A5080862739- Advanced Fiber Optic Sensors
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Spectroscopy and Laser Applications
- Coal Properties and Utilization
- Optical Network Technologies
- Thermal Analysis in Power Transmission
- Mechanical and Optical Resonators
- Smart Materials for Construction
- Atmospheric and Environmental Gas Dynamics
- Combustion and flame dynamics
- Optical Coherence Tomography Applications
- Atmospheric Ozone and Climate
- Landslides and related hazards
- Advanced Optical Sensing Technologies
- Magneto-Optical Properties and Applications
- Lightning and Electromagnetic Phenomena
- Photonic Crystal and Fiber Optics
- Random lasers and scattering media
- Analytical Chemistry and Sensors
Atotech (United States)
2022
WB Electronics (Poland)
2020
Universidad de Alcalá
2014-2018
École Polytechnique Fédérale de Lausanne
2016
According to recent models, non-local effects in dual-probe-sideband Brillouin Optical Time Domain Analysis (BOTDA) systems should be essentially negligible whenever the probe power is below Stimulated Scattering (SBS) threshold. This paper shows that actually there appear this type of before SBS To explain these it necessary take into account a full spectral description process. The pump pulse experiences frequency-dependent deformation affects readout process differently gain and loss...
Systematic errors induced by distortions in the pump pulse of conventional Brillouin distributed fiber sensors are thoroughly investigated. Experimental results, supported a theoretical analysis, demonstrate that two probe sidebands standard optical time-domain analyzers provide non-zero net gain on pulse, inducing severe when scanning pump-probe frequency offset, especially at high power levels. Compared to impact non-local effects reported state-of-the-art, measurements here indicate for...
Brillouin optical time domain analysis (BOTDA) relies typically on the interaction among two counter-propagating waves: 1) a pulsed pump wave and 2) modulated probe wave. The has sidebands, located at ±ν <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> with respect to frequency. Conventional systems detect time-resolved gain/loss by detecting only upper/lower wavelength sideband. In this letter, we show that BOTDA can strongly benefit...
A differential pulse-width pair (DPP) Brillouin distributed fiber sensor is implemented to achieve centimetric spatial resolution over distances of several kilometers. The presented scheme uses a scanning method in which the spectral separation between two probe sidebands kept constant, while optical frequency pump swept scan response. Experimental results show that this avoids detrimental temporal distortions pulses, standard implementation prevent DPP from operating mid-to-long distances....
In this paper, a highly-sensitive distributed shape sensor based on multicore fiber (MCF) and phase-sensitive optical time-domain reflectometry (φ-OTDR) is proposed experimentally demonstrated. The implemented system features high strain sensitivity (down to ∼0.3 µɛ) over 24 m-long MCF with spatial resolution of 10 cm. results demonstrate good repeatability the relative curvature bend orientation measurements. Changes in are successfully retrieved, showing detectable displacements free...
Polarization noise arises in Brillouin optical time-domain analysis due to the strong polarization sensitivity of stimulated scattering. To avoid this noise, it turns out be indispensable perform some kind scrambling, either pump pulse, probe signal or both. This is usually achieved using scrambling/switching systems, which, being mechanical, tend not as robust would desirable. In paper, we propose a completely passive system, with no moving parts, eliminate BOTDA. It based on use...
We evaluate the Brillouin frequency shift (BFS) determination error when utilizing phase spectrum (BPS) instead of gain (BGS) in BOTDA systems. Systems based on BPS perform BFS through a linear fit around zero de-phase region. An analytical expression obtained as function different experimental parameters is provided and experimentally validated. The results show good agreement with theoretical predictions number sampling points, signal-to-noise ratio (SNR) spectral linewidth. For an equal...
We demonstrate a technique allowing to develop fully distributed optical fiber hot-wire anemometer capable of reaching wind speed uncertainty ≈ ±0.15 m/s (±0.54 km/h) at only 60 mW/m dissipated power in the sensing fiber, and within four minutes measurement time.This corresponds similar values than previous papers on anemometry but requires two orders magnitude smaller covers least one order longer distance.This breakthrough is possible thanks extreme temperature sensitivity single-shot...
Brillouin-based temperature and strain sensors have attracted great attention of both the academic industrial sectors in past few decades due to their ability perform distributed measurements. In particular, Brillouin optical time-domain analysis (BOTDA) systems been applied many different scenarios, proving particularly useful those requiring especially wide coverage ranging extremely long distances, such as civil structure monitoring, energy transportation, or environmental applications....
Raman assistance is one of the most interesting routes toward extending range Brillouin optical time-domain analysis (BOTDA) systems. Unfortunately, use amplification normally entails an important relative intensity noise (RIN) transfer probe wave, which severely limits this approach. In letter, we show that RIN problem can be effectively avoided using a slightly modified scheme comprising dual-sideband modulated and balanced detection. Our measurements clearly indicate nearly complete...
Geographical Information Systems (GIS) are often used to assess and monitor the environmental impacts caused by mining activities. The aim of this work was develop a new application produce dynamic maps for monitoring temperature variations in self-burning coal waste pile, under GIS open source environment—GIS-ECOAL (freely available). performance evaluated with distributed measurements gathered S. Pedro da Cova (Portugal) pile. In order obtain data, an optical fiber cable disposed over...
