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Much of recent progress in geophysics can be attributed to the adaptation of heterogeneous high-performance computing architectures. It is projected that the next major leap in many areas of science, and hence hopefully in geophysics too, will be due to the emergence of quantum computers. Finding a right combination of hardware, algorithms, and a use case, however, proves to be a very challenging task — especially when looking for a relevant application that scales efficiently on a quantum computer and is difficult to solve using classical means. We find that maximizing stack power for residual statics correction, an NP-hard combinatorial optimization problem, appears to naturally fit a particular type of quantum computing known as quantum annealing. We express the underlying objective function as a quadratic unconstrained binary optimization, which is a quantum-native formulation of the problem. We choose some solution space and define a proper encoding to translate the problem variables into qubit states. We find that these choices can have a significant impact on the maximum problem size that can fit on the quantum annealer and on the fidelity of the final result. To improve the latter, we embed the quantum optimization step in a hybrid classical-quantum workflow, which aims to increase the frequency of finding the global, rather than some local, optimum of the objective function. Finally, we find that a generic, black-box, hybrid classical-quantum solver also could be used to solve stack-power maximization problems proximal to industrial relevance and capable of surpassing deterministic solvers prone to cycle skipping. A custom-built workflow capable of solving larger problems with an even higher robustness and greater control of the user appears to be within reach in the very near future.

This letter presents a bondwire model in the form of a lumped-element network, which is based on the geometry of the bondwire and landing pads. For the interconnection between a chip and the feedline on a printed circuit board (PCB) substrate, the associated parasitics are calculated, which are responsible for the performance degradation caused by the bondwire at millimeter-wave (mmWave) frequencies. A matching network is realized with planar-lumped elements on the PCB and integrated for impedance mismatch compensation at a center frequency of 60 GHz. Simulations show an operating bandwidth of 50–70 GHz. The proposed solution is first verified by the measurements of PCB-to-PCB bondwire interconnects. Then, as an application example, an antenna-switch chip is placed at the PCB feedline. Remarkable improvements in terms of input matching and insertion loss are observed compared with an unmatched bondwire interconnect.

This letter presents V-band components which are manufactured in PCB technology and designed for 60-GHz center frequency. A proposed multifinger dc-block provides 30% bandwidth (BW) with an input reflection coefficient $V$ -band which is, to the best of the authors’ knowledge, the highest achieved BW of a PCB compatible dc-block in millimeter wave range. The bias-tee structures are realized by integrating an RF choke with the dc-blocks. The bias-tee with a multifinger dc-block shows 31% BW while with the modified-triangle dc-block allows for 48% BW with RF/dc isolation >20 dB. The proposed wideband designs provide a cost-effective solution, e.g., of RF components testing while shielding the respective lab equipment from dc or RF.

Glycogen is the main carbon storage polymer in many organisms and widespread throughout all domains of life. In cyanobacteria glycogen degradation plays an essential role when metabolism changes to a heterotrophic mode during dark phases or the resuscitation from nitrogen starvation. Like many other cyanobacteria the genome ofSynechocystissp. PCC 6803 encodes for several homologues of glycogen catabolic enzymes. The role and regulation of this isoenzymes has so far been only partly understood. Here we show via biochemical analysis that the glycogen phosphorylase GlgP1 is regulated by a C-terminal redox switch unique to certain cyanobacteria. This is the first time a redox regulation of a glycogen degrading enzyme has been shown in prokaryotes. Remarkably, GlgP1 is inactivated in its reduced state and gets activated via oxidation by ROS. We conclude that GlgP1 is especially important for rapid glycogen degradation in certain stress conditions during photoautotrophic growth. We suggest that thereby carbon is channeled through the OPP pathway, to stabilize photosynthesis during situations of high ribulose-1,5-BP demands. Furthermore, we suggest that the concomitant formation of NADPH within this pathway is essential to regenerate ROS scavenging compounds like GSH to reduce potential oxidative damage and to improve survivability under prolonged phases of oxidative stress. In addition, we show for the first time the role of the two glycogen debranching isoenzymes where GlgX1 turned out to be the essential glycogen debranching enzyme during resuscitation from chlorosis, while the role of GlgX2 remains elusive.

