bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photonic ATM switch using vertical‐to‐surface transmission electro‐photonic devices (VSTEPs)
Authors: Nishio Makoto , Takagi Kazuo , Suzuki Shuji , Kaede Kazuhisa , Ogura Ichiro , Numai Takahiro , Kasahara Kenichi 
Published: July 2007

AbstractThis paper proposes a new architecture of photonic ATM switch for the purpose of eventually moving beyond the terabits‐per‐second (Tbps) level throughout ATM operation. The proposed architecture is based on vertical‐to‐surface transmission electro‐photonic devices (VSTEPs) which can be used both as an optical buffer memory and as an optical self‐routing circuit. Since VSTEP is an integrated two‐dimensional array, the VSTEP‐based optical buffer memory using massively parallel optical interconnections based on the free‐space optical beam propagation is an effective solution to achieve ultrahigh throughput in the buffer. The optical cell signal speed in the proposed optical buffer memory can reach about 10 Gbps. By using the VSTEP function as the optical header‐driven gates in a two‐dimensional array, the high‐speed and large‐capacity optical self‐routing circuit can be fabricated without being limited by the electric control circuit operation.In the proposed optical self‐routing circuit, priority control to prevent collision among cell signals at the output port in the case of cell signal contention can easily be achieved. The numbers of possible input and output ports in the self‐routing circuit are estimated to be around 100. An optical header is inserted at the front of the ATM cell signal for processing at the self‐routing circuit. To reduce the overhead of the optical header, a wavelength‐division technique also is proposed for the self‐routing circuit. Finally, experiments on operations of both the buffer memory and the self‐routing circuit with priority control for 1.6‐Gbps optical cells are carried out successfully.
Electrochromism of plasma‐polymerized Yb‐diphthalocyanine film in acidic electrolytes
Authors: Kashiwazaki Naoya 
Published: July 2007

AbstractAn electrochromic display (ECD) using a vacuumdeposited Yb‐diphthalocyanine film exhibits blue‐, greenand red‐colored states by its electrochemical reactions. When an acidic electrolyte was employed, the film exhibits a violet‐colored state and molecule dissociation without exhibiting a blue‐colored state. The stability of color change from green to blue in an acidic electrolyte was improved by usiag a plasma‐polymerized Yb‐diphthalo‐cyanine (pp‐YbPc2) film. The polymeric structure prevents pp‐YbPc2 from dissociation. In using the pp‐YbPc2 film with an acidic electrolyte, the durable ECD was found to be fabricated with a rapid response and high quality.
Temperature dependence of gray‐scale transmittance of thin‐film transistor LCDs driven by the frame rate control method
Authors: Tanaka Takeshi , Ono Kikuo , Konishi Nobutake 
Published: July 2007

AbstractThe temperature dependence of transmittance through a liquid crystal driven by the frame rate control (FRC) method was measured, where two‐level voltages (on/off) were supplied alternatively at intervals of a frame period for gray‐scale representation. The measurements were performed between 0 to 60°C on a 10‐inch diagonal thin‐film transistor LCD (TFT‐LCD) with a TN liquid crystal of normally white mode. The transmittance, with an on‐state voltage supplied in one frame period in every three periods, increased to 57 percent from 10 percent by increasing the temperatures to 60°C from 0°C, while the transmittance of the gray scales by the conventional method which use intermediate voltages show contrary dependence.Since the transmittance was constant as long as the ratio of the response time of liquid crystal to the frame period was kept constant, the transmittance change was attributed to the increase in the response time with temperature. The temperature dependence of the FRC‐driven LCD was well simulated by considering the change in viscosity of the liquid crystal. It was found also that the transient change in the capacitance of the liquid crystal affects the transmittance characteristics.
Multidimensional optical interconnections using beam‐scanning laser diodes
Authors: Itoh Hideo , Mukai Seiji , Watanabe Masanobu , Yajima Hiroyoshi 
Published: July 2007

AbstractSelf‐routing optical spatial interconnections are more flexible than those of fixed‐routing. A beam‐scanning light source is effective for self‐routing interconnections.This paper proposes optical buses and optical data links using far‐field beam‐scanning laser diodes (BSLD). Principles and characteristics of a fringe‐shifting laser diode (a new type of BSLD) are described. Multiple peaks of the fringes are useful for a spatial optical bus interconnection.
Frequency analysis of IC package inductance by the partial element equivalent circuit (PEEC) method
Authors: Nakamata Katsuro , Nishimura Michiaki 
Published: July 2007

