TY - CONF A1 - Krebber, Katerina T1 - Polymer Optical Fibres in Sensing - Applications & Future Demands T2 - IEEE Sensors 2011 Conference CY - Limerick, Ireland DA - 2011-10-28 PY - 2011 AN - OPUS4-24939 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Development of a PMMA-POF based fiber optic inclinometer with smart transport and installation characteristics T2 - 6th European Workshop on Structural Health Monitoring (EWSHM) CY - Dresden, Germany DA - 2012-06-03 PY - 2012 AN - OPUS4-26456 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Smart Technical Textiles Based on Fibre Optic Sensors - Technologies and Applications T2 - CIMTEC 2012: 4. International Conference "Smart Materials, Structures and Systems" CY - Montecatini Terme, Italy DA - 2012-06-10 PY - 2012 AN - OPUS4-26457 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Fiber Optic Sensors in Technical Safety Sciences T2 - Workshop "Trends in Fiber Optics 2012" CY - Jena, Germany DA - 2012-02-23 PY - 2012 AN - OPUS4-26458 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - POF sensors for structural health monitoring - applications and future demands (invited presentation) T2 - 21st International Conference on Plastic Optical Fibers, POF 2012 CY - Atlanta, GA, USA DA - 2012-09-10 PY - 2012 AN - OPUS4-26792 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Mizuno, Y. A1 - Krebber, Katerina A1 - Nakamura, K. ED - Jaroszewicz, L.R. T1 - L-BOFDA: a new sensor technique for distributed Brillouin sensing N2 - We propose a new scheme of Brillouin optical frequency-domain analysis (BOFDA) for distributed fiber-optic strain and temperature sensing, named linear-configured BOFDA (L-BOFDA). In conventional loop-configured BOFDA, light injection into both ends of a fiber under test (FUT) is needed for counter-propagation of pump and probe waves. In contrast, in L-BOFDA, pump and probe waves are injected into the same end of an FUT, and the probe wave Fresnelreflected (or mirror-reflected) at the other end of the FUT is exploited; thus, one-end access is feasible. We show proof-of-concept results of distributed strain measurement in a silica single-mode fiber with L-BOFDA, and discuss the signal-to-noise ratio degradation and the benefit in developing distributed Brillouin sensors based on polymer optical fibers. T2 - EWOFS 2013 - 5th European workshop on optical fibre sensors CY - Kraków, Poland DA - 19.05.2013 KW - Brillouin optical frequency-domain analysis (BOFDA) KW - L-BOFDA KW - Optical fiber sensing KW - Distributed strain measurement KW - Stimulated Brillouin scattering KW - Polymer optical fiber PY - 2013 DO - https://doi.org/10.1117/12.2025378 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 8794 IS - Paper 8794 - 181 SP - 879431-1 EP - 879431-4 AN - OPUS4-28961 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habel, Wolfgang A1 - Krebber, Katerina T1 - Application of fiber-optic sensors for health monitoring purposes in geo-engineering T2 - 4th International forum on opto-electronic sensor-based monitoring in geo-engineering CY - Suzhou, China DA - 2012-10-11 KW - BOFDA KW - Fibre-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 KW - Geophone KW - Fabry-Perot sensor KW - Pile test KW - Impact KW - Acoustic wave PY - 2012 SP - 4 EP - 15 AN - OPUS4-27259 LA - eng 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 - Krebber, Katerina T1 - POFs for sensing applications N2 - The paper highlights the use of polymer optical fibers (POFs) as sensors in selected applications like structural health monitoring in geotechnical and civil engineering, composites monitoring, healthcare monitoring and personnel protection. The recent progress achieved in this field will be reviewed and the main challenges to these innovative fibre optic sensors will be adressed. T2 - 3rd Workshop on specialty optical fibers and their applications CY - Sigtuna, Sweden DA - 28.08.2013 PY - 2013 IS - T3.6 SP - 1 EP - 2 AN - OPUS4-29334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - POFs for Sensing Applications T2 - Workshop on Specialty Optical fiber and their Applications (WSOF) CY - Sigtuna, Sweden DA - 28.08.2013 PY - 2013 AN - OPUS4-29256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karapanagiotis, Christos A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Temperature and humidity discrimination in Brillouin distributed fiber optic sensing using machine learning algorithms N2 - In the last few years, the use of machine learning has emerged in the field of distributed fiber optic sensors as a promising approach to enhance their performance and provide new capabilities. In this study, we use machine learning for simultaneous measurements of temperature and humidity in polyimide (PI)-coated optical fibers based on Brillouin Brillouin optical frequency domain analysis (BOFDA). Different non-linear machine learning algorithms are employed, namely polynomial regression, decision trees and artificial neural networks (ANNs), and their discrimination performance is benchmarked against that of the conventional linear regression. The performance is evaluated using leave-one-out cross-validation to ensure that the models are reliable and able to generalize well on new data. We show that nonlinear machine learning algorithms outperform the conventional linear regression and thus could pave the way towards simultaneous cost-effective temperature and humidity distributed sensing, which has the potential to find attractive new applications in the field of civil and geotechnical engineering, from structural health monitoring of dikes and bridges to subsea cables and long pipelines corrosion detection. T2 - SPIE Photonics Europe 2022 CY - Strasbourg, France DA - 03.04.2022 KW - Distributed Brillouin sensing KW - Machine learning KW - Artificial neural networks KW - Simultaneous temperature and humidity sensing KW - BOFDA PY - 2022 DO - https://doi.org/10.1117/12.2620985 VL - 12139 SP - 1 EP - 7 PB - SPIE AN - OPUS4-54861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Verteilte faseroptische Sensoren zur Zustandsüberwachung von Verbundwerkstoff-Druckbehältern T1 - Distributed fiber optic sensors for structural health monitoring of composite pressure vessels N2 - In diesem Beitrag geben wir einen umfassenden Überblick über unsere Forschung auf dem Gebiet der verteilten faseroptischen Sensorik für die strukturelle Zustandsüberwachung von Wasserstoffdruckbehältern aus Verbundwerkstoffen. Insbesondere zeigen wir, wie die Integration von faseroptischen Sensoren in Druckbehälter aus Verbundwerkstoffen die Sicherheit erhöht und gleichzeitig die Wartungskosten senkt. Die geringe Größe von Lichtwellenleitern ermöglicht ihre Integration in Verbundwerkstoffstrukturen während des Herstellungsprozesses, wodurch eine kontinuierliche Überwachung sowie eine präzise Erkennung und Lokalisierung von Strukturschäden während des Betriebs der Druckbehälter ermöglicht wird. Wir erörtern auch das Potenzial modernster Signalverarbeitungsmethoden und des maschinellen Lernens für die Weiterentwicklung der vorausschauenden Instandhaltung. Die von uns vorgestellten Anwendungen von faseroptischen Sensoren zeigen, dass sie einen wichtigen Beitrag zur Energiewende hin zu erneuerbaren Energien leisten können. KW - Verteilte faseroptische Sensoren KW - Verbundwerkstoffe KW - Wasserstoff-Druckbehälter KW - Strukturüberwachung KW - Maschinelles Lernen PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596290 DO - https://doi.org/10.1515/teme-2023-0170 SN - 0171-8096 SP - 1 EP - 12 AN - OPUS4-59629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karapanagiotis, Christos A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Krebber, Katerina T1 - Monitoring of composite pressure vessels using surface applied distributed fiber optic sensors N2 - In this paper, we report on surface-applied distributed fibre optic sensors for monitoring composite pressure vessels designed for hydrogen storage. Previous reports have revealed that integrating optical fibres within vessel composite structures effectively enables the monitoring of structural behavior throughout their lifetime. However, integrating optical fibres during the manufacturing process is complex and time-consuming. Therefore, we aim to simplify this process by attaching the optical fibres to the vessel’s surface. This method is significantly more timeefficient than the integration process and can be applied to any vessel. Our results demonstrate that surface-applied fibre optic sensors can detect and precisely localise damage. Additionally, signs of damage can be recognised even before the damage occurs. Predictive maintenance using fibre optic sensors could reduce premature maintenance costs and periodic inspections while increasing safety and extending the vessel’s useful service life. The role of machine learning in predictive maintenance is also discussed. T2 - 20th Sensors & their Applications Conference CY - Limerick, Ireland DA - 11.08.2024 KW - Hydrogen KW - Fiber optic sensors KW - Composites KW - Machine learning KW - Structural health monitoring PY - 2024 SP - 1 EP - 4 AN - OPUS4-60911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Woyessa, G. A1 - Schukar, Marcus A1 - Bang, O. A1 - Krebber, Katerina T1 - Response of microstructured plastic optical fiber Bragg grating to gamma radiation N2 - Response of PMMA-based plastic optical fiber Bragg grating (FBG) to gamma radiation is investigated for the first time. FBG wavelength shift as large as 150 pm is observed for irradiation to 18 kGy. T2 - 5th Workshop on specialty optical fibers and their applications CY - Limassol, Cyprus DA - 11.10.2017 KW - Fiber Bragg gratings KW - Optical sensing and sensors KW - Plastic optical fibers KW - Gamma radiation PY - 2017 SP - Poster 19, 1 EP - 2 AN - OPUS4-42586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lu, Xin A1 - Schukar, Marcus A1 - Großwig, S. A1 - Weber, U. A1 - Krebber, Katerina T1 - Monitoring acoustic events in boreholes using wavelengthscanning coherent optical time domain reflectometry in multimode fiber N2 - A distributed acoustic sensor (DAS) based on wavelength-scanning coherent optical time domain reflectometer (WS-COTDR) is tested in an underground gas storage based on a multimode fiber for the first time to the best of our knowledge. The WS-COTDR acquires the reflection spectrum by scanning the wavelength of the laser and uses the spectra to calibrate strain. It overcomes the fading problem which is common for all DAS systems, and possesses the advantage of simple configuration and low-cost. The working principle of the system is well explained and the measurement results are presented. Various artificial and natural acoustic events have been successfully detected by the WS-COTDR. Such a sensor demonstrates several advantages over the traditional DAS systems, so it is supposed to be widely used in the oil and gas industry. T2 - EAGE GeoTech 2021 Second EAGE Workshop on Distributed Fibre Optic Sensing CY - Online meeting DA - 01.03.2021 KW - Leakage detection KW - Distributed acoustic sensing KW - Distributed fiber optic sensing PY - 2021 DO - https://doi.org/10.3997/2214-4609.202131010 SP - Paper 10, 1 PB - European Association of Geoscientists & Engineers CY - Houten, Niederlande AN - OPUS4-52248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lu, Xin A1 - Schukar, Marcus A1 - Großwig, S. A1 - Weber, U. A1 - Krebber, Katerina T1 - Monitoring acoustic events in boreholes using wavelengthscanning coherent optical time domain reflectometry in multimode fiber N2 - A distributed acoustic sensor (DAS) based on wavelength-scanning coherent optical time domain reflectometer (WS-COTDR) is tested in an underground gas storage based on a multimode fiber for the first time to the best of our knowledge. The WS-COTDR acquires the reflection spectrum by scanning the wavelength of the laser and uses the spectra to calibrate strain. It overcomes the fading problem which is common for all DAS systems, and possesses the advantage of simple configuration and low-cost. The working principle of the system is well explained and the measurement results are presented. Various artificial and natural acoustic events have been successfully detected by the WS-COTDR. Such a sensor demonstrates several advantages over the traditional DAS systems, so it is supposed to be widely used in the oil and gas industry. T2 - EAGE GeoTech 2021 CY - Online meeting DA - 01.03.2021 KW - Borehole monitoring KW - Distributed fiber sensing KW - Acoustic sensing PY - 2021 DO - https://doi.org/10.3997/2214-4609.202131010 SP - 1 EP - 5 AN - OPUS4-52152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krebber, Katerina A1 - Weege, S. A1 - Großwig, S. A1 - Obermöller, M. A1 - Perk, M. A1 - Lu, Xin A1 - Schukar, Marcus A1 - Weber, U. A1 - Pfeiffer, T. A1 - Rembe, M. T1 - Kombinierte faseroptische Messungen in Bohrlöchern helfen bei der Detektion von Kleinstleckagen N2 - Seit November 2019 läuft ein breit angelegtes und vom BMWi gefördertes ZIM-Kooperationsprojekt zwischen der Bundesanstalt für Materialforschung und -prüfung (BAM), der IAB'Weimar gGmbH, der GKSO GmbH & Co. Projekt KG, der DEEP.KBB GmbH sowie der Rembe Consulting PartG mbB. Ziel des Forschungsvorhabens sind sowohl die Lokalisierung als auch die Quantifizierung insbesondere sehr kleiner Leckagen in einer Bohrlochverrohrung durch die Nutzung faseroptischer Messtechnik. Durch Messdatenkopplung und den Wegfall bewegungsbedingter Nachteile einer Messsonde werden wesentlich präzisere Ergebnisse zur Bewertung der Bohrlochintegrität als üblich erwartet. T2 - DGMK/ÖGEW-Frühjahrstagung 2020 CY - Meeting was canceled DA - 15.04.2020 KW - Wasserstoffspeicher KW - Kavernenspeicher KW - Verteilte faseroptische akustische Sensorik PY - 2020 VL - 6 SP - 43 EP - 43 PB - DVV Media Group CY - Hamburg AN - OPUS4-52233 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lu, Xin A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Characterizing vibration response of fiber cables for distributed acoustic sensing N2 - The vibration responses of two fiber cables are characterized up to 16 kHz and compared with a standard tight-buffered 900 um fiber. The response of the cables is suppressed due to the cable protection. T2 - 27th International Conference on Optical Fiber Sensors (OFS-27) CY - Alexandria, VA, USA DA - 29.08.2022 KW - Distributed fiber sensing KW - Acoustic sensing KW - Response characterization PY - 2022 AN - OPUS4-56099 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lu, Xin A1 - Schukar, Marcus A1 - Weege, S. A1 - Roske, T. A1 - Krebber, Katerina T1 - Leakage detection at a borehole simulator using distributed acoustic sensing N2 - A distributed acoustic sensing system is used to detect the leakage in a borehole simulator by measuring the leakage induced vibration. The leakage location can be clearly determined by frequency spectrum analysis. T2 - 27th International Conference on Optical Fiber Sensors (OFS-27) CY - Alexandria, VA, USA DA - 29.08.2022 KW - Leakage detection KW - Structural health monitoring KW - Distributed fiber sensing KW - Distributed acoustic sensing PY - 2022 SP - 1 EP - 4 PB - Optica CY - Washington D.C., USA AN - OPUS4-56097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lu, Xin A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Characterizing vibration response of fiber cables for distributed acoustic sensing N2 - The vibration responses of two fiber cables are characterized up to 16 kHz and compared with a standard tight-buffered 900 um fiber. The response of the cables is suppressed due to the cable protection T2 - 27th International Conference on Optical Fiber Sensors (OFS-27) CY - Alexandria, VA, USA DA - 29.08.2022 KW - Response characterization KW - Distributed fiber sensing KW - Acoustic sensing PY - 2022 SP - 1 EP - 4 PB - Optica CY - Washington D.C., USA AN - OPUS4-56096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lu, Xin A1 - Schukar, Marcus A1 - Weege, S. A1 - Roske, T. A1 - Krebber, Katerina T1 - Leakage detection at a borehole simulator using distributed acoustic sensing N2 - A distributed acoustic sensing system is used to detect the leakage in a borehole simulator by measuring the leakage induced vibration. The leakage location can be clearly determined by frequency spectrum analysis. T2 - 27th International Conference on Optical Fiber Sensors (OFS-27) CY - Alexandria, VA, USA DA - 29.08.2022 KW - Structural health monitoring KW - Distributed fiber sensing KW - Distributed acoustic sensing KW - Leakage detection PY - 2022 AN - OPUS4-56098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Schukar, Marcus A1 - Mair, Georg W. A1 - Krebber, Katerina A1 - Seidlitz, Holger T1 - Impact of internal pressure control during manufacturing on residual stresses and safety performance of type 4 pressure vessels N2 - Composite pressure vessels are commonly manufactured using the wet filament winding process, where various process parameters can influence the performance of the finished component. In this study two designs of wet filament wound 6.8-liter type 4 composite pressure vessels were manufactured. Both differ only by the internal pressure used during the filament winding, which primarily influences the residual stress state in the composite structure. An extensive experimental study was carried out, including 10 slow burst tests and strain measurements with fiber optic sensors. Significant differences can be observed in the performance of the two designs even though the used stacking sequence, materials and other manufacturing parameters are the same for both designs. A discussion of the differences in the behavior of both cylinder types is provided, including the strain distribution in slow burst tests and failure mechanism. KW - Residual stresses KW - Slow burst tests KW - Filament winding KW - Type 4 composite pressure vessels KW - Hydrogen PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626663 DO - https://doi.org/10.1016/j.jcomc.2025.100581 SN - 2666-6820 VL - 17 SP - 1 EP - 9 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-62666 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wendt, Mario A1 - Krebber, Katerina A1 - Glötzl, R. ED - Boller, C. T1 - Development of a PMMA-POF based fiber optic inclinometer with smart transport and installation characteristics N2 - We present the state of our work concerning the development of a fiber optic inclinometer based on PMMA POF which provides distributed sensitivity regarding level, direction and location of deformation within critical ground structures. According to the demand for simple less expensive Installation and Operation of reliable sensor Systems a sensor concept has been developed and to our knowledge the first results of a PMMA POF based inclinometer prototype are presented in the following chapters. T2 - EWSHM'12 - 6th European workshop on structural health monitoring 2012 CY - Dresden, Germany DA - 03.07.2012 PY - 2012 SN - 978-3-940283-41-2 IS - Chapt. Optical Sensors SP - 411 EP - 416 CY - Berlin AN - OPUS4-26193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wendt, Mario A1 - Krebber, Katerina T1 - Using optical POF switches for distributed fiber optical strain measurements N2 - During recent research projects FOS sensor Systems based on PMMA (see fig.l) and perfluorined POF have been developed in order to observe critical earth structures [1,2], The sensor Systems enables real distributed Observation of objects due to the use of OTDR technique, whereas an increased Rayleigh backscatter level is observed at the strained fiber section. Fürther both used POF types are very robust which makes the sensor System suitable for harsh environment condilions and secure continuous measurements even within strong deformed structures. These characteristics offer opportunities to complement the arsenal of established electric based sensor Systems. However, due to high cost of OTDR devices the developed sensor System is not ready for the market yet. To make an improvement here the feasibility of optical switches have been investigated in order to use multiple single sensor lines connected to one OTDR device. Despite to the fact that optical switches are established in the field of telecommunication the use for distributed optical measurements is to our knowledge not investigated yet. One question which has to be answered is if strong reflections which occur at fiber couplings disable the Signals of the single sensor lines. A further interest is to secure that the known sensing characteristics of the single System is still provided via optical switch. For this purpose two optical switches each adapted to PMMA and perfluorined characteristics respectively have been tested. Laboratory tests have been conducted, whereas two OTDR units for PMMA and perfluorined POF were available. Finally the switches have been tested during field tests. T2 - POF 2012 - 21st International conference on plastic optical fibers CY - Atlanta, Georgia, USA DA - 10.09.2012 KW - Distributed strain sensors KW - Optical switch KW - OTDR PY - 2012 SP - 133 EP - 136 AN - OPUS4-26743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Günzel, Stephan A1 - Mair, Georg W. A1 - Krebber, Katerina A1 - Seidlitz, Holger T1 - Embedding of Fiber Optic Sensors Under Industrial Conditions and Distributed Strain Sensing in Type 4 Composite Pressure Vessels N2 - The number of in-operation composite pressure vessels is increasing, partly due to their attractiveness for on-board compressed gas storage and transport applications. A possible way to maintain the highest safety levels is through the structural health monitoring of the composite cylinders. Here, the use of fiber optic sensors appears to be a promising approach. However, the integration of the optical fibers into the composite structure of a pressure vessel has been shown to be challenging. In this study, insights on the embedding of optical fibers in the composite structure under industrial conditions are provided. A protection concept for the ingress and egress of the optical fibers is presented. Finally, the results from destructive slow burst tests are evaluated, showing no clear trend in the impact of the embedded optical fibers on the performance of composite pressure vessels. T2 - 24th International Conference on Composite Materials CY - Baltimore, Maryland, USA DA - 04.08.2025 KW - Composite KW - Pressure vessel KW - Filament winding KW - Fiber optic sensors PY - 2025 SP - 3710 EP - 3717 AN - OPUS4-63886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Witt, Jens A1 - Narbonneau, F. A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - De Jonckheere, J. A1 - Jeanne, M. A1 - Kinet, D. A1 - Paquet, B. A1 - Depré, A. A1 - D´Angelo, L.T. A1 - Thiel, T. A1 - Logier, R. T1 - Medical textiles with embedded fiber optic sensors for monitoring of respiratory movement N2 - For patients under Magnetic Resonance Imaging (MRI) spontaneous respiration is constantly at risk of being impaired by anesthetic drugs or by upper airway obstruction. Therefore, continuous monitoring of the breathing activity is needed to assess adequate ventilation or to detect specific obstruction patterns. The paper describes three MRI compatible respiration sensors based on pure optical technologies developed within the EU FP6 project OFSETH. The sensors are based on fiber Bragg gratings, optical time-domain reflectometry and macrobending effects. The developed smart medical textiles can sense elongation up to 3% while maintaining the stretching properties of the textile substrates for patient's comfort. The OFSETH harness allows a continuous measurement of abdominal and thoracic respiration movement while all vitals organs are free for medical staff actions. The sensors were tested in MRI environment and on healthy adults. KW - Fiber optic sensor KW - Polymer optical fiber (POF) sensor KW - Respiratory sensor KW - Smart medical textile KW - MRI KW - Smart textile KW - Healthcare monitoring KW - Optical sensor KW - FBG PY - 2012 DO - https://doi.org/10.1109/JSEN.2011.2158416 SN - 1530-437X SN - 1558-1748 VL - 12 IS - 1 SP - 246 EP - 254 CY - New York, NY, USA AN - OPUS4-25649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Jens A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Demuth, J. A1 - Pazoutová, H. A1 - Sasek, L. A1 - Santostefano, N. A1 - Fiore, L. A1 - Uotila, J. A1 - Pietrowski, P. T1 - POF sensors for personal protective equipment (PPE) N2 - This paper reports about the EU project i-Protect in which fibre optic sensors for measuring heart rate, respiratory rate and skin temperature are being developed. The sensors and monitoring units are integrated into underwear and are communicating wireless via body area network and communication unit with the rescue command centre. All sensors can be removed from the underwear to allow washing the textile. T2 - POF 2012 - 21st International conference on plastic optical fibers CY - Atlanta, Georgia, USA DA - 10.09.2012 KW - Physiological sensor KW - Heart rate KW - Respiratory rate KW - Photoplethysmography KW - Technical textile PY - 2012 SP - 333 EP - 338 AN - OPUS4-27397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hussels, Maria-Teresa A1 - Chruscicki, Sebastian A1 - Habib, Abdel Karim A1 - Krebber, Katerina T1 - Distributed acoustic fibre-optic sensors for condition monitoring of pipelines N2 - Industrial piping systems are particularly relevant to public safety and the continuous availability of infrastructure. However, condition monitoring systems based on many discrete sensors are generally not well-suited for widespread piping systems due to considerable installation effort, while use of distributed fibre-optic sensors would reduce this effort to a minimum. Specifically distributed acoustic sensing (DAS) is employed for detection of third-party threats and leaks in oil and gas pipelines in recent years and can in principle also be applied to industrial plants. Further possible detection routes amenable by DAS that could identify damage prior to emission of medium are subject of a current project at BAM, which aims at qualifying distributed fibre optic methods such as DAS as a means for spatially continuous monitoring of industrial piping systems. Here, first tests on a short pipe are presented, where optical fibres were applied directly to the surface. An artificial signal was used to define suitable parameters of the measurement system and compare different ways of applying the sensor. T2 - Sixth European Workshop on Optical Fibre Sensors CY - Limerick, Ireland DA - 31.05.2016 KW - fibre-optic condition monitoring KW - distributed acoustic sensing (DAS) KW - pipeline monitoring KW - sensor application PY - 2016 SN - 978-1-5106-0219-9 DO - https://doi.org/10.1117/12.2236809 SN - 0277-786X VL - Vol. 9916 SP - Article Number: 99162Y PB - SPIE CY - Bellingham, Washington USA AN - OPUS4-37234 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stajanca, Pavol A1 - Cetinkaya, O. A1 - Schukar, Marcus A1 - Mergo, P. A1 - Webb, D. J. A1 - Krebber, Katerina T1 - Molecular alignment relaxation in polymer optical fibers for sensing applications N2 - A systematic study of annealing behavior of drawn PMMA fibers was performed. Annealing Dynamics were investigated under different environmental conditions by fiber longitudinal shrinkage monitoring. The shrinkage process was found to follow a stretched exponential decay function revealing the heterogeneous nature of the underlying molecular dynamics. The complex dependence of the fiber shrinkage on initial degree of molecular alignment in the fiber, annealing time and temperature was investigated and interpreted. Moreover, humidity was shown to have a profound effect on the annealing process, which was not recognized previously. Annealing was also shown to have considerable effect on the fiber mechanical properties associated with the relaxation of molecular alignment in the fiber. The consequences of fiber annealing for the climatic stability of certain polymer optical fiber-based sensors are discussed, emphasizing the importance of fiber controlled pre-annealing with respect to the foreseeable operating conditions. KW - Polymer optical fibers KW - Optical fiber sensor climatic stability KW - Thermal annealing KW - Molecular alignment relaxation KW - Humidity induced annealing PY - 2016 DO - https://doi.org/10.1016/j.yofte.2015.12.006 SN - 1068-5200 VL - 28 SP - 11 EP - 17 PB - Academic Press CY - Orlando AN - OPUS4-35288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Sporea, D. A1 - Mihai, L. A1 - Negut, D. A1 - Schukar, Marcus A1 - Krebber, Katerina ED - Bunge, C.-A. ED - Kruglov, R. T1 - Gamma radiation induced effects in perfluorinated polymer optical fibers for sensing applications N2 - Radiation induced attenuation in perfluorinated polymer optical fiber was investigated as a potential mean for online. in situ gamma radiation monitoring. Spectral dependence of radiation induced attenuation was measured in the visible and near infrared range. Attenuation spectrum exhibits sharp increase both towards the ultraviolet and infrared side of the spectrum with 3 distinct peaks around 1400 nm. The fiber sensitivity to gamma radiation was further evaluated at two commonly used IR wavelengths (1310nm and l550nm} by pre- and post-irradiation optical time-domain reflectometry measurements. The examined fiber is sensitive up to lOO kGy of total absorbed dose with only minor saturation towards the large dose values. The influence of gamma radiation on the fiber mechanical properties was studied as well. Up to the maximal dose of 100 kGy, no significant deterioration of fiber strength and elasticity was observed. T2 - 3rd International POF Modelling Workshop CY - Nuremberg, Germany DA - 21.09.2015 KW - Perfluorinated POF KW - Gamma radiation KW - Radiation induced losses KW - Radiation dosimetry PY - 2015 SN - 978-3739214993 SP - 95 EP - 103 PB - Books on Demand GmbH CY - Norderstedt AN - OPUS4-35287 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Lacraz, A. A1 - Kalli, K. A1 - Schukar, Marcus A1 - Krebber, Katerina ED - Berghmans, F. ED - Mignani, A. G. T1 - Strain sensing with femtosecond inscribed FBGs in perfluorinated polymer optical fibers N2 - In this work, the potential of fiber Bragg gratings (FBGs) in low-loss perfluorinated polymer optical fibers (PF-POFs) is explored. The FBG is femtosecond-inscribed in a commercial multi-mode (MM) PF-POF based on Cytop® polymer. Femtosecond inscription leads to creation of a highly saturated grating with a number of higher order reflection Peaks visible throughout the visible and near-infrared spectral region. For 2 mm long FBG having a pitch of 2.2895 μm, a total of nine higher-order MM reflection bands are visible spanning from 1548 nm (4th order) to 520 nm (12th order). Strain sensitivity was measured for 6 peak bands in 500-900 nm region, where relatively low cost CCD based spectrometers and broadband LEDs are available. Strain sensitivity increases almost linearly with increasing initial peak wavelength, growing from 4.82 ± 0.02 nm/% measured for 12th order peak at 517 nm to 8.12 ± 0.04 nm/% measured for 7th order peak at 883 nm. These values correspond to roughly 20 % higher sensitivity than silica FBGs exhibit in this spectral range. The gratings in PF-POFs combine the higher strain sensitivity and low-loss operation while maintaining the mechanical advantages of polymer optical fibers. Therefore, they hold a high potential for considerable broadening