Article

Optimization of a DPP-BOTDA sensor with 25 cm spatial resolution over 60 km standard single-mode fiber using Simplex codes and optical pre-amplification

Scuola Superiore Sant’Anna, TeCIP Institute, via G. Moruzzi 1, 56124 Pisa, Italy.
Optics Express (Impact Factor: 3.49). 03/2012; 20(7):6860-9. DOI: 10.1364/OE.20.006860
Source: PubMed

ABSTRACT

Sub-meter distributed optical fiber sensing based on Brillouin optical time-domain analysis with differential pulse-width pairs (DPP-BOTDA) is combined with the use of optical pre-amplification and pulse coding. In order to provide significant measurement SNR enhancement and to avoid distortions in the Brillouin gain spectrum due to acoustic-wave pre-excitation, the pulse width and duty cycle of Simplex coding based on return-to-zero pulses are optimized through simulations. In addition, the use of linear optical pre-amplification increases the receiver sensitivity and the overall dynamic range of DPP-BOTDA measurements. Experimental results demonstrate for first time a spatial resolution of ~25 cm over a 60 km standard single-mode fiber (equivalent to ~240 k discrete sensing points) with temperature resolution of 1.2°C and strain resolution of 24 με.

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Available from: Marcelo A. Soto, Mar 05, 2014
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    • "Dealing with SBS effects, in order to fully exploit the benefits of our technique, optimized return-to-zero pulses have to be used on the Brillouin pulsed pump. In this case we have followed the optimization process reported in [2], which indicates that pulse widths longer than ∼60 ns are required to maximize the DPP Brillouin gain. In addition, to avoid SBS gain interaction among the different pulses within the code sequences (resulting from pre-excited acoustic waves), a bit slot longer than 110 ns has to be used. "
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