AbstractThe recent advancement in ICs toward higher speed and higher density resulted in problems of packages such as delay in signal pulses, increase in noise, etc. To suppress this type of noise, one has to reduce the inductance, capacitance, and resistance of wires associated with the package. Numerical simulation is an effective approach for efficiently finding a wire pattern which gives the minimum values for these circuit elements. Little analysis has been conducted for effective inductance dependent on current distribution because the wires inside the package have complex three‐dimensional structures.This paper describes a simulation system for current distribution and effective inductance. The system uses the partial element equivalent circuit (PEEC) method of calculating current flow in conductor segments. An actual package was analyzed with this simulator. It was shown that the simulated effective inductance as a function of frequency matches the measured value very well. It also was observed how the current distribution inside the conductor varies as the frequency changes. These results confirm the effectiveness of this method in analyzing the current distribution in, and the effective inductance of, package wires.
Simulation of head wear and reproduction envelope by the finite element method
Authors: Mizoh Yoshiaki , Yohda Hiroshi , Kita Hiromi , Kotera Hidetoshi 
Published: July 2007

AbstractThe computational analysis of head wear and the deterioration of the reproduced envelope were studied. The flexible tape was modeled as a thin anisotropic shell and the air‐film was treated by the modified Reynolds equation in the finite element method (FEM). Head wear was calculated by assuming an amount of wear which was inversely proportional to the square of the spacing. The reproduced envelope was calculated from the tape‐head spacing on the gap between the inlet site and the outlet side along the drum rotation. Good agreement between the calculation and the measurement was obtained. The transverse direction stiffness of the tape has a dominant effect on the envelope.
High‐speed LED/PD arrays for optical parallel interface
Authors: Uji Toshio , Fukushima Kiyoshi , Hayashi Junji , Watanabe Isao , Nagahori Takeshi , Ito Masataka 
Published: July 2007

AbstractOptical parallel transmission is an effective technique for various interconnections, e.g., the interface between computer equipment. Monolithically integrated optoelectronic arrays for this purpose are very promising to realize compact, low power‐consuming, highly reliable, and low‐cost systems.In this paper various devices are examined and compared in terms of the forementioned requirements. As the most suitable optical devices, a 12‐channel, 1.3‐μm mesa‐structure planar LED array with high output power at low drive current and a low crosstalk InGaAs pin‐PD array with separated‐unit structure have been developed. Coupled with the GI 62.5 multimode optical fiber, the output power, rise time and fall time of the LED array were ‐16 dB, 2.7 and 1.5 ns, respectively, at 12‐mA drive current.Because of the low‐current operation, the interaction among channels due to heat generation was negligible. A separated‐unit structure was used for PD array to suppress crosstalk. As a result, the capacitance between two channels was as low as 0.05 pF, leading to the measured crosstalk lower than ‐40 dB until hundreds of megahertz 7‐mm thick compact modules with 1.5‐W power consumption have been fabricated and optical parallel transportation of 12‐channel, 150‐Mbit/s/ch for 100‐m distance has been realized with the modules.
An electroacoustic surface‐wave convolver of fabricated from a thin piezoelectric film and a semiconductor
Authors: Yamanouchi Kazuhiko , Kadosawa Fumio 
Published: July 2007

AbstractA surface acoustic wave convolver composed of ZnO with high piezoelectricity and GaAs with high mobility is thought to be a highly efficient active device, and considerable work and development has been carried out on this device. However, no theoretical analysis which takes into account every parameter such as the dependencies on ZnO film thickness and carriers in GaAs has been carried out.In this paper, the propagation characteristic of the surface acoustic wave in the ZnO/GaAs system was analyzed theoretically, taking into account the semiconductor carrier concentration in order to clarify the dependencies of the convolution efficiency of a ZnO/GaAs convolver on the ZnO film thickness, carrier density, and mobility. In addition, the dependencies of the convolution output on the surface acoustic wave oscillation characteristic in the ZnO/GaAs system and carrier density will be shown.
Analysis of ti‐diffused linbo3 optical waveguides by a modified step segment method
Authors: Kitoh Tsutomu , Kawano Kenji 
Published: July 2007

AbstractIn this paper, the modified step segment method (MSSM) is proposed as the highly accurate procedure in the analysis of the diffusion‐type optical waveguides and its accuracy is discussed theoretically. An optical directional coupler with exponential refractive index distribution is treated for which the numerically determined guided modes are compared with the analytical ones. As a result, it is found that the effective refractive index determined by MSSM agrees with the theoretical one and the error is less than 10−6.It also is understood that the convergence of the method is much better than that of the step segment method (SSM). Comparison of the present method with the linear segment one (LSM) indicates that the overflow can be avoided together with a considerable shortening of the CPU time. Therefore, it is concluded that the present method is very effective in the analysis of the diffusion‐type optical waveguides with very high accuracy.
A novel digital signal processing bit synchronizer for a prml recording channel
Authors: Yada Hiroaki , Hayashi Nobuhiro , Yamakoshi Takamichi 
Published: July 2007

