Novel Brillouin Optical Time-Domain Analyzer for Extreme Sensing Range Using High-Power Flat Frequency-Coded Pump Pulses

Floch, Sébastien Le; Sauser, Florian; Llera, Miguel; Rochat, Etienne

doi:10.1109/jlt.2014.2365213

Cited by 37 publications

(34 citation statements)

References 15 publications

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“…On the probe wave side, the power of the CW probe is ultimately limited by the onset of amplified spontaneous Brillouin scattering, which also eventually sets a limit to the SNR on the measurements [5]. To overcome all those limitations to the performance of long-range Brillouin sensors, alternative solutions such as distributed Raman amplification [6][7][8] and optical pulse coding [9][10][11][12][13][14][15] have been proposed, providing a huge improvement in the sensor performance, especially when both techniques are combined in the same system [16,17]. The situation becomes even more critical and demanding in terms of SNR when the real remoteness of the sensor is extended using a linear fiber-loop configuration [17,18], in which half of the fiber is used for sensing while the second half, paired to the sensing segment, is used to convey the probe to the most remote sensing location, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Besides enhancing BOTDA systems for long range [9][10][11][12][13][14][15], optical pulse coding has also be applied to high spatial resolution Brillouin sensors, based for instance in correlation-domain [19]. While coding schemes based on incoherent pulse compression [19,20] have efficiently been used in high spatial resolution sensors, demonstrations in long-range BOTDA have been classically based on unipolar sequences, such as Simplex [9] or Golay [11] codes.…”

Section: Introductionmentioning

confidence: 99%

“…While coding schemes based on incoherent pulse compression [19,20] have efficiently been used in high spatial resolution sensors, demonstrations in long-range BOTDA have been classically based on unipolar sequences, such as Simplex [9] or Golay [11] codes. Two kinds of pulse coding schemes have been recently proposed as a new breach in long range sensing: bipolar codes [12] and time/frequency or colored codes [13][14][15]. Both coding schemes offer improved SNR enhancement in comparison to traditionally-used unipolar coding schemes [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Increasing robustness of bipolar pulse coding in Brillouin distributed fiber sensors

2015

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Abstract:The robustness of bipolar pulse coding against pump depletion issues in Brillouin distributed fiber sensors is theoretically and experimentally investigated. The presented analysis points out that the effectiveness of bipolar coding in Brillouin sensing can be highly affected by the power unbalance between -1's and + 1's elements resulting from depletion and amplification of coded pump pulses. In order to increase robustness against those detrimental effects and to alleviate the probe power limitation imposed by pump depletion, a technique using a three-tone probe is proposed. Experimental results demonstrate that this method allows increasing the probe power by more than 12.5 dB when compared to the existing single-probe tone implementation. This huge power increment, together with the 13.5 dB signal-to-noise enhancement provided by 512-bit bipolar Golay codes, has led to low-uncertainty measurements (< 0.9 MHz) of the local Brillouin peak gain frequency over a real remoteness of 100 km, using a 200 km-long fiber-loop and 2 m spatial resolution. The method is evaluated with a record figure-of-merit of 380'000. Gonzalez-Herraez, and L. Thévenaz, "Extending the real remoteness of long-range Brillouin optical time-domain fiber analyzers," J. Lightwave Technol. 32(1), 152-162 (2014). 18. Y. Dong, L. Chen, and X. Bao, "Extending the sensing range of Brillouin optical time-domain analysis combining frequency-division multiplexing and in-line EDFAs," J.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Increasing robustness of bipolar pulse coding in Brillouin distributed fiber sensors

2015

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“…Different pump pulse coding techniques [26] have been used in recent years to improve the SNR of BOTDA sensors so that measurements can be made with longer fiber lengths [4,27]. In a BOTDA sensor with coding, instead of having a pump signal with a single pulse, the pump wave is composed of multiple pulses, with the total number given by the code length.…”

Section: Probe Dithering In Pulse-coded Botda Sensors For Reducing Pumentioning

confidence: 99%

Non-Local Effects in Brillouin Optical Time-Domain Analysis Sensors

et al. 2017

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Brillouin optical time-domain analysis (BOTDA) sensors have great potential to provide distributed measurements of temperature and strain over large structures with high spatial resolution and measurement precision. However, their performance ultimately depends on the amount of probe and pump pulse power that can be injected into the sensing fiber, which determines the signal-to-noise ratio of the detected measurement signal. The probe wave power is constrained by the generation of noise induced by spontaneous Brillouin scattering and at lower power by the so-called non-local effects. In this work, we focus on the latter. We review the physical origins of non-local effects and analyze the performance impairments that they bring. In addition, we discuss the different methods that have been proposed to counteract these effects comparing their relative merits and ultimate performance. Particularly, we focus on a technique that we have devised to compensate non-local effects which is based on introducing an optical frequency modulation or dithering to the probe wave. This method is shown to provide a comprehensive solution to most of the impairments associated with non-local effects and also to enable some side benefits, such as amplification of the pump pulses to compensate the attenuation of the fiber.

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“…Among different types of codes applied to Brillouin distributed fiber sensing [5][6][7][8][9] , bipolar Golay codes offer the highest SNR enhancement, being 3 dB over traditionally-used unipolar codes 8 . In this paper, serious and very specific detrimental effects resulting from pump depletion in bipolar coded BOTDA sensors are identified.…”

Section: Introductionmentioning

confidence: 99%

200 km fiber-loop Brillouin distributed fiber sensor using bipolar Golay codes and a three-tone probe

2015

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Aiming at taking full advantage of bipolar codes, a method using a three-tone probe is proposed to alleviate the probe power limitation imposed by pump depletion in Golay-coded Brillouin distributed fiber sensors. Experimental results validate the technique, which reduces significantly the measurement distortions induced by the gain/loss unbalance resulting from pump depletion/amplification. The method supports a probe power increment of more than 12.5 dB, resulting in low-uncertainty measurements (< 0.9 MHz) at a real 100 km distance, using a 200 km-long fiber loop and 2 m spatial resolution. The method is evaluated with a record figure-of-merit of 380'000.

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Novel Brillouin Optical Time-Domain Analyzer for Extreme Sensing Range Using High-Power Flat Frequency-Coded Pump Pulses

Cited by 37 publications

References 15 publications

Increasing robustness of bipolar pulse coding in Brillouin distributed fiber sensors

Increasing robustness of bipolar pulse coding in Brillouin distributed fiber sensors

Non-Local Effects in Brillouin Optical Time-Domain Analysis Sensors

200 km fiber-loop Brillouin distributed fiber sensor using bipolar Golay codes and a three-tone probe

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