TY - JOUR A1 - Liehr, Sascha A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Wavelength-scanning coherent OTDR for dynamic high strain resolution sensing N2 - Distributed vibration sensing in optical fibers opened entirely new opportunities and penetrated various sectors from security to seismic monitoring. Here, we demonstrate a most simple and robust approach for dynamic strain measurement using wavelength-scanning coherent optical time domain reflectometry (C-OTDR). Our method is based on laser current modulation and Rayleigh backscatter shift correlation. As opposed to common single-wavelength phase demodulation techniques, also the algebraic sign of the strain change is retrieved. This is crucial for the intended applications in structural health monitoring and modal analysis. A linear strain response down to 47.5 pε and strain noise of 100 pε/√Hz is demonstrated for repetition rates in the kHz range. A field application of a vibrating bridge is presented. Our approach provides a cost-effective high-resolution method for structural vibration analysis and geophysical applications. KW - Fiber optics sensors KW - Optical time domain reflectometry KW - Rayleigh Scattering KW - Distributed acoustic sensing KW - Distributed strain sensing PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448069 DO - https://doi.org/10.1364/OE.26.010573 SN - 1094-4087 VL - 26 IS - 8 SP - 10573 EP - 10588 PB - Optical Society of America AN - OPUS4-44806 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Smart geosynthetics for structural health monitoring applications N2 - Responding to a growing need for intelligent monitoring of critical geotechnical and civil infrastructures, new multifunctional geotextiles and geogrids with integrated optical fibers were developed and investigated within several research projects. Such smart two-dimensional geosynthetics intercorporating optical fibers as distributed sensors provide solutions both for soil reinforcement, erosion control, drainage or environmental protection and for cost-effective monitoring of critical mechanical deformations and temperature distribution in geotechnical and masonry structures at the same time. The integrated fiber optic sensors provide online information about the condition of the monitored structure and about the occurrence and localization of any damage or degradation for the purpose of preventing a total collapse. T2 - The Fiber Society's Spring 2017 Conference CY - Institut für Textiltechnik der RWTH Aachen, Germany DA - 17.05.2017 KW - Smart geosynthetics KW - Sensor-based geotextiles KW - Fiber optic sensor KW - POF sensor KW - Distributed sensing PY - 2017 SP - 43 AN - OPUS4-42560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina ED - Nogueira, R. ED - Rocha, A. M. T1 - Polymer optical fibers as radiation sensors? N2 - Application importance of ionizing radiation has been growing steadily over the last decades. Extensive utilization of ionizing radiation generates demand for development of suitable monitoring techniques. Radiation monitoring systems based on optical fibers offer several key advantages such as small footprint, possibility of remote and real-time measurement as well as electromagnetic immunity. In this contribution, we investigate radiation-induced attenuation (RIA)-based sensing with perfluorinated polymer optical fibers (PF-POFs). The RIA response of two commercial PF-POFs is assessed in a low dose region and performance and limitations of the system are discussed. The concept represents a potential high-sensitivity, low-cost and easy-to-use on-line radiation monitoring system with distributed detection capability T2 - 26thth International Conference on Plastic Optical Fibres (POF 2017) CY - Aveiro, Portugal DA - 13.09.2017 KW - Perfluorinated polymer optical fibers KW - Gamma radiation KW - Radiation monitoring KW - Optical fiber sensor PY - 2017 SN - 978-989-97345-2-4 SP - Paper 5, 1 EP - 4 AN - OPUS4-42318 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina ED - Nogueira, R. ED - Rocha, A. M. T1 - Post-fabrication cladding doping of commercial PMMA polymer optical fiber N2 - Possibility of post-fabrication doping of commercial PMMA fibers using well-known solution doping technique is presented. The cladding of 1 mm PMMA fiber is doped with Rhodamine B with the help of methanol-mediated diffusion of the dye molecules into the fiber material. Doping of the fiber core