@inproceedings{BauerHeinrichFursenkoetal.2017, author = {Bauer, Joachim and Heinrich, Friedhelm and Fursenko, Oksana and Marschmeyer, Steffen and Bluemich, Adrian and Pulwer, Silvio and Steglich, Patrick and Villringer, Claus and Mai, Andreas and Schrader, Sigurd}, title = {Very high aspect ratio through silicon via reflectometry}, series = {Proceedings of SPIE}, booktitle = {Proceedings of SPIE}, issn = {1996-756X}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13758}, year = {2017}, abstract = {Through Silicon Via (TSV) technology is a key feature of new 3D integration of circuits by creation of interconnections using vias, which go through the silicon wafer. Typically, the highly-selective Bosch Si etch process, characterized by a high etch rate and high aspect ratio and forming of scallops on the sidewalls is used. As presented in this paper, we have developed an experimental setup and a respective evaluation algorithm for the control and monitoring of very high aspect ratio TSV profiles by spectroscopic reflectometry. For this purpose square via arrays with lateral dimension from 3 to 10 μm were fabricated by a Bosch etch process and analyzed by our setup. By exploiting interference and diffraction effects of waves reflected from the top and bottom surfaces as well as from the side walls of the TSV patterns, the measurements provided etch depths, CD values and scallop periods. The results were compared with data obtained by a commercial wafer metrology tool. Aspect ratios of up to 35:1 were safely evaluable by our setup.}, language = {en} } @inproceedings{VillringerGilaniZhangetal.2019, author = {Villringer, Claus and Gilani, Taravat Saeb and Zhang, Edward and Pulwer, Silvio and Steglich, Patrick and Schrader, Sigurd and Laufer, Jan}, title = {Development of tuneable Fabry-P{\´e}rot sensors for parallelised photoacoustic signal acquisition}, series = {Proc. SPIE 10878, Photons Plus Ultrasound: Imaging and Sensing 2019, 108780M (8 March 2019)}, booktitle = {Proc. SPIE 10878, Photons Plus Ultrasound: Imaging and Sensing 2019, 108780M (8 March 2019)}, issn = {1996-756X}, doi = {10.1117/12.2509437}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13769}, year = {2019}, abstract = {Fabry-P{\´e}rot (FP) sensors have enabled high resolution 3D photoacoustic (PA) imaging in backward mode. However, raster-scanning of the interrogation laser beam across the sensor can result in slow 3D image acquisition. To overcome this limitation, parallelized PA signal acquisition can be used for which FP sensors with uniform optical thickness are required. In this work, the optical thickness is tuned a) irreversibly through the use of a photopolymer host matrix and b) actively using embedded electro-optic (EO) chromophores. Polymer spacers (5 μm) were deposited using spin coating and sandwiched between two dielectric mirrors and transparent ITO electrodes. The employed polymer guest-host system consists of an EO chromophore (2-methyl-4-nitroaniline) and poly(vinyl cinnamate). EO tuneability was induced using contact poling and a tuneability of 68 pm was demonstrated. The optical thickness was homogenised by raster scanning a UV beam whilst varying the exposure time across a 4 mm2 detection aperture.}, language = {en} } @inproceedings{PulwerFiebelkornZeschetal.2019, author = {Pulwer, Silvio and Fiebelkorn, Richard and Zesch, Christoph and Steglich, Patrick and Villringer, Claus and Villasmunta, Francesco and Gedat, Egbert and Handrich, Jan and Schrader, Sigurd and Vandenhouten, Ralf}, title = {Endoscopic orientation by multimodal data fusion}, series = {Proc. SPIE 10931, MOEMS and Miniaturized Systems XVIII}, booktitle = {Proc. SPIE 10931, MOEMS and Miniaturized Systems XVIII}, issn = {1996-756X}, doi = {10.1117/12.2508470}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-11420}, year = {2019}, abstract = {To improve the feasibility of endoscopic inspection processes we developed a system that provides online information about position, orientation and viewing direction of endoscopes, to support the analysis of endoscopic images and to ease the operational handling of the equipment. The setup is based on an industrial endoscope consisting of a camera, various MEMS and multimodal data fusion. The software contains algorithms for feature and geometric structure recognition as well as Kalman filters. To track the distal end of the endoscope and to generate 3D point cloud data in real time the optical and photometrical characteristics of the system are registered and the movement of the endoscope is reconstructed by using image processing techniques.