Bipolar optical pulse coding for performance enhancement in BOTDA sensors.
A pump signal based on bipolar pulse coding and single-sideband suppressed-carried (SSB-SC) modulation is proposed for Brillouin optical time-domain analysis (BOTDA) sensors. Making a sequential use of the Brillouin gain and loss spectra, the technique is experimentally validated using bipolar complementary-correlation Golay codes along a 100 km-long fiber and 2 m spatial resolution, fully resolving a 2 m hot-spot at the end of the sensing fiber with no distortion introduced by the decoding algorithm. Experimental results, in good agreement with the theory, indicate that bipolar Golay codes provide a higher signal-to-noise ratio enhancement and stronger robustness to pump depletion in comparison to optimum unipolar pulse codes known for BOTDA sensing.
EPFL Swiss Federal Institute of Technology, Institute of Electrical Engineering, SCI-STI-LT, Station 11, CH-1015Lausanne, Switzerland. marcelo.soto@epfl.ch
Marcelo A
MA
Soto
Sébastien
S
Le Floch
Luc
L
Thévenaz
D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008027:Light; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014159:Transducers