1-cm-Spatial-Resolution Brillouin Optical Time-Domain Analysis Based on Bright Pulse Brillouin Gain and Complementary Code

Mao, Yuan; Guo, Nan; Yu, Kuanglu; Tam, Hwa Yaw; Lu, Chao

doi:10.1109/jphot.2012.2226710

Cited by 40 publications

(20 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among them, Brillouin Optical Time Domain Analyzer (BOTDA) sensor systems have been well developed for distributed temperature and strain sensing, which are useful in structural health monitoring, geotechnical engineering and so on [5][6][7][8]. In such systems, two counter-propagating signals, pump and probe with different frequencies, interact with an acoustic wave.…”

Section: Introductionmentioning

confidence: 99%

Signal processing using artificial neural network for BOTDA sensor system

et al. 2016

View full text Add to dashboard Cite

We experimentally demonstrate the use of artificial neural network (ANN) to process sensing signals obtained from Brillouin optical time domain analyzer (BOTDA). The distributed temperature information is extracted directly from the local Brillouin gain spectra (BGSs) along the fiber under test without the process of determination of Brillouin frequency shift (BFS) and hence conversion from BFS to temperature. Unlike our previous work for short sensing distance where ANN is trained by measured BGSs, here we employ ideal BGSs with different linewidths to train the ANN in order to take the linewidth variation due to different conditions from the training and testing phases into account, making it feasible for long distance sensing. Moreover, the performance of ANN is compared with other two techniques, Lorentzian curve fitting and cross-correlation method, and our results show that ANN has higher accuracy and larger tolerance to measurement error, especially at large frequency scanning step. We also show that the temperature extraction from BOTDA measurements employing ANN is significantly faster than the other two approaches. Hence ANN can be an excellent alternative tool to process BGSs measured by BOTDA and obtain temperature distribution along the fiber, especially when large frequency scanning step is adopted to significantly reduce the measurement time but without sacrifice of sensing accuracy.

show abstract

Section: Introductionmentioning

confidence: 99%

Signal processing using artificial neural network for BOTDA sensor system

et al. 2016

View full text Add to dashboard Cite

show abstract

“…In recent years, to enhance the SNR of BOTDA systems, various techniques and schemes have been established [6,7,8,9,10,11,12,13,14,15,16,17,18,19]. Coherent detection has been applied for Brillouin signal detection to improve the SNR [7,8] and to obtain additional Brillouin phase information for reduction of the non-local effects [9].…”

Section: Introductionmentioning

confidence: 99%

“…Coherent detection has been applied for Brillouin signal detection to improve the SNR [7,8] and to obtain additional Brillouin phase information for reduction of the non-local effects [9]. Optical coding techniques have been employed to achieve highly sensitive BOTDA systems without sacrifice of the spatial resolution [10,11]. Moreover, in order to reduce the pump loss and depletion, distributed Raman and Brillouin amplification has been applied in BOTDA systems [12,13].…”

Section: Introductionmentioning

confidence: 99%

Bi-Directional Brillouin Optical Time Domain Analyzer System for Long Range Distributed Sensing

Guo

Wang

et al. 2016

Sensors

View full text Add to dashboard Cite

We propose and experimentally demonstrate a novel scheme of bi-directional Brillouin time domain analyzer (BD-BOTDA) to extend the sensing range. By deploying two pump-probe pairs at two different wavelengths, the Brillouin frequency shift (BFS) distribution over each half of the whole fiber can be obtained with the simultaneous detection of Brillouin signals in both channels. Compared to the conventional unidirectional BOTDA system of the same sensing range, the proposed BD-BOTDA scheme enables distributed sensing with a performance level comparable to the conventional one with half of the sensing range and a spatial resolution of 2 m, while maintaining the Brillouin signal-to-noise ratio (SNR) and the BFS uncertainty. Based on this technique, we have achieved distributed temperature sensing with a measurement range of 81.9 km fiber at a spatial resolution of 2 m and BFS uncertainty of ~0.44 MHz without introducing any complicated components or schemes.