In this letter, we propose fundamental path loss (PL) models which play vital roles in promoting the intraheart communication system design of future deeply implanted leadless pacemakers inside the cardiac chambers. Initially, employing a plane wave approach yields the attenuation of the electric field in homogeneous heart tissue, while a modified Friis equation in the lossy medium is utilized to evaluate the power transmission between transmitting and receiving antennas in homogeneous heart tissue in the far-field zone. An Hertzian dipole excitation is used to separate the mismatch and ohmic losses of the antenna from the path loss in an anatomical human body simulation environment. Based on this theoretical and full-wave simulation setup, PL models are derived and comprehensively compared at different potential frequency bands [Medical Implant Communication Service (MICS) 402—405 MHz, Wireless Medical Telemetry Service (WMTS) 608–614 MHz, Industrial, Scientific, and Medical (ISM) 867–869 MHz, and 2400–2500 MHz], and the validity of applying the Friis equation in this scenario is verified.

The present publication investigates the optical scattering behavior of an artificial near-field coupled double-resonant plasmonic molecule on a glass substrate formed by a linear arrangement of three gold nanobars. The aim of the proposed symmetrical structure arrangement is to achieve a significant increase in the feedback of optically induced coherent mechanical oscillations on the scattering cross-section. Based on the description of isolated dipole-like plasmonic nanostructures, it is shown how an increase of the modulation strength can be achieved by systematic utilization and modification of the inherent near-field coupling effect. It is shown which differences exist compared to an isolated plasmonic nanostructure, especially for the NIR spectral range. To the best of our knowledge, this is the first investigation showing the behavior of coherent acoustic vibrations in such artificial plasmonic molecules at an optical carrier wavelength of 1560 nm which is particularly interesting for applications in the field of optical communication.

While conventional silicon photonic (SiP) waveguides achieve high data rates with low loss, they can only be placed on top of the chip surfaces horizontally. In this article, we present a design approach for multimode chip-to-chip interconnects with similar low-loss and high-bandwidth density properties as SiP waveguides. The state-of-the-art fabrication of optical through silicon via (OTSV) requires conventional back end of line (BEOL) processing with an additional step: metal coating lowers the loss of air-filled TSVs. Alternatively, the TSV is converted into a polymer waveguide by filling of low-loss polymer (Ormocore) to achieve

This article presents an innovative way for additive manufacturing of optical multimode waveguides for short range data transmission. By the use of aerosol jet printing between conditioning lines on flexible foils, low cost, and low weight polymer optical waveguides can be easily fabricated. The main advantages – compared to other waveguide manufacturing techniques – are the maximum fabricable waveguide length (not limited by panel- or wafer size), technology costs and 3D-ability. Furthermore, the printing allows for very long structures, which are not limited to wafer or panel sizes. In order to classify the new manufacturing approach and compare it to other technologies such as photolithography, imprinting, dispensing and ion-exchange, results on the mechanical (shear strength) and optical performance (transmittance, near field and attenuation) are presented. In addition, the experimental results on the data transmission performance are important to prove the suitability of the waveguides for high-speed communication applications. In this context, nearly error-free transmission up to 10 Gbit/s was achieved at a wavelength of 850 nm.

Regulation of glycogen metabolism is of vital importance in organisms of all three kingdoms of life. Although the pathways involved in glycogen synthesis and degradation are well known, many regulatory aspects around the metabolism of this polysaccharide remain undeciphered. Here, we used the unicellular cyanobacterium Synechocystis as a model to investigate how glycogen metabolism is regulated in nitrogen-starved dormant cells, which entirely rely on glycogen catabolism to resume growth upon nitrogen repletion. We identified phosphoglucomutase 1 (PGM1) as a key regulatory point in glycogen metabolism, and post-translational modification as an essential mechanism for controlling its activity. We could show that PGM1 is phosphorylated ata residue in the regulatory latch domain (Ser 47) during nitrogen starvation, which inhibits its activity. Inactivation of PGM1 by phosphorylation at Ser 47 prevents premature degradation of the glycogen stores and appears to be essential for survival of Synechocystis in the dormant state. Remarkably, this regulatory mechanism seems to be evolutionary conserved in PGM1 enzymes, from bacteria to humans.

