OTDR based on Brillouin dynamic grating in an e-core two-mode fiber for simultaneous measurement of strain and temperature distribution

Discriminative measurement of strain and temperature distribution is experimentally demonstrated by optical time-domain reflectometry of Brillouin dynamic grating (BDG-OTDR) in an elliptical core two-mode fiber (e-core TMF). The acoustic waves generated by the amplified spontaneous Brillouin scattering of LP<inf>01</inf> mode in x-polarization are used to reflect the LP<inf>11</inf> mode in x- and y-polarizations. Distribution maps of intermodal birefringence between the LP01 and LP11 modes with two different polarizations are measured to separate strain and temperature induced spectral shift of the BDG in a 95 m e-core TMF with 2.0 m spatial resolution. The strain and temperature sensitivities are measured to be −0.082 MHz/με and 6.8 MHz/°C for the pair of LP<inf>01</inf><sup>x</sup>-LP<inf>11</inf><sup>x</sup> modes, and −0.095 MHz/με and 3.9 MHz/°C for the pair of LP<inf>01</inf><sup>x</sup>-LP<inf>11</inf><sup>x</sup> modes, respectively.

[1]  Kwang Yong Song,et al.  Mapping of intermodal beat length distribution in an elliptical-core two-mode fiber based on Brillouin dynamic grating. , 2014, Optics express.

[2]  Kazuo Hotate,et al.  All-optical dynamic grating generation based on Brillouin scattering in polarization-maintaining fiber. , 2008 .

[3]  T. Parker,et al.  A fully distributed simultaneous strain and temperature sensor using spontaneous Brillouin backscatter , 1997, IEEE Photonics Technology Letters.

[4]  Kwang Yong Song.  High-sensitivity optical time-domain reflectometry based on Brillouin dynamic gratings in polarization maintaining fibers. , 2012, Optics express.

[5]  Kazuo Hotate,et al.  One-laser-based generation/detection of Brillouin dynamic grating and its application to distributed discrimination of strain and temperature. , 2011, Optics express.

[6]  L. Thévenaz,et al.  Brillouin gain spectrum characterization in single-mode optical fibers , 1997 .

[7]  Luc Thevenaz,et al.  Time-Domain Distributed Fiber Sensor With 1 cm Spatial Resolution Based on Brillouin Dynamic Grating , 2010, Journal of Lightwave Technology.

[8]  Zuyuan He,et al.  Complete discrimination of strain and temperature using Brillouin frequency shift and birefringence in a polarization-maintaining fiber. , 2009, Optics express.

[9]  Liang Chen,et al.  Distributed Temperature and Strain Discrimination with Stimulated Brillouin Scattering and Rayleigh Backscatter in an Optical Fiber , 2013, Sensors.

[10]  Kwang Yong Song,et al.  Characterization of Nonlinear Temperature Dependence of Brillouin Dynamic Grating Spectra in Polarization-Maintaining Fibers , 2015, Journal of Lightwave Technology.

[11]  M. A. Farahani,et al.  Accurate estimation of Brillouin frequency shift in Brillouin optical time domain analysis sensors using cross correlation. , 2011, Optics letters.

[12]  Kazuo Hotate,et al.  Correlation-based distributed measurement of a dynamic grating spectrum generated in stimulated Brillouin scattering in a polarization-maintaining optical fiber. , 2009, Optics letters.