@inproceedings{DenglerVinogradovZiemannetal.2021, author = {Dengler, Simon Andreas and Vinogradov, Juri and Ziemann, Olaf and Engelbrecht, Rainer and Schmauß, Bernhard}, title = {Low Cost POF OTDR Reaches 200 m Sensing Distance}, volume = {2021}, publisher = {The International Committee on Polymer Optical Fibers, ICPOF}, address = {Jinhua City}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:92-opus4-26577}, pages = {13}, year = {2021}, language = {en} } @inproceedings{VinogradovMorfDengleretal.2021, author = {Vinogradov, Juri and Morf, Fabian and Dengler, Simon Andreas and Engelbrecht, Rainer and Ziemann, Olaf}, title = {FPGA and APD Based Optical Time Domane Reflectometry in Sensor Applications}, series = {The 28th International Conference on Plastic Optical Fibers 2019-11-20}, booktitle = {The 28th International Conference on Plastic Optical Fibers 2019-11-20}, year = {2021}, abstract = {This paper shows an optical time domain reflectometry (OTDR) system based on an avalanche photodiode (APD) receiver, a 520 nm laser diode transmitter, a high-speed analog-to-digital converter (ADC) and a commercially available field programmable gate array (FPGA). This approach allows OTDR measurements up to 200 m and provides a spatial resolution of 20 cm. Depending on the number of averaging, the measurement time can be between 5 s and 50 s for a range up to 200 m with a good signal to noise ratio.}, language = {en} } @inproceedings{VinogradovKruglovWetzeletal.2024, author = {Vinogradov, Juri and Kruglov, Roman and Wetzel, Ulrich and Engelbrecht, Rainer and Ziemann, Olaf}, title = {200 m Gigabit POF Link Based on 520 nm Laser Diode and PAM Media Converter}, series = {International Conference on Plastic Optical Fibers}, volume = {Proceedings 2024}, booktitle = {International Conference on Plastic Optical Fibers}, year = {2024}, abstract = {This paper shows the results on the data transmission over distances of up to 350 m SI-POF with KDPOF Media Converter based on Gigabit POF Transceiver KD1001 (KD-EVK1001MC Evaluation Kit) and laser diode (LD) operating at 520 nm. A bit rate of 1 Gbit/s with 16-PAM modulation scheme can be achieved over 200 m SI-POF. At longer distances, the bit rate is automatically reduced by KDPOF transceiver according to the actual channel capacity.}, language = {en} } @inproceedings{VinogradovKruglovZiemannetal.2024, author = {Vinogradov, Juri and Kruglov, Roman and Ziemann, Olaf and Engelbrecht, Rainer}, title = {Incoherent OFDR System for Distances up to 200 m SI-POF}, series = {International Conference on Plastic Optical Fibers ; Proceedings 2024}, booktitle = {International Conference on Plastic Optical Fibers ; Proceedings 2024}, year = {2024}, abstract = {We report on a proposal for an incoherent optical frequency domain reflectometry (I-OFDR) for 1-mm core diameter PMMA SI-POF. An avalanche photodiode receiver and optimized transmitter based on a 515-nm laser diode allow measurement up to 200 m SI-POF. The measurements have been carried out using a vector network analyzer; the subsequent data processing has been implemented in MATLAB.}, language = {en} } @inproceedings{DenglerRoseeuGonzalezLuberetal.2022, author = {Dengler, Simon Andreas and Roseeu Gonzalez, R. V. and Luber, M. and Ziemann, Olaf and Engelbrecht, Rainer and Schmauss, B.}, title = {Performance Evaluation of Reference Reflections in Polymer Optical Fibers for Strain Sensing}, series = {27th International Conference on Optical Fiber Sensors}, booktitle = {27th International Conference on Optical Fiber Sensors}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, isbn = {978-1-957171-14-2}, doi = {10.1364/ofs.2022.tu2.6}, year = {2022}, abstract = {We present a robust concept for quasi distributed strain measurement using optical time domain reflectometry (OTDR) in polymer optical fibers (POF). The spatial shifts of discrete reflective events in the OTDR trace are evaluated as reference points. It is shown how such reference reflections can be prepared and which properties can be expected.}, language = {en} } @inproceedings{DenglerSchmidtLuberetal.2021, author = {Dengler, S. and Schmidt, N. and Luber, M. and Fischer, J. and Ziemann, Olaf and Engelbrecht, Rainer and Hangen, H.}, title = {B8.3 Influence of Temperature on Distributed Strain Sensing with OTDR in Polymer Optical Fibers}, series = {SMSI 2021 - Sensors and Instrumentation}, booktitle = {SMSI 2021 - Sensors and Instrumentation}, publisher = {AMA Service GmbH, Von-M{\"u}nchhausen-Str. 49, 31515 Wunstorf, Germany}, isbn = {978-3-9819376-4-0}, doi = {10.5162/smsi2021/b8.3}, pages = {155 -- 156}, year = {2021}, abstract = {Strain in ground and earthworks can be measured by polymer optical fibers (POF) applied to geotextiles. We measure the increase of backscatter (IOB) in the fiber under strain using optical time domain reflectometry (OTDR). The effect of temperature on this measurement principle is investigated. The local backscatter changes by 0.003 dB/K for common ambient temperature. In addition it is shown, that temperature depended viscoelastic properties of the polymer does affect IOB.}, language = {en} } @inproceedings{RostanKruglovEngelbrecht2023, author = {Rostan, Katharina and Kruglov, Roman and Engelbrecht, Rainer}, title = {2x2 Factorial Calibration of FBG Sensors for Simultaneous Measurement of Temperature and Humidity in PEM Fuel Cells}, series = {Sensor and Measurement Science International Conference 2023}, volume = {2023}, booktitle = {Sensor and Measurement Science International Conference 2023}, publisher = {AMA Service GmbH, Von-M{\"u}nchhausen-Str. 49, 31515 Wunstorf, Germany}, isbn = {978-3-9819376-8-8}, doi = {10.5162/SMSI2023/P56}, pages = {388 -- 389}, year = {2023}, abstract = {Fiber Bragg grating (FBG) sensor technology is expected to make an important contribution to extending the lifetime of polymer electrolyte membrane (PEM) fuel cells. It allows accurate measurements of in-situ operating temperature and humidity, which is essential for an accurate control of both. For these applications an accurate and reliable calibration is crucial. This paper demonstrates the successful use of a 2x2 factorial calibration method for calibration of two standard FBGs for application in a PEM fuel cell. The calibrated low-cost FBG sensor allows temperature and humidity measurements with a RMS error (RMSE) of 0.45°C and 4.8 \%RH, respectively.}, language = {en} } @inproceedings{DenglerLuberNeffetal.2023, author = {Dengler, Simon Andreas and Luber, Michael and Neff, L{\´e}on and Hangen, Hartmut and Schmauss, Bernhard and Ziemann, Olaf and Engelbrecht, Rainer}, title = {OTDR Strain and Force Sensing by POF on Geotextiles in a Geotechnical Application Test}, series = {28th International Conference on Optical Fiber Sensors}, booktitle = {28th International Conference on Optical Fiber Sensors}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, isbn = {978-1-957171-30-2}, doi = {10.1364/OFS.2023.W4.91}, year = {2023}, abstract = {With polymer optical fibers (POF) attached to geotextiles, optical time domain reflectometry (OTDR) can be used to measure strain of the geotextile spatially resolved in soil. We test the technique in a geotechnical application test and thus demonstrate the functionality of the sensor for field use.}, language = {en} } @inproceedings{RostanKruglovEngelbrecht2024, author = {Rostan, Katharina and Kruglov, Roman and Engelbrecht, Rainer}, title = {Entwicklung und Charakterisierung eines Erbium-dotierten Glasfasersensors zur Temperaturmessung}, year = {2024}, language = {de} } @inproceedings{EngelbrechtRostanWeilandetal.2022, author = {Engelbrecht, Rainer and Rostan, K. and Weiland, J. and Luber, M. and Schiebahn, A. and Reisgen, U.}, title = {Modal Distribution in Polymer Optical Fibers as Sensor for Load Monitoring in Semi-Structural Adhesive Bonds}, series = {27th International Conference on Optical Fiber Sensors}, booktitle = {27th International Conference on Optical Fiber Sensors}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, doi = {10.1364/ofs.2022.w2.3}, year = {2022}, abstract = {PMMA polymer optical fibers embedded in semi-structural polyurethane adhesive bonds serve as economical load sensor for structural health monitoring by evaluating load-dependent optical transmission as well as modal distribution measured by a far-field camera. Scaling of sensor quantities by the sensitive fiber length is shown.}, language = {en} } @inproceedings{EngelbrechtSaurKruglov2021, author = {Engelbrecht, Rainer and Saur, G. and Kruglov, R.}, title = {B8.4 12 nm Spectral Shift with a VCSEL in the Near Infrared in a 10 µs Time Interval}, series = {SMSI 2021 - Sensors and Instrumentation}, booktitle = {SMSI 2021 - Sensors and Instrumentation}, publisher = {AMA Service GmbH, Von-M{\"u}nchhausen-Str. 49, 31515 Wunstorf, Germany}, isbn = {978-3-9819376-4-0}, doi = {10.5162/smsi2021/b8.4}, pages = {157 -- 158}, year = {2021}, abstract = {An optical wavelength tuning range up to 12 nm has been achieved within 10 μs, using VCSELs operating in the near infrared. The range has been measured with an interferometric setup and an optical spectrum analyzer respectively. Potentially, low-cost sensor systems based on tunable diode laser absorption spectroscopy or coherent optical frequency domain reflectometry could be realized, achieving sub-mm two-point range resolution or even better single-point range precision within a few microseconds for a single measurement.}, language = {en} } @inproceedings{EngelbrechtDenglerLuberetal.2021, author = {Engelbrecht, Rainer and Dengler, S. and Luber, M. and Fischer, J. and Hangen, H.}, title = {SHM at Giant Mine Heaps by OTDR Sensing with Polymer Optical Fibers}, series = {Optical Fiber Sensors Conference 2020 Special Edition}, booktitle = {Optical Fiber Sensors Conference 2020 Special Edition}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, doi = {10.1364/ofs.2020.th4.7}, year = {2021}, abstract = {Results from field measurement campaigns for structural health monitoring (SHM) at giant mine heaps by optical time domain reflectometry (OTDR) in polymer optical fibers (POF) are presented. Polymer geogrids built for soil reinforcement are fitted with POF for strain sensing as part of a geosynthetic sealing system designed to protect the heap from infiltration of surface water. Strain is detected by a local increase of backscatter. Measurements on eight sensor lines have been performed over a time period of six months to monitor the system behavior and potential development of or cracks within the underlying base of a sealing system. Results show the usability of this technology for strain sensing and SHM in such a harsh environment. Challenges still exist in the quantitative evaluation of the fiber sensor data due to cross sensitivity to fiber bending and lateral pressure.}, language = {en} } @inproceedings{DenglerVinogradovEngelbrechtetal.2022, author = {Dengler, Simon Andreas and Vinogradov, Juri and Engelbrecht, Rainer and Schmauß, Bernhard}, title = {Recent Progress in POF OTDR Strain Sensing}, series = {International Conference on Plastic Optical Fibers}, volume = {Proceedings 2022}, booktitle = {International Conference on Plastic Optical Fibers}, year = {2022}, language = {en} } @inproceedings{EngelbrechtRostanWeilandetal.2022, author = {Engelbrecht, Rainer and Rostan, Katharina and Weiland, Josef and Luber, Michael and Schiebahn, Alexander and Reisgen, Uwe}, title = {Modal Distribution in Polymer Optical Fibers as Sensor for Load Monitoring in Semi-Structural Adhesive Bonds}, series = {27th International Conference on Optical Fiber Sensors}, booktitle = {27th International Conference on Optical Fiber Sensors}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, isbn = {978-1-957171-14-2}, doi = {10.1364/OFS.2022.W2.3}, year = {2022}, abstract = {PMMA polymer optical fibers embedded in semi-structural polyurethane adhesive bonds serve as economical load sensor for structural health monitoring by evaluating load-dependent optical transmission as well as modal distribution measured by a far-field camera. Scaling of sensor quantities by the sensitive fiber length is shown.}, language = {en} } @inproceedings{KruglovEngelbrecht2023, author = {Kruglov, Roman and Engelbrecht, Rainer}, title = {Rapid and High-Resolution Tunable Diode Laser Spectroscopy within 10 µs for Combustion Gas Analysis}, series = {Optica Sensing Congress 2023 (AIS, FTS, HISE, Sensors, ES)}, booktitle = {Optica Sensing Congress 2023 (AIS, FTS, HISE, Sensors, ES)}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, isbn = {978-195717124-1}, doi = {10.1364/sensors.2023.stu2d.3}, pages = {2}, year = {2023}, abstract = {We report on a rapid high-resolution absorption spectroscopy with a VCSEL reaching a peak tuning speed of 2.1 nm/µs (8.8 cm-1/µs) near 1.5 µm. An overall tuning range of up to 12 nm can be achieved within a 12 µs injection current pulse.}, language = {en} } @inproceedings{SaurKruglovEngelbrecht2020, author = {Saur, Gregor and Kruglov, Roman and Engelbrecht, Rainer}, title = {Microsecond Optical Frequency Tuning of DFB Laser Diodes for Coherent Optical Frequency Domain Reflectometry}, volume = {2020}, publisher = {AMA Service GmbH}, address = {Wunstorf, Germany}, isbn = {978-3-9819376-2-6}, doi = {10.5162/SMSI2020/C6.2}, pages = {189 -- 190}, year = {2020}, abstract = {Optical frequency tuning ranges up to 600 GHz or 4.8 nm have been achieved within microseconds and a standard telecom DFB laser diode operating at 1550 nm. The dynamic optical frequency tuning is induced by electrical current pulse injection and measured using an interferometric setup. Potentially, low-cost sensor systems based on optical coherence tomography (OCT) or coherent optical frequency domain reflectometry (c-OFDR) could be realized, achieving sub-mm two-point range resolution or even better single-point range precision within a few microseconds for a single measurement.}, language = {en} } @inproceedings{StuteKirchbachGieseetal.2024, author = {Stute, Andreas and Kirchbach, Lucas and Giese, Andreas and Bachmann, Alexander and Braun, Bernd and Engelbrecht, Rainer}, title = {Optical Enabling Technologies for QT}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:92-opus4-42924}, year = {2024}, abstract = {Overview of the research topics at TH Nuremberg for optical quantumtechnologies. Deterministic generation of NV-Centers, Integrated Spin Qubits, Micro-Optics Designs of Optical Interfaces, Lab Courses and Fabrication Devices}, subject = {Nichtabbildende Optik}, language = {en} } @inproceedings{RostanKruglovSeissetal.2023, author = {Rostan, Katharina and Kruglov, Roman and Seiß, Volker and Thiel, Susanne and Eichelbaum, Maik and Engelbrecht, Rainer}, title = {In-situ Temperature and Humidity Measurement in PEM Fuel Cells with Off-the-shelf FBG}, series = {28th International Conference on Optical Fiber Sensors}, volume = {2023}, booktitle = {28th International Conference on Optical Fiber Sensors}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, isbn = {978-1-957171-30-2}, doi = {10.1364/OFS.2023.Tu3.36}, pages = {4}, year = {2023}, abstract = {We propose a cost efficient fiber Bragg grating (FBG) sensor for measuring temperature and humidity in polymer electrolyte membrane fuel cells (PEMFC). The multiparameter sensor works with two conventional FBG and achieves an RMSE better than 0.45°C and 4.8 \%RH.}, language = {en} } @inproceedings{EngelbrechtLuberVinogradovetal.2025, author = {Engelbrecht, Rainer and Luber, Michael and Vinogradov, Juri and Hemmerlein, Moritz and Pick, Mathias and Ziemann, Olaf}, title = {Range Extension of PMMA POF Sensors Beyond 100 M for Monitoring Large Infrastructures}, series = {33rd International Conference on Plastic Optical Fibers}, booktitle = {33rd International Conference on Plastic Optical Fibers}, pages = {5}, year = {2025}, abstract = {A POF integral length and extension sensor based on phase detection of intensity modulated light with fiber sensor lengths beyond 100 m for monitoring large infrastructures is discussed. A theory for a scaling law of the precision limit over length and modulation frequency is presented. Experimental results using green light for sensor ranges above 100 m are shown.}, language = {en} }