was not possible even at extended doping times. The proposed method represents rather simple and cheap way for preparing custom cladding-doped POFs with high flexibility of dopant choice and fiber length. Produced cladding-doped fibers have potential for various sensing or lighting applications. T2 - 26th International Conference on Plastic Optical Fibres (POF 2017) CY - Aveiro, Portugal DA - 13.09.2017 KW - Polymer optical fibers KW - Fluorescent dyes KW - Solution doping KW - Polymethyl methacrylate PY - 2017 SN - 978-989-97345-2-4 SP - Paper 14, 1 EP - 4 AN - OPUS4-42319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schreier, Andy A1 - Liehr, Sascha A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Investigation on the influence of humidity on stimulated Brillouin backscattering in perfluorinated polymer optical fibers N2 - In this paper perfluorinated graded-index polymer optical fibers are characterized with respect to the influence of relative humidity changes on spectral transmission absorption and Rayleigh backscattering. The hygroscopic and thermal expansion coefficient of the fiber are determined to be CHE = (7.4 +/- 0.1) 10^-6 %r.h.^-1 and CTE = (22.7 +/- 0.3) 10^-6 K^-1, respectively. The influence of humidity on the Brillouin backscattering power and linewidth are presented for the first time to our knowledge. The Brillouin backscattering power at a pump wavelength of 1319 nm is affected by temperature and humidity. The Brillouin linewidth is observed to be a function of temperature but not of humidity. The strain coefficient of the BFS is determined to be CS = (146.5 +/- 0.9) MHz/% for a wavelength of 1319 nm within a strain range from 0.1 % to 1.5 %. The obtained results demonstrate that the humidity-induced Brillouin frequency shift is predominantly caused by the swelling of the fiber over-cladding that leads to fiber straining. KW - Brillouin KW - Polymer optical fibre KW - Humidity PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465932 DO - https://doi.org/10.3390/s18113952 SN - 1424-8220 VL - 18 IS - 11 SP - 3952, 1 EP - 12 PB - MDPI CY - Basel, Switzerland AN - OPUS4-46593 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Krebber, Katerina A1 - Glötzl, R. ED - Boller, C. T1 - Temperature-corrected determination of mechanical deformations in geotechnical structures using Brillouin-based fiber optic sensors N2 - Structural Health Monitoring based on distributed Brillouin measuring techniques has been playing bigger and bigger role for applications in large-scale critical structures over the last decade. The Brillouin sensing techniques make use of low-loss single-mode optical fibers as distributed sensors allowing compound strain and temperature profile discrimination along the measured section even over several tens of kilometers. Thereby, the measured Brillouin frequency shift (BFS) features much stronger dependence on the longitudinal strain in the sensor fiber than on the temperature distribution along the fiber optic sensor. By detection of slight structural changes in monitored civil structures, such as dams, pipelines and tunnels, the influence of temperature on the measured BFS cannot be neglected. In simple cases of fiber optic sensors embedded deeply enough into earth structures no significant temperature gradients caused by weather conditions such as sunrays could be observed. The temperature contributes here only to the signal offset and the local mechanical deformations arisen due to soil displacement can be read directly from the distribution of the BFS. Also special cable solutions for separate determination of temperature and strain have been tested by us under field conditions. The use of two separate optical fibers for strain and temperature detection limits the spatial resolution and measurement accuracy in the determination of both physical quantities. In search of the optimal sensory solution for monitoring of mechanical deformations taking into account the temperature component in the measured signal the use of so called nonzero dispersion-shifted fibers has been investigated in several laboratory tests. Due to different doping concentration in the core new resonance acoustic modes can propagate in such optical fibers which results in multipeak structure in the Brillouin gain spectrum (BGS). The appearance of more than one resonance peak in the BGS offers the possibility to realize simultaneous measurement of