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Alloatti L.,Institute of Photonics and Quantum Electronics IPQ | Alloatti L.,Institute of Microstructure Technology IMT | Korn D.,Institute of Photonics and Quantum Electronics IPQ | Palmer R.,Institute of Photonics and Quantum Electronics IPQ | And 17 more authors.
Optics Express | Year: 2011

CMOS-compatible optical modulators are key components for future silicon-based photonic transceivers. However, achieving low modulation voltage and high speed operation still remains a challenge. As a possible solution, the silicon-organic hybrid (SOH) platform has been proposed. In the SOH approach the optical signal is guided by a silicon waveguide while the electro-optic effect is provided by an organic cladding with a high χ(2)-nonlinearity. In these modulators the optical nonlinear region needs to be connected to the modulating electrical source. This requires electrodes, which are both optically transparent and electrically highly conductive. To this end we introduce a highly conductive electron accumulation layer which is induced by an external DC "gate" voltage. As opposed to doping, the electron mobility is not impaired by impurity scattering. This way we demonstrate for the first time data encoding with an SOH electro-optic modulator. Using a first-generation device at a data-rate of 42.7 Gbit/s, widely open eye diagrams were recorded. The measured frequency response suggests that significantly larger data rates are feasible. ©2011 Optical Society of America.


Liu X.,Light Technology | Liu X.,Institute of Microstructure Technology IMT | Lebedkin S.,Institute of Nanotechnology INT | Besser H.,Karlsruhe Institute of Technology | And 13 more authors.
ACS Nano | Year: 2015

Organic semiconductor distributed feedback (DFB) lasers are of interest as external or chip-integrated excitation sources in the visible spectral range for miniaturized Raman-on-chip biomolecular detection systems. However, the inherently limited excitation power of such lasers as well as oftentimes low analyte concentrations requires efficient Raman detection schemes. We present an approach using surface-enhanced Raman scattering (SERS) substrates, which has the potential to significantly improve the sensitivity of on-chip Raman detection systems. Instead of lithographically fabricated Au/Ag-coated periodic nanostructures on Si/SiO2 wafers, which can provide large SERS enhancements but are expensive and time-consuming to fabricate, we use low-cost and large-area SERS substrates made via laser-assisted nanoreplication. These substrates comprise gold-coated cyclic olefin copolymer (COC) nanopillar arrays, which show an estimated SERS enhancement factor of up to ∼107. The effect of the nanopillar diameter (60-260 nm) and interpillar spacing (10-190 nm) on the local electromagnetic field enhancement is studied by finite-difference-time-domain (FDTD) modeling. The favorable SERS detection capability of this setup is verified by using rhodamine 6G and adenosine as analytes and an organic semiconductor DFB laser with an emission wavelength of 631.4 nm as the external fiber-coupled excitation source. © 2014 American Chemical Society.


Schindler P.C.,Karlsruhe Institute of Technology | Schmogrow R.,Karlsruhe Institute of Technology | Dreschmann M.,Karlsruhe Institute of Technology | Meyer J.,Karlsruhe Institute of Technology | And 16 more authors.
Journal of Optical Communications and Networking | Year: 2013

We demonstrate a remotely seeded flexible passive optical network (PON) with multiple low-speed subscribers but only a single optical line terminal transceiver operating at a data rate of 31.25 Gbits/s. The scheme is based on a colorless frequency division multiplexing (FDM)-PON with centralized wavelength control. Multiplexing and demultiplexing in the optical network unit (ONU) is performed in the electronic domain and relies either on FDM with Nyquist sinc-pulse shaping or on orthogonal frequency division multiplexing (OFDM). This way the ONU can perform processing at low speed in the baseband. Further, the ONU is colorless by means of a remote seed for upstream transmission and a remote local oscillator for heterodyne reception, all of which helps in keeping maintenance and costs for an ONU potentially low and will simplify wavelength allocation in a future software defined network architecture. To extend the reach, semiconductor optical amplifiers are used for optical amplification in the downstream and upstream. © 2009-2012 OSA.


Waldbaur A.,Institute of Microstructure Technology IMT | Waterkotte B.,Fritz Haber Institute | Waterkotte B.,Institute of Functional Interfaces IFG | Schmitz K.,Fritz Haber Institute | And 3 more authors.
Small | Year: 2012

Protein patterns of different shapes and densities are useful tools for studies of cell behavior and to create biomaterials that induce specific cellular responses. Up to now the dominant techniques for creating protein patterns are mostly based on serial writing processes or require templates such as photomasks or elastomer stamps. Only a few of these techniques permit the creation of grayscale patterns. Herein, the development of a lithography system using a digital mirror device which allows fast patterning of proteins by immobilizing fluorescently labeled molecules via photobleaching is reported. Grayscale patterns of biotin with pixel sizes in the range of 2.5 μm are generated within 10 s of exposure on an area of about 5 mm2. This maskless projection lithography method permits the rapid and inexpensive generation of protein patterns definable by any user-defined grayscale digital image on substrate areas in the mm2 to cm2 range. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Weimann C.,Karlsruhe Institute of Technology | Fratz M.,Fraunhofer Institute for Physical Measurement Techniques | Wolfelschneider H.,Fraunhofer Institute for Physical Measurement Techniques | Freude W.,Karlsruhe Institute of Technology | And 4 more authors.
Applied Optics | Year: 2015

We improve the accuracy of distance measurements with synthetic-wavelength interferometry by referencing the spectral spacing of the free-running light sources to a high-precision radio-frequency oscillator. In addition, we increase the unambiguity range with a time-of-flight technique. Distances to scattering technical surfaces can be measured with micrometer accuracy and an unambiguity range of 1.17 m. The measurement rate amounts to 300 Hz. © 2015 Optical Society of America.


