TY - JOUR A1 - Villasmunta, Francesco A1 - Heise, Patrick A1 - Breiter, Manuela A1 - Schrader, Sigurd A1 - Schenk, Harald A1 - Regehly, Martin A1 - Mai, Andreas T1 - Monolithically Integrated Optical Through-Silicon Waveguides for 3D Chip-to-Chip Photonic Interconnects JF - IEEE Journal of Selected Topics in Quantum Electronics N2 - The scaling limitations of electrical interconnects are driving the demand for efficient optical chip-to-chip links. We report the first monolithic integration of air-clad optical through-silicon waveguides in silicon, fabricated via Bosch and cryogenic deep reactive-ion etching. Rib, single-bridge, and double-bridge designs with 50 μm cores and up to 150 μm propagation lengths have been evaluated. Cryogenic-etched rib waveguides achieve the highest median transmission (66%, −1.80 dB), compared to Bosch-etched ribs (62%, −2.08 dB). Across all geometries, 3 dB alignment windows range from 9.3 μm to 49.2 μm, with Bosch-etched double-bridge waveguides providing the broadest tolerance. We show that geometric fidelity outweighs sidewall roughness for transmission and alignment in these large-core, multimode optical through-silicon waveguides. This technology provides a scalable, complementary metal-oxide semiconductor-compatible pathway toward 3D photonic interconnects. KW - optical waveguide KW - optical device fabrication KW - silicon KW - three-dimensional display KW - optical loss KW - optical interconnection KW - coupling KW - optical surface wave KW - optical coupling KW - coupler KW - silicon photonics KW - three-dimensional integrated circuit KW - through-silicon vias (TSV) Y1 - 2026 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20828 VL - 32 IS - 2 PB - IEEE ER - TY - JOUR A1 - Steglich, Patrick A1 - Mai, Christian A1 - Villringer, Claus A1 - Dietzel, Birgit A1 - Bondarenko, Siegfried A1 - Ksianzou, Viachaslau A1 - Villasmunta, Francesco A1 - Zesch, Christoph A1 - Pulwer, Silvio A1 - Burger, Martin A1 - Bauer, Joachim A1 - Heinrich, Friedhelm A1 - Schrader, Sigurd A1 - Vitale, Francesco A1 - De Matteis, Fabio A1 - Prosposito, Paolo A1 - Casalboni, Mauro A1 - Mai, Andreas T1 - Silicon-organic hybrid photonics: an overview of recent advances, electro-optical effects and CMOS integration concepts JF - Journal of Physics: Photonics N2 - In recent decades, much research effort has been invested in the development of photonic integrated circuits, and silicon-on-insulator technology has been established as a reliable platform for highly scalable silicon-based electro-optical modulators. However, the performance of such devices is restricted by the inherent material properties of silicon. An approach to overcoming these deficiencies is to integrate organic materials with exceptionally high optical nonlinearities into a silicon-on-insulator photonic platform. Silicon–organic hybrid photonics has been shown to overcome the drawbacks of silicon-based modulators in terms of operating speed, bandwidth, and energy consumption. This work reviews recent advances in silicon–organic hybrid photonics and covers the latest improvements to single components and device concepts. Special emphasis is given to the in-device performance of novel electro-optical polymers and the use of different electro-optical effects, such as the linear and quadratic electro-optical effect, as well as the electric-field-induced linear electro-optical effect. Finally, the inherent challenges of implementing non-linear optical polymers on a silicon photonic platform are discussed and a perspective for future directions is given. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13882 SN - 2515-7647 VL - 3 IS - 2 ER - TY - JOUR A1 - Regehly, Martin A1 - Hecht, Stefan T1 - Split-Aperture Xolography – Linear Volumetric Photoactivation with Short Axial Dimension and Low out of Focus Excitation JF - Advanced Science N2 - Spatially confined photo-excitation with the lowest possible activation of the remaining volume is of central importance for high-resolution high-density optical data storage, fluorescence microscopy, 3D-lithography, and 3D-printing. Two-photon absorption (2PA) enables such applications yet leads to slow processing speed due to the underlying non-linear absorption process. Here, Split-Aperture Xolography (SAX), is introduced which uses stepwise excitation of dual-color responsive molecules to initiate a linear volumetric photo-reaction process that is up to several orders of magnitude more efficient than 2PA. The capabilities of SAX are investigated in a scenario study for focusing systems with high numerical aperture (NA) using a Python implementation of vectorial diffraction theory. The intersecting half-cones generated by the split illuminated entrance aperture of the objective reduce the axial focal spot size of the activation distribution by up to a factor of two compared to 2PA targeting the same electronic transition. A steep average decline of the activation probability with the fifth power away from focus is found for a wide range of directions. This is significantly better in comparison to 2PA and prevents that undesired out-of-focus excitation events sum-up with subsequent irradiations. This approach is expected to be advantageous for volumetric methods at the nanoscale. KW - photoswitch KW - split-aperture xolography KW - two-photon absorption KW - vectorial diffraction KW - volumetric 3D printing Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20749 VL - 12 IS - 31 PB - Wiley ER - TY - CHAP A1 - Villasmunta, Francesco A1 - Steglich, Patrick A1 - Villringer, Claus A1 - Schrader, Sigurd A1 - Schenk, Harald A1 - Mai, Andreas A1 - Regehly, Martin ED - Chen, Ray T. ED - Schröder, Henning T1 - Design, fabrication, and characterization of integrated optical through-silicon waveguides for 3D photonic interconnections T2 - Optical Interconnects XXIV N2 - In the context of an ever-growing volume of data generated by established and emerging technologies, such as 5G, the Internet of Things, artificial intelligence, machine learning, blockchain, and virtual reality, faster communication speed is demanded by data centers and high-performance computing. Transceiver requirements surged from 100 to 400 Gb/s and beyond. In this scenario, photonics aims to enable Tb/s optical communication at energies below 1 pJ/bit. Targeting higher communication rates while maintaining a low power budget can significantly benefit from 3D photonic chip architectures. This paper presents the simulation-based design, fabrication, and characterization of a monolithically integrated optical through-silicon waveguide that facilitates the connection between different surfaces of a silicon chip. Deep reactive ion etching was employed in both the Bosch and Cryogenic variants to evaluate the effect of sidewall roughness on propagation losses. The mechanical stability of the waveguide was ensured by interrupting the annular trench with a bridging structure. The high-refractive-index contrast to air provides tight light confinement for a core size of up to 50 μm and multimode operation at 1550 nm. The morphology was characterized using scanning electron microscopy (SEM), and optical transmission characterization was performed using relative power loss measurements. A tunable laser source was buttcoupled to a waveguide to analyze light transmission efficiency. Preliminary measurements using single-mode fiber show that the transmitted values exceeded 99% for all structures. KW - multimode photonics KW - cryogenic etching KW - ICP-DRIE KW - optical interconnects KW - silicon photonics KW - 3D chip stacking Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-19759 VL - 12892 PB - Society of Photo-Optical Instrumentation Engineers (SPIE) ER - TY - JOUR A1 - Bauer, Joachim A1 - Heinrich, Friedhelm A1 - Villasmunta, Francesco A1 - Villringer, Claus A1 - Reck, Johanna A1 - Peters, Sven A1 - Treffer, Alexander A1 - Kuhnt, Christian A1 - Marschmeyer, Steffen A1 - Fursenko, Oksana A1 - Stolarek, David A1 - Mai, Andreas A1 - Regehly, Martin T1 - Reflectometric method for measuring residual oxides in through-silicon vias for 3D chip integration JF - Optics Express N2 - A significant aspect of fabricating 3D chip architectures is ensuring proper contact between the different layers of the chip, which often requires removing the underside of isolation layers before filling vias with conductive material. Currently, scanning electron microscopy is the established method for investigating such structures. In this paper, we propose a rapid, non-destructive optical analysis technique for the simultaneous measurement of through-silicon vias (TSV) depths, silicon wafer thickness, and residual oxide thickness. The proposed method utilizes Fourier peak shift analysis (FPSA) of reflectance measurements in the near-infrared (1200 nm—2200 nm) spectral regions. The application of FPSA to representative samples taken from a commercial TSV integration process for MEMS and CMOS fabrication demonstrated good agreement with reference scanning electron microscopy measurements, confirming the feasibility of the method for in-line and in-situ metrology. The results indicate that FPSA has great potential for