Measurement Range Elongation Based on Temporal Gating in Brillouin Optical Correlation Domain Distributed Simultaneous Sensing of Strain and Temperature

Yamashita, Rodrigo Kendy; Zou, Weiwen; He, Zuyuan; Hotate, Kazuo

doi:10.1109/lpt.2012.2192725

Cited by 35 publications

(16 citation statements)

References 8 publications

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“…As for the BDG-BOCDA system, performance improvement schemes have already been introduced [111][112][113]. Additionally, a prototype model has already been fabricated for the application of the aircraft SHM.…”

Section: Discriminative and Distributed Measurement Of Strain And Temmentioning

confidence: 99%

Brillouin Optical Correlation-Domain Technologies Based on Synthesis of Optical Coherence Function as Fiber Optic Nerve Systems for Structural Health Monitoring

Hotate

2019

Applied Sciences

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Brillouin optical correlation-domain technologies are reviewed as “fiber optic nerve systems” for the health monitoring of large structures such as buildings, bridges, and aircraft bodies. The Brillouin scattering property is used as a sensing mechanism for strain and/or temperature. Continuous lightwaves are used in the technologies, and their optical coherence properties are synthesized to realize position-selective measurement. This coherence manipulation technology is called the “synthesis of optical coherence function (SOCF)”. By utilizing SOCF technologies, stimulated Brillouin scattering is generated position-selectively along the fiber, which is named “Brillouin optical correlation domain analysis (BOCDA)”. Spontaneous Brillouin scattering, which takes place at any portion along the fiber, can also be measured position-selectively by the SOCF technology. This is called “Brillouin optical correlation domain reflectometry (BOCDR)”. When we use pulsed lightwaves that have the position information, sensing performances, such as the spatial resolution, are inherently restricted due to the Brillouin scattering nature. However, in the correlation-domain technologies, such difficulties can be reduced. Superior performances have been demonstrated as distribution-sensing mechanisms, such as a 1.6-mm high spatial resolution, a fast measurement speed of 5000 points/s, and a 7000-με strain dynamic range, individually. The total performance of the technologies is also discussed in this paper. A significant feature of the technologies is their random accessibility to discrete multiple points that are selected arbitrarily along the fiber, which is not realized by the time domain pulsed-lightwave technologies. Discriminative and distributed strain/temperature measurements have also been realized using both the BOCDA technology and Brillouin dynamic grating (BDG) phenomenon, which are associated with the stimulated Brillouin scattering process. In this paper, the principles, functions, and applications of the SOCF, BOCDA, BOCDR, and BDG-BOCDA systems are reviewed, and their historical aspects are also discussed.

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Section: Discriminative and Distributed Measurement Of Strain And Temmentioning

confidence: 99%

Brillouin Optical Correlation-Domain Technologies Based on Synthesis of Optical Coherence Function as Fiber Optic Nerve Systems for Structural Health Monitoring

Hotate

2019

Applied Sciences

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“…(12), (13), and (16) remain relevant to the PPS configuration. In moving to the PPS from the CDS, Eqs.…”

Section: Pump-probe Schemementioning

confidence: 99%

“…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

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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...

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“…Even when this condition is cleared, the FUT is a PMF with different refractive indices for the pump and read lightwaves. The situation is especially critical when the measurement range is long 9 . Considering a PMF with a birefringence of 3x10 -4 , after passing through a 500-m long PMF, the delay between the lightwaves due to the refractive index difference is around 10 cm of fiber.…”

Section: Introductionmentioning

confidence: 99%

Effect of pump-read optical path difference on the measurement of Brillouin dynamic grating spectra localized by the correlation domain technique with a single laser setup

2014

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In correlation domain distributed measurement of Brillouin dynamic grating (BDG) in polarization maintaining fiber, adjustment of the frequency modulation (FM) phase between the pump and read lightwaves is essential. We experimentally evaluated the phase difference impact on the measurement. A single laser setup can acquire the BDG spectra with higher stability, but the FM phase relation is fixed. Therefore the FM synchronization is not guaranteed for all points of the fiber under test due to the birefringence of the fiber. In this report, we varied the optical path difference between the pump and the read lightwaves, showing the spectrum degradation.

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Measurement Range Elongation Based on Temporal Gating in Brillouin Optical Correlation Domain Distributed Simultaneous Sensing of Strain and Temperature

Cited by 35 publications

References 8 publications

Brillouin Optical Correlation-Domain Technologies Based on Synthesis of Optical Coherence Function as Fiber Optic Nerve Systems for Structural Health Monitoring

Brillouin Optical Correlation-Domain Technologies Based on Synthesis of Optical Coherence Function as Fiber Optic Nerve Systems for Structural Health Monitoring

Chirped fiber Brillouin frequency-domain distributed sensing

Effect of pump-read optical path difference on the measurement of Brillouin dynamic grating spectra localized by the correlation domain technique with a single laser setup

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