TY - JOUR A1 - Kasinathan, M. A1 - Babu Rao, C. A1 - Murali, N. A1 - Jayakumar, T. A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Bond monitoring in temperature dependent applications using Brillouin optical time domain analyser JF - Journal of Optics N2 - Adhesive bond has to be evaluated for its integrity over a range of temperature. Adhesive is being used to bond the sensors with structures. There is no validated technique to test its performance. In this paper, we propose a Brillouin Optical Time Domain Analyzer (BOTDA) based methodology to detect temperature-induced adhesive bond failure below room temperature using distributed fiber optic sensor. The differential coefficient of thermal expansion of the structure and fiber sensor can lead to bond failure at low temperature. Optical fiber impregnated in the structure will experience differential temperature/strain due to debond of the adhesive. This leads to the frequency and amplitude decomposition of the Brillouin spectra. This is a good indication for real-time monitoring of the integrity of a bond. KW - Adhesive bond KW - Brillouin scattering KW - optical fiber sensor KW - Brillouin optical time domain analysis KW - distributed sensor PY - 2016 DO - https://doi.org/10.1007/s12596-015-0266-5 VL - 45 IS - 1 SP - 44 EP - 49 PB - Springer AN - OPUS4-37923 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krebber, Katerina A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Nöther, N. A1 - Wendt, Mario A1 - Wosniok, Aleksander A1 - Daum, Werner T1 - Structural health monitoring by distributed fiber optic sensors embedded into technical textiles JF - Technisches Messen N2 - Technical textiles with embedded distributed fiber optic sensors have been developed for the purposes of structural health monitoring in geotechnical and civil engineering. The distributed fiber optic sensors are based on Brillouin scattering in silica optical fibers and OTDR in polymer optical fibers. Such 'smart' technical textiles are used for reinforcement of geotechnical and masonry structures. The embedded fiber optic sensors provide online information about the condition of the structure and about the occurrence and location of any damage or degradation.-------------------------------------------------------------------------------------------------------------------------------------------------------- Technische Textilien mit integrierten faseroptischen Sensoren eröffnen neue Möglichkeiten der Zustandsüberwachung (structural health monitoring) in Geotechnik und Ingenieurbau. Die verteilt messenden Sensoren basieren auf der Brillouin-Streuung in Glasfasern und auf der OTDR in polymeroptischen Fasern. Derartige 'intelligente' technische Textilien werden in erster Line zur Verstärkung von geotechnischen Bauwerken und von Gebäuden genutzt. Die integrierten Sensoren liefern eine zeitnahe Information über den bestimmungsgemäßen Zustand des Bauwerks sowie über die Entstehung und den Ort von lokalen Bauwerksschäden. KW - Fiber optic sensor KW - Distributed sensor KW - Brillouin scattering KW - Polymer optical fiber KW - Strain sensor KW - Smart geotextiles KW - Faseroptischer Sensor KW - Verteilter Sensor KW - Brillouin-Streuung KW - Polymeroptische Faser KW - Dehnungssensor KW - Intelligentes Geotextil PY - 2012 DO - https://doi.org/10.1524/teme.2012.0238 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 79 IS - 7-8 SP - 337 EP - 347 PB - Oldenbourg CY - München AN - OPUS4-26387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mizuno, Y. A1 - Lenke, Philipp A1 - Krebber, Katerina A1 - Nakamura, K. T1 - Characterization of Brillouin gain spectra in polymer optical fibers fabricated by different manufacturers at 1.32 and 1.55 µm JF - IEEE photonics technology letters N2 - We characterize the Brillouin gain spectra (BGS) in perfluorinated graded-index polymer optical fibers (PFGI-POFs) at 1.32 µm and 1.55 µm. Three kinds of PFGI-POFs with the same core diameter, but which are fabricated by different manufacturers, are tested. For all the PFGI-POFs, the Stokes power measured at 1.32 µm is higher than that at 1.55 µm due to the lower propagation loss, but significant differences in Stokes power are observed among the three. Based on the measurement obtained by the optical time-domain reflectometry, we show that the actual propagation loss of the PFGI-POFs plays a crucial role in observing BGS. KW - Brillouin gain spectrum (BGS) KW - Brillouin scattering KW - Nonlinear optics KW - Polymer optical fiber (POF) PY - 2012 DO - https://doi.org/10.1109/LPT.2012.2206803 SN - 1041-1135 VL - 24 IS - 17 SP - 1496 EP - 1498 PB - IEEE CY - New York, NY, USA AN - OPUS4-26319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -