%0 Journal Article %A Angulo Vinuesa, Xabier %A Soto Hernández, Marcelo Alfonso %A Martín López, Sonia %A Chin, S.H. %A Ania Castañón, Juan Diego %A Corredera, Pedro %A Rochat, Etienne %A González Herráez, Miguel %A Thévenaz, Luc %T Brillouin optical time-domain analysis over a 240 km-long fiber loop with no repeater %D 2012 %@ 0277-786X %U http://hdl.handle.net/10017/26584 %X In this paper we combine the use of optical pulse coding and seeded second-order Raman amplification to extend the sensing distance of Brillouin optical time-domain analysis (BOTDA) sensors. Using 255-bit Simplex coding, the power levels of the Raman pumps and the Brillouin pump and probe signals were adjusted in order to extend the real physical sensing distance of a BOTDA sensor up to 120 km away from the sensor interrogation unit, employing a 240-km long loop of standard single-mode fiber (SSMF) with no repeater. To the best of our knowledge, this is the first time that distributed measurements are carried out over such a long distance with no active device inserted into the entire sensing loop, constituting a considerable breakthrough in the field. %K Brillouin scattering %K Raman scattering %K Distributed optic fiber sensor %K Optical pulse coding %K Strain sensing %K Temperature sensing %K Ciencias tecnológicas %K Electrónica %K Technology %K Electronics %~ Biblioteca Universidad de Alcala