longitudinal strain and temperature by analysis of applicable BFSs as function of both physical quantities using only one low cost optical fiber. T2 - EWSHM'12 - 6th European workshop on structural health monitoring 2012 CY - Dresden, Germany DA - 03.07.2012 KW - Structural health monitoring KW - Brillouin scattering KW - Distributed sensor PY - 2012 SN - 978-3-940283-41-2 VL - 1 SP - 417 EP - 422 CY - Berlin AN - OPUS4-26311 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Eine Sammlung durch Maschinelles Lernen unterstützter Verteilter Faseroptischer Sensoren für Infrastrukturmonitoring T1 - A collection of machine learning assisted distributed fiber optic sensors for infrastructure monitoring N2 - In this paper, we present a collection of machine learning assisted distributed fiber optic sensors (DFOS) for applications in the field of infrastructure monitoring. We employ advanced signal processing based on artificial neural networks (ANNs) to enhance the performance of the dynamic DFOS for strain and vibration sensing. Specifically, ANNs in comparison to conventional and computationally expensive correlation and linearization algorithms, deliver lower strain errors and speed up the signal processing allowing real time strain monitoring. Furthermore, convolutional neural networks (CNNs) are used to denoise the dynamic DFOS signal and enable useable sensing lengths of up to 100 km. Applications of the machine learning assisted dynamic DFOS in road traffic and railway infrastructure monitoring are demonstrated. In the field of static DFOS, machine learning is applied to the well-known Brillouin optical frequency domain analysis (BOFDA) system. Specifically, CNN are shown to be very tolerant against noisy spectra and contribute towards significantly shorter measurement times. Furthermore, different machine learning algorithms (linear and polynomial regression, decision trees, ANNs) are applied to solve the well-known problem of cross-sensitivity in cases when temperature and humidity are measured simultaneously. The presented machine learning assisted DFOS can potentially contribute towards enhanced, cost effective and reliable monitoring of infrastructures. N2 - In diesem Beitrag stellen wir eine Sammlung von verteilten faseroptischen Sensoren (DFOS) vor, die mit Hilfe von Maschinellem Lernen arbeiten und für Anwendungen im Bereich der Infrastrukturüberwachung geeignet sind. Wir setzen hierbei fortschrittliche Signalverarbeitung auf der Grundlage Künstlicher Neuronaler Netze ein, um die Leistungsfähigkeit dynamischer DFOS für die Messung von Dehnungen und Vibrationen zu verbessern. Insbesondere Künstliche Neuronale Netze (ANNs) liefern im Vergleich zu konventionellen und rechenintensiven Korrelations- und Linearisierungsalgorithmen geringere Dehnungsfehler und beschleunigen die Signalverarbeitung, so dass eine Dehnungsüberwachung in Echtzeit möglich ist. Darüber hinaus wenden wir Convolutional Neural Networks (CNNs) an, um dynamische DFOS-Signale zu entrauschen und damit nutzbare Messlängen von bis zu 100 km zu ermöglichen. Es werden Anwendungsbeispiele dieser durch Maschinelles Lernen unterstützten dynamischen DFOS in den Bereichen des Straßenverkehrsmonitorings und der Zug- und Gleisüberwachung aufgezeigt. Im Bereich der statischen DFOS wird Maschinelles Lernen auf das Verfahren der Optischen Brillouin-Frequenzbereichsanalyse (BOFDA) angewendet. Insbesondere CNN erweisen sich hier als sehr robust gegenüber verrauschten Spektren und tragen zu deutlich kürzeren Messzeiten bei. Darüber hinaus werden verschiedene Algorithmen des maschinellen Lernens (lineare und polynome Regression, Entscheidungsbäume, ANNs) angewandt, um das bekannte Problem der Querempfindlichkeit bei DFOS in den Fällen zu lösen, in denen Temperatur und Feuchtigkeit gleichzeitig gemessen werden sollen. Die hier vorgestellten, durch Maschinelles Lernen unterstützten, DFOS können zu einer verbesserten, kostengünstigen und zuverlässigen Überwachung von Infrastrukturen beitragen. KW - Artificial neural networks KW - Brillouin sensing KW - Distributed acoustic sensing KW - Fibre optic sensors KW - Infrastructure monitoring PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569044 DO - https://doi.org/10.1515/teme-2022-0098 SN - 0171-8096 SP - 1 EP - 19 PB - De Gruyter AN - OPUS4-56904 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Krebber, Katerina T1 - Machine Learning Approaches in Brillouin