Strong Cancellation of RIN Transfer in a Raman-Assisted BOTDA Using Balanced Detection

Dominguez-Lopez, Alejandro; Lopez-Gil, Alexia; Martín‐López, Sonia; Gonzalez-Herraez, Miguel

doi:10.1109/lpt.2014.2336699

Cited by 20 publications

(8 citation statements)

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“…The use of DSB modulation to generate the probe wave has therefore become a widespread solution in the past few years. Moreover, it can be fully exploited if balanced detection [11,12] is used upon reception.…”

Section: Introductionmentioning

confidence: 99%

Non-local effects in dual-probe-sideband Brillouin optical time domain analysis

Dominguez-Lopez¹,

Angulo-Vinuesa²,

Lopez-Gil³

et al. 2015

Opt. Express

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According to recent models, non-local effects in dual-probesideband Brillouin Optical Time Domain Analysis (BOTDA) systems should be essentially negligible whenever the probe power is below the Stimulated Brillouin Scattering (SBS) threshold. This paper shows that actually there appear non-local effects in this type of systems before the SBS threshold. To explain these effects it is necessary to take into account a full spectral description of the SBS process. The pump pulse experiences a frequency-dependent spectral deformation that affects the readout process differently in the gain and loss configurations. This paper provides a simple analytical model of this phenomenon, which is validated against compelling experimental data, showing good agreement. The main conclusion of our study is that the measurements in gain configuration are more robust to this non-local effect than the loss configuration. Experimental and theoretical results show that, for a total probe wave power of ~1 mW (500 μW on each sideband), there is an up-shifting of ~1 MHz in the Brillouin Frequency Shift (BFS) retrieved from the Brillouin Loss Spectrum, whereas the BFS extracted from the measured Brillouin Gain Spectrum is up-shifted only ~0.6 MHz. These results are of particular interest for manufacturers of longrange BOTDA systems.

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Section: Introductionmentioning

confidence: 99%

Non-local effects in dual-probe-sideband Brillouin optical time domain analysis

Dominguez-Lopez¹,

Angulo-Vinuesa²,

Lopez-Gil³

et al. 2015

Opt. Express

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“…In case the RIN noise is removed, e.g. by applying the balanced detection technique [40], it is possible to significantly reduce the number of averages, thus upgrading the FoM up to 500 by using only Raman assistance. This is slightly beyond the expectation of FoM increase in the discussion of the present paper, but in reasonable agreement if we consider the evolution of components along the experiments.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, it is also possible to shift the working frequency of the BOTDA to a frequency range in which the RIN transfer is smaller [38]. Recently, it has been shown that the RIN transfer problem can be completely solved using a dual-sideband probe scheme and balanced detection [39,40].…”

Section: Raman Amplificationmentioning

confidence: 99%

Limits of BOTDA Range Extension Techniques

et al. 2016

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Abstract-Brillouin-based temperature and strain sensors have attracted great attention of both the academic and industrial sectors in the past few decades due to their ability to perform distributed measurements. Particularly, Brillouin Optical Time Domain Analysis (BOTDA) systems have been applied in many different scenarios, proving particularly useful in those requiring especially wide coverage ranging extremely long distances, such as in civil structure monitoring, energy transportation or environmental applications. The extension of the measuring range in these sensors has therefore become one of the main areas of research and development around BOTDA. To do so, it is necessary to increase the Signal to Noise Ratio (SNR) of the retrieved signal. So far, several techniques have been applied in order to achieve this goal, such as pre-amplification before detection, pulse coding or Raman amplification. Here, we analyze these techniques in terms of their performance limits and provide guidelines that can assist in finding out which is the best configuration to break current range limitations. Our analysis is based on physical arguments as well as current literature results.Index Terms-Brillouin scattering, distributed optic fiber sensing, distributed Raman scattering, optical fibers, optical pulse coding. I. INTRODUCTIONMONG the different available techniques to perform distributed measurements of strain and temperature, Brillouin Optical Time-Domain Analysis (BOTDA) [1,2] is presently recognized as one of the most consolidated. This fiber sensing technology is widely used in different application domains (civil engineering, pipelines, fire detection, etc.). BOTDA technology finds its root on the non-linear optical effect occurring in optical fibers and called Stimulated Brillouin Scattering (SBS) [3]. SBS is an acousto-optic process that manifests as a narrowband amplification of a probe beam when an intense coherent pump light beam is introduced through the opposite end of a single-mode fiber. The distributed feature is provided to the BOTDA by pulsing the pump wave and analyzing the retrieved probe wave as function of the time-of-flight of the pump pulse within the fiber, as depicted in Fig.1.Range and resolution are two of the most important features of these systems, which are normally limited to 20-30 km with 1-2 meter resolution in standard systems [4]. Attenuation, an intrinsic fiber feature, is the limiting factor in terms of range as it reduces the intensity of the signals within the fiber, therefore decreasing the Signal to Noise Ratio (SNR) as the monitored distance increases. Resolution, which is set by the spatial length of the employed pump pulses, is restricted by the associated issues when the pulse duration is reduced. First, a spectral broadening will manifest on the retrieved wave (leading to a higher uncertainty) and also a shorter interaction length will be obtained among the pump and probe wave, leading to a corresponding SNR decrease. Both factors lead to a non-proportional increase of ...

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“…However, in order to mitigate the effects of RIN transfer, 3 methods have been proposed: i) use of low-RIN Raman pumps, such as semiconductor lasers [12], ii) use of balanced detection [24], and iii) the use of a vector-BOTDA system based on heterodyne detection [25].…”

Section: Distributed Raman Amplificationmentioning

confidence: 99%

Going beyond limits in Brillouin distributed fibre sensors: Challenges and possible approaches

Soto

Thévenaz

2014

2014 IEEE 5th International Conference on Photonics (ICP)

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Abstract-Brillouin distributed optical fibre sensing has been a subject of intense research and industrial development for more than twenty years, demonstrating its capabilities to be an effective and powerful measurement tool for a wide range of applications. Making use of sophisticated implementations, remarkable progresses on the sensing performance have been reported in the last decade, allowing significant improvements in spatial resolution and sensing range. However, the demand for distributed sensors with more performing features is steadily growing, imposing new and more challenging requirements to the sensor design. This paper presents a brief overview of the fundamentals of Brillouin distributed fibre sensing and reviews the main current limitations and challenges faced when the sensing capabilities are pushed beyond the state-of-the-art. Different possible approaches and methods to enhance and compare the sensing performance are also discussed.

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Strong Cancellation of RIN Transfer in a Raman-Assisted BOTDA Using Balanced Detection

Cited by 20 publications

References 10 publications

Non-local effects in dual-probe-sideband Brillouin optical time domain analysis

Non-local effects in dual-probe-sideband Brillouin optical time domain analysis

Limits of BOTDA Range Extension Techniques

Going beyond limits in Brillouin distributed fibre sensors: Challenges and possible approaches

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