The Second Quantum Revolution facilitates the engineering of new classes of sensors, communication technologies, and computers with unprecedented capabilities. Supply chains for quantum technologies are emerging, some focused on commercially available components for enabling technologies and/or quantum-technologies research infrastructures, others with already higher technology-readiness levels, near to the market.In 2018, the European Commission has launched its large-scale and long-term Quantum Flagship research initiative to support and foster the creation and development of a competitive European quantum technologies industry, as well as the consolidation and expansion of leadership and excellence in European quantum technology research. One of the measures to achieve an accelerated development and uptake has been identified by the Quantum Flagship in its Strategic Research Agenda: The promotion of coordinated, dedicated standardisation and certification efforts.Standardisation is indeed of paramount importance to facilitate the growth of new technologies, and the development of efficient and effective supply chains. The harmonisation of technologies, methodologies, and interfaces enables interoperable products, innovation, and competition, all leading to structuring and hence growth of markets. As quantum technologies mature, the time has come to start thinking about further standardisation needs.This article presents insights on standardisation for quantum technologies from the perspective of the CEN-CENELEC Focus Group on Quantum Technologies (FGQT), which was established in June 2020 to coordinate and support the development of standards relevant for European industry and research.

Description, The carbon sensor SbtB perceives diurnal oscillation of c-di-AMP to control glycogen synthesis and nighttime survival., Because of their photosynthesis-dependent lifestyle, cyanobacteria evolved sophisticated regulatory mechanisms to adapt to oscillating day-night metabolic changes. How they coordinate the metabolic switch between autotrophic and glycogen-catabolic metabolism in light and darkness is poorly understood. Recently, c-di-AMP has been implicated in diurnal regulation, but its mode of action remains elusive. To unravel the signaling functions of c-di-AMP in cyanobacteria, we isolated c-di-AMP receptor proteins. Thereby, the carbon-sensor protein SbtB was identified as a major c-di-AMP receptor, which we confirmed biochemically and by x-ray crystallography. In search for the c-di-AMP signaling function of SbtB, we found that both SbtB and c-di-AMP cyclase–deficient mutants showed reduced diurnal growth and that c-di-AMP–bound SbtB interacts specifically with the glycogen-branching enzyme GlgB. Accordingly, both mutants displayed impaired glycogen synthesis during the day and impaired nighttime survival. Thus, the pivotal role of c-di-AMP in day-night acclimation can be attributed to SbtB-mediated regulation of glycogen metabolism.

We study analytically and numerically the possibility of vortex modes propagation over planar dielectric rectangular waveguides, and consider the problem of waveguide geometry optimization for the support of vortex modes. The results show, that theoretically rectangular waveguides can provide transmission of quasi-TE and quasi-TM modes with high purity states of orbital angular momentum (OAM) in the dominant field component. However, only for the quasi-generate mode of azimuthal order ±1 the constituent eigenmodes can propagate in a phase-matched regime, and the vortex modes of higher azimuthal orders can propagate only with a certain beat length. Moreover, as the target azimuthal order increases, the normalized power of the corresponding OAM state in the modal superposition decreases. The analytical predictions have been verified by numerical electromagnetic simulations of silicon nitride waveguides providing field distributions and OAM spectra of the corresponding modal superpositions.

Regulation of glycogen metabolism is of vital importance in organisms of all three kingdoms of life. Although the pathways involved in glycogen synthesis and degradation are well known, many regulatory aspects around the metabolism of this polysaccharide remain undeciphered. Here, we used the unicellular cyanobacterium Synechocystis as a model to investigate how glycogen metabolism is regulated in dormant nitrogen-starved cells, which entirely rely on glycogen catabolism to restore growth. We found that the activity of the enzymes involved in glycogen synthesis and degradation is tightly controlled at different levels via post-translational modifications. Phosphorylation of phosphoglucomutase 1 (Pgm1) on a peripheral residue (Ser63) regulates Pgm1 activity and controls the mobilization of the glycogen stores. Inhibition of Pgm1 activity via phosphorylation on Ser63 appears essential for survival of Synechocystis in the dormant state. Remarkably, this regulatory mechanism seems to be conserved from bacteria to humans. Moreover, phosphorylation of Pgm1 influences the formation of a metabolon, which includes Pgm1, oxidative pentose phosphate cycle protein (OpcA) and glucose-6-phosphate dehydrogenase (G6PDH). Analysis of the steady-state levels of the metabolic products of glycogen degradation together with protein-protein interaction studies revealed that the activity of G6PDH and the formation of this metabolon are under additional redox control, likely to ensure metabolic channeling of glucose-6-phosphate to the required pathways for each developmental stage. Significance statement In this study, we showed that post-translational modification of phosphoglucomutase 1 (Pgm1) via phosphorylation at a peripheral residue is a key, evolutionary-conserved regulatory mechanism that controls the utilization of the glycogen reserves. We identified Pgm1 as a central metabolic valve, associating with oxidative pentose phosphate cycle protein (OpcA) and glucose-6-phosphate dehydrogenase (G6PDH) into a metabolon. This interaction is regulated by the phosphorylation state of Pgm1 and the redox state of OpcA, and probably allows direction of the carbon flux into the required metabolic pathways.