AbstractThe partial‐response maximum likelihood (PRML) system currently is investigated for practical applications as a modulation/demodulation scheme for digital magnetic recording equipment.This paper proposes a construction of the bit synchronizer by complete digital signal processing. The operational principle is verified by experiment. The proposed bit synchronizer is composed of the decision‐feedback digital PLL and the interpolator. The decision‐feedback digital PLL receives the data‐asynchronous sampled signal sequence as the input, which is the result of sampling by the fixed clock of two samples/bit, and regenerates the clock. The interpolator calculates the signal value at the data point indicated by the phase of the decision‐feedback digital PLL output. The result is given to the Viterbi decoder.By applying the proposed scheme, the PRML demodulator from the equalizer to the Viterbi decoder can be realized as a digital signal processing circuit, which operates synchronously with the single fixed master clock. A PRML demodulator is constructed based on the proposed bit synchronizer, and the operational principle is verified by an experiment using a magnetic disk device. The bit‐error rate less than 10−6is obtained for the channel bit rate of 10 Mbps.
High‐frequency properties of nbn(g)/al nanobridge‐type josephson mixers
Authors: Wang Zhen , Kawakami Akira , Komiyama Bokuji , Hamasaki Katsuyoshi , Matsui Toshiaki 
Published: July 2007

AbstractTo reduce the self‐heating effect and thermal noise in bridge‐type Josephson mixers, all‐NbN nanobridges with an Al “direct shunt” resistor were fabricated.This paper describes the millimeter‐wave response and mixing properties of the NbN(g)/Al nanobridge‐type Josephson mixers in the 100‐GHz frequency. The effective noise temperature TNeff of the nanobridges was decreased to the bath temperature (liquid helium temperature, 4.2 K) by the Al “direct shunt” resistor and the millimeter‐wave induced steps were clearly observed at higher voltage (∼4 mV) than in the nanobridge without the Al “direct shunt” resistor.The millimeter‐wave current dependence of the height of the millimeter‐wave induced steps was analyzed quantitatively, taking into account the thermal noise in the RSCJ model. The simulated result agreed with the experimental result very well. The systematic decrease of the induced step height with an increase of millimeter‐wave current was explained as the increase of effective noise temperature due to absorption of millimeter‐wave power. In the 100‐GHz Josephson mixing experiment, a large IF power output was obtained at a voltage up to about 1.6 mV. The effective noise power NEP and conversion efficiency were about 3 × 10−20 W/Hz and 0.2, respectively.
Directional coupler‐type wavelength filters having an integrated multiple‐waveguide structure
Authors: Shimada Kazuhiko , Kambayashi Toshio 
Published: July 2007

AbstractThis paper proposes an optical filter consisting of GaInAsP/InP waveguides whose performance is examined analytically. This filter is composed of a vertical three‐ or four‐waveguide directional coupler. Based on an eigenmode analytical method, a compact and demultiplexing device is realized. The propagation characteristics of such devices are calculated as being expressed in terms of the superposition of the eigenmodes.A design criterion for both a demultiplexer and bandpass filter is presented. The demultiplexing of the two wavelengths of 1.545 and 1.585 μm with a crosstalk level better than ‐23 dB at a coupling length 265 μm is demonstrated. Also, with a multiple quantum well waveguide, a value of 6.9 nm for the ‐15 dB bandwidth at a coupling length 972 μm is obtained. Furthermore, the demultiplexing of the three wavelengths of 1.51, 1.545, and 1.60 μm is found to be possible in a four‐guide coupler structure (coupling length 942 μm) with MQW waveguides.
Autostereoscopic 3‐D display using LCD‐generated parallax barrier
Authors: Isono Haruo , Yasuda Minoru , Sasazawa Hideaki 
Published: July 2007

AbstractA newly developed liquid crystal display‐generated (LCD‐generated) parallax barrier method for an autostereoscopic three‐dimensional (3‐D) display is described. This system consists of two LCD panels constituting a 3‐D display and a slit barrier. Compared to a conventional parallax barrier method, the slit barrier is not fixed but variable electrically. Therefore, the method can be flexible for any desired multiviewpoint 3‐D image display system. The compatibility with the usual 2‐D image display is fully ensured. Also, both 2‐D and 3‐D images can simultaneously be displayed. A prototype 3‐D image display apparatus suitable for a personal computer has been demonstrated to indicate a strong feasibility for a new 3‐D image display application.
Two‐port crystal resonator for high‐precision oscillator
Authors: Ueno Yoshifusa 
Published: July 2007

