In a new distributed fiber optic sensing system, single-ended double-pulse input is used to strengthen Brillouin backscattered light by increasing the population of acoustic phonons. The first pulse (pump pulse), has a wide pulsewidth (tens or hundreds of us) and is used to generate a nonlinear population of acoustic phonons in the sensing fiber. Whereas the second pulse (probe pulse) has a different central wavelength and a much narrower pulse-width (several ns), and is emitted into the sensing fiber with a controlled time delay to absorb the generated abundant acoustic phonons, so that strong Anti-Stokes light can be generated. In this way, Brillouin backscattered light can be detected easily, leading to higher signal to noise ratio and better spatial resolution (less than 1 m), as well as good temperature and strain resolution, and longer sensing distance.

Date Published: 8 March 2014
PDF: 5 pages
Proc. SPIE 9062, Smart Sensor Phenomena, Technology, Networks, and Systems Integration 2014, 906203 (8 March 2014); doi: 10.1117/12.2043924

Published in SPIE Proceedings Vol. 9062:
Smart Sensor Phenomena, Technology, Networks, and Systems Integration 2014
Wolfgang Ecke; Kara J. Peters; Norbert G. Meyendorf; Theodoros E. Matikas, Editor(s)