar to increase the SNR of Brillouin distributed sensors, which leads to far higher accuracy.