}, language = {en} } @inproceedings{PulwerSteglichVillringeretal.2016, author = {Pulwer, Silvio and Steglich, Patrick and Villringer, Claus and Bauer, Joachim and Burger, Martin and Franz, M. and Grieshober, K. and Wirth, F. and Blondeau, J. and Rautenberg, J. and Mouti, S. and Schrader, Sigurd}, title = {Triangulation-based 3D surveying borescope}, publisher = {SPIE}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15307}, pages = {51 -- 56}, year = {2016}, abstract = {In this work, a measurement concept based on triangulation was developed for borescopic 3D-surveying of surface defects. The integration of such measurement system into a borescope environment requires excellent space utilization. The triangulation angle, the projected pattern, the numerical apertures of the optical system, and the viewing angle were calculated using partial coherence imaging and geometric optical raytracing methods. Additionally, optical aberrations and defocus were considered by the integration of Zernike polynomial coefficients. The measurement system is able to measure objects with a size of 50 μm in all dimensions with an accuracy of ± 5 μm. To manage the issue of a low depth of field while using an optical high resolution system, a wavelength dependent aperture was integrated. Thereby, we are able to control depth of field and resolution of the optical system and can use the borescope in measurement mode with high resolution and low depth of field or in inspection mode with low resolution and higher depth of field. First measurements of a demonstrator system are in good agreement with our simulations.}, language = {en} } @article{BondarenkoHuelsemannMaietal.2021, author = {Bondarenko, Siegfried and H{\"u}lsemann, Marcel and Mai, Andreas and Steglich, Patrick}, title = {Fiber-to-chip light coupling using a graded-index lensed fiber collimator}, series = {Optical Engineering}, volume = {60}, journal = {Optical Engineering}, number = {1}, publisher = {SPIE}, issn = {1560-2303}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13749}, year = {2021}, abstract = {Fiber-to-chip light coupling using a graded-index (GRIN) fiber collimator is investigated. Our experiments with grating couplers and strip waveguides fabricated in a photonic integrated circuit technology reveal that the peak coupling efficiency of a GRIN fiber collimator is 7.8 dB lower than that of a single-mode fiber. However, the 3-dB alignment tolerance is improved by a factor of about 5.7 giving rise to pluggable sensor solutions. This work opens a path toward a cost-effective and portable sensor platform based on pluggable photonic biosensors using GRIN fiber collimators.}, language = {en} } @misc{SteglichVillringerPulweretal.2016, author = {Steglich, Patrick and Villringer, Claus and Pulwer, Silvio and Bauer, Joachim and Heinrich, Friedhelm and Casalboni, Mauro and Schrader, Sigurd}, title = {Advanced Nanophotonics: Silicon-Organic Hybrid Technology}, series = {Wissenschaftliche Beitr{\"a}ge 2016}, volume = {20}, journal = {Wissenschaftliche Beitr{\"a}ge 2016}, issn = {0949-8214}, doi = {10.15771/0949-8214_2016_1_6}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-5337}, pages = {45 -- 48}, year = {2016}, abstract = {Integrated photonic devices have gained increasing research interests. Especially silicon photonics have become very attractive for various optical applications. Using silicon-on-insulator as a material platform provides the ability to fabricate photonic devices with electronic devices on a single chip. Driven by substantial research investments, the integration of photonic devices on silicon-on-insulator substrates has reached a degree of maturity that already permits industrial adoption. However, silicon has the disadvantage of linear electro-optical effects, and, therefore, advanced modulation formats are difficult to realize when using silicon-based high-speed modulators. Hence, a new approach was proposed: the silicon-organic hybrid technology. This technology is a viable extension of the silicon-on-insulator material system for efficient high-speed modulation. We herewith present our theoretical and experimental investigations of the silicon-organic hybrid slot-waveguide ring resonator. The advanced device design is described in detail, which allows using both, the efficient silicon-on-insulator strip-waveguides and the silicon-organic hybrid slot-waveguides in single ring resonator. For the first time, we report the transmission spectra of such a resonator covered with an electro-optical polymer.}, language = {en} } @article{SteglichMaiVillringeretal.2018, author = {Steglich, Patrick and Mai, Christian and Villringer, Claus and Pulwer, Silvio and Casalboni, Mauro and Schrader, Sigurd and Mai, Andreas}, title = {Quadratic electro-optic effect in silicon-organic hybrid slot-waveguides}, series = {Optics Letters}, volume = {43}, journal = {Optics Letters}, number = {15}, issn = {1539-4794}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-12148}, year = {2018}, abstract = {This Letter reports on the quadratic electro-optic effect of polymers, observed in a silicon slot-waveguide at low voltages. We demonstrate that in narrow slots, the electro-optic response with respect to refractive index change is strong enough for on-chip wavelength tuning and intensity modulation using voltages as low as 1 V. A silicon slot-waveguide embedded by a nonlinear optical polymer, consisting of the dye Disperse Red 1 in poly(methyl methacrylate), serves as the phase shifter in a racetrack ring resonator. As deduced from the experimental data, the third-order susceptibility of the utilized electro-optic polymer is about 2·10-19 m2/V2. The demonstrated low-voltage operation and inherently thermal stability show the potential for silicon-organic hybrid devices using the quadratic electro-optic effect.}, language = {en} } @article{SteglichMaiVillringeretal.2021, author = {Steglich, Patrick and Mai, Christian and Villringer, Claus and Dietzel, Birgit and Bondarenko, Siegfried and Ksianzou, Viachaslau and Villasmunta, Francesco and Zesch, Christoph and Pulwer, Silvio and Burger, Martin and Bauer, Joachim and Heinrich, Friedhelm and Schrader, Sigurd and Vitale, Francesco and De Matteis, Fabio and Prosposito, Paolo and Casalboni, Mauro and Mai, Andreas}, title = {Silicon-organic hybrid photonics: an overview of recent advances, electro-optical effects and CMOS integration concepts}, series = {Journal of Physics: Photonics}, volume = {3}, journal = {Journal of Physics: Photonics}, number = {2}, issn = {2515-7647}, doi = {10.1088/2515-7647/abd7cf}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13882}, year = {2021}, abstract = {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.}, language = {en} } @inproceedings{BadoniBonaiutoCasalbonietal.2020, author = {Badoni, Davide and Bonaiuto, Vincenzo and Casalboni, Mauro and De Matteis, Fabio and Di Giuseppe, Giovanni and Frontini, Luca and Gunnella, Roberto and Liberali, Valentino and Mai, Andreas and Paoluzzi, Giovanni and Prosposito, Paolo and Salamon, Andrea and Salina, Gaetano and Sargeni, Fausto and Schrader, Sigurd and Stabile, Alberto and Steglich, Patrick}, title = {Characterization and Tests of Different Mach-Zehnder Silicon Photonic Modulator Configurations}, series = {Photonics and Photoactive Materials}, booktitle = {Photonics and Photoactive Materials}, editor = {Prosposito, Paolo}, publisher = {Materials Research Forum LLC}, address = {Millersville, PA}, isbn = {978-1-64490-071-0}, doi = {10.21741/9781644900710-1}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13731}, pages = {1 -- 5}, year = {2020}, abstract = {We designed and produced an integrated silicon photonic circuit, in a single chip with IHP SG25H4_EPIC 0.25 µm technology. A Mach-Zehnder interferometer with an alternative shape for better integration, together with a standard-shape Mach-Zehnder interferometer have been realized. In this work, preliminary results of comparative performance measurements between the two Mach-Zehnder interferometer are shown.}, language = {en} } @inproceedings{SteglichMaiStolareketal.2016, author = {Steglich, Patrick and Mai, Christian and Stolarek, David and Lischke, Stefan and Kupijai, Sebastian and Villringer, Claus and Pulwer, Silvio and Heinrich, Friedhelm and Bauer, Joachim and Meister, Stefan and Knoll, Dieter and Casalboni, Mauro and Schrader, Sigurd}, title = {Partially slotted silicon ring resonator covered with electro-optical polymer}, series = {Proceedings of SPIE}, booktitle = {Proceedings of SPIE}, issn = {1996-756X}, doi = {10.1117/12.2217725}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13771}, year = {2016}, abstract = {In this work, we present for the first time a partially slotted silicon ring resonator (PSRR) covered with an electro-optical polymer (Poly[(methyl methacrylate)-co-(Disperse Red 1 acrylate)]). The PSRR takes advantage of both a highly efficient vertical slot waveguide based phase shifter and a low loss strip waveguide in a single ring. The device is realized on 200 mm silicon-on-insulator wafers using 248 nm DUV lithography and covered with the electro-optic polymer in a post process. This silicon-organic hybrid ring resonator has a small footprint, high optical quality factor, and high DC device tunability. A quality factor of up to 105 and a DC device tunability of about 700 pm/V is experimentally demonstrated in the wavelength range of 1540 nm to 1590 nm. Further, we compare our results with state-of-the-art silicon-organic hybrid devices by determining the poling efficiency. It is demonstrated that the active PSRR is a promising candidate for efficient optical switches and tunable filters.}, language = {en} } @inproceedings{SteglichPaulMaietal.2021, author = {Steglich, Patrick and Paul, Martin and Mai, Christian and B{\"o}hme, Andrea and Bondarenko, Siegfried and Weller, Michael G. and Mai, Andreas}, title = {A monolithically integrated micro fluidic channel in a silicon-based photonic-integrated-circuit technology for biochemical sensing}, series = {Proc. SPIE 11772, Optical Sensors 2021}, booktitle = {Proc. SPIE 11772, Optical Sensors 2021}, doi = {10.1117/12.2588791}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13925}, year = {2021}, abstract = {In this work, a cost-effective optofluidic system is propossed and preliminary experimental results are presented. A microfluidic channel monolithically integrated into a photonic integrated circuit technology is used in conjunc- tion with a cyclo-olefin copolymer (COC) substrate to provide fluidic in- and output ports. We report on initial experimental results as well as on the simple and cost-effective fabrication of this optofluidic system by means of micro-milling.