TY - CONF A1 - Liehr, Sascha A1 - Nöther, N. A1 - Steffen, Milan A1 - Gili, O. A1 - Krebber, Katerina ED - López-Higuera, J.M. ED - Jones, J. ED - López-Amo, M. ED - Santos, J.L. T1 - Performance of digital incoherent OFDR and prospects for optical fiber sensing applications N2 - We propose a digital implementation of the incoherent optical frequency domain reflectometry (I-OFDR) technique for precise backscatter measurement and optical fiber sensing applications. Specific performance parameters of the I-OFDR are discussed and compared to an analog vector network analyzer-based I-OFDR system. Improved sensitivity, dynamic range and signal stability of the digital I-OFDR is presented and demonstrated by means of quasi-distributed length change measurement. T2 - OFS2014 - 23rd International conference on optical fibre sensors CY - Santander, Spain DA - 02.06.2014 KW - Optical fiber sensors KW - Backscatter measurement KW - Strain sensor KW - OFDR KW - OTDR PY - 2014 DO - https://doi.org/10.1117/12.2059639 SN - 0277-786X SN - 1996-756X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 9157 SP - 915737-1 EP - 915737-4 AN - OPUS4-30899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Wendt, Mario A1 - Krebber, Katerina A1 - Glötzl, R. A1 - Schneider-Glötzl, J. A1 - Gabino, L. A1 - Krywult, L. ED - Bernadette Havranek, ED - Masoud Motavalli, ED - Urs Meier, 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 KW - Distributed sensor KW - Optical fiber sensor KW - Geotextile KW - Technical textile KW - POF sensor KW - Structural health monitoring KW - SHM KW - OTDR KW - Fiber optic sensors KW - Polymer optical fibers (POF) KW - Strain sensor PY - 2009 SN - 978-3-905594-52-2 IS - Paper 520 SP - 1 EP - 7(?) CY - Zurich, Switzerland AN - OPUS4-19787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liehr, Sascha A1 - Wendt, Mario A1 - Krebber, Katerina A1 - Münich, J.C. A1 - Stempniewski, L. A1 - Metschies, H. ED - Bernadette Havranek, ED - Masoud Motavalli, ED - Urs Meier, T1 - Distributed polymer optical fiber sensors integrated in technical textiles for monitoring of masonry structures T2 - 4th International conference on structural health monitoring of intelligent infrastructure CY - Zurich, Switzerland DA - 2009-07-22 KW - Structural health monitoring KW - Fiber optic sensors KW - OTDR KW - Polymer optical fibers (POF) KW - POF sensors KW - Distributed sensor KW - Strain sensor KW - Technical textiles KW - Masonry PY - 2009 SN - 978-3-905594-52-2 IS - Paper 521 SP - 1 EP - 7(?) CY - Zurich, Switzerland AN - OPUS4-19788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Krebber, Katerina T1 - A novel quasi-distributed fibre optic displacement sensor 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. KW - Strain sensor KW - Optical frequency domain reflectometry KW - OFDR KW - Optical fibre KW - Fibre sensors KW - Quasi-distributed sensors KW - Dynamic strain measurement PY - 2010 UR - http://iopscience.iop.org/0957-0233/21/7/075205/pdf/0957-0233_21_7_075205.pdf DO - https://doi.org/10.1088/0957-0233/21/7/075205 SN - 0957-0233 SN - 1361-6501 VL - 21 IS - 7 SP - 075205-1 - 075205-6 PB - IOP Publ. Ltd. CY - Bristol AN - OPUS4-21812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krebber, Katerina A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Witt, Jens A1 - Schukar, Marcus ED - Ecke, Wolfgang ED - Kara J. Peters, ED - Norbert G. Meyendorf, T1 - Smart technical textiles with integrated POF sensors N2 - Fiber optic sensors based on polymer optical fibers (POF) take advantage of the high elasticity and high break-down strain of POF. Because of their outstanding elastic properties, POF are well suited for integration into technical textiles like geotextiles and medical textiles. Smart textiles with incorporated POF sensors, able to sense various mechanical and physical quantities, can be realized. The integration of POF as a sensor into geotextiles for monitoring of displacement of soil is very attractive since POF can be used for distributed strain measurement of strain values of more than 40 %. An online monitoring of critical mechanical deformations of geotechnical structures like dikes, dams, slopes, embankments as well as of masonry structures can be ensured. Medical textiles that incorporate POF sensors can control vital physiological parameters like respiratory movement and can be used for wearable health monitoring of patients requiring a continuous medical assistance and