Waldbaur A.,Institute of Microstructure Technology IMT | Kittelmann J.,Karlsruhe Institute of Technology | Radtke C.P.,Karlsruhe Institute of Technology | Hubbuch J.,Karlsruhe Institute of Technology | Rapp B.E.,Institute of Microstructure Technology IMT
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2013

We describe a generic microfluidic interface design that allows the connection of microfluidic chips to established industrial liquid handling stations (LHS). A molding tool has been designed that allows fabrication of low-cost disposable polydimethylsiloxane (PDMS) chips with interfaces that provide convenient and reversible connection of the microfluidic chip to industrial LHS. The concept allows complete freedom of design for the microfluidic chip itself. In this setup all peripheral fluidic components (such as valves and pumps) usually required for microfluidic experiments are provided by the LHS. Experiments (including readout) can be carried out fully automated using the hardware and software provided by LHS manufacturer. Our approach uses a chip interface that is compatible with widely used and industrially established LHS which is a significant advancement towards near-industrial experimental design in microfluidics and will greatly facilitate the acceptance and translation of microfluidics technology in industry. © 2013 The Royal Society of Chemistry.


Kittelmann J.,Karlsruhe Institute of Technology | Radtke C.P.,Karlsruhe Institute of Technology | Waldbaur A.,Institute of Microstructure Technology IMT | Neumann C.,Institute of Microstructure Technology IMT | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Since the early days microfluidics as a scientific discipline has been an interdisciplinary research field with a wide scope of potential applications. Besides tailored assays for point-of-care (PoC) diagnostics, microfluidics has been an important tool for large-scale screening of reagents and building blocks in organic chemistry, pharmaceutics and medical engineering. Furthermore, numerous potential marketable products have been described over the years. However, especially in industrial applications, microfluidics is often considered only an alternative technology for fluid handling, a field which is industrially mostly dominated by large-scale numerically controlled fluid and liquid handling stations. Numerous noteworthy products have dominated this field in the last decade and have been inhibited the widespread application of microfluidics technology. However, automated liquid handling stations and microfluidics do not have to be considered as mutually exclusive approached. We have recently introduced a hybrid fluidic platform combining an industrially established liquid handling station and a generic microfluidic interfacing module that allows probing a microfluidic system (such as an essay or a synthesis array) using the instrumentation provided by the liquid handling station. We term this technology “Microfluidic on Liquid Handling Stations (μF-on-LHS)â€? - a classical “best of both worldsâ€?- approach that allows combining the highly evolved, automated and industry-proven LHS systems with any type of microfluidic assay. In this paper we show, to the best of our knowledge, the first droplet microfluidics application on an industrial LHS using the μF-on-LHS concept. © 2014 SPIE.


Pires L.,Institute of Microstructure Technology IMT | Heckel A.,Institute of Microstructure Technology IMT | Sachsenheimer K.,Institute of Microstructure Technology IMT | Rapp B.E.,Institute of Microstructure Technology IMT
Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012 | Year: 2012

In this work we report on a multichannel label-free impedimetric sensor platform that is suitable for high-throughput analysis of affinity binding. The sensor is based on electrochemical impedance spectroscopy (EIS) and a surface modification of gold electrodes using a carboxy functionalized conductive polymer (polypyrrole). Concentrations of Biotinylated Bovine Serum Albumin (bBSA) down to 1 ng/ml were achieved using this setup.


Waldbaur A.,Institute of Microstructure Technology IMT | Carneiro B.,Institute of Microstructure Technology IMT | Hettich P.,Institute of Microstructure Technology IMT | Rapp B.E.,Institute of Microstructure Technology IMT
Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012 | Year: 2012

In this work we introduce CAMF, a process that allows the creation of a physical microfluidic structure from a conceptual block drawing (similar to an electronic circuit diagram) within a few hours. This paper describes the physical creation of a microfluidic chip via maskless lithography based on a digital mirror device (DMD) from digital 3D models created automatically with custom-written software.


Nguyen H.H.D.,Institute of Microstructure Technology IMT | Hollenbach U.,Institute of Microstructure Technology IMT | Ostrzinski U.,Micro Resist Technology GmbH | Pfeiffer K.,Micro Resist Technology GmbH | And 2 more authors.
Applied Optics | Year: 2016

This paper introduces a unique method to fabricate free-form symmetrical three-dimensional single-mode waveguides embedded in a newly developed photopolymer. The fabrication process requires only one layer of a single material by combining two-photon lithography and external monomer diffusion resulting in a high refractive index contrast of 0.013. The cured material exhibits high chemical and thermal stability. Transmission loss of 0.37 dB/cm at 850 nm is achieved. Due to the fact that waveguide arrays are produced with high density, this technique could pave the way for three-dimensional optical interconnects at the board level with high complexity and bandwidth density. © 2016 Optical Society of America.

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