real-time process monitoring and control during 3D chip manufacturing. KW - effective refractive index KW - Fourier transforms KW - near infrared KW - ray tracing KW - scanning electron microscopy KW - thin film Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20633 VL - 33 IS - 15 SP - 32175 EP - 32189 PB - Optica ER - TY - JOUR A1 - Bauer, Joachim A1 - Fursenko, Oksana A1 - Marschmeyer, Steffen A1 - Heinrich, Friedhelm A1 - Villasmunta, Francesco A1 - Villringer, Claus A1 - Zesch, Christoph A1 - Schrader, Sigurd T1 - Spectroscopic reflectometry for characterization of Through Silicon Via profile of Bosch etching process JF - Journal of Vacuum Science & Technology B N2 - Through Silicon Via (TSV) technology is a key in 3D integration of circuits by the creation of interconnects using vias, which go through the full silicon wafer. Typically, a highly-selective Bosch Si etch process is used. It is characterized by a high etch rate at a high aspect ratio, whereby scallops on the sidewalls are generated. In this work, square via arrays with dimensions from 3 to 50 μm and up to 300 μm depth were fabricated and analyzed by spectroscopic reflectometry. The reflectometric data are compared to simulations by a novel theoretical approach. In order to simulate the reflectance spectra of TSV arrays, a combination of 2D and 3D rigorous coupled wave analysis was applied. Besides the via depth, the sidewall angle and the corner radius of the bottom profile were considered in the model. The general requirements on spectral resolution in TSV metrology are discussed. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-16093 VL - 37 IS - 6 PB - American Vacuum Society (AVS) ER - TY - GEN A1 - van de Sand, Ron A1 - Reiff-Stephan, Jörg T1 - FrostByte Dataset N2 - It is with great pleasure that we announce the release of the “Frost Byte” dataset. The dataset was collected during research on fault detection and diagnosis (FDD) approaches and their transferability to heterogeneous systems of industrial refrigeration systems at the Technical University of Applied Sciences Wildau. The data collection took place between 2018 and 2019 and is intended to supplement the ASHRAE 1043-RP dataset (Comstock & Braun, 1999), which has been the only publicly available data source in this area to date. For comparison purposes, the method of data collection was chosen similarly, whereby this dataset collection was carried out using a ~ 100 kW refrigeration capacity ammonia system with plate heat exchangers. The dataset contains steady-state data equally sampled from five classes: 1. Normal (fault-free operating condition) 2. Reduced Condenser Water Flow 3. Reduced Evaporator Water Flow 4. Non-Condensable Gases 5. Refrigeration Leak Each class was investigated under changing operational conditions and varying fault severity levels (SL). KW - predictive maintenance KW - FDD KW - machine learning Y1 - 2021 U6 - https://doi.org/10.15771/1894 N1 - Related dissertation: van de Sand, R. (2021). A Predictive maintenance model for heterogeneous industrial refrigeration systems. https://hdl.handle.net/2108/323763 Related journal article: van de Sand, R., Corasaniti, S., & Reiff-Stephan, J. (2021). Data-driven fault diagnosis for heterogeneous chillers using domain adaptation techniques. Control Engineering Practice, 112, 104815. https://doi.org/10.1016/j.conengprac.2021.104815 ER - TY - GEN A1 - Hartmann, Lutz A1 - Tatai, Tiberiu-Mihai A1 - Kaiser, Mario A1 - Dreyer, Christian T1 - Erwärmung von Materialien und Werkstoffen durch Anwendung von Mikrowellentechnologien T2 - Wissenschaftliche Beiträge 2019 N2 - Die Erwärmung unterschiedlicher Materialien im ­Kontext verschiedener Anwendungen kann anhand der Bestrahlung mit Mikrowellen in geeignet konstruierten Öfen erfolgen. Der vorliegende Beitrag beginnt mit einer Vorstellung der mikroskopischen Mechanismen der Erwärmung von Materie mittels Mikrowellen sowie einem Abriss ihrer theoretischen Beschreibung. Im Folgenden werden die breitbandige dielektrische Spektroskopie und die Simulation elektromagnetischer Felder als Hilfsmittel eingeführt, die Effizienz des mikrowellenbasierten Heizens für bestimmte Materialien vorab einschätzen zu können. Nach der Vorstellung zweier unterschiedlicher Mikrowellenanlagen, namentlich eines Kammer- und eines Durchlaufmikrowellenofens, wird die thermische Behandlung unterschiedlicher Materialien mittels Mikrowellen an drei Beispielen illustriert. N2 - The heating of various materials in the context of different applications can be achieved by irradiation with microwaves in properly constructed microwave ovens. This article starts with an introduction to the microscopic mechanisms of heating of matter followed by a survey of their theoretical description. Both, broadband dielectric spectroscopy and the simulation of electromagnetic fields will be presented as convenient tools to estimate the efficiency of microwave-based heating of certain materials prior to any experiment. In addition to an introduction of two different microwave ovens, namely a chamber oven and a throughput oven, the thermal treatment of different materials is illustrated by three examples. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10812 SN - 0949-8214 VL - 23 SP - 39 EP - 48 ER - TY - GEN A1 - Hotes, Andreas G. A1 - Schwahn, Klaus-Jürgen A1 - Fabienke, Henrike T1 - Betrachtung von neuartigen Antriebs- und Kraftstoffkonzepten mit dem Ziel der Konzeption ­einer Hybridtankstelle für den Flugplatz Schönhagen für die Versorgung von Luftfahrzeugen mit nachhaltigen Kraftstoffen T2 - Wissenschaftliche Beiträge 2019 N2 - Dieser wissenschaftliche Beitrag befasst sich zunächst mit der Betrachtung von neuartigen und nachhaltigen Antriebs- und Kraftstoffkonzepten für den Einsatz in der Luftfahrt, die zum Erreichen der hochgesteckten Klimaschutzziele auf nationaler, europäischer und internationaler Ebene beitragen sollen. Um die Energieversorgung dieser Luftfahrzeuge gewährleisten zu können, wurde ein Tankstellensystem beispielhaft für den Flugplatz Schönhagen konzipiert, welches Strom, Wasserstoff und Power-to-Liquid-Kraftstoff für Elektro-, Wasserstoff- und Luftfahrzeuge mit konventionellem Verbrennungsmotor sowie für Hybridflugzeuge zur Verfügung stellen soll. Ziel dieses Konzeptes ist die komplette Eigenproduktion der Kraftstoffe auf dem Flugplatz. Hierzu wurden rechtliche, wirtschaftliche und vor allem technische Voraussetzungen untersucht und ausgewertet sowie Berechnungen bezüglich der benötigten Kraftstoff- und Stromkapazitäten durchgeführt. N2 - This paper will initially focus on novel and sustainable propulsion and fuel concepts for use in aviation, which should contribute to the achievement of ambitious climate protection goals at national, European an international level. To ensure the energy supply of these aircrafts, a filling station system was designed as an example for the Schönhagen airfield, which provides electricity, hydrogen and power-to-liquid-fuel for electric and hydrogen driven aircrafts, aircrafts with conventional combustion engines as well as for hybrid aircrafts. The aim of this concept is the complete in-house production of fuels on the airfield. For this purpose, legal, economic, and above all technical requirements, were examined and evaluated and calculations were carried out regarding the required fuel and power capacities. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-11939 SN - 0949-8214 VL - 23 SP - 49 EP - 55 ER - TY - GEN A1 - Gerhard, Christoph A1 - Letien, Emilie A1 - Cressent, Thomas A1 - Hofmann, Mandy T1 - Impact of the plasma power on plasma-induced increase in absorption of fused silica T2 - Wissenschaftliche Beiträge 2019 N2 - In the last decades, laser machining of fused silica has gained in importance where the main challenge is to overcome the high transmission of this medium in order to achieve surface absorption. One approach is plasma treatment using hydrogenous process gases. In doing so, a near-surface glass layer is chemically modified by a removal of oxygen and an implantation of hydrogen, resulting in the formation of optically active defects and an increase in absorption. Against this background, the impact of the plasma power on plasma-induced increase in absorption of fused silica was investigated in the present work. Here, the highest efficiency of the plasma treatment process was found at the lowest applied plasma power whereas for higher plasma powers, a notably lower increase in absorption was observed. This effect is attributed to the decomposition of plasma species required for initiating the formation of optically active defects within the glass. Such decomposition increases with rising power due to the corresponding increase in electric field strength within the plasma. This finding is of substantial interest for an extensive understanding of plasma-glass interactions. N2 - Die Laserbearbeitung von Quarzglas hat in den letzten Jahrzehnten an Bedeutung gewonnen. Dabei besteht die Herausforderung darin, die hohe Transmission dieses Mediums zu überwinden. Hierzu stellt eine Plasmabehandlung mittels wasserstoffhaltigen Prozessgasen einen Ansatz dar. Dabei wird eine oberflächennahe