}, language = {en} } @article{SteglichBondarenkoMaietal.2020, author = {Steglich, Patrick and Bondarenko, Siegfried and Mai, Christian and Paul, Martin and Weller, Michael G. and Mai, Andreas}, title = {CMOS-Compatible Silicon Photonic Sensor for Refractive Index Sensing Using Local Back-Side Release}, series = {IEEE Photonics Technology Letters}, volume = {32}, journal = {IEEE Photonics Technology Letters}, number = {19}, issn = {1941-0174}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13649}, pages = {1241 -- 1244}, year = {2020}, abstract = {Silicon photonic sensors are promising candidates for lab-on-a-chip solutions with versatile applications and scalable production prospects using complementary metal-oxide semiconductor (CMOS) fabrication methods. However, the widespread use has been hindered because the sensing area adjoins optical and electrical components making packaging and sensor handling challenging. In this work, a local back-side release of the photonic sensor is employed, enabling a separation of the sensing area from the rest of the chip. This approach allows preserving the compatibility of photonic integrated circuits in the front-end of line and metal interconnects in the back-end of line. The sensor is based on a micro-ring resonator and is fabricated on wafer-level using a CMOS technology. We revealed a ring resonator sensitivity for homogeneous sensing of 106 nm/RIU.}, language = {en} } @inproceedings{SteglichMai2021, author = {Steglich, Patrick and Mai, Andreas}, title = {Analysis of BTO-on-Si-waveguides for energy-efficient electro-optical modulators}, series = {Proc. SPIE 11775, Integrated Optics: Design, Devices, Systems and Applications VI}, booktitle = {Proc. SPIE 11775, Integrated Optics: Design, Devices, Systems and Applications VI}, doi = {10.1117/12.2592501}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13934}, year = {2021}, abstract = {In this work, we analyze a horizontal slot waveguide configuration, which evaluates the potential for an integration of barium titanate (BTO) based modulators into a photonic integrated circuit (PIC) technology based on siliconon- insulator (SOI) wafer. The waveguide configuration consists of a doped crystal silicon layer, a Ba0:7Sr0:3TiO3 (BST) template layer, a barium titanate (BTO) layer and a doped poly-silicon layer on top. In contrast to current approaches, we analyze the performance of this waveguide-structure by using a vertical electrode configuration that is formed by the doped silicon layer. In this way, the electric field strength is dramatically increased compared to current horizontal electrode configuration.}, language = {en} } @article{SteglichMaiVillringeretal.2020, author = {Steglich, Patrick and Mai, Christian and Villringer, Claus and Mai, Andreas}, title = {Direct observation and simultaneous use of linear and quadratic electro-optical effects}, series = {Journal of Physics D: Applied Physics}, volume = {53}, journal = {Journal of Physics D: Applied Physics}, number = {12}, issn = {1361-6463}, doi = {10.1088/1361-6463/ab6059}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13032}, year = {2020}, abstract = {We report on the direct observation and simultaneous use of the linear and quadratic electro-optical effect and propose a method by which higher-order susceptibilities of electro-optical materials can be determined. The evaluation is based on the separation of the second- and third-order susceptibilities and the experimental technique uses a slot waveguide ring resonator fabricated in integrated photonic circuit technology, which is embedded by a guest-host polymer system consisting of the azobenzene dye Disperse Red 1 in a poly(methyl methacrylate) matrix as an active electro-optical material. The contribution of both effects on the electro-optical response under the influence of static and time-varying electrical fields is investigated. We show that the quadratic electro-optical effect has a significant influence on the overall electro-optical response even with acentric molecular orientated molecules. Our findings have important implications for developing electro-optical devices based on polymer-filled slot waveguides and give rise to advanced photonic circuits.}, language = {en} } @article{BauerGutkeHeinrichetal.2020, author = {Bauer, Joachim and Gutke, Marko and Heinrich, Friedhelm and Edling, Matthias and Stoycheva, Vesela and Kaltenbach, Alexander and Burkhardt, Martin and Gruenefeld, Martin and Gamp, Matthias and Gerhard, Christoph and Steglich, Patrick and Steffen, Sebastian and Herzog, Michael and Dreyer, Christian and Schrader, Sigurd}, title = {Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses}, series = {Optical Materials Express}, volume = {10}, journal = {Optical Materials Express}, number = {9}, issn = {2159-3930}, doi = {10.1364/OME.393844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13472}, pages = {2085 -- 2099}, year = {2020}, abstract = {In this work we present a novel optical polymer system based on polyurethane elastomer components, which combines excellent UV transparency with high thermal stability, good hardness, high surface tension and long pot life. The material looks very promising for encapsulation and microlensing applications for chip-on-board (CoB) light-emitting diodes (LED). The extinction coefficient k, refractive index n, and bandgap parameters were derived from transmission and reflection measurements in a wavelength range of 200-890 nm. Thermogravimetry and differential scanning calorimetry were used to provide glass transition and degradation temperatures. The surface tension was determined by means of contact angle measurements. As proof of concept, a commercial InGaN-CoB-LED is used to demonstrate the suitability of the new material for the production of microlenses.