The combustion of coal wastes resulting from mining is particular environmental concern, and the importance proper management involving real-time assessment their status identification probable evolution scenarios recognized. Continuous monitoring temperature emission levels certain gases allows for possibility planning corrective actions to minimize negative impact on surroundings. Optical fiber technology well suited this purpose here we describe main attributes results obtained a optic...
Given the strong polarization sensitivity of Stimulated Brillouin Scattering (SBS), in Optical Time Domain Analysis (BOTDA) it turns out to be indispensable perform some kind scrambling, either pump pulse, or probe signal (or both). This is usually accomplished using scrambling/switching systems, which, being mechanical, tend not as robust would desirable. In this paper we propose a completely passive system, with no moving parts, scrambling BOTDA. It based on use balanced detection among...
Standard multimode optical fibers normally support transmission over some 100 modes. Large differences in the propagation constant and spatial distribution of distinct modes degrade performance phase-sensitive time-domain reflectometry measurements. In this work, we present a new realization coherent interrogation technique using single-mode operation fibers. We demonstrate effectively distributed strain sensing on three different Up to 4 km fiber has been correctly interrogated, featuring...
In this Letter, we present and demonstrate a novel technique for distributed measurements in Brillouin optical time-domain analysis based on the use of nonlinear phase-shift induced by stimulated scattering. Employing Sagnac interferometer (SI), position-resolved spectrum (BPS) along fiber can be obtained, benefiting from sensitivity to nonreciprocal phase-shifts SI scheme. This proposal simplifies existing methods retrieve BPS distribution an since phase modulation, filtering,...
The phase shift feature of Stimulated Brillouin Scattering is rarely used for the development sensors based on Optical Time-Domain Analysis (BOTDA).However, this shows significant interest sensing thanks to its linear dependence around Frequency Shift.Up now, distributed Phase Shift (BPS) measurements required complex modulations, high-bandwidth detection and sharp filtering.Recently, we introduced possibility developing simple BPS in BOTDA using baseband technology.The basic idea was use a...
Up to now, complex (phase and intensity) measurements in Brillouin Optical Time-Domain Analysis (BOTDA) systems required phase modulation methods high-bandwidth (multi-GHz) detection. In this work, we propose a novel technique that is able retrieve simultaneously both gain/loss characteristics of the interaction by just introducing Sagnac Interferometer (SI) on standard BOTDA sensing scheme. The described analytically demonstrated experimentally. With technique, reliability increase produced...
The combustion of coal wastes resulting from mining is particular environmental concern and therefore the importance proper management involving real-time assessment their status identification probable evolution scenarios recognized. Continuous monitoring temperature emission levels certain gases opens possibility to plan corrective actions minimize negative impact in surroundings. Optical fiber technology well-suited this purpose work it described main attributes a optic sensing system...
The possibility to perform distributed measurements of the effective refractive index difference between distinct modes in few mode optical fibers is demonstrated using phase sensitive time domain reflectometry. Effective differences LP02, LP21a and LP21b are measured with for a spatial resolution 24m.
It is presented an optical fiber sensing system projected to operate in the demanding conditions associated with coal waste piles combustion. Distributed temperature measurement and spot gas are requirements for such a system. A field prototype has been installed continuously gathering data, which will input geological model of combustion aiming understand their dynamics evolution. Results on distributed ammonia measurement, being noticed any significant methane emission short time period...
In this work we demonstrate an extremely simple BOTDA scheme capable of delivering distributed Brillouin Phase Shift measurements along optical fiber. It is based on exploiting the non-reciprocity Stimulated Scattering effect. This easily characterized by means a suitably tuned Sagnac Interferometer. The technique advantageous as, in comparison with previous methods, no complex modulation, sharp filtering and highbandwidth detection needed. Theoretical experimental proofs concept are given.
Non-local effects have been traditionally identified as one of the most limiting factors performance Brillouin optical time-domain analyzers. These phenomena, directly linked with energy gained/lost by pump pulse, limit probe power and ultimately SNR system. Several solutions proposed, although none offers possibility to increase until its limit, onset amplified spontaneous scattering. In this work, we propose a technique that avoids non-local permits set at maximum, reaching 100 km sensing...
We evaluate the Brillouin frequency shift (BFS) determination error when using phase spectrum (BPS) instead of gain (BGS) in BOTDA setups. compare obtained BFS both cases, with theoretical arguments and experimental data. In comparison to gain, for an equal SNR linewidth, generally provides a better fit smaller spans. This result opens possible way reduce measurement time certain systems by feature.
In the past few decades, Brillouin-based distributed temperature and strain sensors have attracted attention of both academic industrial sectors. particular, B-OTDA systems been lately a trendy study area due to their numerous well proofed applications, such as in monitoring large civil structures, energy transportation or environmental applications. One main areas research focuses on extension measuring range. To do so, it becomes necessary increase signal noise ratio (SNR) sensor,...
We propose the use of balanced detection in Brillouin Optical Time Domain Analysis (BOTDA) sensors. Balanced can be effectively accomplished among Stokes and anti-Stokes bands probe signal. This type leads to a doubling trace amplitude at least √2 increase signal noise ratio over conventional configuration. Moreover, it complete cancellation common-mode signal, including relative intensity Raman-assisted configurations. show all these benefits both theoretically experimentally.