show abstract

“…5 Since the temperature and strain dependencies of the Brillouin frequency (typically ∼1.2 MHz∕K 6 and 500 MHz∕%, 7 respectively, near 1550 nm for conventional fiber 5 ) are not insignificant, it is natural that this phenomenon has been adapted for use in distributed sensor technologies, [8][9][10][11] with very impressive results. High-sensitivity and resolution measurement schemes and configurations have been demonstrated, [12][13][14][15][16][17][18][19][20] and a commercial market exists for such distributed sensing systems. Resolution is defined in this context to be the ability to resolve two events that are in close proximity to each other, or alternatively, to resolve a certain temperature or strain change within a given range in the sensor fiber.…”

Section: Introductionmentioning

confidence: 99%

Chirped fiber Brillouin frequency-domain distributed sensing

2014

View full text Add to dashboard Cite

A frequency-domain distributed temperature/strain sensor based on a longitudinally graded optical fiber (LGF) is proposed and evaluated. In an LGF, the Brillouin scattering frequency, ν B , changes (i.e., is chirped) lengthwise monotonically and thus every position along the fiber has a unique ν B . Any change locally (at some position) in the fiber environment will result in a measurable change in the shape of the Brillouin gain spectrum (BGS) near the frequency component mapped to that position. This is demonstrated via measurements and modeling for an LGF with local heating. The LGF is one with ∼100 MHz Brillouin frequency gradient over 16.7 m, with 1.1 and 1.7 m segments heated up to 40 K above ambient. A measurement of the BGS can enable the determination of a thermal (or strain) distribution along a sensor fiber, thus rendering the system one that is in the frequency domain. A sensitivity analysis is also presented for both coherent and pump-probe BGS measurement schemes. The modeling results suggest that the frequency-domain systems based on fibers with a chirped Brillouin frequency are highly suited as inexpensive event sensors (alarms) and have the potential to reach submeter position determination with sub-1-K temperature accuracies at >1 kHz sampling rates. Limitations to the technique are discussed. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. IntroductionThe Brillouin scattering frequency, ν B , is related to the optical wavelength, λ o , and the acoustic velocity, V, by ν B ¼ 2Vn mode ∕λ o . It is well known that both the acoustic velocity and the refractive index of a glass usually are functions of its thermomechanical environment; i.e., temperature and any applied stress or strain to the material. The word "usually" is used as a qualifier because it is possible to realize multicomponent materials of which physical properties, such as the refractive index, are immune to temperature or strain/stress. 1-4 However, in conventional pure silica or GeO 2 -doped silica core optical fibers, the Brillouin scattering frequency is dependent on both the temperature and strain, with the usual dependence being an increasing frequency with increasing temperature or strain. 5 Since the temperature and strain dependencies of the Brillouin frequency (typically ∼1.2 MHz∕K 6 and 500 MHz∕%, 7 respectively, near 1550 nm for conventional fiber 5 ) are not insignificant, it is natural that this phenomenon has been adapted for use in distributed sensor technologies, [8][9][10][11] with very impressive results. High-sensitivity and resolution measurement schemes and configurations have been demonstrated, 12-20 and a commercial market exists for such distributed sensing systems. Resolution is defined in this context to be the ability to resolve two events that are in close proximity to each other, or alternatively, to resolve a certain temperatu...

show abstract

1-cm-Spatial-Resolution Brillouin Optical Time-Domain Analysis Based on Bright Pulse Brillouin Gain and Complementary Code

Cited by 40 publications

References 13 publications

Signal processing using artificial neural network for BOTDA sensor system

Signal processing using artificial neural network for BOTDA sensor system

Bi-Directional Brillouin Optical Time Domain Analyzer System for Long Range Distributed Sensing

Chirped fiber Brillouin frequency-domain distributed sensing

Contact Info

Product

Resources

About