}, language = {en} } @unpublished{SteglichRabusSadaetal.2021, author = {Steglich, Patrick and Rabus, Dominik G. and Sada, Cinzia and Paul, Martin and Weller, Michael G. and Mai, Christian and Mai, Andreas}, title = {Silicon Photonic Micro-Ring Resonators for Chemical and Biological Sensing: A Tutorial}, series = {TechRxiv}, journal = {TechRxiv}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-16840}, year = {2021}, abstract = {Silicon photonic micro-ring resonators (MRR) developed on the silicon-on-insulator (SOI) platform, owing to their high sensitivity and small footprint, show great potential for many chemical and biological sensing applications such as label-free detection in environmental monitoring, biomedical engineering, and food analysis. In this tutorial, we provide the theoretical background and give design guidelines for SOI-based MRR as well as examples of surface functionalization procedures for label-free detection of molecules. After introducing the advantages and perspectives of MRR, fundamentals of MRR are described in detail, followed by an introduction to the fabrication methods, which are based on a complementary metal-oxide semiconductor (CMOS) technology. Optimization of MRR for chemical and biological sensing is provided, with special emphasis on the optimization of waveguide geometry. At this point, the difference between chemical bulk sensing and label-free surface sensing is explained, and definitions like waveguide sensitivity, ring sensitivity, overall sensitivity as well as the limit of detection (LoD) of MRR are introduced. Further, we show and explain chemical bulk sensing of sodium chloride (NaCl) in water and provide a recipe for label-free surface sensing.}, language = {en} } @article{BondarenkoVillringerSteglich2019, author = {Bondarenko, Siegfried and Villringer, Claus and Steglich, Patrick}, title = {Comparative Study of Nano-Slot Silicon Waveguides Covered by Dye Doped and Undoped Polymer Cladding}, series = {Applied Sciences}, volume = {9}, journal = {Applied Sciences}, number = {1}, publisher = {MDPI}, issn = {2076-3417}, doi = {10.3390/app9010089}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-10716}, year = {2019}, abstract = {Nonlinear optical dyes doped in optical polymer matrices are widely used for electro-optical devices. Linear optical properties change with dye concentration, which leads to a change in modal properties, especially in nano-structured integrated waveguides such as silicon slot-waveguides. Here, we investigate the influence of a nonlinear optical dye on the performance of a silicon-organic hybrid slot-waveguide. A simulation study of the modal and optical confinement properties is carried out and dependence of the structural parameters of the slot-waveguide and the organic cladding material is taken into account. As cladding material, a guest-host polymer system is employed comprising the nonlinear optical dye Disperse Red 1 (DR1) doped in a poly[methyl methacrylate] (PMMA) matrix. The refractive indices of doped and undoped PMMA were deduced from ellipsometric data. We present a guideline for an optimized slot-waveguide design for the fabrication in silicon-on-insulator technology giving rise to scalable, high-performance integrated electro-optical modulators.}, language = {en} } @incollection{Steglich2018, author = {Steglich, Patrick}, title = {Silicon-on-Insulator Slot Waveguides: Theory and Applications in Electro-Optics and Optical Sensing}, series = {Emerging Waveguide Technology}, booktitle = {Emerging Waveguide Technology}, editor = {You, Kok Yeow}, publisher = {IntechOpen}, isbn = {978-1-78923-493-0}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-10563}, publisher = {Technische Hochschule Wildau}, pages = {187 -- 210}, year = {2018}, abstract = {This chapter deals with the basic concept of silicon-on-insulator (SOI) slot waveguides,including slot waveguide theory, fabrication steps, and applications. First, in the theorysection, a modal field expression and the characteristic equation is derived, which is alsovalid for higher-order modes. SOI slot waveguide structures are simulated and character-istic values like the effective refractive indices and the field confinement factors are deter-mined. The fabrication section describes typical SOI fabrication steps and the limits ofcurrent fabrication techniques. Additionally, developments regarding loss reduction inSOI slot waveguides are given from the fabrication point of view. This is followed by thetheory and practice of slot waveguide based electro-optical modulators. Here, the SOI slotwaveguide is embedded in an organic nonlinear optical material in order to achieverecord-low voltage-length products. In the field of optical sensors, it is shown that slotwaveguides enable remarkable waveguide sensitivity for both refractive index sensingand surface sensing.