TY - CONF A1 - Stajanca, Pavol A1 - Cetinkaya, O. A1 - Schukar, Marcus A1 - Mergo, P. A1 - Krebber, Katerina T1 - Climatic stability of polymer optical fibers for sensing applications N2 - Systematic investigation of annealing behavior of drawn PMMA fibers was performed. Dynamics of annealing process were measured under different environmental conditions by fiber longitudinal shrinkage monitoring. Process was found to follow stretched exponential decay function indicating heterogeneous nature of underlying molecular dynamics. Consequences of fiber annealing for climatic stability of polymer optical fiber-based sensors are discussed, emphasizing importance of fiber controlled post-fabrication annealing. Dependence of induced fiber shrinkage on annealing time, temperature and fiber drawing conditions is investigated and interpreted. In addition, strong influence of humidity on annealing process was observed, which was not recognized in previous studies. This further highlights role of fiber post-fabrication thermal treatment with respect to intended operating conditions. T2 - POF 2015 - 24th International conference on plastic optical fibers CY - Nuremberg, Germany DA - 22.09.2015 KW - Polymer optical fibers KW - Polymethyl methacrylate KW - Climatic stability KW - Fiber annealing PY - 2015 SP - 209 EP - 212 AN - OPUS4-34422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lu, Xin A1 - Hicke, Konstantin A1 - Breithaupt, Mathias A1 - Strangfeld, Christoph T1 - Distributed Humidity Sensing in Concrete Based on Polymer Optical Fiber N2 - We present a preliminary investigation on distributed humidity monitoring during the drying process of concrete based on an embedded polymer optical fiber (POF). The water dissipated into the POF changes several properties of the fiber such as refractive index, scattering coefficient and attenuation factor, which eventually alters the Rayleigh backscattered light. The optical time Domain reflectometer (OTDR) technique is performed to acquire the backscattered signal at the wavelengths 650 nm and 500 nm, respectively. Experimental results show that the received signal increases at 650 nm while the fiber attenuation factor clearly increases at 500 nm, as the concrete dries out. In the hygroscopic range, the information retrieved from the signal change at 650 nm agrees well with the measurement result of the electrical humidity sensors also embedded in the concrete sample. KW - Distributed fiber optic sensing KW - Distributed humidity sensing KW - Polymer optical fibers KW - Concrete drying KW - Material moisture KW - Embedded humidity sensors PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537644 DO - https://doi.org/10.3390/polym13213755 SN - 2073-4360 VL - 13 IS - 21 SP - 3755 PB - MDPI CY - Basel, Switzerland AN - OPUS4-53764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol T1 - Fiberoptic sensors for composite/plastic components monitoring N2 - An overview of Division 8.6 activities on using optical fiber sensors for composite monitoring is given. T2 - Workshop an der TU Chemnitz CY - Chemnitz, Germany DA - 06.05.2019 KW - Fiberoptic sensors KW - Composites KW - Sensor intergration KW - Polymer optical fibers PY - 2019 AN - OPUS4-47969 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 - Liehr, Sascha A1 - Nöther, Nils A1 - Krebber, Katerina T1 - Incoherent optical frequency domain reflectometry and distributed strain detection in polymer optical fibers N2 - We present, to our knowledge for the first time, the possibility of measuring the backscatter signal of perfluorinated polymer optical fibers (POF) using an incoherent optical frequency domain reflectometry (OFDR) technique. The OFDR setup is described and it is shown that the dynamic range and measurement speed are superior to standard OTDR systems. It is shown for the first time that distributed detection of strain in POF is possible using the OFDR technique. KW - Optical frequency domain reflectometry KW - OFDR KW - OTdr KW - Polymer optical fibers KW - POF KW - Fiber sensors KW - Distributed sensors KW - Strain sensors PY - 2010 DO - https://doi.org/10.1088/0957-0233/21/1/017001 SN - 0957-0233 SN - 1361-6501 VL - 21 IS - 1 SP - 017001-1 - 017001-4 PB - IOP Publ. Ltd. CY - Bristol AN - OPUS4-21625 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 - Krebber, Katerina T1 - Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring N2 - Fibreoptic sensors (FOS) represent sensing technology with small footprint, low invasiveness, electromagnetic passivity and immunity, plus potential for remote and real-time monitoring. Modern FOS techniques allow truly temporally- and spatially-continuous monitoring over extended distances; a feature not attainable with any other sensing technology. Moreover, depending on their particular material composition and design, optical fibres can be made resistant to high temperatures, chemicals and ionizing radiation. Due to this unique combination of advantageous properties, ever since their