treatment. The biocompatibility of POF is an important criterion for selecting POF as a medical sensor. The paper shows selected examples of using POF sensors for the mentioned monitoring purposes. T2 - Smart Sensor Phenomena, Technology, Networks, and Systems 2008 CY - San Diego, California, USA DA - 2008-03-10 KW - Fiber optic sensors KW - Polymer optical fibers (POF) KW - POF sensors KW - Geotextiles KW - Medical textiles KW - Strain sensor KW - Respiratory monitoring KW - POF OTDR KW - Distributed sensor KW - Geotechnical structures PY - 2008 SN - 978-0-8194-7119-2 DO - https://doi.org/10.1117/12.776758 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 6933 IS - 6933 SP - 69330V-1 - 69330V-15 PB - SPIE CY - Bellingham AN - OPUS4-17680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Krebber, Katerina A1 - Seeger, M. A1 - Thiele, E. A1 - Metschies, H. A1 - Gebreselassie, B. A1 - Münich, J.C. A1 - Stempniewski, L. ED - Francis Berghmans, ED - Mignani, Anna Grazia ED - Cutolo, Antonello ED - Patrick P. Meyrueis, ED - Thomas P. Pearsall, T1 - Distributed strain measurement with polymer optical fibers integrated into multifunctional geotextiles N2 - Fiber optic sensors based on polymer optical fibers (POF) have the advantage of being very elastic and robust at the same time. Unlike silica fibers, standard PMMA POF fibers can be strained to more than 40% while fully maintaining their light guiding properties. We investigated POF as a distributed strain sensor by analysing the backscatter increase at the strained section using the optical time domain reflectometry (OTDR) technique. This sensing ability together with its high robustness and break-down strain makes POF well-suited for integration into technical textiles for structural health monitoring purposes. Within the European research project POLYTECT (Polyfunctional textiles against natural hazards) technical textiles with integrated POF sensors, among others sensors are being developed for online structural health monitoring of geotechnical structures. Mechanical deformation in slopes, dams, dikes, embankments and retrofitted masonry structures is to be detected before critical damage occurs. In this paper we present the POF strain sensor properties, reactions to disturbing influences as temperature and bends as well as the results of the different model tests we conducted within POLYTECT. We further show the potential of perfluorinated graded-index POF for distributed strain sensing with increased spatial resolution and measurement lengths. T2 - Optical Sensors 2008 CY - Strasbourg, France DA - 2008-04-07 KW - Fiber optic sensors KW - OTDR KW - Polymer optical fibers (POF) KW - POF sensors KW - Distributed sensor KW - Strain sensor KW - Geotextiles KW - Structural health monitoring PY - 2008 SN - 978-0-8194-7201-4 DO - https://doi.org/10.1117/12.780508 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 7003 IS - 7003 SP - 700302-1 - 700302-15 PB - SPIE CY - Bellingham AN - OPUS4-17951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Krebber, Katerina ED - Santos, J.L. ED - Culshaw, B. ED - López-Higuera, J.M. ED - MacPherson, W.N. T1 - A novel fiber optic technique for quasi-distributed and dynamic measurement of length change and refractive index N2 - We present a novel technique for dynamic and simultaneous measurement of displacement and refractive indices at multiple reflection points in optical fibers. This quasi-distributed sensor is based on the incoherent optical frequency domain reflectometry (I-OFDR) technique and allows for m-resolution length change measurement and precise refractive index measurement. We show that the dynamic measurement ability and the simple sensor design allows for new applications in the field of structural health monitoring and chemical process control. T2 - 4th European workshop on optical fibre sensors CY - Porto, Portugal DA - 2010-09-08 KW - Quasi-distributed sensor KW - Strain sensor KW - Length change measurement KW - Optical fiber sensor KW - Refractive index sensor KW - Structural health monitoring KW - OFDR PY - 2010 SN - 978-0-8194-8083-5 DO - https://doi.org/10.1117/12.866325 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 7653 SP - 76532V-1 - 76532V-4 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-22380 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 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 - 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 -