Abstract

In this paper we propose the use of optimized bi-directional distributed Raman amplification to enhance the operating range of Brillouin optical time-domain analysis (BOTDA) sensors. In particular by combining high-power fiber-Raman lasers and polarization-multiplexed Fabry-Perot lasers operating at 1450 nm with low relative-intensity-noise (RIN), we demonstrate distributed sensing (using first-order Raman amplification) over 120 km of standard single-mode fiber with 2 meter spatial resolution and with a strain/temperature accuracy of 45 mu epsilon/2.1 degrees C respectively.