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000228179 005__ 20190317000708.0
000228179 013__ $$d20171026$$bUS$$cA1$$aUS2017307474
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000228179 02470 $$2EPO Family ID$$a54365328
000228179 02470 $$2TTO$$a6.1417
000228179 037__ $$aPATENT
000228179 245__ $$aMethod and apparatus for measuring the local birefingence along an optical waveguide
000228179 269__ $$a2016
000228179 260__ $$c2016
000228179 336__ $$aPatents
000228179 500__ $$aPriority data: PCT/IB2014/064598 17.09.2014 IB
000228179 520__ $$aThis invention relates to a system and method to determine the distributed birefringence profile along an optical fibre. Birefringence manifests as different refractive indices for two orthogonal states of polarization of the light propagating in the optical fibre. The technique is based on the correlation among sets of measurements acquired using phase‐sensitive optical time‐domain reflectometry (ϕOTDR), launching light into the fibre with multiple states of polarization. The correlation between the measurements performed while sweeping the laser frequency gives a resonance (correlation) peak at a frequency detuning that is proportional to the refractive index difference between the two orthogonal polarizations. This enables measurements of the local value of the phase birefringence at any position along the optical fibre, so that longitudinal fluctuations of its value can be evaluated. Such fluctuations can be induced either accidentally during cabling and installation processes, or voluntarily due to varying conditions or environmental quantities such as temperature, strain and pressure, or even unintentionally as a result of a badly controlled manufacturing process.
000228179 700__ $$0240503$$g106544$$aThevenaz, Luc
000228179 700__ $$aGonzalez Herraez, Miguel
000228179 700__ $$0247069$$g195294$$aSoto Hernandez, Marcelo Alfonso
000228179 700__ $$aMartins, Hugo Fidalgo
000228179 700__ $$aLu, Xin
000228179 8564_ $$uhttps://infoscience.epfl.ch/record/228179/files/P2808PC00%20Publication%20WO2016042507.pdf$$zPublisher's version$$s2382256$$yPublisher's version
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000228179 917Z8 $$x106544
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000228179 937__ $$aEPFL-PATENT-228179
000228179 973__ $$aEPFL
000228179 980__ $$aPATENT