of polymer optical fiber Bragg gratings application range. T2 - Photonics Europe 2016, Optical Sensing and Detection IV CY - Brussels, Belgium DA - 03.04.2016 KW - Fiber Bragg gratings KW - Fiber optics sensors KW - Perfluorinated polymer optical fiber KW - Cytop KW - Strain sensitivity PY - 2016 SN - 978-1-5106-0144-4 DO - https://doi.org/10.1117/12.2225081 SN - 0277-786X VL - 9899 SP - 989911-1 EP - 989911-7 PB - SPIE AN - OPUS4-35926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lu, Xin A1 - Chruscicki, Sebastian A1 - Schukar, Marcus A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Application of Intensity-Based Coherent Optical Time Domain Reflectometry to Bridge Monitoring N2 - Although distributed fiber sensing techniques have been widely used in structural health monitoring, the measurement results of bridge monitoring, particularly under destructive testing, have rarely been reported. To the best of our knowledge, this paper is the first report of distributed vibration measurement results, which we obtained during a three-day destructive test on an abolished bridge. A coherent optical time domain reflectometry (COTDR) was used to acquire the vibration information while the bridge was being sawed. The obtained signal was analyzed in time and frequency domain. Some characteristics of the sawing-induced vibration were retrieved by the short-time Fourier transform; the vibration exhibited several high frequency components within the measured range up to 20 kHz and all the components appeared in the same time slot. Some unexpected signals were also detected. Thorough analysis showed that they are quite different from the sawing-induced vibration and are believed to originate from internal damage to the bridge (probably the occurrence of cracks). KW - Destructive testing KW - Structural health monitoring KW - Distributed fiber sensing KW - Distributed acoustic sensing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547451 DO - https://doi.org/10.3390/s22093434 VL - 22 IS - 9 SP - 3434 PB - MDPI AN - OPUS4-54745 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kinet, D. A1 - Witt, Jens A1 - Grillet, A. A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Giannone, D. A1 - Pirotte, F. T1 - Silica Fibre Bragg Grating Sensor Embedded into a Textile Fabric for Large Strain Applications N2 - A FBG written on standard silica fibre, with coating transparent at 248nm, was integrated on an elastic textile fabric. The so-formed optical gauge showed a linear relationship when strained up to 40%. T2 - Bragg Gratings, Photosensitivity and Poling in Glass Waveguides (BGPP) and Nonlinear Photonics (NP) Topical Meeting and Tabletop Exhibit 2007 CY - Quebec City, Quebec, Canada DA - 2007-09-02 KW - Silica Fibre KW - Fibre Bragg Grating KW - Fibre Optic Sensor KW - Strain Sensor KW - FBG KW - Textile Fabric KW - Large Strain Application PY - 2007 SN - 1-55752-847-0 SP - 1 EP - 3 AN - OPUS4-16008 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Scheer, M. ED - Gerald Gerlach, ED - Peter Hauptmann, T1 - Faser-Bragg-Gitter-Sensoren überwachen Strahlung am Elektronenspeicherring BESSY II T2 - 8. Dresdner Sensor-Symposium CY - Dresden, Deutschland DA - 2007-12-10 KW - Faser-Bragg-Gitter KW - Fasersensoren KW - Strahlungssensoren KW - Strahlungseffekte KW - Strahlungsdosimetrie KW - Elektronenspeicherring PY - 2007 SN - 978-3-940046-45-1 N1 - Serientitel: Dresdner Beiträge zur Sensorik – Series title: Dresdner Beiträge zur Sensorik IS - 29 SP - 141 EP - 144 PB - TUDpress, Verlag der Wissenschaften GmbH CY - Dresden AN - OPUS4-16375 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grillet, A. A1 - Kinet, D. A1 - Witt, Jens A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Pirotte, F. A1 - Depré, A. T1 - Optical Fiber Sensors Embedded Into Medical Textiles for Healthcare Monitoring N2 - The potential impact of optical fiber sensors embedded into medical textiles for the monitoring of respiratory movements in a magnetic resonance imaging environment is presented. We report on three different designs, all textile based: a macrobending sensor, a Bragg grating sensor, and a time reflectometry sensor. In all three cases, the sensing principle is based on the measure of the elongation of the abdominal circumference during breathing movements. We demonstrate that the three sensors can successfully sense textile elongations between 0% and 3%, while maintaining the stretching properties of the textile substrates for a good comfort of the patients. KW - Fiber Bragg grating KW - Fiber-optic sensor KW - Mac-robending sensor KW - Medical textile KW - Medical resonance imaging (MRI) KW - Polymer fiber (POF) optical time domain reflectometry (OTDR) sensor PY - 2008 DO - https://doi.org/10.1109/JSEN.2008.926518 SN - 1530-437X SN - 1558-1748 VL - 8 IS - 7 SP - 1215 EP - 1222 CY - New York, NY, USA AN - OPUS4-17799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Scheer, M. T1 - Strahlungsüberwachung mit Faser-Bragg-Gitter-Sensoren am Elektronenspeicherring BESSY II N2 - Die Eignung von Faser-Bragg-Gitter-(FBG)-Sensoren zur Messung ionisierender Strahlung wurde an einem Undulator des Elektronenspeicherrings BESSY II untersucht. Über einen Zeitraum von 20 Wochen wurde eine durch Strahlung verursachte Bragg-Wellenlängenänderung der FBG-Sensoren von 25pm gemessen, was einer Strahlendosis von 720 Gy entspricht. The suitability of using fiber Bragg grating (FBG) sensors for the measurement of ionizing radiation on the electron storage ring BESSY II by measuring the Bragg wavelength shift caused by radiation was investigated. During a time period of 20 weeks a Bragg wavelength shift of 25pm caused by the ionizing radiation was measured by FBG sensors at the storage ring. This Bragg wavelength shift corresponds to a radiation dose value of 720 Gy. KW - Faseroptische Sensoren KW - Faser-Bragg-Gitter KW - Dosimetrie KW - Strahlungssensoren KW - Elektronenspeicherring KW - Fiber optic sensors KW - Fiber Bragg gratings KW - Radiation dosimetry KW - Radiation sensors KW - Electron storage ring PY - 2008 DO - https://doi.org/10.1524/teme.2008.0834 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 75 IS - 4 SP - 245 EP - 250 PB - Oldenbourg CY - München AN - OPUS4-17655 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Witt, Jens A1 - Schukar, Marcus A1 - Large, M. A1 - Thiel, T. T1 - Technology and Applications of Smart Technical Textiles Based on POF T2 - 17th International Conference on Plastic Optical Fibers (POF 2008), August 25-28, 2008 CY - Santa Clara, California, USA DA - 2008-08-25 KW - Fiber optic sensors KW - Polymer optical fibers (POF) KW - POF sensors KW - Smart technical textiles PY - 2008 SP - 1 EP - 10 AN - OPUS4-17870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Witt, Jens A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Polymeroptische Fasersensoren für die Atmungssensorik T2 - 19th International Scientific Conference Mittweida CY - Mittweida, Deutschland DA - 2008-11-05 KW - Faseroptischer Sensor KW - Medizinische Textilien KW - Intelligente Textilien KW - Atmungssensor KW - OTDR KW - POF KW - Mikrostrukturierte POF (mPOF) KW - Langperiodische Gitter (LPG) PY - 2008 SN - 1437-7624 SN - 1430-3698 IS - 5 SP - 21 EP - 25 CY - Mittweida AN - OPUS4-18404 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Witt, Jens A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Medizinische Textilien mit integrierten polymeroptischen Fasern zur Atmungssensorik KW - Atmungssensor KW - Intelligente Textilien KW - Faseroptischer Sensor KW - POF-Sensor KW - OTDR KW - Respiration sensor KW - Intelligent textile KW - Fiberoptic sensor KW - POF sensor KW - OTDR PY - 2008 DO - https://doi.org/10.1524/teme.2008.0905 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 75 IS - 12 SP - 1 EP - 8 PB - Oldenbourg CY - München AN - OPUS4-18587 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steffen, Milan A1 - Schukar, Marcus A1 - Witt, Jens A1 - Krebber, Katerina A1 - Large, M. A1 - Argyros, A. T1 - Investigation of MPOF-LPGs for sensing applications N2 - The versatility of MPOF offers a variety of sensing applications. In this paper the influence of strain, temperature and humidity is investigated. The results show that MPOF LPGs are well suited for strain sensing. Further investigations have to be made to clarify the behaviour on temperature and humidity in more detail. T2 - POF 2009 - 18th International conference on plastic optical fibers CY - Sydney, Australia DA - 2009-09-07 KW - Mikrostrukturierte Polymerfasern (MPOF) KW - Langperiodische Gitter (LPG) KW - Faseroptische Sensorik KW - Dehnungssensor KW - Klimatische Effekte PY - 2009 IS - Session 1 (S1_25) SP - 1 EP - 4 CY - Sydney, Australia AN - OPUS4-19887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Jens A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Jonckheere, J. de A1 - Paquet, B. A1 - Depré, A. T1 - Respiratory sensor based on POF OTDR N2 - We report on the characterization and test of a respiratory sensor based on POF OTDR, developed for monitoring of patients during MRI examination. The sensor is based on an optical fibre integrated into an elastic belt using a macrobending layout. T2 - POF 2009 - 18th International conference on plastic optical fibers CY - Sydney, Australia DA - 2009-09-07 KW - Faseroptischer Sensor KW - Medizinische Textilien KW - Intelligente Textilien KW - Atmungssensor KW - OTDR KW - POF PY - 2009 IS - Session 6 ( S6_74) SP - 1 EP - 4 CY - Sydney, Australia AN - OPUS4-19889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Large, M. A1 - Lwin, R. T1 - Climatic investigations of microstructured polymer optical fibers N2 - The behaviour of optical transmission of microstructured polymer optical fibers (MPOFs) by varying temperature and humidity was investigated whereas different MPOFs with varying hole structures and manufacturing procedures were used. T2 - POF 2009 - 18th International conference on plastic optical fibers CY - Sydney, Australia DA - 2009-09-07 KW - Mikrostrukturierte Polymerfasern (MPOF) KW - Klimatische Effekte KW - Faseroptische Sensorik KW - Langperiodische Gitter (LPG) PY - 2009 IS - Session 1 (S1_25) SP - 1 EP - 4 CY - Sydney, Australia AN - OPUS4-19916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Jens A1 - Steffen, Milan A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Investigation of sensing properties of microstructured polymer optical fibres N2 - We investigated sensing properties of single mode poly methyl methacrylate (PMMA) microstructured polymer optical fibres (MPOF) with mechanically imprinted long period gratings (LPG). After preparation of the MPOF end-faces the samples were elongated with silica fibres. These samples were used to measure the influence of strain to the LPG wavelength which showed the viscoelastic nature of PMMA. We also measured the influence of temperature and humidity. The results show that MPOF LPGs are well suited for strain sensing. One MPOF LPG was stitched to a textile. Using this textile we measured a simulated respiratory motion. T2 - Photonics Europe 2010: Nanophotonics and photonics materials CY - Brussels, Belgium DA - 2010-04-12 KW - Microstructured polymer optical fibre KW - Long period grating KW - Strain sensor KW - Humidity sensor KW - Temperature sensor KW - Respiratory sensor PY - 2010 SN - 978-0-8194-8206-8 DO - https://doi.org/10.1117/12.854656 SN - 0277-786X VL - 7714 IS - 7714-12 SP - 77140F-1 - 77140F-12 AN - OPUS4-21740 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 - Schukar, Marcus A1 - Wendt, Mario A1 - Witt, Jens A1 - Wosniok, Aleksander T1 - Technology and applications of smart technical textiles based on fibre optic sensors N2 - Technical textiles with embedded fibre optic sensors habe been developed for the purposes of the structural health monitoring in geotechnical and civil engineering as well as for healthcare monitoring in the medical sector. The paper shows selected examples of using such sensor-based smart textiles for different applications. T2 - International conference "Optical sensors" CY - Karlsruhe, Germany DA - 2010-06-21 PY - 2010 IS - STuC2.pdf SP - 1 EP - 2(?) AN - OPUS4-21567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Technology and Applications of Smart Technical Textiles Based on Fibre Optic Sensors T2 - OSA International Conference "Optical Sensors" CY - Karlsruhe, Germany DA - 2010-06-21 PY - 2010 AN - OPUS4-22074 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina A1 - Grillet, A. A1 - Witt, Jens A1 - Schukar, Marcus A1 - Kinet, D. A1 - Thiel, T. A1 - Pirotte, F. A1 - Depré, A. T1 - Optical fibre sensors embedded into technical textile for healthcare (ofseth) T2 - 16th International Conference on Plastic Optical Fibers (POF 2007) CY - Turin, Italy DA - 2007-09-10 PY - 2007 SP - 227 EP - 233 PB - International Cooperative of Plastic Optical Fibers (ICPOF) CY - Turin, Italy AN - OPUS4-15824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Optical fibre sensors embedded into technical textile for healthcare (OFSETH) T2 - POF 2007 CY - Turin, Italy DA - 2007-09-09 PY - 2007 AN - OPUS4-15805 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Smart technical textiles with integrated POF sensors T2 - SPIE Proceed of 15th Smart Structures/NDE International Symposium CY - San Diego, CA, USA DA - 2008-03-09 PY - 2008 AN - OPUS4-16753 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Witt, Jens A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Medical textiles for monitoring of respiratory movements by POF sensors T2 - OPTO 2008 - Photonic Metrology, 8th International Conference on Optical Technologies for Sensing and Measurement CY - Nürnberg, Germany DA - 2008-05-06 KW - POF KW - Fibre optic sensor KW - Medical textile KW - Respiration sensor KW - OTDR PY - 2008 SN - 978-3-9810993-3-1 IS - Chapter 4.2 SP - 99 EP - 104 AN - OPUS4-17475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Jens A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - Demuth, J. A1 - Sasek, L. T1 - Heart rate sensor for integration into personal protective equipment N2 - This paper reports on a fibre optic sensor for heart rate measurement which is developed within the framework of the FP7 EU project i-Protect. Goal is integration of the sensor into personal protective equipment Two different sensor prototypes based on polymer optical fibre (POF) were developed. One is based on long period gratings in microstrutured POF and the other one is based on macrobending effects in POF. T2 - POF 2011 - 20th International conference on plastic optical fibers CY - Bilbao, Spain DA - 14.09.2011 KW - Heart rate sensor KW - Long period grating KW - Macrobending sensor KW - Microstructured POF (mPOF) KW - Personal protective equipment (PPE) KW - Physiological sensor PY - 2011 SP - 1 EP - 5 AN - OPUS4-24500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Distributed POF Sensors - Recent Progress and New Challenges T2 - 19th International Conference on POF CY - Yokohama, Japan DA - 2010-10-19 PY - 2010 AN - OPUS4-22417 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Jens A1 - Narbonneau, F. A1 - Schukar, Marcus A1 - Krebber, Katerina A1 - De Jonckheere, J. A1 - Jeanne, M. A1 - Kinet, D. A1 - Paquet, B. A1 - Depré, A. A1 - D´Angelo, L.T. A1 - Thiel, T. A1 - Logier, R. ED - Santos, J.L. ED - Culshaw, B. ED - López-Higuera, J.M. ED - MacPherson, W.N. T1 - Smart medical textiles with embedded optical fibre sensors for continuous monitoring of respiratory movements during MRI N2 - We report on three respiration sensors based on pure optical technologies developed during the FP6 EU project OFSETH. The developed smart medical textiles can sense elongation up to 3%, while maintaining the stretching properties of the textile substrates for a good comfort of the patient. The sensors, based on silica and polymer fibre, are developed for monitoring of patients during MRI examination. The OFSETH harness allows a continuous measurement of respiration movements while all vitals organs are free for medical staff actions. The sensors were tested in MRI environment and on healthy adults. T2 - 4th European workshop on optical fibre sensors CY - Porto, Portugal DA - 2010-09-08 KW - Respiratory sensor KW - Fibre optic sensor KW - Optical time-domain reflectometry (OTDR) KW - MRI KW - Smart textile KW - Healthcare monitoring KW - Fibre Bragg grating (FBG) PY - 2010 SN - 978-0-8194-8083-5 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 7653 SP - Paper 115, 76533B-1 - 76533B-4 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-22552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Jens A1 - Steffen, Milan A1 - Schukar, Marcus A1 - Krebber, Katerina ED - Santos, J.L. ED - Culshaw, B. ED - López-Higuera, J.M. ED - MacPherson, W.N. T1 - Investigation of sensing properties of long period gratings based on microstructured polymer optical fibres N2 - We investigated the sensing properties of a single mode Poly Methyl Methacrylate (PMMA) Microstructured Polymer Optical Fibre (MPOF) with mechanically imprinted Long Period Grating (LPG). We measured the influence of strain to the LPG wavelength which showed the viscoelastic nature of PMMA. We also measured the influence of temperature and humidity to the LPG wavelength. T2 - 4th European workshop on optical fibre sensors CY - Porto, Portugal DA - 2010-09-08 KW - Microstructured polymer optical fibre KW - Long period grating KW - Strain sensor KW - Humidity sensor KW - Temperature sensor PY - 2010 SN - 978-0-8194-8083-5 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 7653 SP - Paper 112, 76530I-1 - 76530I-4 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-22553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilder, Constanze A1 - Schukar, Marcus A1 - Steffen, Milan A1 - Krebber, Katerina T1 - Structural health monitoring of composite structures by distributed fibre optic sensors N2 - Structural Health Monitoring of composite materials gains in importance with the increasing use of Composite structures for safety-related applications, e.g. in aerospace. Because of the material properties of composites, defects often occur inside the structures and raise the demand for integrated sensors. The advantages of optical fibres predestine them not only for the surface-application on composite structures but also for the Integration into composite structures. Even without quasi-distributed sensors such as FBGs or LPGs, the optical fibre itself can be used to measure the structure and occurring events over the entire fibre length by distributed sensing techniques. This paper presents the surface-application of polyimide coated silica optical fibres onto PEEK specimens and the integration of copper and polyimide coated silica optical fibres into an AS-4/PEEK Composite to be used as distributed fibre optic sensors for SHM. Results from distributed measurements by optical backscatter reflectometry based on Rayleigh backscattering are shown. T2 - 5th International symposium on NDT in aerospace CY - Singapore DA - 13.11.2013 KW - Structural health monitoring (SHM) KW - Composite structures KW - Optical fibre KW - Distributed fibre optic sensors KW - Optical backscatter reflectometry PY - 2013 SN - 1435-4934 SP - 1 EP - 7 AN - OPUS4-29687 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilder, Constanze A1 - Schukar, Marcus A1 - Steffen, Milan A1 - Krebber, Katerina ED - López-Higuera, J.M. ED - Jones, J. ED - López-Amo, M. ED - Santos, J.L. T1 - Evaluating distributed fibre optic sensors integrated into thermoplastic composites for structural health monitoring N2 - Strain sensors used for structural health monitoring (SHM) must provide reliable measurement data during their entire service lifetime. To achieve this for fibre optic sensors integrated into composites, the integration of the sensor has to be adapted according to the process conditions. This paper describes the fabrication of thermoplastic composite samples with integrated distributed fibre optic sensors (DFOS) based on copper-nickel and polyimide coated silica optical fibres. The performance of these DFOS as SHM sensors is evaluated in terms of reliability by measurements derived from comparative measurements with resistance strain gauges and from fatigue tests with 10 million load cycles. T2 - OFS2014 - 23rd International conference on optical fibre sensors CY - Santander, Spain DA - 02.06.2014 KW - Distributed fibre optic sensor KW - Integrated sensor KW - Reliability KW - Structural health monitoring KW - Strain gauge KW - Optical frequency domain reflectometry KW - Fatigue test PY - 2014 DO - https://doi.org/10.1117/12.2058604 SN - 0277-786X SN - 1996-756X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 9157 SP - 91575Q-1 - 91575Q-4 AN - OPUS4-30861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karapanagiotis, Christos A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Duffner, Eric A1 - Ulbricht, Alexander A1 - Prager, Jens A1 - Krebber, Katerina T1 - Structural health monitoring of