Nitrogen starvation induces developmental transitions in cyanobacteria. Whereas complex multicellular cyanobacteria of the order Nostocales can differentiate specialized cells that perform nitrogen fixation in the presence of oxygenic photosynthesis, non-diazotrophic unicellular strains, such as Synechococcus elongatus or Synechocystis PCC 6803, undergo a transition into a dormant non-growing state. Due to loss of pigments during this acclimation, the process is termed chlorosis. Cells maintain viability in this state for prolonged periods of time, until they encounter a useable nitrogen source, which triggers a highly coordinated awakening process, termed resuscitation. The minimal set of cellular activity that maintains the viability of cells during chlorosis and ensures efficient resuscitation represents the organism’s equivalent of the BIOS, the basic input/output system of a computer, that helps “booting” the operation system after switching on. This review summarizes the recent research in the resuscitation of cyanobacteria, representing a powerful model for the awakening of dormant bacteria.

This paper presents the design of a 60 GHz grounded coplanar waveguide (GCPW) based Marchand balun that is robust against variations of substrate height or dielectric constant. The via-free design and minimum trace width and trace-to-trace clearance of 0.1 mm makes this balun compatible for fabrication with economical printed circuit board (PCB) development technology. For optimal choice of height for a given substrate with known dielectric constant, simulation results show 33% bandwidth with maximum amplitude and phase imbalance of 0.2 dB and 13 degree, respectively. The substrate dependency analysis in terms of height and dielectric constant show the possibility of implementing this GCPW balun on substrates with deviations in height or dielectric constant with tolerable performance degradation. It provides a cost-effective rapid solution of measuring differential antennas and commercially available differential millimeter-wave components using single-ended laboratory equipment. Simulation results are verified through fabrication and laboratory measurements of two baluns backto-back connected through their differential ports. The measured results are in accordance with the simulated results.

By moving carrier frequencies to higher and higher frequency bands, larger bandwidths can be provided for data-hungry wireless applications. The submillimeter wave region is a promising candidate for future systems. In order to accommodate sophisticated modulation formats, coherent local oscillators in the transmitter (TX) and the receiver (RX) are needed for efficient operation. However, traditional methods of analog carrier recovery (e.g., narrowband filtering of the residual carrier and reamplification) fail at such high frequencies and for many modulation formats. Also, digital carrier recovery algorithms used in conjunction with free-running oscillators are too power hungry and hard to realize for high data rates above 10 Gb/s. In this paper, carrier recovery schemes based on the parallel transmission of a reference frequency together with the payload data suitable for high data rates in the submillimeter waveband are proposed. They are demonstrated at 300-GHz carrier frequency. The corresponding electronic circuits for the TX and the RX are designed, manufactured, and characterized.

In this paper, we present a bidirectional interruption-free multimode waveguide coupler for optical bus systems on board and module level. The principle is based on directional core–core coupling and allows for adjustable coupling powers by tuning the overlap area. By adding a bending to one of the coupling partners, it is possible to obtain specific asymmetric coupling rates depending on the coupling direction (module to bus or vice versa). The proposed approach is extensively analyzed by optical simulation (beam propagation method) and measurements including experiments on the attenuation, the coupling rate, and the bit rate performance.