Distributed Fiber Optic Sensors N2 - This paper presents reported machine learning approaches in the field of Brillouin distributed fiber optic sensors (DFOSs). The increasing popularity of Brillouin DFOSs stems from their capability to continuously monitor temperature and strain along kilometer-long optical fibers, rendering them attractive for industrial applications, such as the structural health monitoring of large civil infrastructures and pipelines. In recent years, machine learning has been integrated into the Brillouin DFOS signal processing, resulting in fast and enhanced temperature, strain, and humidity measurements without increasing the system’s cost. Machine learning has also contributed to enhanced spatial resolution in Brillouin optical time domain analysis (BOTDA) systems and shorter measurement times in Brillouin optical frequency domain analysis (BOFDA) systems. This paper provides an overview of the applied machine learning methodologies in Brillouin DFOSs, as well as future perspectives in this area. KW - Distributed fiber optic sensors KW - BOTDA KW - BOFDA KW - Machine learning KW - Strain and temperature measurements KW - Artificial neural networks PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580145 DO - https://doi.org/10.3390/s23136187 VL - 23 IS - 13 SP - 1 EP - 26 PB - MDPI AN - OPUS4-58014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Machine learning assisted BOFDA for simultaneous temperature and strain sensing in a standard optical fiber N2 - We report, to our knowledge for the first time on simultaneous distributed temperature and strain sensing in a standard telecom optical fiber using a machine learning assisted Brillouin frequency domain analysis (BOFDA) system. The well-known temperature and strain cross-sensitivity problem is addressed by developing a BOFDA system with a high signal-to-noise ratio and applying machine learning. The spectrum consists of four highly resolved peaks, whose Brillouin frequency shifts are extracted and serve as features for the machine learning algorithms. The spectra result from a 450-m standard SMF-28 optical fiber, and particularly from a segment of 30 m. This fiber segment is coiled around a stretcher and placed in a climate chamber. The applied temperature and strain values range from 20 °C to 40 °C and from 0 µɛ to 1380 µɛ, respectively. The total measurement time to achieve a high SNR and resolve four peaks with a spatial resolution of 6 m is 16 min. To discriminate temperature and strain effects, simple frequentist and more sophisticated Bayesian-based algorithms are employed with the powerful Gaussian process regression (GPR) delivering the best performance in terms of temperature and strain errors, which are found to be 2 °C and 45 µɛ, respectively. These errors are calculated using leave-one-out cross-validation, so that an unbiased estimation of the sensor’s performance is provided. KW - Machine learning KW - Brillouin distributed fiber optic sensors KW - Temperature and strain sensing KW - BOFDA PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569155 DO - https://doi.org/10.1364/OE.480224 SN - 1094-4087 VL - 31 IS - 3 SP - 5027 EP - 5041 PB - OPTICA AN - OPUS4-56915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Wosniok, Aleksander A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Time-Efficient Convolutional Neural Network-Assisted Brillouin Optical Frequency Domain Analysis N2 - To our knowledge, this is the first report on a machine-learning-assisted Brillouin optical frequency domain analysis (BOFDA) for time-efficient temperature measurements. We propose a convolutional neural network (CNN)-based signal post-processing method that, compared to the conventional Lorentzian curve fitting approach, facilitates temperature extraction. Due to its robustness against noise, it can enhance the performance of the system. The CNN-assisted BOFDA is expected to shorten the measurement time by more than nine times and open the way for applications, where faster monitoring is essential. KW - Fiber-optic sensors KW - Machine learning KW - Temperature and strain monitoring KW - Brillouin distributed sensing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524631 DO - https://doi.org/10.3390/s21082724 VL - 21 IS - 8 SP - 2724 PB - MDPI AN - OPUS4-52463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Hicke, Konstantin A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Distributed humidity fiber-optic sensor based on BOFDA using a simple machine learning approach N2 - We report, to our knowledge for the first time, on distributed relative humidity sensing in silica polyimide-coated optical fibers using Brillouin optical frequency domain analysis (BOFDA). Linear regression, which is a simple and well-interpretable algorithm in machine learning and statistics, is utilized. The algorithm is trained using as features the Brillouin frequency shifts and linewidths of the fiber’s multipeak Brillouin spectrum. To assess and improve the effectiveness of the regression algorithm, we make use of machine learning concepts to estimate the model’s uncertainties and select the features that contribute most to the model’s performance. In addition to relative humidity, the model is also able to simultaneously provide distributed temperature information addressing the well-known cross-sensitivity effects. KW - Fiber optics sensors KW - Machine learning KW - Brillouin distributed sensing KW - Humidity sensing KW - Simultaneous temperature and humidity sensing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546294 DO - https://doi.org/10.1364/OE.453906 VL - 30 IS - 8 SP - 12484 EP - 12494 PB - OPTICA AN - OPUS4-54629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Multiscale reinforcement of Semi-Crystalline Thermoplastic Sheets and Honeycombs (M-RECT) T2 - ITHEC 2014, 2nd International Conference and Exhibition on Thermoplastic Composites CY - Bremen, Germany DA - 2014-10-27 PY - 2014 AN - OPUS4-32029 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reiche, T. A1 - Teichmann, H. A1 - Krebber, Katerina A1 - Salomon, O. A1 - Wood, A. T1 - Multiscale reinforcement of semi-crystalline thermoplastic sheets and honeycombs (M-RECT) N2 - M-RECT was a European FP7 funded project investigating multiscale reinforced thermoplastic composites. The project involved the functionalisation of carbon nanotubes (CNT) with a view to: • Improving their performance and ease of dispersion • Improving the damping characteristics of composites • Evaluating the mechanical performance of CNT reinforced laminates • Developing modelling Software for the design of materials and components • Developing sensor Systems to provide feedback on the local strains within such composites This presentation seeks to provide a general overview of the results from the project with particular emphasis T2 - ITHEC 2014 - 2nd International Conference and Exhibition on Thermoplastic Composites CY - Bremen, Germany DA - 27.10.2014 KW - Carbon nanotubes KW - Multiscale thermoplastic-matrix composites KW - Modelling PY - 2014 SN - 978-3933339256 SP - 12 EP - 15 AN - OPUS4-32353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Fiber Optic Sensors for SHM - From Laboratory to Industrial Applications (invited lecture) T2 - OSA Conference "Applied Industrial Optics: Spectroscopy, Imaging and Metrology (AIO)" CY - Seattle, WA, USA DA - 2014-07-13 PY - 2014 AN - OPUS4-31131 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Nöther, N. A1 - Steffen, Milan A1 - Gili, O. A1 - Krebber, Katerina ED - López-Higuera, J.M. ED - Jones, J. ED - López-Amo, M. ED - Santos, J.L. T1 - Performance of digital incoherent OFDR and prospects for optical fiber sensing applications N2 - We propose a digital implementation of the incoherent optical frequency domain reflectometry (I-OFDR) technique for precise backscatter measurement and optical fiber sensing applications. Specific performance parameters of the I-OFDR are discussed and compared to an analog vector network analyzer-based I-OFDR system. Improved sensitivity, dynamic range and signal stability of the digital I-OFDR is presented and demonstrated by means of quasi-distributed length change measurement. T2 - OFS2014 - 23rd International conference on optical fibre sensors CY - Santander, Spain DA - 02.06.2014 KW - Optical fiber sensors KW - Backscatter measurement KW - Strain sensor KW - OFDR KW - OTDR PY - 2014 DO - https://doi.org/10.1117/12.2059639 SN - 0277-786X SN - 1996-756X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 9157 SP - 915737-1 EP - 915737-4 AN - OPUS4-30899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina T1 - Fiber optic sensors for SHM - from laboratory to industrial applications N2 - The paper highlights the research activities in Germany and Europe in the development of distributed fiber optic sensor for structural