A distributed optical fiber sensor with the capability of simultaneously measuring temperature and strain is proposed using a large effective area non-zero dispersion shifted fiber (LEAF) with sub-meter spatial resolution. The Brillouin frequency shift is measured using Brillouin optical time-domain analysis (BOTDA) with differential pulse-width pair technique, while the spectrum shift of the Rayleigh backscatter is measured using optical frequency-domain reflectometry (OFDR). These shifts are the functions of both temperature and strain, and can be used as two independent parameters for the discrimination of temperature and strain. A 92 m measurable range with the spatial resolution of 50 cm is demonstrated experimentally, and accuracies of ±1.2 °C in temperature and ±15 με in strain could be achieved.
References
[1]
Smith, J.; Brown, A.; DeMerchant, M.; Bao, X. Simultaneous distributed strain and temperature measurement. Appl. Opt. 1999, 38, 5372–5377.
[2]
Zou, L.; Sezerman, O.M. Method and System for Simultaneous Measurement of Strain and Temperature. U.S. Patent US 7,599,047 B2, 2009.
[3]
Lee, C.C.; Chiang, P.W.; Chi, S. Utilization of a dispersion-shifted fiber for simultaneous measurement of distributed strain and temperature through Brillouin frequency shift. IEEE Photon. Technol. Lett. 2001, 13, 1094–1096.
[4]
Zou, L.; Bao, X.; Afshar, V.S.; Chen, L. Dependence of the Brillouin frequency shift on strain and temperature in a photonic crystal fiber. Opt. Lett. 2004, 29, 1485–1487.
[5]
Bao, X.; Yu, Q.; Chen, L. Simultaneous stain and temperature measurements with polarization-maintaining fibers and their error analysis by use of a distributed Brillouin loss system. Opt. Lett. 2004, 29, 1342–1344.
[6]
Alahbabi, M.N.; Cho, Y.T.; Newson, T.P. Simultaneous temperature and strain measurement with combined spontaneous Raman and Brillouin scattering. Opt. Lett. 2005, 30, 1276–1278.
[7]
Bolognini, G.; Soto, M.A.; Pasquale, F.D. Fiber-optic distributed sensor based on hybrid Raman and Brillouin scattering employing multiwavelength Fabry-Pérot lasers. IEEE Photon. Technol. Lett. 2009, 21, 1523–1525.
[8]
Bolognini, G.; Soto, M.A. Optical pulse coding in hybrid distributed sensing based on Raman and Brillouin scattering employing Fabry-Pérot lasers. Opt. Express 2010, 18, 8459–8465.
[9]
Zou, W.; He, Z.; Hotate, K. Complete discrimination of strain and temperature using Brillouin frequency shift and birefringence in a polarization-maintaining fiber. Opt. Express. 2009, 17, 1248–1255.
[10]
Zou, W.; He, Z.; Hotate, K. Demonstration of Brillouin distributed discrimination of strain and temperature using a polarization-maintaining optical fiber. IEEE Photon. Technol. Lett. 2010, 22, 526–528.
[11]
Dong, Y.; Chen, L.; Bao, X. High-spatial-resolution time-domain simultaneous strain and temperature sensor using Brillouin scattering and birefringence in a polarization-maintaining fiber. IEEE Photon. Technol. Lett. 2010, 22, 1364–1366.
[12]
Zou, W.; He, Z.; Hotate, K. One-laser-based generation/detection of Brillouin dynamic grating and its application to distributed discrimination of strain and temperature. Opt. Express 2011, 19, 2363–2370.
[13]
Froggatt, M.E.; Gifford, D.K.; Kreger, S.T.; Wolfe, M.S.; Soller, B.J. Distributed Strain and Temperature Discrimination in Unaltered Polarization Maintaining Fiber. In Optical Fiber Sensors, OSA Technical Digest (CD); Optical Society of America: Cancún, Mexico, 2006. paper ThC5.
[14]
Li, W.; Bao, X.; Li, Y.; Chen, L. Differential pulse-width pair BOTDA for high spatial resolution sensing. Opt. Express 2008, 16, 21616–21625.
[15]
Dong, Y.; Bao, X.; Li, W. Differential Brillouin gain for improving the temperature accuracy and spatial resolution in a long-distance distributed fiber sensor. Appl. Opt. 2009, 48, 4297–4301.
[16]
Glombitza, U.; Brinkmeyer, E. Coherent frequency-domain reflectometry for characterization of single-mode integrated optical waveguides. IEEE J. Lightwave Technol. 1993, 11, 1377–1384.
[17]
Froggatt, M.; Moore, J. High-spatial-resolution distributed strain measurement in optical fiber with Rayleigh scatter. Appl. Opt. 1998, 37, 1735–1740.
[18]
Soller, B.J.; Wolfe, M.; Froggatt, M.E. Polarization Resolved Measurement of Rayleigh Backscatter in Fiber-Optic Components. Proceedings of Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference; Technical Digest (CD),Optical Society of America: Anaheim, CA, USA, 2005. paper NWD3.
[19]
Soller, B.J.; Gifford, D.K.; Wolfe, M.S.; Froggatt, M.E. High resolution optical frequency domain reflectometry for characterization of components and assemblies. Opt. Express 2005, 13, 666–674.
[20]
Froggatt, M.E.; Gifford, D.K.; Kreger, S.; Wolfe, M.; Soller, B.J. Characterization of polarization-maintaining fiber using high-sensitivity optical-frequency-domain reflectometry. IEEE J. Lightwave Technol. 2006, 24, 4149–4154.
Koyamada, Y.; Imahama, M.; Kubota, K.; Hogari, K. Fiber-optic distributed strain and temperature sensing with very high measurand resolution over long range using coherent OTDR. IEEE J. Lightwave Technol 2009, 27, 1142–1146.
[23]
Duncan, R.G.; Soller, B.J.; Gifford, D.K.; Kreger, R.J.; Seeley, R.J.; Sang, A.K.; Wolfe, M.S.; Froggatt, M.E. OFDR-Based Distributed Sensing and Fault Detection for Single- and Multi-Mode Avionics Fiber-Optics. Presented at Joint Conference on Aging Aircraft, Palm Springs, CA, USA, 16–19 April 2007.
