57-km single-ended spontaneous Brillouin-based distributed fiber temperature sensor using microwave coherent  detection

Maughan, Sally M.; Kee, H.H.; Newson, T.P.

doi:10.1364/ol.26.000331

Cited by 53 publications

(28 citation statements)

References 12 publications

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“…In the coherent detection system, the Brillouin spectra were obtained by taking time-domain backscattering traces for a series of beat frequencies, covering the expected Brillouin frequency shifts [10] . After each set of spectra was obtained, the frequency shift of the Brillouin backscatter was determined for each point of interest along the fiber by fitting each individual spectrum to a Lorentzian curve, considering that the spontaneous Brillouin line is known to be of this shape.…”

Section: Was Placed In An Oven At 85mentioning

confidence: 99%

Dual-source distributed optical fiber sensor for simultaneous temperature and strain measurements

Chen

Zhang

et al. 2012

中国光学快报

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A dual-source distributed optical fiber sensor system with combined Raman and Brillouin scatterings is designed for simultaneous temperature and strain measurements. The optimal Raman and Brillouin signals can be separately obtained by adjusting the powers of the two sources using an optical switch. The temperature and strain can be determined by processing the optimal Raman and Brillouin signals. The experimental result shows that 1.7• C temperature resolution and 60-µε strain resolution can be achieved at a 24.7-km distance.OCIS Recently, intensive research has been aimed at the development of distributed optical fiber sensors (DOFSs) because of their notable advantages such as continuous strain and temperature measurements, and strong resistance to electromagnetic interference and corrosion. Some primary applications have been made in monitoring large structures such as dams, tunnels, pipelines, oil wells, bridges, landslides, etc [1] . In the DOFS system based on the Brillouin optical time domain reflectometry (BOTDR) technique, temperature and strain variations can be measured using the Brillouin frequency shift combined with a change in Brillouin intensity. However, the accuracy of the intensity measurement limits the performance of long-range combined temperature and strain sensors [2] . The Brillouin frequency shift is dependent on both temperature and strain, whereas the Raman signal is only sensitive to temperature. Moreover, the intensity of the Raman signal exhibits more sensitivity to temperature (∼0.8%/ • C) [3] than the anti-Stokes Brillouin signal (∼0.36%/ • C) [2] . Thus, the Brillouin intensity can be replaced by the Raman intensity. The temperature along the fiber can be determined using the Raman intensity, whereas the strain can be computed using the Brillouin frequency shift. Commercial Raman distributed temperature sensors can now readily achieve 1• C temperature resolution for a 30-km distance [4] . Therefore, the temperature resolution and strain would be greatly improved if the Raman distributed temperature sensor is combined with Brillouin frequency measurement. In this letter, we propose a method for measuring the anti-Stokes Raman intensity and Brillouin frequency shift generated from dual sources with optimal output optical power to obtain the temperature and strain along the fiber.The DOFS system for simultaneous temperature and strain measurements is shown in Fig. 1. The seed laser light radiated from the distributed feedback laser diode (DFB-LD) is split using a 90/10 coupler, with 10% of the power used to produce the local oscillator (LO) for coherent detection and 90% of the power amplified by the erbium-doped fiber amplifiers (EDFAs). The continuous light is converted to pulse light using the acoustooptic modulator (AOM) and amplified using EDFA2. After passing through the circulator (C1), the pulse light is launched into the fiber for measurement. The polarization scrambler (PS) is used to reduce polarization noise [5] . The spontaneous Raman and Brillouin backscattered signa...

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Section: Was Placed In An Oven At 85mentioning

confidence: 99%

Dual-source distributed optical fiber sensor for simultaneous temperature and strain measurements

Chen

Zhang

et al. 2012

中国光学快报

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“…In many applications, these sensors avoid the need of thousands of pin-point sensors and complicated multiplexing schemes. Among these, distributed Brillouin sensors have attracted much research interest in the past years [25][26][27][28][29][30], and are now widely used for the monitoring of strain and temperature distribution within large structures in civil engineering [26]. Several techniques have been proposed for performing distributed Brillouin sensing, and the principal configurations have been summarized in Figure 3.…”

Section: Potential Benefits and Drawbacks In Fiber Sensingmentioning

confidence: 99%

“…Several techniques have been proposed for performing distributed Brillouin sensing, and the principal configurations have been summarized in Figure 3. In the Brillouin Optical Time Domain Reflectometer (BOTDR) configuration [27], a pump pulse is launched into the fibre and the spontaneous Brillouin backscattered light is synchronously analysed as a function of the time (distance along the fiber) using heterodyne detection. For each position, the pump-Stokes frequency shift is determined, which is then translated into strain or temperature values.…”