Glasschicht durch Entfernung von Sauerstoff und Implantation von Wasserstoff chemisch modifiziert, woraus die Ausbildung optisch aktiver Defekte und ein Anstieg der Absorption resultieren. Vor diesem Hintergrund wurde in dieser Arbeit der Einfluss der Plasmaleistung auf die plasmainduzierte Absorptionssteigerung untersucht. Die höchste Effizienz der Plasmabehandlung wurde bei der geringsten applizierten Leistung erzielt, wohingegen bei höheren Plasmaleistungen nennenswert geringere Absorptionssteigerungen beobachtet wurden. Dieser Effekt wird auf den Zerfall von Plasmaspezies, die für eine Ausbildung optisch aktiver Defekte benötigt werden, zurückgeführt, welcher mit ansteigender Leistung und dem damit einhergehenden Anstieg der elektrischen Feldstärke im Plasma anwächst. Diese Erkenntnis ist von hohem Interesse für ein umfassendes Verständnis von Plasma-Glas-Wechselwirkungen. N2 - Ces dernières décennies, les applications laser en usine composées de silice fondue ont gagné en importance, l'enjeu consistant à surmonter le problème de la transmission élevée de ce milieu dans le but d’obtenir l’absorption de surface. Une façon d’aborder le problème est d’appliquer le traitement au plasma en utilisant des procédés au gaz de dihydrogène. En agissant ainsi, une couche de verre proche de la surface est modifiée chimiquement par l’ablation d’oxygène et l’implantation d’hydrogène, ce qui provoque la formation de défauts optiquement actifs et l’augmentation de l’absorption. Dans ce contexte, l’impact de la puissance du plasma sur l’augmentation de l’absorption de silice fondue induite par le plasma a été étudié dans cet article. Ici, la meilleure efficacité du traitement au plasma a été constatée à la puissance de plasma la plus faible tandis que pour de plus fortes puissances, une augmentation bien plus faible en absorption a été observée. Cet effet est attribué à la décomposition des espèces de plasma requises dans la formation des défauts optiquement actifs à l’intérieur du verre. Une telle décomposition augmente avec la montée de puissance due à l'augmentation de force du champ électrique dans le plasma. Cette découverte est d’un intérêt considérable pour une compréhension plus poussée des interactions plasma-verre. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10802 SN - 0949-8214 VL - 23 SP - 33 EP - 37 ER - TY - GEN A1 - Handrich, Jan A1 - Vandenhouten, Ralf T1 - Erweiterung eines landmarkenbasierten Innenraumortungsverfahrens für Mobilgeräte mit ARCore T2 - Wissenschaftliche Beiträge 2019 N2 - Die Lokalisierung in Innenräumen, die sich nicht auf Satellitennavigation wie GPS verlassen kann, ist nach wie vor eine Herausforderung. Viele Methoden zur Lokalisierung in Innenräumen beruhen auf Funksignalen oder anderen Sendern (z.B. Infrarot), die eine kostenintensive Infrastruktur erfordern, die in einem Gebäude installiert werden muss. Außerdem sind diese Techniken ungenau, wenn Reflexionen der Signale in einem Gebäude auftreten. Die Forschungsgruppe Telematik der TH Wildau hat für diese Problemstellung ein optisches Verfahren zur Innenraumlokalisierung entwickelt, das die Kamera eines mobilen Geräts verwendet. Dieser Ansatz erfordert nur die Verfügbarkeit von mehreren identifizierbaren Landmarken, die kostengünstig in einem Gebäude installiert werden können. In diesem Beitrag soll eine Möglichkeit vorgestellt werden, dieses landmarkenbasierte Verfahren mit der Augmented Reality-Bibliothek ARCore von Google zu erweitern, um eine kontinuierliche Positionsermittlung zu ermöglichen, auch wenn vorübergehend keine Landmarken durch die Gerätekamera erfasst ­werden können. N2 - Indoor localization, which cannot rely on satellite navigation such as GPS, remains a challenge. Many indoor localization methods depend on radio signals or other transmitters (e.g. infrared) that require a costly infrastructure to be installed in a building. In addition, these techniques are inaccurate when reflections of the signals occur in a building. The telematics research group at TH Wildau has developed an optical method for indoor localization for this problem that uses the camera of a mobile device. This approach only requires the availability of several identifiable landmarks that can be installed cost-effectively in a building. In this article, a way is presented to extend this landmark based method with Google's Augmented Reality library ARCore to enable continuous position tracking even if no landmarks can be captured by the device ­camera temporarily. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10790 SN - 0949-8214 VL - 23 SP - 27 EP - 32 ER -