hydrogen pressure vessels using distributed fiber optic sensing N2 - We report on distributed fiber optic sensing-based monitoring of hydrogen composite overwrapped pressure vessels (COPV) to simultaneously increase the operational lifespan and mitigate maintenance costs. Our approach represents, to the best of our knowledge, the first application of distributed fiber optic sensing for COPV Type IV monitoring, where the sensing fibers are attached to the surface, rather than integrated into the composite material. Specifically, we attach an optical fiber of 50 m to the pressure vessel's surface, covering both the cylindrical and dome sections. We note that our fiber optic sensing technique relies on swept wavelength interferometry providing strain information along the entire length of the optical fiber with high spatial resolution even at the millimeter scale. When the vessel is pressurized, the sensing optical fiber shows a linear strain response to pressure at every position along the fiber. After thousands of load cycles, the vessel finally fails with the optical fiber detecting and precisely localizing the damage in the vessel’s blind dome area. Furthermore, we discuss the potential of state-of-the-art signal processing methods and machine learning for advancing predictive maintenance. This could reduce the number of regular inspections, mitigate premature maintenance costs, and simultaneously increase the vessel’s remaining safe service life. We believe that the structural health monitoring of hydrogen pressure vessels with fiber optic sensors can enhance trust in hydrogen technology contributing to the energy transition in the future. T2 - 11th European Workshop on Structural Health Monitoring CY - Potsdam, Germany DA - 10.06.2024 KW - Hydrogen KW - Fiber optic sensors KW - Composites KW - Machine learning KW - Structural health monitoring PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602731 UR - https://www.ndt.net/search/docs.php3?id=29701 SP - 1 EP - 7 PB - NDT.net AN - OPUS4-60273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Jens A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Müller, Bernd R. A1 - Krebber, Katerina T1 - MPOF LPGs as radiation sensors N2 - We investigated to our knowledge for the first time the capabilities of long period gratings (LPG) in single-mode microstructured polymer optical fibre (mPOF) as real-time gamma dosimeter. The fibre is made from polymethyl methacrylate (PMMA) with a polycarbonate jacket. We measured the radiation-induced wavelength shift of the mPOF LPG loss feature wavelength and the radiation-induced attenuation of a mPOF for different wavelength between 600 nm and 800 nm for gamma radiation with an energy distribution between 6 keV and 18 keV. T2 - POF 2011 - 20th International conference on plastic optical fibers CY - Bilbao, Spain DA - 14.09.2011 KW - Microstructured polymer optical fibre (mPOF) KW - Long period grating (LPG) KW - Radiation sensor PY - 2011 SP - 1 EP - 3 AN - OPUS4-24499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Mihai, L. A1 - Sporea, D. A1 - Negut, D. A1 - Sturm, Heinz A1 - Schukar, Marcus A1 - Krebber, Katerina ED - Webb, D. J. ED - Scully, P. ED - Sugden, K. T1 - Impacts of gamma irradiation on cytop plastic optical fibres N2 - Impact of gamma radiation on transmission of a commercial Cytop polymer optical fibre (Lucina, Asahi Glass Company) is investigated. Spectral dependence of radiation induced attenuation in the investigated fibre is measured in the VIS-NIR spectral region. Besides attenuation increase, radiation is found to increase fibre susceptibility to water as well. While pristine Cytop fibre is rather humidity insensitive, strong humidity related absorption in the NIR region is observed after fibre irradiation. Selective irradiation of separate fibre sections is proposed as a way of fibre humidity sensitization and quasi-distributed water detection is demonstrated using optical time domain reflectometry at 1310 nm. T2 - POF 2016: 25th International Conference on Plastic Optical Fibres CY - Birmingham, UK DA - 13.09.2016 KW - Polymer optical fibers KW - Cytop KW - Gamma radiation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403216 SN - 9781854494085 SP - 114 EP - 117 CY - Birmingham AN - OPUS4-40321 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stajanca, Pavol A1 - Mihai, L. A1 - Sporea, D. A1 - Negut, D. A1 - Sturm, Heinz A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Effects of gamma radiation on perfluorinated polymer optical fibers N2 - The paper presents the first complex study of Gamma radiation effects on a low-loss perfluorinated polymer optical fiber (PF-POF) based on Cytop® polymer. Influence of gamma radiation on fiber’s optical, mechanical and climatic performance is investigated. The radiation-induced attenuation (RIA) in the visible and near-infrared region (0.4 μm-1.7 mm) is measured and its origins are discussed. Besides attenuation increase, radiation is also shown to decrease the thermal degradation stability of the fiber and to increase its susceptibility to water. With regard to complex fiber transmission performance upon irradiation, the optimal operation wavelength region of PF-POF-based systems intended for use in Radiation environments is determined to be around 1.1 μm. On the other hand, the investigated fiber holds potential for low-cost RIA-based optical fiber dosimetry applications with sensitivity as high as 260 dBm⁻¹/kGy in the visible region. KW - Perfluorinated polymer optical fibers KW - Cytop KW - Gamma radiation KW - Radiation-induced attenuation PY - 2016 DO - https://doi.org/10.1016/j.optmat.2016.05.027 SN - 0925-3467 VL - 58 SP - 226 EP - 233 PB - Elsevier AN - OPUS4-36462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Wavelength-scanning distributed acoustic sensing for structural monitoring and seismic applications N2 - We introduce wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) for dynamic vibration sensing along optical fibers. The method is based on spectral shift computation from Rayleigh backscatter spectra. Artificial neural networks (ANNs) are used for fast and high-resolution strain computation from raw measurement data. The applicability of the method is demonstrated for vibration monitoring of a reinforced concrete bridge. We demonstrate another application example for quasi-static and dynamic measurement of ground deformation and surface wave propagation along a dark fiber in a telecommunication cable. T2 - 7th International Symposium on Sensor Science CY - Napoli, Italy DA - 09.05.2019 KW - Optical fiber sensor KW - Distributed acoustic sensor (DAS) KW - Optical time domain reflectometry KW - Rayleigh scattering KW - Artificial neural networks KW - Structural health monitoring KW - Seismic measurement PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487733 DO - https://doi.org/10.3390/proceedings2019015030 SN - 2504-3900 VL - 15 SP - Paper 30, 1 EP - 5 PB - MDPI CY - Basel AN - OPUS4-48773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kapa, Thomas A1 - Schreier, Andy A1 - Krebber, Katerina T1 - A 100-km BOFDA Assisted by First-Order Bi-Directional Raman Amplification N2 - We present, to our knowledge for the first time, a 100-km Brillouin Optical Frequency-Domain Analysis (BOFDA) employing a 200-km fiber loop. Compared to our previous publication, enhanced sensor length, sensor accuracy and spatial resolution are presented. The performance improvements are achieved by applying distributed Raman amplification (DRA) and a digital high-pass filter. We report on temperature measurements over sensing distances of 75 km and 100 km both with a 12.5-m spatial resolution. Temperature changes of 5 °C have been measured along 75 km sensing fiber. A temperature change of 30 °C has been detected at 99.5 km. KW - Distributed sensing KW - Fiber optics sensors KW - Stimulated Brillouin scattering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476577 DO - https://doi.org/10.3390/s19071527 SN - 1424-8220 VL - 19 IS - 7 SP - 1527, 1 EP - 9 PB - MDPI CY - Basel, Switzerland AN - OPUS4-47657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Smart Geosynthetics Based on Distributed Fiber Optic Sensors in Geotechnical Engineering N2 - Smart geosynthetics with embedded optical fibers as distributed sensors provide solutions both for applications in geotechnical engineering and for cost-effective monitoring of critical infrastructures. The incorporation of glass or polymer optical fibers (GOFs or POFs) in geotextiles and geogrids allows early detection of mechanical deformations, temperature and humidity. This paper presents selected examples of smart geosynthetics based on Brillouin and Rayleigh scattering effects in incorporated fiber optic sensors for monitoring of large geotechnical structures like dikes, dams, railways, embankments or slopes. The focus of the presented work is on real field tests of measurement capability with respect to the chosen measurement principle and used fiber type. KW - Polymer optical fiber (POF) KW - Smart geosynthetics KW - Fiber optic sensor KW - Distributed sensing KW - Glass optical fiber (GOF) PY - 2019 SN - 0046-5828 SP - 91 EP - 95 PB - Southeast Asian Geotechnical Society CY - Bangkok AN - OPUS4-48068 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreier, Andy A1 - Liehr, Sascha A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Comparison of solution approaches for distributed humidity sensing in perfuorinated graded-index polymer optical fibers N2 - We compare four different sensing solutions suitable for distributed fiber optic humidity sensing in per uorinated graded-index polymer optical fibers (PFGI-POFs). Compared to silica fbers, polymer optical fibers over advantageous beneffits including signifficantly higher break down strain, fracture toughness and humidity sensitivity. Various humidity-related effects in PFGI-POFs have been reported in the last years including measured attenuation and length changes as well as Brillouin frequency and Bragg wavelength shifts. The four aforementioned methods could serve as a basis for distributed and quasi-distributed humidity sensing and are described here closely with an emphasis on plausible cross effects to temperature and strain. The main focus of this paper lies on the comparison of four approaches with regard to method complexity, sensitivity to humidity, spatial resolution, real-time capability and effort to compensate for cross effects. T2 - SPIE Optics + Optoelectronics