Section: Potential Benefits and Drawbacks In Fiber Sensingmentioning

confidence: 99%

Progress in Brillouin Slow Light and Its Impact in Fiber Sensing

Gonzalez-Herraez

Song

Chin

et al. 2006

Optical Fiber Sensors

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“…In many applications, these sensors avoid the need for thousands of pinpoint sensors and complicated multiplexing schemes. Among these, distributed Brillouin sensors have attracted much research interest in the past years [1][2][3][4][5][6][7] and are now widely used for the monitoring of strain and temperature distribution within large structures in civil engineering. 2 Several techniques have been proposed for performing distributed Brillouin sensing, and the principal configurations have been summarized in Fig.…”

mentioning

confidence: 99%

“…In the Brillouin optical time-domain reflectometer (BOTDR) configuration, a pump pulse is launched into the fiber (ϳ200 ns duration, ϳ150 mW of peak power), and the spontaneous Brillouin backscattered light is synchronously analyzed as a function of the time (distance along the fiber) by using heterodyne detection. 3 For each position the pump-Stokes frequency shift is determined, which is then translated into strain or temperature values.…”

mentioning

confidence: 99%

Time biasing due to the slow-light effect in distributed fiber-optic Brillouin sensors

2006

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(Doc. ID 65774) The influence of the slow-light effect on the performance of distributed Brillouin sensors is studied. We show that, while in most situations it can be neglected, it may greatly affect the results obtained for certain experimental configurations. More specifically, for one of the experimental arrangements described in the literature (a strong continuous-wave pump and a weak pulsed probe) we show that this effect induces a large time biasing of the traces that depends not only on the fiber length but also on the frequency separation between pump and probe. This biasing reduces the available resolution in this experimental arrangement. Distributed fiber-optic sensors offer unique capabilities for the monitoring of quantities such as temperature and strain over long distances. In many applications, these sensors avoid the need for thousands of pinpoint sensors and complicated multiplexing schemes. Among these, distributed Brillouin sensors have attracted much research interest in the past years 1-7 and are now widely used for the monitoring of strain and temperature distribution within large structures in civil engineering.2 Several techniques have been proposed for performing distributed Brillouin sensing, and the principal configurations have been summarized in Fig. 1, together with the typical parameters used in experimental setups selected from representative publications. In the Brillouin optical time-domain reflectometer (BOTDR) configuration, a pump pulse is launched into the fiber (ϳ200 ns duration, ϳ150 mW of peak power), and the spontaneous Brillouin backscattered light is synchronously analyzed as a function of the time (distance along the fiber) by using heterodyne detection. 3For each position the pump-Stokes frequency shift is determined, which is then translated into strain or temperature values.In the Brillouin optical time-domain analysis 4 (BOTDA-1) configuration, however, the Brillouin interaction is performed in the stimulated regime, thus requiring two counterpropagating waves, a powerful pulsed pump wave (ϳ50 ns with ϳ70 mW of peak power) and a weak probe wave ͑ϳ100 W͒. If particular phase-matching conditions are met (namely, f pump Ϸ f probe + B , B being the Brillouin shift), an acoustic wave is generated that scatters photons from the pump to the probe wave. This leads to a local amplification of the probe wave, which yields a time-dependent variation of the detected probe signal in the pump end. An earlier version of this technique 5 (labeled BOTDA-2 in Fig. 1) uses a powerful, continuous-wave (cw) pump wave ͑ϳ6 mW͒ and a weak pulsed probe wave (ϳ50 ns pulse length with ϳ1 mW of peak power) tuned at f probe Ϸ f pump + B . The position-dependent Brillouin attenuation of the pump induced by the probe is recorded in terms of a variation in the cw pump power detected from the probe end. Schemes similar to BOTDA-1 and BOTDA-2 can be developed in the frequency domain. 6 The conclusions of the analysis of the timedomain configuration can be exactly translated into the frequency...

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57-km single-ended spontaneous Brillouin-based distributed fiber temperature sensor using microwave coherent detection

Cited by 53 publications

References 12 publications

Dual-source distributed optical fiber sensor for simultaneous temperature and strain measurements

Dual-source distributed optical fiber sensor for simultaneous temperature and strain measurements

Progress in Brillouin Slow Light and Its Impact in Fiber Sensing

Time biasing due to the slow-light effect in distributed fiber-optic Brillouin sensors

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