Multi point strain and temperature sensing based on Brillouin optical time domain reflectometry.

In this paper, multiple points of strain and temperature measurement in real-time is investigated using a Brillouin optical time domain reflectometry (BOTDR) system. The Brillouin frequency shift (BFS) is analysed with strain and temperature effects applied at various locations of the sensing fibre. In addition, a passive depolarizer was employed in order to reduce the polarization noise. The temperature and strain coefficients are found to be 0.79 MHz/°C and 0.057 MHz/µe.