health monitoring (SHM) like the monitoring of geotechnical and civil infrastructures and presents selected results achieved within these projects. T2 - OSA Optics & photonics congress - Imaging and applied optics CY - Seattle, Washington, USA DA - 13.07.2014 PY - 2014 SN - 978-1-55752-308-2 DO - https://doi.org/10.1364/AIO.2014.AM4A.1 SP - 1 EP - 2 AN - OPUS4-31195 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Muanenda, Y. S. A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Relative change measurement of physical quantities using dual-wavelength coherent OTDR N2 - We propose the use of alternating pulse wavelengths in a direct-detection coherent optical time domain reflectometry (C-OTDR) setup not only to measure strain and temperature changes but also to determine the correct algebraic sign of the change. The sign information is essential for the intended use in distributed mode shape analysis of civil engineering structures. Correlating relative backscatter signal shifts in the temporal/signal domain allows for measuring with correct magnitude and sign. This novel approach is simulated, experimentally implemented and demonstrated for temperature change measurement at a spatial resolution of 1 m. KW - Fiber optics sensors KW - Backscattering KW - Rayleigh KW - C-OTDR KW - Distributed sensing KW - Temperature measurement KW - Strain measurement PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389449 DO - https://doi.org/10.1364/OE.25.000720 SN - 1094-4087 VL - 25 IS - 2 SP - 720 EP - 729 PB - Optical Society of America CY - Washington, DC, USA AN - OPUS4-38944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hicke, Konstantin A1 - Krebber, Katerina ED - Chung, Y. ED - Jin, W. ED - Lee, B. ED - Canning, J. ED - Nakamura, K. ED - Yuan, L. T1 - Towards efficient real-time submarine power cable monitoring using distributed fibre optic acoustic sensors N2 - Online condition monitoring of submarine power cables helps to avert failures and damages produced by mechanical impacts. We report, to our knowledge for the first time, on investigations regarding the feasibility of distributed fiber optic acoustic sensors based on C-OTDR, with the sensor fibres being embedded in the cable, to detect vibrations due to mechanical disturbances along the cable. We present first results of sensing experiments where acoustic signals are transmitted through water to simulate the corresponding submarine conditions. Furthermore, we show results evaluating the usefulness of fibre commonly embedded in existing power cable designs for our sensing purposes. T2 - 25th International Conference on Optical Fiber Sensors CY - Jeju-City, Jeju, Republic of Korea DA - 24.04.2017 KW - Distributed acoustic sensing KW - Power cable monitoring KW - C-OTDR KW - Fibre optic sensors KW - DAS PY - 2017 SN - 978-1-5090-4850-2 DO - https://doi.org/10.1117/12.2267474 SN - 0277-786X SN - 1996-756X VL - 10323 SP - 1032390-1 EP - 1032390-4 PB - SPIE CY - Bellingham, WA, USA AN - OPUS4-40088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hicke, Konstantin A1 - Hussels, Maria-Teresa A1 - Eisermann, René A1 - Chruscicki, Sebastian A1 - Krebber, Katerina ED - Chung, Y. ED - Jin, W. ED - Lee, B. ED - Canning, J. ED - Nakamura, K. ED - Yuan, L. T1 - Condition monitoring of industrial infrastructures using distributed fibre optic acoustic sensors N2 - Distributed fibre optic acoustic sensing (DAS) can serve as an excellent tool for real-time condition Monitoring of a variety of industrial and civil infrastructures. In this paper, we portray a subset of our current Research activities investigating the usability of DAS based on coherent optical time-domain reflectometry (C-OTDR) for innovative and demanding condition Monitoring applications. Specifically, our application-oriented Research presented here aims at acoustic and vibrational condition monitoring of pipelines and piping systems, of rollers in industrial heavy-duty conveyor belt systems and of extensive submarine power cable installations, respectively. T2 - 25th International Conference on Fiber Optic Sensors CY - Jeju-City, Jeju, Republic of Korea DA - 24.04.2017 KW - Condition monitoring KW - Distributed fibre optic acoustic sensing KW - Fibre optic sensors KW - Industrial monitoring KW - DAS PY - 2017 SN - 978-1-5090-4850-2 DO - https://doi.org/10.1117/12.2272463 SN - 0277-786X SN - 1996-756X VL - 10323 SP - 103230J-1 EP - 103230J-4 PB - SPIE CY - Bellingham, WA, USA AN - OPUS4-40091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hicke, Konstantin A1 - Hussels, Maria-Teresa A1 - Eisermann, René A1 - Chruscicki, Sebastian A1 - Krebber, Katerina T1 - Distributed Fibre Optic Acoustic and Vibration Sensors for Industrial Monitoring Applications N2 - We investigate the usability of distributed fibre optic acoustic sensing (DAS) for innovative and advanced monitoring applications in industrial and civil infrastructure installations. In this paper, we report on our ongoing application-oriented research activities regarding the utilization of DAS based on coherent optical time-domain reflectometry (C-OTDR) for condition monitoring of a variety of infrastructures. Specifically, our research presented here aims at acoustic condition monitoring of and fault detection in pipelines and industrial piping systems, at acoustic condition monitoring of rollers in industrial conveyor belt installations, and at acoustic condition monitoring of and threat detection in extensive submarine power cables, respectively. Furthermore, we show a method to mitigate the effect of sensitivity fading of C-OTDR based DAS due to unstable environmental conditions via the modification of the sensor fibre. This can help to provide a continuous adequate sensor functionality for a number of different industrial monitoring applications. T2 - SENSOR 2017 - 18th International Conference on Sensors and Measurement Technology CY - Nuremberg, Germany DA - 30.05.2017 KW - distributed acoustic sensing KW - fibre optic sensors KW - condition monitoring KW - industrial monitoring KW - C-OTDR PY - 2017 SN - 978-3-9816876-4-4 DO - https://doi.org/10.5162/sensor2017/B7.3 SP - 274 EP - 279 PB - AMA Service GmbH CY - Wunstorf AN - OPUS4-40473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina ED - Webb, D. J. ED - Scully, P. ED - Sugden, K. T1 - Radiation induced attenuation in perfluorinated polymer optical fibres for dosimetry applications N2 - Real-time measurement of radiation-induced attenuation (RIA) in a commercial perfluorinated polymer optical fibre (PF-POF) is performed with regard to on-line Radiation monitoring purposes. Spectral character and dose dependence of fibre’s RIA is measured in 450-900 nm spectral region. Fibre exhibited high radiation sensitivity in the visible region with strong increase towards the UV wavelengths. Good linearity and high sensitivity reaching up to 130 dBm-1/kGy was demonstrated in the VIS region for a low-dose range. This of-the-shelf PF-POF could be therefore interesting for on-line remote dosimetry applications. T2 - POF 2016: 25th International Conference on Plastic Optical Fibres CY - Birmingham, UK DA - 13.09.2016 KW - Perfluorinated polymer optical fibers KW - Gamma radiation monitoring KW - Radiation induced attenuation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403221 SN - 978-1-85449-408-5 SP - 167 EP - 170 CY - Birmingham AN - OPUS4-40322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina ED - Chung, Y. ED - Jin, W. ED - Lee, B. ED - Canning, J. ED - Nakamura, K. ED - Yuan, L. T1 - Towards on-line radiation monitoring with perfluorinated polymer optical fibers N2 - Sensitivity of two commercial perfluorinated (PF) polymer optical fibers (POFs) to gamma radiation was measured, compared and exploited for dosimetry purposes. Fiber radiation induced attenuation (RIA) was found to be highly wavelength dependent and pronounced towards the UV part of the spectrum. PF-POFs were shown to be highly radiation sensitive and RIA-based on-line radiation monitoring with sensitivity as high as 135 dBm-1/kGy was demonstrated at 460 nm with co-extruded PF-POF. In addition, thanks to low inherent attenuation in the near-infrared region, possibility of distributed radiation detection with PF-POFs was demonstrated for the first time, utilizing optical time domain reflectometry. T2 - 25th International Conference on Optical Fiber Sensors CY - Jeju, Republic of Korea DA - 24.04.2017 KW - Radiation-induced attenuation KW - Perfluorinated polymer optical fibers KW - Cytop KW - Gamma radiation KW - Optical fiber dosimetry KW - Optical fiber sensors KW - Distributed radiation sensing PY - 2017 SN - 978-1-5090-4850-2 DO - https://doi.org/10.1117/12.2256354 SN - 0277-786X SN - 1996-756X VL - 10323 SP - 103231O-1 EP - 103231O-4 PB - SPIE AN - OPUS4-40323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -