@inproceedings{HenselRothMerzetal.2019, author = {Hensel, Alexander and Roth, Frederick and Merz, Corinna and Franke, J{\"o}rg and Kaloudis, Michael}, title = {Investigation of Pressureless Sintered Interconnections on Plasma Based Additive Copper Metallization for 3-Dimentional Ceramic Substrates in High Temperature Applications}, series = {22nd Microelectronics and Packaging Conference (EMPC) \& Exhibition, 16 Sep 2019 - 19 Sep 2019, Conference Center PISA, Italy}, booktitle = {22nd Microelectronics and Packaging Conference (EMPC) \& Exhibition, 16 Sep 2019 - 19 Sep 2019, Conference Center PISA, Italy}, year = {2019}, subject = {Sintern}, language = {en} } @article{KeferSauerHessleretal.2020, author = {Kefer, Stefan and Sauer, Theresia and Hessler, Steffen and Kaloudis, Michael and Hellmann, Ralf}, title = {Microstructure-Based Fiber-to-Chip Coupling of Polymer Planar Bragg Gratings for Harsh Environment Applications}, series = {Sensors (Basel)}, volume = {20}, journal = {Sensors (Basel)}, number = {19}, doi = {10.3390/s20195452}, pages = {5452 -- 5452}, year = {2020}, abstract = {This article proposes and demonstrates a robust microstructure-based fiber-to-chip coupling scheme for planar Bragg grating devices. A polymer planar Bragg grating substrate is manufactured and microstructured by means of a micromilling process, while the respective photonic structures are generated by employing a sophisticated single-writing UV-exposure method. A stripped standard single mode fiber is inserted into the microstructure, which is filled with a UV-curable adhesive, and aligned with the integrated waveguide. After curing, final sensor assembly and thermal treatment, the proposed coupling scheme is capable of withstanding pressures up to 10 bar, at room temperature, and pressures up to 7.5 bar at an elevated temperature of 120 °C. Additionally, the coupling scheme is exceedingly robust towards tensile forces, limited only by the tensile strength of the employed single mode fiber. Due to its outstanding robustness, the coupling scheme enables the application of planar Bragg grating devices in harsh environments. This fact is underlined by integrating a microstructure-coupled photonic device into the center of a commercial-grade carbon fiber-reinforced polymer specimen. After its integration, the polymer-based Bragg grating sensor still exhibits a reflection peak with a dynamic range of 24 dB, and can thus be employed for sensing purposes.}, language = {en} } @article{KeferSauerHessleretal.2020, author = {Kefer, Stefan and Sauer, Theresia and Hessler, Steffen and Kaloudis, Michael and Schmauss, Bernhard and Hellmann, Ralf}, title = {Robust Polymer Planar Bragg Grating Sensors Embedded in Commercial-Grade Composites}, series = {Polymers}, volume = {12}, journal = {Polymers}, number = {3}, doi = {10.3390/polym12030715}, pages = {715 -- 715}, year = {2020}, abstract = {This contribution demonstrates the functionality of polymer planar Bragg grating (PPBG) sensors integrated into commercial-grade carbon fiber reinforced polymer (CFRP) components. Multiple CFRP specimens are generated by curing a stack of pre-impregnated fibers inside of a heated mechanical press, exposing the polymer sensor to a pressure of 7 bar and a temperature of 120 °C for 2 h. After integration, the sensor still exhibits a strong and evaluable signal. Subsequent flexural experiments reveal a linear response of the integrated sensor's Bragg wavelength to the CFRP specimen's maximum deflection. Additional findings demonstrate that the embedded PPBG can be used to detect plastic deformations of a CFRP workpiece, whereas a linear correlation of plastic deformation to the resulting Bragg signal offset is determined. A plausibility check of the obtained results is delivered by a comparison of three-point flexural experiments on bulk CFRP workpieces, without integrated sensors and additional specimens featuring external optical sensors affixed to their surface. It is found that PPBGs based on cyclic olefin copolymers are able to overcome the temperature-related limitations of traditional polymer-based optical sensors and can thus be directly integrated into commercial-grade composites during production.}, subject = {Bragg-Reflektor}, language = {en} } @incollection{KeferRothKaloudisetal.2021, author = {Kefer, Stefan and Roth, Frederick and Kaloudis, Michael and Schmauss, Bernhard and Hellmann, Ralf}, title = {Monitoring of Composite Bicycle Components using Polymer Planar Bragg Gratings}, series = {SMSI 2021 - Sensors and Instrumentation}, booktitle = {SMSI 2021 - Sensors and Instrumentation}, publisher = {AMA Service GmbH}, address = {Wunstorf, Germany}, isbn = {978-3-9819376-4-0}, doi = {10.5162/SMSI2021/B9.2}, pages = {161 -- 162}, year = {2021}, abstract = {This study demonstrates mobile load monitoring of a composite bicycle component using an application- customized polymer planar Bragg grating sensor, evaluated by a mobile interrogation unit. After a referencing procedure, the mechanical load of a seat post is monitored while cycling through a test track.}, subject = {Bragg-Reflektor}, language = {en} }