}, language = {en} } @misc{SteglichVillringerPulweretal.2017, author = {Steglich, Patrick and Villringer, Claus and Pulwer, Silvio and Dietzel, Birgit and Ksianzou, Viachaslau and Schrader, Sigurd}, title = {Chip-integrierte photonische Bauelemente}, series = {Wissenschaftliche Beitr{\"a}ge 2017}, volume = {21}, journal = {Wissenschaftliche Beitr{\"a}ge 2017}, issn = {0949-8214}, doi = {10.15771/0949-8214_2017_7}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-9426}, pages = {55 -- 59}, year = {2017}, abstract = {In unserer hochtechnologisierten Gesellschaft spielt die optische Daten{\"u}bertragung aufgrund der stetig wachsenden Informationsvielfalt eine immer bedeutendere Rolle. In den Anf{\"a}ngen der Nachrichtentechnik waren Datenraten von wenigen bit/s realisierbar. Heute werden mittels optischer Technologien {\"U}bertragungsraten von mehreren Gbit/s umgesetzt. M{\"o}glich wird dies durch neue Entwicklungen in der Chip-integrierten Photonik. Beispiele daf{\"u}r sind Chip-integrierte elektrooptische Modulatoren und Schalter. In diesem Artikel werden neue Entwicklungen in der Chip-integrierten Photonik diskutiert und die experimentelle Charakterisierung der Bauelemente in Form eines Ringresonators beschrieben. F{\"u}r die Experimente wird exemplarisch ein photonisches Bauelement genutzt, das aus einem hybriden Silizium-Polymer-Materialsystem besteht. Die Ergebnisse zeigen, dass diese Materialkombination vielversprechend f{\"u}r zuk{\"u}nftige Chip-integrierte photonische Bauelemente mit extrem geringem Energiebedarf ist.}, language = {de} } @misc{SteglichKsianzouVillringeretal.2018, author = {Steglich, Patrick and Ksianzou, Viachaslau and Villringer, Claus and Pulwer, Silvio and Schrader, Sigurd}, title = {Theorie der Modenlinienspektroskopie zur optischen Charakterisierung von Polymerschichten}, series = {Wissenschaftliche Beitr{\"a}ge 2018}, volume = {22}, journal = {Wissenschaftliche Beitr{\"a}ge 2018}, issn = {0949-8214}, doi = {10.15771/0949-8214_2018_4}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-10248}, pages = {31 -- 38}, year = {2018}, abstract = {Die Modenlinienspektroskopie kann zur hochpr{\"a}zisen Charakterisierung von Polymerschichten bez{\"u}glich des Brechungsindex verwendet werden. Das vorliegende Manuskript behandelt die Theorie der Modenlinienspektroskopie und beginnt dabei mit den theoretischen Grundlagen eines planaren Wellenleiters, die zum Verst{\"a}ndnis der Modenlinienspektroskopie notwendig sind. Die hier pr{\"a}sentierten expliziten Herleitungen k{\"o}nnen genutzt werden, um die Modenlinienspektroskopie so zu modifizieren, dass auch die Messung des Pockelseffektes m{\"o}glich ist. Eine Anwendungsm{\"o}glichkeit soll in der zuk{\"u}nftigen Bestimmung des Pockelskoeffizienten bestehen, der f{\"u}r die Weiterentwicklung von polymerbasierten elektrooptischen Modulatoren ben{\"o}tigt wird. Zudem werden der Aufbau und die experimentelle Herangehensweisen beschrieben und die Brechungsindexbestimmung wird exemplarisch am Beispiel einer Wirt-Gast-Polymerschicht demonstriert.}, language = {de} } @article{SteglichHuelsemannDietzeletal.2019, author = {Steglich, Patrick and H{\"u}lsemann, Marcel and Dietzel, Birgit and Mai, Andreas}, title = {Optical Biosensors Based on Silicon-On-Insulator Ring Resonators: A Review}, series = {Molecules}, volume = {24}, journal = {Molecules}, number = {3}, issn = {1420-3049}, doi = {10.3390/molecules24030519}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-10822}, year = {2019}, abstract = {Recent developments in optical biosensors based on integrated photonic devices are reviewed with a special emphasis on silicon-on-insulator ring resonators. The review is mainly devoted to the following aspects: (1) Principles of sensing mechanism, (2) sensor design, (3) biofunctionalization procedures for specific molecule detection and (4) system integration and measurement set-ups. The inherent challenges of implementing photonics-based biosensors to meet specific requirements of applications in medicine, food analysis, and environmental monitoring are discussed.}, language = {en} } @article{SteglichVillringerDietzeletal.2019, author = {Steglich, Patrick and Villringer, Claus and Dietzel, Birgit and Mai, Christian and Schrader, Sigurd and Casalboni, Mauro and Mai, Andreas}, title = {On-Chip Dispersion Measurement of the Quadratic Electro-Optic Effect in Nonlinear Optical Polymers Using a Photonic Integrated Circuit Technology}, series = {IEEE Photonics Journal}, volume = {11}, journal = {IEEE Photonics Journal}, number = {3}, issn = {1943-0655}, doi = {10.1109/JPHOT.2019.2917665}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-12307}, year = {2019}, abstract = {A novel method to determine the dispersion of the quadratic electro-optic effect in nonlinear optical materials by using a silicon-on-insulator microring resonator is presented. The microring consists of a silicon slot waveguide enabling large dc electric field strength at low applied voltages. The dispersion of third-order hyperpolarizability of a linear conjugated dye is approximated by using a two-level model for the off-resonant spectral region. As an example, the dispersion of the resonance wavelength of the resonator filled with a dye doped polymer was measured in dependence of the applied dc voltage. The polymer was poly (methylmethacrylate) doped with 5 wt\% disperse red 1 (DR1), and the measurements have been carried out at the telecommunication wavelength band around 1550 nm (optical C-band). The described measurements represent a new technique to determine the dispersion of the third-order susceptibility and molecular hyperpolarizability of the material filled into the slot of the ring-resonator.