Universität Stuttgart
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Item Open Access 15 Gbit/s integrated laser diode driver using 0.3 μm gate length quantum well transistors(1992) Wang, Zhigong; Berroth, Manfred; Nowotny, Ulrich; Gotzeina, Werner; Hofmann, Peter; Hülsmann, Axel; Kaufel, Gudrun; Köhler, Klaus; Raynor, Brian; Schneider, JoachimAn integrated laser diode driver was realised using enhancement/depletion 0.3 μm recessed-gate AlGaAs/GaAs quantum well transistors. Fully-open eye diagrams were observed at bit rates up to 10 Gbit/s with 50 Ω loads. The maximum DC and modulation current were 25 and 45 mA, respectively. The power consumption is less than 450 mW.Item Open Access 10 Gbit/s monolithic integrated optoelectronic receiver using an MSM photodiode and AlGaAs/GaAs HEMTs(1991) Hurm, Volker; Rosenzweig, Josef; Ludwig, Manfred; Axmann, Albert; Benz, Willi; Berroth, Manfred; Osorio, Ricardo; Hülsmann, Axel; Kaufel, Gudrun; Köhler, Klaus; Raynor, Brian; Schneider, JoachimA 10 Gbit/s monolithic integrated optoelectronic receiver has been fabricated with a metal-semiconductor-metal (MSM) photodiode and enhancement/depletion 0.5 μm recessed-gate AlGaAs/GaAs HEMTs. A -3 dB bandwidth of 11.3 GHz has been achieved.Item Open Access 10 Gb/s monolithic integrated MSM-photodiode AlGaAs/GaAs-HEMT optoelectronic receiver(1991) Hurm, Volker; Rosenzweig, Josef; Ludwig, Manfred; Benz, Willi; Osorio, Ricardo; Berroth, Manfred; Hülsmann, Axel; Kaufel, Gudrun; Köhler, Klaus; Raynor, Brian; Schneider, JoachimA photoreceiver based on a metal-semiconductor-metal (MSM) photodiode and AlGaAs/GaAs HEMTs is presented. The photoreceiver was fabricated using a 0.5-μm recessed-gate process for double delta-doped quantum-well HEMTs. The following mean values for the enhancement and depletion HEMT parameters, respectively, have been obtained: threshold voltages of 0.1 and -0.5 V, transconductances of 500 and 390 mS/mm, source resistances of 0.7 and 0.6 Ω-mm, and transit frequencies of 35 and 30 GHz. This process includes photodiodes. A deep wet etch was used to deposit the photodiodes on an undoped GaAs buffer layer.Item Open Access High-frequency equivalent circuit of GaAs FET's for large-signal applications(1991) Berroth, Manfred; Bosch, RolandThe application of GaAs field effect transistors in digital circuits requires a valid description by an equivalent circuit at all possible gate and drain bias voltages for all frequencies from DC up to the gigahertz range. An equivalent circuit is presented which takes into account the gate current of positively biased transistors as well as the symmetrical nature of the devices at low drain voltages. A fast method of determining the elements of the equivalent circuit at all bias points without frequency limitations is presented. Direct computation from analytical expressions, without iteration, allows this parameter extraction procedure to be used for real-time on-wafer parameter extraction. Large-signal calculations are possible by inserting the voltage dependences evaluation for the elements into suitable simulation programs, such as SPICE.Item Open Access Broad-band determination of the FET small-signal equivalent circuit(1990) Berroth, Manfred; Bosch, RolandA method to determine the broadband small-signal equivalent circuit of field-effect transistors (FETs) is proposed. This method is based on an analytic solution of the equations for the Y parameters of the intrinsic device and allows direct determination of the circuit elements at any specific frequency or averaged over a frequency range. The validity of the equivalent circuit can be verified by showing the frequency independence of each element. The method can be used for the whole range of measurement frequencies and can be applied to devices exhibiting severe low-frequency effects.Item Open Access Silicon integrated dual-mode interferometer with differential outputs(2017) Hoppe, Niklas; Scheck, Pascal; Sweidan, Rami; Diersing, Philipp; Rathgeber, Lotte; Vogel, Wolfgang; Riegger, Benjamin R.; Southan, Alexander; Berroth, ManfredThe dual-mode interferometer (DMI) is an attractive alternative to Mach-Zehnder interferometers for sensor purposes, achieving sensitivities to refractive index changes close to state-of-the-art. Modern designs on silicon-on-insulator (SOI) platforms offer thermally stable and compact devices with insertion losses of less than 1 dB and high extinction ratios. Compact arrays of multiple DMIs in parallel are easy to fabricate due to the simple structure of the DMI. In this work, the principle of operation of an integrated DMI with differential outputs is presented which allows the unambiguous phase shift detection with a single wavelength measurement, rather than using a wavelength sweep and evaluating the optical output power spectrum. Fluctuating optical input power or varying attenuation due to different analyte concentrations can be compensated by observing the sum of the optical powers at the differential outputs. DMIs with two differential single-mode outputs are fabricated in a 250 nm SOI platform, and corresponding measurements are shown to explain the principle of operation in detail. A comparison of DMIs with the conventional Mach-Zehnder interferometer using the same technology concludes this work.Item Open Access 28-51 GHz dynamic frequency divider based on 0.15 μm T-gate Al0.2Ga0.8As/In0.25Ga0.75As MODFETs(1993) Thiede, Andreas; Tasker, Paul; Hülsmann, Axel; Köhler, Klaus; Bronner, Wolfgang; Schlechtweg, Michael; Berroth, Manfred; Braunstein, Jürgen; Nowotny, UlrichThe design and performance of a 28-51 GHz dynamic frequency divider based on pseudomorphic Al0.2Ga0.8As/In0.25Ga0.75As MODFETs with 0.15 μm mushroom-shaped gates are presented. The circuit has a power consumption of approximately 440 mW and a chip area of approximately 200x220 μm2.Item Open Access Integrated laser-diode voltage driver for 20-Gb/s optical systems using 0.3- μm gate length quantum-well HEMT's(1993) Wang, Zhigong; Berroth, Manfred; Nowotny, Ulrich; Ludwig, Manfred; Hofmann, Peter; Hülsmann, Axel; Köhler, Klaus; Raynor, Brian; Schneider, JoachimAn integrated laser-diode voltage driver (LDVD) making use of enhancement/depletion AlGaAs-GaAs quantum-well high electron mobility transistors (QW HEMTs) with gate lengths of 0.3 μm has been developed. Its large signal bandwidth is 12 GHz. Eye diagrams of the output signal at bit rates up to 8 Gb/s show an opening similar to that of the input signal. Supporting material is given indicating that the LDVD might operate at bit rates up to 20 Gb/s. The maximum output current is over 90 mA; the maximum modulation voltage of 800 mV corresponds to 40-mA modulation current for a laser diode with 20-Ω dynamic resistance. The power consumption is less than 500 mW.Item Open Access An 18-34-GHz dynamic frequency divider based on 0.2-μm AlGaAs/GaAs/AlGaAs quantum-well transistors(1993) Thiede, Andreas; Berroth, Manfred; Nowotny, Ulrich; Seibel, Jörg; Bosch, Roland; Köhler, Klaus; Raynor, Brian; Schneider, JoachimThe design and performance of a dynamic frequency divider was presented. This digital IC demonstrates the ability of the authors' AlGaAs/GaAs/AlGaAs quantum-well FETs with gate lengths of 0.2 μm. Stable operation was achieved in the frequency range from 18 GHz up to 34 GHz with a power consumption of 250 mW. To the authors' knowledge, this is the best result ever reported for HEMT circuits, and is similar to the frequency limit achieved by use of AlGaAs/GaAs HBTs.Item Open Access A 2.5 ns 8 x 8-b parallel multiplier using 0.5 μm GaAs/GaAlAs heterostructure field effect transistors(1991) Berroth, Manfred; Hurm, Volker; Nowotny, Ulrich; Hülsmann, Axel; Kaufel, Gudrun; Köhler, Klaus; Raynor, Brian; Schneider, JoachimTo increase performance of GaAs LSI digital circuits, a 0.5 μm recessed gate process has been developed and utilized for an 8x8-b parallel multiplier. The chip contains about 3000 heterostructure field effect transistors and has a power consumption of 1.5 W. The best results of the maximum multiplication time measured were below 2.5 nsec.