emergence, FOS have been attracting considerable attention for monitoring tasks in harsh, hazardous and difficult-to-access locations. The potential of FOS has been recognized also in the field of radioactive waste management and fibreoptic sensors belong to the most promising technologies for nuclear waste repositories (NWR) monitoring. Vast majority of distributed fibreoptic sensor applications rely on use of silica-based optical fibres as sensing elements. At the same time, distributed measurement of local temperature and strain along the fibre are the most common monitoring tasks addressed by fibreoptic sensors. Nevertheless, FOS offer much larger flexibility both in terms of utilized sensing fibre as well as targeted measurand. In this contribution, we will review some of more alternative implementations of FOS that are being explored at “Fibre Optic Sensors” division of Federal Institute for Material Research and Testing (BAM), in Berlin. The main focus will be twofold. On one side, we will address FOS applications with polymer optical fibres (POF), that may enable monitoring of large strains (>100%) and high-sensitivity radiation detection. On the other side, we will present our activities in the area of distributed acoustic sensing (DAS); one of the most recent developments in the fibreoptic sensing field enabling highly-dynamic vibration sensing with nanostrain sensitivity. We will introduce the principles of the addressed FOS technologies, present application examples from our case studies, discuss advantages and limitations of the techniques and highlight their potential for NWR monitoring. T2 - Modern 2020 Final Conference CY - Paris, France DA - 09.04.2019 KW - Fiberoptic sensors KW - Nuclear waste disposal KW - Polymer optical fibers KW - Distributed acoustic sensing KW - Distributed radiation monitoring PY - 2019 UR - http://www.modern2020.eu/final-conference/programme.html AN - OPUS4-47789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Polymer optical fibers for sensing applications: Ionizing radiation monitoring N2 - In the last decades, considerable attention has been paid to the development of polymer optical fibers (POFs) that may in certain cases represent more suitable or cost-effective alternative to their glass-based counterparts. Among other applications, special attention was paid to the utilization of optical fiber sensors in radiation environments. A concept of attenuation-based radiation sensing with perfluorinated POFs is here presented as a potential candidate for low-cost easy-to-use on-line radiation monitoring system. T2 - The Fiber Society 2017 Spring Conference: Next Generation Fibers for Smart Products CY - Aachen, Germany DA - 17.05.2017 KW - Polymer optical fibers KW - Radiation monitoring KW - Cytop PY - 2017 SP - 50 AN - OPUS4-43026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Polymer optical fibers for sensing applications: ionizing radiation monitoring N2 - In the last decades, considerable attention has been paid to the development of polymer optical fibers (POFs) that may, in certain cases, represent more suitable or cost effective alternative to their glass based counterparts. Due to some of their unique properties, POFs have found their applications in the area of data transmission, lighting as well as optical sensing. Compared to the glass based fiber sensors, POFs are more robust and flexible yielding sensors suitable also for larger strain applications. They have better biocompatibility and are generally more acceptable for medical applications. In addition, POFs can provide higher inherent sensitivity to some of the more alternative measurands such as humidity or ionizing radiation. Over the last three years, BAM’s Division 8.6 has been participating in the European FP7 project “TRIPOD” devoted to the development of POF technology for sensing applications. Project activities and main technological achievements will be reviewed. Special attention will be paid to the utilization of optical fiber sensors in radiation environments. In the recent years, ionizing radiation has found numerous applications also outside the nuclear industry, e.g. in material processing, sterilization or medical applications. With increasing importance of radiation processes, demand for suitable monitoring techniques is rising as well. Among available dosimetry solutions, optical fiber based dosimeters offer numerous advantages such as electromagnetic immunity, small dimensions and possibility of remote and real time monitoring. A concept of attenuation based radiation sensing with perfluorinated POFs will be investigated and presented as a potential candidate for low cost easy to use on line radiation monitoring system. T2 - The Fiber Society 2017 Spring Conference CY - Aachen, Germany DA - 17.05.2017 KW - Polymer optical fibers KW - Fiber Bragg grating sensors KW - Gamma radiation KW - Radiation monitoring PY - 2017 AN - OPUS4-40325 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 -