TY - CONF A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Krebber, Katerina T1 - Improvements of the distributed strain sensor based on optical time domain reflectometry measurement in polymer optical fibers N2 - Sensing characteristics of standard polymer optical fibers (POF) are further studied using the optical time domain reflectometry (OTDR) technique. The level of the backscattering inside POF, which highly increases at locations where strain is applied to the fiber, is further investigated with respect to spectral behavior, strain rate and span of time from the stretching event. An algorithem to overcome the problem of the decrease of spatial resolution as a result of pulse broadening due to modal disperion, is proposed. The research is carried out on the background of the development of a new strain sensor that is integrated in technical textiles. T2 - 17th International Conference on Plastic Optical Fibers (POF 2008) CY - Santa Clara, California, USA DA - 2008-08-25 KW - Distributed strain sensor KW - Optical fiber sensor KW - POF KW - Scatter KW - PMMA KW - Spatial resolution PY - 2008 IS - Paper 1 SP - 1 EP - 5 AN - OPUS4-18210 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Wendt, Mario A1 - Krebber, Katerina T1 - Perfluorinated graded-index polymer optical fibers for distributed measurement of strain N2 - Recently, we have proposed, to our knowledge for the first time, to use perfluorinated graded-index polymer optical fiber (POF) for distributed measurement of strain. Thanks to their low attenuation and low modal dispersion compared to standard-POF, this fiber type allows to extend the measurement length to more than 500 meters at increased spatial resolution. In this paper, two mechanisms for strain sensing are introduced. As in standard PMMA POF, strain in the fiber can be detected by evaluating the local backscatter increase occurring at strained fiber sections. Further, we propose, to our knowledge for the first time, a true distributed length change measurement in POF using cross-correlation analysis of the fiber’s characteristic backscatter signature. Using this technique, it is possible to measure relative displacement between different fiber sections avoiding signal fading failures that are inherent in other measurement principles. Cross-sensitivities to the sensor signal, as fiber bends and temperature, are investigated and quantified. T2 - 17th International Conference on Plastic Optical Fibers (POF 2008) CY - Santa Clara, California, USA DA - 2008-08-25 KW - Distributed strain sensor KW - Optical fiber sensor KW - Perfluorinated POF KW - POF sensors PY - 2008 IS - Paper 64 SP - 1 EP - 5 AN - OPUS4-18209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - Distributed Polymer Optical Fiber Sensors in Geotextiles for Monitoring of Earthwork Structures T2 - 4th International Conference on Structural Health Monitoring of Intelligent Infrastructure CY - Zurich, Switzerland DA - 2009-07-22 PY - 2009 AN - OPUS4-20477 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - POF Sensors Integrated in Technical Textiles for Monitoring of Earthwork Structures and Masonry T2 - 7th International Workshop on Structural Health Monitoring (IWSHM) CY - Stanford, CA, USA DA - 2009-09-09 PY - 2009 AN - OPUS4-20478 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - Distributet perfluorinated POF strain sensor using OTDR and OFDR techniques T2 - Twentieth International Conference on Optical Fibre Sensors CY - Edinburgh, Scotland DA - 2009-10-05 PY - 2009 AN - OPUS4-20505 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider-Gloetzl, J. A1 - Gloetzl, R. A1 - Krebber, Katerina A1 - Liehr, Sascha A1 - Wendt, Mario A1 - Wosniok, Aleksander T1 - Geotechnical monitoring of construction activities by distributed fiber optic sensors embedded in geotextiles T2 - 5th European workshop on structural-health-monitoring 2010 CY - Sorrento, Italy DA - 2010-06-29 KW - Foundation engineering KW - Geotechnical monitoring KW - Smart textiles KW - Distributed fiber optic sensors KW - POF sensors KW - Brillouin sensors PY - 2010 IS - SS4-07 SP - 1 EP - 6 AN - OPUS4-21872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Nöther, Nils A1 - Wendt, Mario A1 - Wosniok, Aleksander ED - Santos, J.L. ED - Culshaw, B. ED - López-Higuera, J.M. ED - MacPherson, W.N. T1 - Distributed fiber optic sensors embedded in technical textiles for structural health monitoring 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 can be used for reinforcement of geotechnical and masonry structures and the embedded fiber optic sensors can provide information about the condition of the structures and detect the presence of any damages and destructions in real time. Thus, structural health monitoring of critical geotechnical and civil infrastructures can be realized. The paper highlights the results achieved in this innovative field in the framework of several German and European projects. T2 - 4th European workshop on optical fibre sensors CY - Porto, Portugal DA - 2010-09-08 KW - Fiber optic sensor KW - Distributed sensor KW - Brillouin sensor KW - Polymer optical fibers (POF) KW - POF sensor KW - POF OTDR KW - Strain sensor KW - Technical textiles KW - Geotextiles PY - 2010 SN - 978-0-8194-8083-5 DO - https://doi.org/10.1117/12.868052 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 7653 SP - 76530A-1 - 76530A-12 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-21948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - A novel fiber optic technique for quasi-distributed and dynamic measurement of length change and refractive index T2 - 4th European Workshop on Optical Fibre Sensors CY - Oporto, Portugal DA - 2010-09-08 PY - 2010 AN - OPUS4-22053 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - A novel technique for quasi-distributed and dynamic length change measurement in optical fibers T2 - OSA Optics and Photonics Congress CY - Karlsruhe, Germany DA - 2010-06-21 PY - 2010 AN - OPUS4-22049 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Krebber, Katerina A1 - Weigand, F. A1 - Thiele, E. T1 - Distributed strain measurement with polymer optical fiber integrated in technical textiles using the optical time domain reflectometry technique N2 - The presented research is carried out on the background of the development of a new strain sensor, integrated in technical textiles using the optical time domain reflectometry (OTDR) technique. We investigated the effect of increased scattering in POF due to applied strain as a distributed sensor including research on long-term stability and reliability of this sensor. T2 - 16th International Conference on Plastic Optical Fibers (POF 2007) CY - Turin, Italy DA - 2007-09-10 PY - 2007 SP - 21 EP - 24 PB - International Cooperative of Plastic Optical Fibers (ICPOF) CY - Turin, Italy AN - OPUS4-16435 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Krebber, Katerina T1 - A dynamic fiber optic strain and power change sensor N2 - A dynamic and quasi-distributed sensor principle for simultaneous measurement of length changes and optical power changes between reflection points in an optical fiber is presented. The technique is based on the incoherent optical frequency domain reflectometry (I-OFDR). Length change resolutions < 1 µm and measurement repetition rates up to 2 kHz can be achieved using standard single-mode and multi-mode optical fibers. Simultaneous length change and refractive index measurement as well as field test results showing the deformation of a masonry building under seismic load are presented. Promising fields of application for this technique are the structural health monitoring sector and chemical process control. T2 - 21st International conference on optical fibre sensors CY - Ottawa, Canada DA - 15.05.2011 KW - Distributed sensor KW - Strain sensor KW - Optical fiber sensor KW - Structural health monitoring KW - OFDR KW - Dynamic sensor PY - 2011 SN - 978-0-8194-8246-4 DO - https://doi.org/10.1117/12.884577 VL - 7753 SP - 775351-1 EP - 775351-4 AN - OPUS4-24266 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liehr, Sascha ED - Mukhopadhyay, S.C. T1 - Polymer optical fiber sensors in structural health monitoring N2 - This chapter summarizes the recent development in the relatively new and emerging field of structural health monitoring using polymer optical fiber (POF) sensors, also referred to as plastic optical fiber sensors. The extraordinary mechanical properties of POF in terms of strainability and ruggedness allows for measurement applications that could not or only insufficiently be solved with existing techniques. A great number of measurement parameters relevant for structural health monitoring applications, such as strain, displacement, crack width, vibrations or moisture can be measured with POF sensors. Numerous sensing principles have been proposed during the last 20 years and the most promising techniques and developments for SHM will be introduced. The focus is on the measurement of physical quantities for early damage detection and propagation, structural surveillance and analysis of dynamic processes. PY - 2011 SN - 978-3-642-21098-3 DO - https://doi.org/10.1007/978-3-642-21099-0 SN - 1876-1100 N1 - Serientitel: Lecture Notes in Electrical Engineering – Series title: Lecture Notes in Electrical Engineering VL - 96 SP - 297 EP - 333 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-24343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Krebber, Katerina ED - De Roeck, G. ED - Degrande, G. ED - Lombaert, G. ED - Müller, G. T1 - A novel quasi-distributed long-gauge fiber optic strain sensor system for dynamic measurement N2 - We present a novel technique based on incoherent optical frequency domain reflectometry (OFDR) to measure length changes quasi-distributed between reflection points in optical fibres. The technique enables length changes to be measured with a resolution better than 1 µm and allows for static and dynamic measurement capabilities up to 2 kHz. We demonstrate that dynamic measurements of multiple fibre sections can be conducted independently from each other with high precision. Due to the precise and dynamic measurement capabilities, the proposed sensor system is expected to open new fields of application, especially in the structural-health-monitoring sector. Possible applications are discussed in the paper. T2 - EURODYN 2011 - 8th International conference on structural dynamics CY - Leuven, Belgium DA - 04.07.2011 KW - Distributed sensor KW - Strain sensor KW - Optical fiber sensor KW - Structural health monitoring KW - OFDR KW - Length change measurement KW - Dynamic sensor PY - 2011 SN - 978-90-760-1931-4 SP - 2097 EP - 2102 AN - OPUS4-24347 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - A novel quasi-distributed long-gauge fiber optic strain sensor system for dynamic measurement T2 - 8th International Conference on Structural Dynamics, EURODYN 2011 CY - Leuven, Belgium DA - 2011-07-04 PY - 2011 AN - OPUS4-24776 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - Hangüberwachung mit optischen Polymerfasern T2 - VDI/VDE-GMA Expertenforum "Strukturmonitoring und Zustandsüberwachung 2011" CY - Nuremberg, Germany DA - 2011-06-07 PY - 2011 AN - OPUS4-24777 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - A dynamic fiber optic strain and power change sensor N2 - A dynamic and quasi-distributed sensor principle for simultaneous measurement of length changes and optical power changes between reflection points in an optical fiber is presented. The technique is based on the incoherent optical frequency domain reflectometry (I-OFDR). The calculation of phase and amplitude changes from few measurement points in the frequency domain yields precise and dynamic length and optical power change results up to 2 kHz and μm-resolution. Test results showing the deformation of a masonry building under seismic load are presented. Promising fields of application for this technique are the structural health monitoring sector and chemical process control. T2 - 21st International Conference on Optical Fiber Sensors CY - Ottawa, Canada DA - 15.05.2011 PY - 2011 AN - OPUS4-24930 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - Verteilte faseroptische Sensoren und Anwendung im geotechnischen Monitoring T2 - Faseroptische Sensoren - Messsysteme mit Zukunft CY - Weimar, Germany DA - 2012-09-24 PY - 2012 AN - OPUS4-26793 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - Fiber optic bend and temperature sensing in femtosecond laserstructured POF T2 - 22nd International Conference on Optica Fiber Sensors (OFS-22) CY - Beijing, China DA - 2012-10-15 PY - 2012 AN - OPUS4-27174 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Burgmeier, J. A1 - Krebber, Katerina A1 - Schade, Wolfgang T1 - Femtosecond laser structuring of polymer optical fibers for backscatter sensing N2 - Focused femtosecond laser pulses are used to create scattering damage in the core of polymer optical fibers (POF). The resulting structures are investigated regarding morphology by light microscopy and backscattered intensity using optical time domain reflectometry (OTDR). Quasi-distributed optical fiber sensing is proposed by evaluating backscatter changes at the inscribed scatter centers. Application examples for quasi-distributed measurement of fiber bends and temperature are demonstrated. KW - Femtosecond laser KW - Micromachining KW - Optical fiber sensors KW - Polymer optical fiber KW - Polymer PY - 2013 DO - https://doi.org/10.1109/JLT.2013.2250483 SN - 0733-8724 SN - 1558-2213 VL - 31 IS - 9 SP - 1418 EP - 1425 PB - Institute of Electrical and Electronics Engineers CY - New York, NY AN - OPUS4-28733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Burgmeier, J. ED - Jaroszewicz, L.R. T1 - Quasi-distributed measurement on femtosecond laser-induced scattering voids using incoherent OFDR and OTDR N2 - We propose to use focused femtosecond laser pulses to create scattering damage in standard singlemode optical fibres as reference points for quasi-distributed sensing applications. Such sensor fibres are interrogated with incoherent optical frequency domain reflectometry (I-OFDR) technique and optical time domain reflectometry (OTDR). A performance comparison of both techniques with the clear advantage of the I-OFDR is presented as well as a quasi-distributed length change measurement application. Also dynamic measurement based on the I-OFDR technique is demonstrated on a femtosecond laser-induced sensor chain. T2 - EWOFS 2013 - 5th European workshop on optical fibre sensors CY - Kraków, Poland DA - 19.05.2013 KW - Optical fiber sensors KW - Femtosecond laser KW - Strain sensor KW - OFDR KW - OTDR PY - 2013 SN - 978-0-81949-634-8 DO - https://doi.org/10.1117/12.2026780 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 8794 IS - Paper 8794 - 181 SP - 87943N-1 EP - 87943N-4 AN - OPUS4-28734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - Quasi-distributed measurement on femtosecond laser-induced scattering voids using incoherent OFDR and OTDR T2 - 5th European Workshop on Optical Fiber Sensors CY - Kraków, Poland DA - 2013-05-19 PY - 2013 AN - OPUS4-28742 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -