scholarly journals A Novel Method of Spectra Processing for Brillouin Optical Time Domain Reflectometry

Fibers ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 60
Author(s):  
Fedor L. Barkov ◽  
Yuri A. Konstantinov ◽  
Anton I. Krivosheev
Keyword(s):  
Optical Sensors ◽  
Time Domain ◽  
Signal To Noise Ratio ◽  
Conventional Technique ◽  
Time Domain Reflectometry ◽  
New Method ◽  
Special Technique ◽  
Single Spectrum ◽  
Modal Birefringence ◽  
Optical Time

A new method of Brillouin spectra post-processing, which could be applied in modern distributed optical sensors: Brillouin optical time domain analyzers/reflectometers (BOTDA/BOTDR), has been demonstrated. It operates by means of the correlation analysis performed with special technique («backward-correlation»). It does not need any additional data for time or space averaging and operates with the single spectrum only. We have simulated the method accuracy dependence on signal-to-noise ratio (SNR) and other parameters. It is shown that the new method produces better results at low SNRs than conventional technique, based on finding of Brillouin spectrum maximum, do. These results are in a good agreement with the experiment. Finally, we have estimated the performance of the new method for its application in polarization-BOTDA set-up for a polarization maintaining (PM) fiber modal birefringence distributed study.

scholarly journals Time-expanded phase-sensitive optical time-domain reflectometry

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Miguel Soriano-Amat ◽  
Hugo F. Martins ◽  
Vicente Durán ◽  
Luis Costa ◽  
Sonia Martin-Lopez ◽  
...  
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Random Phase ◽  
Environmental Variable ◽  
Time Domain Reflectometry ◽  
Trade Offs ◽  
Optical Time Domain Reflectometry ◽  
Phase Sensitive ◽  
Spatio Temporal ◽  
Optical Time

AbstractPhase-sensitive optical time-domain reflectometry (ΦOTDR) is a well-established technique that provides spatio-temporal measurements of an environmental variable in real time. This unique capability is being leveraged in an ever-increasing number of applications, from energy transportation or civil security to seismology. To date, a wide number of different approaches have been implemented, providing a plethora of options in terms of performance (resolution, acquisition bandwidth, sensitivity or range). However, to achieve high spatial resolutions, detection bandwidths in the GHz range are typically required, substantially increasing the system cost and complexity. Here, we present a novel ΦOTDR approach that allows a customized time expansion of the received optical traces. Hence, the presented technique reaches cm-scale spatial resolutions over 1 km while requiring a remarkably low detection bandwidth in the MHz regime. This approach relies on the use of dual-comb spectrometry to interrogate the fibre and sample the backscattered light. Random phase-spectral coding is applied to the employed combs to maximize the signal-to-noise ratio of the sensing scheme. A comparison of the proposed method with alternative approaches aimed at similar operation features is provided, along with a thorough analysis of the new trade-offs. Our results demonstrate a radically novel high-resolution ΦOTDR scheme, which could promote new applications in metrology, borehole monitoring or aerospace.

scholarly journals Влияние дрейфа частоты лазера в фазочувствительной рефлектометрии

2019 ◽  
Vol 127 (10) ◽  
pp. 603
Author(s):  
А.А. Жирнов ◽  
К.В. Степанов ◽  
А.О. Чернуцкий ◽  
А.К. Федоров ◽  
Е.Т. Нестеров ◽  
...  
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Frequency Instability ◽  
Laser Frequency ◽  
Time Domain Reflectometry ◽  
Laser Source ◽  
Optical Time Domain Reflectometry ◽  
Phase Sensitive ◽  
Optical Time ◽  
Theoretical Results

AbstractThe influence of the laser frequency drift on the operation of phase-sensitive optical time domain reflectometry (φ-OTDR) systems is considered. Theoretical results based on a new numerical φ-OTDR model demonstrating the influence of the laser frequency instability on a signal are reported. This model is verified based on experimental data. It has been used to calculate the signal-to-noise ratio (SNR) of the system for different parameters of the laser source stability. As a result, quantitative requirements for lasers used in φ-OTDR systems are formulated.

scholarly journals Distributed Static and Dynamic Strain Measurements in Polymer Optical Fibers by Rayleigh Scattering

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5049
Author(s):  
Agnese Coscetta ◽  
Ester Catalano ◽  
Enis Cerri ◽  
Ricardo Oliveira ◽  
Lucia Bilro ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Time Domain ◽  
Rayleigh Scattering ◽  
Cost Effective ◽  
Time Domain Reflectometry ◽  
Dynamic Strain ◽  
Strain Measurements ◽  
Graded Index ◽  
Optical Time ◽  
Polymer Optical Fibers

We demonstrate the use of a graded-index perfluorinated optical fiber (GI-POF) for distributed static and dynamic strain measurements based on Rayleigh scattering. The system is based on an amplitude-based phase-sensitive Optical Time-Domain Reflectometry (ϕ-OTDR) configuration, operated at the unconventional wavelength of 850 nm. Static strain measurements have been carried out at a spatial resolution of 4 m and for a strain up to 3.5% by exploiting the increase of the backscatter Rayleigh coefficient consequent to the application of a tensile strain, while vibration/acoustic measurements have been demonstrated for a sampling frequency up to 833 Hz by exploiting the vibration-induced changes in the backscatter Rayleigh intensity time-domain traces arising from coherent interference within the pulse. The reported tests demonstrate that polymer optical fibers can be used for cost-effective multiparameter sensing.

scholarly journals Recent Advances in Phase-Sensitive Optical Time Domain Reflectometry (Ф-OTDR)

2021 ◽  
Vol 11 (1) ◽  
pp. 1-30
Author(s):  
Yunjiang Rao ◽  
Zinan Wang ◽  
Huijuan Wu ◽  
Zengling Ran ◽  
Bing Han
Keyword(s):  
Fiber Optics ◽  
Time Domain ◽  
Acoustic Waves ◽  
Rapid Development ◽  
Development Stage ◽  
Time Domain Reflectometry ◽  
Rayleigh Backscattering ◽  
Optical Time Domain Reflectometry ◽  
Phase Sensitive ◽  
Optical Time

AbstractPhase-sensitive optical time domain reflectometry (Ф-OTDR) is an effective way to detect vibrations and acoustic waves with high sensitivity, by interrogating coherent Rayleigh backscattering light in sensing fiber. In particular, fiber-optic distributed acoustic sensing (DAS) based on the Ф-OTDR with phase demodulation has been extensively studied and widely used in intrusion detection, borehole seismic acquisition, structure health monitoring, etc., in recent years, with superior advantages such as long sensing range, fast response speed, wide sensing bandwidth, low operation cost and long service lifetime. Significant advances in research and development (R&D) of Ф-OTDR have been made since 2014. In this review, we present a historical review of Ф-OTDR and then summarize the recent progress of Ф-OTDR in the Fiber Optics Research Center (FORC) at University of Electronic Science and Technology of China (UESTC), which is the first group to carry out R&D of Ф-OTDR and invent ultra-sensitive DAS (uDAS) seismometer in China which is elected as one of the ten most significant technology advances of PetroChina in 2019. It can be seen that the Ф-OTDR/DAS technology is currently under its rapid development stage and would reach its climax in the next 5 years.

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