}, language = {en} } @article{AnandSteglichKreissletal.2024, author = {Anand, Ketan and Steglich, Patrick and Kreissl, Jochen and Chavarin, Carlos Alvarado and Spirito, Davide and Franck, Max and Lecci, Giulia and Costina, Ioan and Herfurth, Norbert and Katzer, Jens and Mai, Christian and Becker, Annette and Reithmaier, Johann Peter and Zimmermann, Lars and Mai, Andreas}, title = {Adhesive-free bonding for hetero-integration of InP based coupons micro-transfer printed on SiO2 into Complementary Metal-Oxide-Semiconductor backend for Si photonics application on 8" wafer platform}, series = {Thin Solid Films}, journal = {Thin Solid Films}, number = {140399}, publisher = {Elsevier}, issn = {0040-6090}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-19240}, year = {2024}, abstract = {Micro-Transfer printing (µTP) is a promising technique for hetero-integration of III-V materials into Si-based photonic platforms. To enhance the print yield by increasing the adhesion between the III-V material and Si or SiO2 surface, an adhesion promoter like Benzocyclobutene is typically used as interlayer. In this work, we demonstrate µTP of InP based coupons on SiO2 interlayer without any adhesive interlayer and investigate the mechanism of adhesive free bonding. Source coupons are InP-based coupon stacks on a sacrificial layer that is removed by a chemical wet etch with FeCl3. For the target we fabricated amorphous-Si waveguides on 8" wafer encapsulated by a High Density Plasma SiO2 which was planarized by a chemical mechanical polishing procedure. We used O2 plasma to activate both source and target to increase adhesion between coupon and substrate. To get a better understanding of the bonding mechanism we applied several surface characterization methods. Root mean square roughness of InP and SiO2 was measured by atomic force microscopy before and after plasma activation. The step height of the micro-transfer printed source coupon on the target wafer is estimated by optical step profiler. We used Raman peak position mappings of InP to analyze possible strain and contact angle measurements on SiO2, before and after plasma activation to observe a change in the hydrophilicity of the surface. X-ray Photoelectron Spectroscopy analysis was used to characterize the surface energy states of P2p, In3d, O1s for InP source and Si2p, O1s for SiO2 target. Our results demonstrate direct bonding of InP coupons by means of µTP without the need of a strain-compensation layer. In this way, a promising route towards Complementary Metal-Oxide-Semiconductor compatible use of µTP for the hetero-integration of InP is provided.}, language = {en} } @article{SteglichLecciMai2022, author = {Steglich, Patrick and Lecci, Giulia and Mai, Andreas}, title = {Surface Plasmon Resonance (SPR) Spectroscopy and Photonic Integrated Circuit (PIC) Biosensors: A Comparative Review}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {8}, publisher = {MDPI}, issn = {1424-8220}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-16018}, year = {2022}, abstract = {Label-free direct-optical biosensors such as surface-plasmon resonance (SPR) spectroscopy has become a gold standard in biochemical analytics in centralized laboratories. Biosensors based on photonic integrated circuits (PIC) are based on the same physical sensing mechanism: evanescent field sensing. PIC-based biosensors can play an important role in healthcare, especially for point-of-care diagnostics, if challenges for a transfer from research laboratory to industrial applications can be overcome. Research is at this threshold, which presents a great opportunity for innovative on-site analyses in the health and environmental sectors. A deeper understanding of the innovative PIC technology is possible by comparing it with the well-established SPR spectroscopy. In this work, we shortly introduce both technologies and reveal similarities and differences. Further, we review some latest advances and compare both technologies in terms of surface functionalization and sensor performance.}, language = {en} } @article{SteglichSchasfoort2022, author = {Steglich, Patrick and Schasfoort, Richard B. M.}, title = {Surface Plasmon Resonance Imaging (SPRi) and Photonic Integrated Circuits (PIC) for COVID-19 Severity Monitoring}, series = {COVID}, volume = {2}, journal = {COVID}, number = {3}, publisher = {MDPI}, issn = {2673-8112}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-16004}, pages = {389 -- 397}, year = {2022}, abstract = {Direct optical detection methods such as surface plasmon resonance imaging (SPRi) and photonic-integrated-circuits (PIC)-based biosensors provide a fast label-free detection of COVID-19 antibodies in real-time. Each technology, i.e., SPRi and PIC, has advantages and disadvantages in terms of throughput, miniaturization, multiplexing, system integration, and cost-effective mass production. However, both technologies share similarities in terms of sensing mechanism and both can be used as high-content diagnostics at or near to point of care, where the analyte is not just quantified but comprehensively characterized. This is significant because recent results suggest that not only the antibody concentration of the three isotypes IgM, IgG, and IgA but also the strength of binding (affinity) gives an indication of potential COVID-19 severity. COVID-19 patients with high titers of low affinity antibodies are associated with disease severity. In this perspective, we provide some insights into how SPR and PIC technologies can be effectively combined and complementarily used for a comprehensive COVID-19 severity monitoring. This opens a route toward an immediate therapy decision to provide patients a treatment in an early stage of the infection, which could drastically lowers the risk of a severe disease course.}, language = {en} } @article{MaiMaiSteglich2022, author = {Mai, Andreas and Mai, Christian and Steglich, Patrick}, title = {From Lab-on-chip to Lab-in-App: Challenges towards silicon photonic biosensors product developments}, series = {Results in Optics}, volume = {9}, journal = {Results in Optics}, publisher = {Elsevier}, issn = {2666-9501}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-16687}, year = {2022}, abstract = {This work presents and evaluates different approaches of integrated optical sensors based on photonic integrated circuit (PIC) technologies for refractive index sensing. Bottlenecks in the fabrication flow towards an applicable system are discussed that hinder a cost-effective mass-production for disposable sensor chips. As sensor device, a waveguide coupled micro-ring based approach is chosen which is manufactured in an 8" wafer level process. We will show that the co-integration with a reproducible, scalable and low-cost microfluidic interface is the main challenge which needs to be overcome for future application of silicon technology based PIC sensor chips.}, language = {en} } @article{BauerFursenkoHeinrichetal.2022, author = {Bauer, Joachim and Fursenko, Oksana and Heinrich, Friedhelm and Gutke, Marko and Kornejew, Eckhart and Br{\"o}del, Oliver and Dietzel, Birgit and Kaltenbach, Alexander and Burkhardt, Martin and Edling, Matthias and Steglich, Patrick and Herzog, Michael and Schrader, Sigurd}, title = {Determination of optical constants and scattering properties of transparent polymers for use in optoelectronics}, series = {Optical Materials Express}, volume = {12}, journal = {Optical Materials Express}, number = {1}, publisher = {Optica Publishing Group}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15666}, pages = {204 -- 224}, year = {2022}, abstract = {Knowledge of optical constants, i.e. refractive index n and extinction coefficient k, and light scattering properties of optical polymers are required to optimize micro-optics for light-emitting diodes in terms of efficiency, color properties and light distribution. We present here a model-based diagnostic approach to determine the optical properties of polymers, which should be particularly useful in the development of plastics for optical applications. Optical constants and scattering coefficients were obtained from transmission and reflection measurements in a wavelength range from UV to NIR taking into account scattering effects due to rough surfaces and volume inhomogeneity. Based on the models for the dielectric function, the molecular optical transition energies Eg, critical point energies, Urbach energies and exciton transition energies were determined. Rayleigh and Mie scattering model and van de Hulst\&\#x0027;s anomalous diffraction theory were applied to characterize scattering due to volume inhomogeneities. Scalar diffraction theory was applied to account for surface roughness scattering. Atomic force microscopy with nanomechanical characterization was used to characterize domains in size and shape and to assign optical scattering to a suitable morphological model. The combined optical and mechanical characterization help to improve the qualification of new polymer materials for optical applications.}, language = {en} } @article{VillringerSteglichPulweretal.2021, author = {Villringer, Claus and Steglich, Patrick and Pulwer, Silvio and Schrader, Sigurd and Laufer, Jan}, title = {Electro-optical properties of doped polymers with high transparency in the visible wavelength range}, series = {Optical Materials Express}, volume = {11}, journal = {Optical Materials Express}, number = {11}, publisher = {Optica Publishing Group}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15480}, pages = {3801 -- 3811}, year = {2021}, abstract = {The electro-optical (EO) properties of poly(methyl methacrylate) and the photopolymer poly(vinyl cinnamate) doped with varying concentrations of the EO chromophore 2-Methyl-4-nitroaniline were measured. The EO polymers were embedded in Fabry-P{\´e}rot etalons for the simultaneous determination of the Pockels and Kerr coefficients from measurements of the fringe shift induced by an external electric field. It was found that the host polymer has a significant impact on the EO performance and that the undoped host polymers exhibit a significant Pockels effect. Moreover, the Kerr effect provides a substantial contribution of 27\% to the total change of the refractive index at relatively high electric field strengths of E = 91.2 MV m-1.}, language = {en} }