Pulse coding linearization for Brillouin optical time-domain analysis sensors

Abstract

We introduce a simple method to extend the performance of pulse coding techniques in their application to Brillouin optical time-domain analysis sensors (BOTDA). It is based on using a simple logarithmic processing on the detected probe wave that compensates the deviation from linearity of the sensor response for long code lengths. The technique ensures that the accumulated effect of a sequence of pulses is equal to the linear addition of the effects of the individual components, which is the essential condition to ensure a correct decoding of the probe gain measurement. We experimentally demonstrate compensation of the Brillouin frequency shift error induced by the accumulated gain nonlinearity. Furthermore, a proof-ofconcept 80-km sensing link within a total 200-km fiber loop demonstrated better than 2-MHz precision with 2m spatial resolution.

Application of Raman and Brillouin Scattering Phenomena in Distributed Optical Fiber Sensing

“…In addition, use of long coded sequences has been demonstrated to lower the threshold of amplified spontaneous Brillouin scattering in the fiber. Techniques such as linearization using logarithmic processing of the probe response [25] allow maintaining superposition with coding while probe dithering has been demonstrated to address the limitations of pump depletion and lowered amplified spontaneous scattering threshold due to coding [24].…”

Latest research on long-range Brillouin distributed sensing

“…In addition, we have devised a very simple technique to ensure the linearity of pulse coding in BOTDA. 29 It is based in using a linearized version of the intensity variation that is calculated by taking the natural logarithm of the detected probe intensity wave and subtracting its DC component:…”

Total variation denoising and Euclidean distance based distributed temperature monitoring in Brillouin optical time-domain analysis sensors

“…Alternatively, the realizations of long-distant sensing using pulse coding techniques have been reported in Ref. (Iribas et al, 2017;Mariñelarena et al, 2018). The combination of Raman amplification and pulse coding technique has also been reported to attain high-performance sensing with improved accuracy and resolution (Soto et al, 2012).…”