CY - Prague, Czech Republic DA - 01.04.2019 KW - Distributed sensing KW - Humidity KW - Polymer optical fibre PY - 2019 SN - 978-1-5106-2723-9 DO - https://doi.org/10.1117/12.2522307 SN - 0277-786X SN - 1996-756X SP - 1102808-1 EP - 1102808-9 PB - SPIE AN - OPUS4-47844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stajanca, Pavol A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Distributed Fiberoptic Sensor for Simultaneous Humidity and Temperature Monitoring Based on Polyimide-Coated Optical Fibers N2 - Along temperature, humidity is one of the principal environmental factors that plays an important role in various application areas. Presented work investigates possibility of distributed fiberoptic humidity monitoring based on humidity-induced strain measurement in polyimide (PI)-coated optical fibers. Characterization of relative humidity (RH) and temperature response of four different commercial PI- and one acrylate-coated fiber was performed using optical backscattering reflectometry (OBR). The study addresses issues of temperature-humidity cross sensitivity, fiber response stability, repeatability, and the influence of annealing. Acrylate-coated fiber exhibited rather unfavorable nonlinear RH response with strong temperature dependence, which makes it unsuitable for humidity sensing applications. On the other hand, humidity response of PI-coated fibers showed good linearity with fiber sensitivity slightly decreasing at rising temperatures. In the tested range, temperature sensitivity of the fibers remained humidity independent. Thermal annealing was shown to considerably improve and stabilize fiber RH response. Based on performed analysis, a 20 m sensor using the optimal PI-coated fibers was proposed and constructed. The sensor uses dual sensing fiber configuration for mutual decoupling and simultaneous measurement of temperature and RH variations. Using OBR, distributed dual temperature-RH monitoring with cm spatial resolution was demonstrated for the first time. KW - Distributed humidity sensing KW - Fiberoptic sensors KW - Polyimide-coated optical fibers KW - Optical frequency-domain reflectometry KW - Dual sensing PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498871 DO - https://doi.org/10.3390/s19235279 VL - 19 IS - 23 SP - 5279 PB - MDPI AN - OPUS4-49887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Schreier, Andy A1 - Krebber, Katerina T1 - Distributed BOFDA measurement on an 86 m long perfluorinated polymer optical fiber N2 - We present our research on the development of a Brillouin optical frequency-domain analysis (BOFDA) using a perfluorinated graded-index polymer optical fiber (PFGI-POF) as a sensing fiber. The described works include investigations both on the selection of the setup components with respect to mode coupling effects and on the impact of the humidity cross-sensitivity. The suitability of the developed POF-based BOFDA is proved by a distributed measurement on an 86 m long PFGI-POF recorded with the spatial resolution of 6 m. T2 - 28th International Conference on Plastic Optical Fibers CY - Yokohama, Japan DA - 20.11.2019 KW - Brillouin sensing KW - BOFDA KW - Perfluorinated graded-index polymer optical fiber KW - PFGI-POF PY - 2019 SP - 27 EP - 28 AN - OPUS4-49865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hicke, Konstantin A1 - Chruscicki, Sebastian A1 - Krebber, Katerina ED - Kalli, K. ED - O'Keeffe, S. O. ED - Brambilla, G. T1 - Real-time distributed temperature gradient sensing using amplitude-based C-OTDR and sensing fiber with inscribed scattering dots N2 - We present a technique for distributed temperature gradient sensing in real-time along an optical fiber utilizing simple amplitude-based direct-detection coherent optical time domain reflectometry (C-OTDR) and a special sensing fiber. Our technique enables us to determine phase changes or low-frequency variations of the C-OTDR signal stemming from temperature variations. The distinct feature of the used sensing fiber is its structuring with equidistant strongly scattering dots. Consecutive pairs of these scatterers form the dominant local interferometers, effectively overwriting the otherwise highly nonlinear transfer function of common optical fiber. This enables a quasi-phase-resolved evaluation of perturbation responses originating from temperature changes at sensor positions between the scatterers. Using our method, we show the measurement of a nonlinear temperature transient from a heating process with a maximum temperature gradient of 0.8 °C over 20 s and a total temperature increase of 28.4 °C. This method requires almost no post-processing and can be used for simultaneous distributed vibration sensing (DVS) and quantification of local temperature gradients in a single fiber, e.g., for the use in condition monitoring of infrastructure or industrial installations. T2 - Seventh European Workshop on Optical Fibre Sensors, 2019 CY - Limassol, Cyprus DA - 01.10.2019 KW - C-OTDR KW - DVS KW - Distributed vibration sensing KW - Distributed temperature gradient sensing KW - Fibre optic sensors KW - Structured fiber KW - Power cable monitoring PY - 2019 SN - 978-1-51063-123-6 DO - https://doi.org/10.1117/12.2539925 VL - 11199 SP - 1119920-1 EP - 1119920-4 PB - SPIE CY - Bellingham, WA, USA AN - OPUS4-49926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Stajanca, Pavol A1 - Krebber, Katerina ED - Kalli, K. ED - Brambilla, G. ED - O'Keeffe, S. T1 - Investigation of bare and tight-buffered optical fibers towards distributed humidity sensing N2 - Humidity is one of principal environmental parameters that plays an important role in various application areas. Using measurement of strain induced in an optical fiber by a water swellable coating represents a promising approach for realization of distributed humidity sensing (DHS). In this work, humidity and temperature response of four different commercial PI-coated fibers and four tight-buffered (TB) fibers is investigated with the aim of evaluating their potential for development of DHS in context of water ingress sensor for high-voltage power cable splices. PI-coated fibers exhibited close-to-linear humidity and temperature response. While the temperature response is relatively coating-independent, magnitude of humidity response was broadly correlated to the relative fiber-to-coating thickness ratio. In contrast, both humidity and temperature response of TB fibers is strongly influenced by buffer type, with Leoni TB900L fiber with Hytrel buffer exhibiting largest humidity and temperature sensitivity. While the response of tight-buffered fibers is generally nonlinear, roughly three-times higher humidity response can be achieved with TB900L compared to the most sensitive PI-coated fiber. Using the TB fiber can be, therefore, advantageous for simpler water detection applications, such as one targeted in this study, when larger sensitivity is more important than the linear response of the sensor. KW - Distribute fiberoptic sensor KW - Distributed humidity sensing KW - Water ingress detection KW - Optical backscatter reflectometry KW - Tight-buffered fibers KW - Polyimide-coated fibers PY - 2019 SN - 978-1-51063-124-3 DO - https://doi.org/10.1117/12.2539819 VL - 11199 SP - 111991X-1 PB - SPIE CY - Bellingham, Washington, USA AN - OPUS4-49207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fuggini, C. A1 - Zangani, D. A1 - Wosniok, Aleksander A1 - Krebber, Katerina A1 - Franitza, P. A1 - Gabino, L. A1 - Weigand, F. T1 - Innovative approach in the use of geotextiles for failures prevention in railway embankments N2 - Maintenance and renewal costs of a typical railway, track and substructure represents 50–60% of the total costs of such infrastructure over its entire service life. Innovations in track and substructure are therefore fundamental to achieve a significant impact on the overall cost reduction for the railways. Therefore new solutions for track improvements that are effective and that can minimize the interruption of traffic are needed. Moreover, failures of railway embankments happened recently in different regions of the world. Such events, such as the one happened in UK in February 2013 (http://www.bbc.co.uk/news/uk-england-south-yorkshire-21441070), are showing the importance of monitoring track and infrastructure coupled with the use of numerical models for the localization of the critical areas and the design of appropriate countermeasures. Indeed embankment failures, landslides and uneven settlements and similar events are becoming much more common than in the past due to climate changes, and this requires the infrastructure managers to look from a different perspective infrastructure maintenance issues. What was previously consider as “extreme” is now “common” and thus actions need to be taken to be ready when such events will happen. The aim is to mitigate their effects on the infrastructure and to minimize disruptions to train services and reduce maintenance costs to restore the normal service conditions. If this mental change happens, then the need for solutions and techniques for global asset monitoring and ground stabilization will probably increase. Among the others, geotextiles and geogrids for soil reinforcement used in combination with condition monitoring techniques have the potential for minimizing catastrophic events, whilst at the same time providing a good balance among costs and benefits (i.e. sustainability). The paper describe a case study where the use of multifunctional geotextiles, able to provide both strengthening and monitoring functions, has been tested along a railroad near the city of Chemnitz (Germany). The results are here reported to show the potential use and the innovative aspect of this solution. T2 - 6th Transport Research Arena (TRA) CY - Warsaw, Poland DA - 18.04.2016 KW - smart geotextile KW - failure prevention KW - railway embankment KW - fiber optic sensor KW - distributed sensor PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379256 DO - https://doi.org/10.1016/j.trpro.2016.05.154 VL - 14 SP - 1875 EP - 1883 PB - Elsevier B.V. AN - OPUS4-37925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Breithaupt, Mathias A1 - Krebber, Katerina T1 - Distributed humidity sensing in PMMA optical fibers at 500 nm and 650 nm wavelengths N2 - Distributed measurement of humidity is a sought-after capability for various fields of application, especially in the civil engineering and structural health monitoring sectors. This article