This letter presents the design and measurements of a monolithically integrated photonic receiver manufactured in 0.25 μm SiGe BiCMOS electro-photonic technology. The receiver consists of an on-chip germanium photodiode directly connected to the transimpedance amplifier (TIA). An on-chip, low-noise feedback loop compensates the dc photocurrent. The circuit provides a maximum bandwidth of 35.6 GHz at a gain of 59.2 dBQ with a noise of 12.34 pA/√(Hz) while consuming only 80 mW. In combination with a 20 GHz, 1550 nm electro-optical transmitter, a maximum data rate of 50 Gb/s at a bit error rate of less than 10 -12 was measured. To the best of the authors' knowledge, this is the fastest error-free detected data rate reported for a monolithically integrated photonic receiver. Additionally, the feedback resistor of the TIA can be tuned via a MOSFET allowing error-free operation at 20 Gb/s with a sensitivity of only -13 dBm. In this setting the input-referred noise is only 8.16 pA/√(Hz).

This paper presents a planar Marchand balun design for 60 GHz applications. This design provides a low cost and rapid solution of testing commercially available mmWave ICs working with differential signalling on the PCB with the available single-ended laboratory equipment. This microstrip-based balun is designed to be compatible for PCB implementation keeping the minimum line and gap width greater than 0.1 mm. Simulation results indicate 30% bandwidth with a maximum amplitude and phase mismatch of 1.7 dB and 11° respectively. For the practical demonstration, two back-to-back connected baluns are fabricated on Isola I-TERA MT40 substrate along with special CPW-to-microstrip conversion structures for probe-station measurements. Measured results are compared with the simulated response to evaluate the design. Furthermore, a re-simulation taking into account the manufacturing deviations is carried out showing results in good agreement with the measured data.

This paper presents in-body to on-body and inbody to in-body channel models of a planar wideband elliptical ring implanted antenna in the lower part of Ultra-WideBand (UWB, 3.1 to 5.1 GHz). The results are verified inside a practical UWB liquid phantom with the help of a wideband on-body monopole antenna. Moreover, the design principle of the inbody and on-body antennas, as well as their simulated and measured reflection coefficients are presented. The channel characterization inside the lossy medium gives a deep insight of wireless capsule endoscope technology (WCE) and helps to evaluate the radiation performance of the previously designed planar elliptical ring implanted antenna

In an effort to develop a cost-efficient technology for wireless high-temperature surface acoustic wave sensors, this study presents an evaluation of a combined method that integrates physical vapor deposition with electroless deposition for the fabrication of platinum-based planar antennas. The proposed manufacturing process becomes attractive for narrow, thick, and sparse metallizations for antennas in the MHz to GHz frequency range. In detail, narrow platinum-based lines of a width down to 40 &mu, m were electroless-deposited on &gamma, Al 2O 3 substrates using different seed layers. At first, the electrolyte chemistry was optimized to obtain the highest deposition rate. Films with various thickness were prepared and the electrical resistivity, microstructure, and chemical composition in the as-prepared state and after annealing at temperatures up to 1100 ∘C were evaluated. Using these material parameters, the antenna was simulated with an electromagnetic full-wave simulation tool and then fabricated. The electrical parameters, including the S-parameters of the antenna, were measured. The agreement between the simulated and the realized antenna is then discussed.

A MIMO system for 60 GHz wireless communication based on Radio-over-Fiber (RoF) technique is designed and discussed. In this paper, a $2 \times 2$ antenna array on 300 micron quartz (Silica) substrate with a bandwidth of 6 GHz for operating in V-band (50 GHz-75 GHz) is designed. The achieved gain is 9 dB. Moreover, a novel wideband planar bias tee (BT) circuit with a quarter-wave coupled-line is designed on the same substrate. It will provide proper biasing for millimeter wave photodiodes through the RF-choke and isolates the antenna from the bias. Simulation results show that the return loss is below 15 dB for the entire 45 GHz to 75 GHz band and it reaches to 45 dB at 60 GHz, while the insertion loss is lower than 0.5 dB. The overall performance of the complete antenna and BT circuit has been calculated by the 3D full-wave electromagnetic field simulator CST.

In this paper, the results of the successful fabrication as well as the optical backscattering characterization of single plasmonic gold dipole nanoantennas on a SiO2/Si layered substrate are shown. The nanoantennas were designed for a scattering resonance in the NIR range. In contrast to usually used glass substrates, a six inch Siwafer with a thermally oxidized SiO2 layer in combination with an electron beam lithography lift-off fabrication process has been used for the sake of compatibility with microelectronics fabrication processes. In order to achieve high structural resolutions, a bilayer resist system with different exposure sensitivities was realized. In a second step, the entire resist thickness of 540 nm was reduced to 150 nm in a single layer. The SiO2 thickness was chosen in a way that the optical near-field interactions of the nanoantennas with the silicon substrate are decoupled. The SEM characterization of the fabricated structures shows precise nanoantenna geometries with low edge roughness in the case of the bilayer resist system. The aspect ratio of the fabricated nanoantenna structures is slightly decreased compared to the desired value of five. Depending on the applied e-beam exposure dose, an increase of the structural cross-section, i.e. critical dimension of the dipole width, was observed. Furthermore, the single resist layer introduces some structuring issues. The spectral behavior of the nanoantenna structures was investigated with an optical confocal broadband backscattering measurement setup allowing the spectral characterization of single nanoantenna structures. The developed numerical models helped to understand the impact of the manufacturing imperfections providing improved designs.

The layout of an integrated millimetre-scale on-chip THz spectrometer is presented and its peformance demonstrated. The device is based on eight Schottky-diode detectors which are combined with narrowband THz antennas, thereby enabling the simultaneous detection of eight frequencies in the THz range on one chip. The size of the active detector area matches the focal spot size of superradiant THz radiation utilized in bunch compression monitors of modern linear electron accelerators. The 3 dB bandwidth of the on-chip Schottky-diode detectors is less than 10% of the center frequency and allows pulse-resolved detection at up to 5 GHz repetition rates. The performance of a first prototype device is demonstrated at a repetition rate of 100 kHz at the quasi-cw SRF linear accelerator ELBE operated with electron bunch charges between a few pC and 100 pC.

Large scale data centers (DC) and high performance computing (HPC) systems require more and more computing power at higher energy efficiency. They are already consuming megawatts of power, and a linear extrapolation of trends reveals that they may eventually lead to unrealistic power consumption scenarios in order to satisfy future requirements (e.g., Exascale computing). Conventional complementary metal oxide semiconductor (CMOS)-based electronic interconnects are not expected to keep up with the envisioned future board-to-board and chip-to-chip (within multi-chip-modules) interconnect requirements because of bandwidth-density and power-consumption limitations. However, low-power and high-speed optics-based interconnects are emerging as alternatives for DC and HPC communications; they offer unique opportunities for continued energy-efficiency and bandwidth-density improvements, although cost is a challenge at the shortest length scales. Plasmonics-based interconnects on the other hand, due to their extremely small size, offer another interesting solution for further scaling operational speed and energy efficiency. At the device-level, CMOS compatibility is also an important issue, since ultimately photonics or plasmonics will have to be co-integrated with electronics. In this paper, we survey the available literature and compare the aforementioned interconnect technologies, with respect to their suitability for high-speed and energy-efficient on-chip and off-chip communications. This paper refers to relatively short links with potential applications in the following interconnect distance hierarchy: local group of racks, board to board, module to module, chip to chip, and on chip connections. We compare different interconnect device modules, including low-energy output devices (such as lasers, modulators, and LEDs), photodetectors, passive devices (i.e., waveguides and couplers) and electrical circuitry (such as laserdiode drivers, modulator drivers, transimpedance, and limiting amplifiers). We show that photonic technologies have the potential to meet the requirements for selected HPC and DC applications in a shorter term. We also present that plasmonic interconnect modules could offer ultra-compact active areas, leading to high integration bandwidth densities, and low device capacitances allowing for ultra-high bandwidth operation that would satisfy the application requirements further into the future.

Current trends in electronic industry, such as Internet of Things (IoT) and Cloud Computing call for high interconnect bandwidth, increased number of active devices and high IO count. Hence the integration of on silicon optical waveguides becomes an alternative approach to cope with the performance demands. The application and fabrication of horizontal (planar) and vertical (Through Silicon Vias - TSVs) optical waveguides are discussed here. Coupling elements are used to connect both waveguide structures. Two micro-structuring technologies for integration of coupling elements are investigated: μ-mirror fabrication by nanoimprint (i) and dicing technique (ii). Nanoimprint technology creates highly precise horizontal waveguides with polymer (refractive index nC = 1.56 at 650 nm) as core. The waveguide ends in reflecting facets aligned to the optical TSVs. To achieve Total Internal Reflection (TIR), SiO2 (nCl = 1.46) is used as cladding. TSVs (diameter 20-40μm in 200-380μm interposer) are realized by BOSCH process1, oxidation and SU-8 filling techniques. To carry out the imprint, first a silicon structure is etched using a special plasma etching process. A polymer stamp is then created from the silicon template. Using this polymer stamp, SU-8 is imprinted aligned to vertical TSVs over Si surface.Waveguide dicing is presented as a second technology to create coupling elements on polymer waveguides. The reflecting mirror is created by 45° V-shaped dicing blade. The goal of this work is to develop coupling elements to aid 3D optical interconnect network on silicon interposer, to facilitate the realization of the emerging technologies for the upcoming years.

In future, computing platforms will invoke massive parallelism by using a huge number of processing elements. These elements need broadband interconnects to communicate with each other. Following More-than-Moore concepts, soon large numbers of processors will be arranged in 3D chip-stacks. This trend to stack multiple dies produces a demand for high-speed intraconnects (within the 3D stack) which enable an efficient operation. Besides wireless electronic solutions (inductive or capacitive as well as using antennas), optical connectivity is an option for bit rates up to the Tbit/s range, too. We investigated different candidates for optical TSVs. For optical transmission via optical Through-Silicon-Vias, we were able to demonstrate negligible losses and dispersion.

The carrier frequencies of wireless systems are expanded to higher and higher frequency bands where huge bandwidths for data-hungry applications can be realized. One of the prospective regions is the sub-millimeterwave band. Wireless transmission needs coherent local oscillators at the transmitter and receiver for efficient operation. At such high frequencies, traditional methods of analog carrier recovery (e.g. narrowband filtering of the residual carrier and re-amplification) fail. At the same time, for high data rates above 10 Gbit/s, digital carrier recovery algorithms used in conjunction with free-running oscillators are too power-hungry and hard to realize. In this paper, a carrier recovery for a 300 GHz system based on the parallel transmission of a reference frequency together with the payload data is proposed. The corresponding electronic circuits for the transmitter and receiver are designed, manufactured and characterized.

A prospective frequency band for short range communication is around 300 GHz where sufficient bandwidth is available for high data rates. Up- and down converters providing around 20 GHz bandwidth at a carrier frequency within 260 GHz to 400 GHz have been used. At such high frequencies, the propagation properties differ significantly from the known behavior at lower frequencies. Hence, different scenarios have been investigated: direct line-of-sight transmission, multiple reflections at dielectric surfaces and reflection on compound materials such as computer boards (PCBs). Data rates up to 42 Gbit/s have been shown. Additionally, an advanced modulation format (PAM-4) has been tested.

Phased array antennas can cover a wide range of applications, e.g. localizing passive tags. Depending on the specifications for antenna gain, beam width and scanning range, different types and numbers of antenna elements are required. This kind of flexibility is provided by a customizable approach consisting of a control module and backplanes that carry RF and antenna modules where amplitude and phase shifting needed for beamforming takes place. Furthermore, an initial calibration of the antenna has to be carried out in order to compensate for tolerances in the manufacturing process. In this paper, a 4×4 array is realized and presented which allows full 2D beamsteering. Comprehensive measurement results are shown and discussed.

This paper presents the design and fabrication of a fiber-optic refractive index (RI) sensor. The novel concept employs a long-period fiber grating (LPG) to achieve surface plasmon resonance (SPR) of a single cladding mode at the gold-coated tip of a single-mode fiber. The sensor combines a high level of sensitivity, a miniaturized sensing area and simple intensity-based interrogation, and is intended for biosensing using portable point-of-care devices or highly integrated lab-on-chip systems.

The subject of the work presented is a novel fiber-optic bio-sensor suitable for miniaturized systems. The sensor concept employs a long periodic fiber Bragg-grating (LPG) for the excitation of surface-plasmon waves (SPW) sensitive to molecular binding processes on the sensor surface. Here we present the principle of operation as well as modeling results concerning the operating wavelength and its influence on sensor sensitivity and LPG parameters.