Brillouin Optical Time Domain Analysis in silica fibers at 850 nm wavelength

Brillouin scattering properties of silica fibers at 850 nm wavelength were experimentally investigated using a Brillouin optical time-domain analysis (BOTDA) scheme. In the single-mode 780-HP fiber, the Brillouin frequency shift (BFS) and FHWM of the Brillouin Gain Spectrum were found to be ∼ 19795 MHz and 90 MHz, respectively. The estimated peak Brillouin gain is 0.32(mW)-1. The temperature and strain dependences of BFS were determined as well. Distributed sensing capability was demonstrated at a minimum spatial resolution of 1.5 m and a fiber length of 100 m. As a proof-of-principle, the temperature and strain dependencies of the BFS in SFM-28 fiber have been determined at 850 nm and 1550 nm wavelengths, suggesting its possible use for temperature/strain discrimination.