presents a method for distributed humidity sensing along polymethyl methacrylate (PMMA) polymer optical fibers (POFs) by analyzing wavelength-dependent Rayleigh backscattering and attenuation characteristics at 500 nm and 650 nm wavelengths. Spatially resolved humidity sensing is obtained from backscatter traces of a dual-wavelength optical time domain reflectometer (OTDR). Backscatter dependence, attenuation dependence as well as the fiber length change are characterized as functions of relative humidity. Cross-sensitivity effects are discussed and quantified. The evaluation of the humidity-dependent backscatter effects at the two wavelength measurements allows for distributed and unambiguous measurement of relative humidity. The technique can be readily employed with low-cost standard polymer optical fibers and commercial OTDR devices. KW - Optical fiber sensor KW - Humidity sensor KW - Distributed sensor KW - Polymer optical fiber KW - Rayleigh scattering PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396363 UR - http://www.mdpi.com/1424-8220/17/4/738 DO - https://doi.org/10.3390/s17040738 SN - 1424-8220 VL - 17 IS - 4 SP - Article 738, 1 EP - 12 PB - MDPI CY - Basel, Switzerland AN - OPUS4-39636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Radiation-induced attenuation of perfluorinated polymer optical fibers for radiation monitoring N2 - Due to some of their unique properties, optical fiber dosimeters are attractive and extensively researched devices in several radiation-related areas. This work evaluates the Performance and potential of commercial perfluorinated polymer optical fibers (PF-POFs) for radiation Monitoring applications. Gamma radiation-induced attenuation (RIA) of two commercial PF-POFs is evaluated in the VIS spectral region. Influence of a dose rate and temperature on RIA measurement is investigated, along with defect stability and measurement repeatability. Co-extruded PF-POFs are identified as more suitable for radiation monitoring applications due to lower dose-rate dependence. With co-extruded PF-POF, RIA measurement holds potential for highly-sensitive radiation Monitoring with good reproducibility. The results show that operation in the blue part of the spectrum provides most favorable performance in terms of the largest nominal Radiation sensitivity, lower temperature, and dose-rate dependence as well as higher defect stability. We demonstrate for the first time to our knowledge, that PF-POFs can be used for distributed detection of radiation with doses down to tens of Grays. The off-the-shelf, user-friendly PF-POF could be of interest as a cheap, disposable sensor for various applications, especially of a more qualitative nature. KW - Perfluorinated polymer optical fiber KW - Cytop KW - Ionizing radiation KW - Radiation-induced attenuation KW - Gamma radiation monitoring PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419504 DO - https://doi.org/10.3390/s17091959 SN - 1424-8220 VL - 17 IS - 9 SP - Article 1959, 1 EP - 12 PB - MDPI AN - OPUS4-41950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fasano, A. A1 - Woyessa, G. A1 - Stajanca, Pavol A1 - Markos, C. A1 - Stefani, A. A1 - Nielsen, K. A1 - Rasmussen, H. K. A1 - Krebber, Katerina A1 - Bang, O. T1 - Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors N2 - Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C. We also characterize the mPOF optically and mechanically, and further test the sensitivity of the PC FBG to strain and temperature. We demonstrate that the PC FBG can bear temperatures as high as 125°C without malfunctioning. In contrast, polymethyl methacrylate-based FBG technology is generally limited to temperatures below 90°C. KW - Fiber optics sensors KW - Fiber Bragg gratings KW - Microstructured fibers KW - Fiber characterization KW - Polymers PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355591 DO - https://doi.org/10.1364/OME.6.000649 SN - 2159-3930 VL - 6 IS - 2 SP - 649 EP - 659 PB - OSA Publishig AN - OPUS4-35559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Krebber, Katerina ED - Harun, S.W. ED - Arof, H. T1 - Smart technical textiles based on fiber optic sensors N2 - Smart technical textiles are by definition textiles that can interact with their environment. They can sense and react to environmental conditions and external stimuli from mechanical, thermal, chemical or other sources. Such textiles are multifunctional or even “intelligent” which is fulfilled by a number of sensors incorporated in the textiles. The embedded sensors are sensitive to various parameters such as temperature, strain, chemical, biological and other substances. PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-289397 SN - 978-953-51-1148-1 DO - https://doi.org/10.5772/54244 IS - Section 3 / Chapter 12 SP - 319 EP - 344 PB - InTech AN - OPUS4-28939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Krebber, Katerina T1 - Application of quasi-distributed and dynamic length and power change measurement using optical frequency domain reflectometry N2 - Application results of a dynamic technique for simultaneous measurement of length changes and optical power changes between multiple reflection points in an optical fiber are presented. The technique is based on incoherent optical frequency domain reflectometry (I-OFDR) and allows for measuring for example length changes and optical power changes quasi-distributed at repetition rates up to 2 kHz. Precise measurement with length change resolutions in the µm-range can be conducted using standard single-mode or multi-mode fibers. Previous results of dynamic refractive index change measurement and the use of polymer optical fibers for high-strain measurement are concluded and possible sources of measurement inaccuracies are discussed. Field test results with sensors installed on a masonry building during a seismic shake test are presented. The versatility and simplicity of this technique makes it potentially interesting for application in the structural health monitoring sector and chemical process control. KW - Distributed strain sensor KW - Dynamic measurement KW - Optical fiber sensor KW - Refractive index sensors KW - Structural health monitoring PY - 2012 DO - https://doi.org/10.1109/JSEN.2011.2157126 SN - 1530-437X SN - 1558-1748 VL - 12 IS - 1 SP - 237 EP - 245 CY - New York, NY, USA AN - OPUS4-25565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina A1 - Liehr, Sascha A1 - Witt, Jens ED - Liao, Y. ED - Jin, W. ED - Sampson, D.D. ED - Yamauchi, R. ED - Chung, Y. ED - Nakamura, K. ED - Rao, Y. T1 - Smart technical textiles based on fiber optic sensors N2 - Smart technical textiles containing fiber optic sensors have been developed and successfully demonstrated for the purposes of the structural health monitoring in geotechnical and civil engineering as well as for healthcare monitoring in the medical sector. The paper highlights the results achieved in this innovative field in the framework of several German and European projects and shows selected examples of using such fiber-sensor-based technical textiles in different geotechnical and medical applications. T2 - OFS2012 - 22nd International conference on optical fiber sensors CY - Beijing, China DA - 15.10.2012 KW - Fiber optic sensor KW - Distributed fiber optic sensor KW - Polymer optical fibers (POF) KW - POF sensor KW - POF OTDR KW - Technical textiles KW - Geotextiles KW - Medical textiles PY - 2012 DO - https://doi.org/10.1117/12.981342 SN - 0277-786X SN - 1996-756X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 8421 SP - 84212A-1 EP - 84212A-10 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-26915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Smart Technical Textiles Based on Fibre Optic Sensors (invited lecture) T2 - 22nd International Conference on Optical Fiber Sensors (OFS-22) CY - Beijing, China DA - 2012-10-15 PY - 2012 AN - OPUS4-26907 LA - deu 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 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 - 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 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. N2 - 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 - CONF A1 - Mizuno, Y. A1 - Lenke, Peter A1 - Krebber, Katerina A1 - Nakamura, K. T1 - Brillouin gain spectrum characterization in POF fabricated by different manufacturers at 1.32 and 1.55 um N2 - The Brillouin gain spectra (BGS) in perfluorinated graded-index polymer optical fibers (PFGl-POFs) are characterized at 1.32 and 1.55 pm. Three kinds of PFGl-POFs with the same core diameter but fabricated by different manufacturers are tested. For all the PFGl-POFs, the Stokes power measured at 1.32 pm is higher than that at 1.55 pm eine to the lower propagation loss, but significant difference in Stokes power is observed among the three. Based on the measurement by optical time-domain reflectometry, we show that the actual Propagation loss of the PFGl-POFs plays a crucial role in observing BGS. T2 - POF 2012 - 21st International conference on plastic optical fibers CY - Atlanta, Georgia, USA DA - 10.09.2012 KW - Brillouin scattering KW - Perfluorinated graded-index polymer optical fiber KW - Optical time-domain reflectometry KW - Nonlinear optics PY - 2012 SP - 96 EP - 99 AN - OPUS4-26742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Burgmeier, J. A1 - Krebber, Katerina A1 - Schade, W. ED - Liao, Y. ED - Jin, W. ED - Sampson, D.D. ED - Yamauchi, R. ED - Chung, Y. ED - Nakamura, K. ED - Rao, Y. T1 - Fiber optic bend and temperature sensing in femtosecond laser-structured POF N2 - We propose focused femtosecond laser irradiation to create stable and permanent scattering damage in large-core polymer optical fibers. Possible sensing applications using optical time domain reflectometry are discussed and presented. Experiments show that quasi-distributed fiber bend sensors and absolute temperature sensors can be realized by evaluating backscatter intensities. T2 - OFS2012 - 22nd International conference on optical fiber sensors CY - Beijing, China DA - 15.10.2012 KW - Polymer optical fiber KW - POF KW - Optical fiber sensors KW - Bend sensor KW - Temperature sensor KW - Femtosecond laser KW - OTDR KW - Reflectometry PY - 2012 DO - https://doi.org/10.1117/12.976051 SN - 0277-786X SN - 1996-756X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 8421 SP - 84213I-1 EP - 84213I-4 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-27221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -