Phase-sensitive optical time domain reflectometer assisted by first-order raman amplification for distributed vibration sensing over >100 km
AuthorsFidalgo Martins, Hugo; Martín López, Sonia; Corredera, Pedro; Filograno, M. L.; Frazão, O.; [et al.]
IdentifiersPermanent link (URI): http://hdl.handle.net/10017/26341
Institute of Electrical and Electronics Engineers
Ministerio de Economía y Competitividad
Comunidad de Madrid
Journal of Lightwave Technology, 2014, v. 32, p. 1510-1518.
Optical fiber sensors
Phase-sensitive optical time domain reflectometry (OTDR)
info:eu-repo/grantAgreement/EC/FP7/307441/EU/Ubiquitous optical FIbre NErves/U-FINE
info:eu-repo/grantAgreement/MINECO//TEC2012-37958-C02-01/ES/TECNOLOGIAS DE SEGURIDAD CIVIL BASADAS EN FIBRA OPTICA/
info:eu-repo/grantAgreement/EC/Interreg Sudoe/SOE3%2FP2%2FP714/EU/Gestión ecológica de pilas de residuos de carbón en combustión/ECOAL-MGT
info:eu-repo/grantAgreement/MINECO//TEC2012-37958-C02-02/ES/TECNOLOGIAS DE FIBRA OPTICA PARA LA SEGURIDAD CIVIL/
© 2014 IEEE
In this study, the authors present an experimental and theoretical description of the use of first order Raman amplification to improve the performance of a Phase-sensitive optical time domain reflectometer (φ OTDR) when used for vibration measurements over very long distances. A special emphasis is given to the noise which is carefully characterized and minimized along the setup. A semiconductor optical amplifier and an optical switch are used to greatly decrease the intra-band coherent noise of the setup and balanced detection is used to minimize the effects of RIN transferred from the Raman pumps. The sensor was able to detect vibrations of up to 250 Hz (close to the limits set by the time of flight of light pulses) with a resolution of 10 m in a range of 125 km. To achieve the above performance, no post-processing was required in the φOTDR signal. The evolution of the φOTDR signal along the fiber is also shown to have a good agreement with the theoretical model.