Time and frequency pump-probe multiplexing to enhance the signal response of Brillouin optical time-domain analyzers.
A technique to enhance the response and performance of Brillouin distributed fiber sensors is proposed and experimentally validated. The method consists in creating a multi-frequency pump pulse interacting with a matching multi-frequency continuous-wave probe. To avoid nonlinear cross-interaction between spectral lines, the method requires that the distinct pump pulse components and temporal traces reaching the photo-detector are subject to wavelength-selective delaying. This way the total pump and probe powers launched into the fiber can be incrementally boosted beyond the thresholds imposed by nonlinear effects. As a consequence of the multiplied pump-probe Brillouin interactions occurring along the fiber, the sensor response can be enhanced in exact proportion to the number of spectral components. The method is experimentally validated in a 50 km-long distributed optical fiber sensor augmented to 3 pump-probe spectral pairs, demonstrating a signal-to-noise ratio enhancement of 4.8 dB.
Marcelo A
MA
Soto
Amelia Lavinia
AL
Ricchiuti
Liang
L
Zhang
David
D
Barrera
Salvador
S
Sales
Luc
L
Thévenaz
D015374:Biosensing Techniques; D055100:Optical Fibers; D055620:Optical Phenomena; D055095:Optics and Photonics / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013057:Spectrum Analysis; D013997:Time Factors