AbstractA change of the oscillation frequency of an oscillator has commonly been achieved by changing the load capacitance of a crystal oscillator. Since the frequency changes nonlinearly with load capacitance, the rate of the frequency change varies with load capacitance. Therefore, when the frequency change through aging effects and/or due to the change in load capacitance occurs in TCXOs and VCTCXOs, the frequency shift must be compensated. However, the amount of compensation would be different before and after its adjustment.This paper describes a newly developed two‐port crystal resonator. This resonator has two independent load capacitances so that the frequency response and the oscillation frequency shift due to a temperature and/or capacitance fluctuation can be compensated independently. This function cannot be achieved in a conventional oscillator which has only one load capacitance.A formula to calculate the rate of a frequency change due to temperature and capacitance fluctuation has been derived by using the equivalent circuit of the two‐port crystal oscillator. The calculated value was found to be in good agreement with experimental result by taking into account stray capacitance. Therefore, this formula is useful for designing a two‐port crystal oscillator.
a‐SI TFTS with Stacked Gate Insulator of CVD‐SiO2/PECVD‐SiNx
Authors: Fukuda Kaichi , Ibaraki Nobuki 
Published: July 2007

AbstractA‐Si thin‐film transistors (TFTs) with a stacked gate insulator of thermal CVD‐SiO2/PECVD‐SiNxwere developed. In an a‐Si TFT, the threshold voltage (Vthshifts when the gate is biased for a long time. The stability ofVthis influenced strongly by the characteristic of the gate insulator. Therefore, the high quality of the gate insulator is essential to achieve high performance in a TFT.When an SiO2film is formed by thermal CVD, the invasion of nitrogen to the SiO2film is minimized and the defect density is lower than in plasma‐enhanced chemical vapor deposition (PECVD)‐SiO2. The properties of a TFT are strongly dependent on the SiO2deposition temperature and is improved by increasing the deposition temperature.When the gate SiO2was deposited at 430°C, the field effect mobility μ was about 1 cm2/Vs and theVthshift was greatly reduced. It is expected that theVthshift in a TFT with a thermal SiO2gate for LCD driving is one‐third that in a TFT with a PECVD‐SiOxNygate used for the same purpose. Using the former TFTs, the time‐dependent degradation of LCD due to the degradation of the subthreshold characteristic of TFTs was largely reduced.
Present status and future of driver LSI
Authors: Saitoh Sei , Ikeda Naoyasu 
Published: July 2007

AbstractLiquid crystal displays (LCDs) presently are used for display applications in many fields. New areas of interest for LCDs include how to cope with the large size, high resolution, multiple color, low power consumption, small thickness, and applications to multimedia. The keys to these subjects are the driving methods and driver LSIs. It is not too much to say that the driving method and display quality of LCD are determined by driver LSIs. In particular, driver LSIs are extremely important in realizing multiple color displays.This paper describes the present status and future of driver LSIs for driving full‐color, thin‐film transistor (TFT)‐LCDs for OA applications.
Inverse‐staggered polycrystalline silicon thin‐film transistors fabricated by excimer laser irradiation
Authors: Ono Kikuo , Ogawa Kazuhiro , Sakuta Hiroki , Konishi Nobutake 
Published: July 2007

AbstractFundamental device performance, mobility distribution, and threshold voltage shift characteristics of inverted staggered polycrystalline thin‐film transistors (TFTs) are discussed. The present TFT uses a polycrystalline silicon (p‐Si) crystallized by excimer laser as semiconductor layer and SiN prepared by CVD method as gate insulator. The TFT was fabricated onto glass substrate of 100 mm2at a maximum temperature of 300°C. Measurements of the distribution of mobility were carried out with devices placed at every 0.3 mm pitch. As a result, the mobility μ of TFT made at laser intensity of 200 mJ/cm2is 20.9 cm2/V · s and the off‐current is 2 × 1011A. TFT was found to be very uniform except for a region where a superposition of 200 mJ/cm2laser irradiation over a weak laser intensity was made.The analysis indicates that the region for low micrometer is the area irradiated by a laser intensity 110 to 170 mJ/cm2. The region irradiated with laser intensity of this range also was found to be in a mixed state of amorphous silicon of depleted hydrogen atoms and crystalline consisting of fine grains. A shift voltage at 20 V gate dc voltage at 104s after the application of the voltage is 0.2 V, 1/25 time smaller compared to a‐Si TFT. The presentp‐Si TFT is demonstrated to exhibit high‐device performance for liquid crystal display.
A new two‐dimensional analysis method for polycrystalline‐silicon tfts
Authors: Yamada So , Kato Noriji , Koyanagi Mitsumasa 
Published: July 2007

AbstractA new device simulation method for polycrystal‐line‐silicon thin‐film transistors (denoted as poly‐Si TFTs) is developed. The method is suitable to estimate the TFT characteristics and to analyze the operation mechanisms. In this simulation the influences of grain boundaries are incorporated into the carrier mobility model and the two‐dimensional distributions of the electrostatic potential and carrier concentrations are solved numerically.This simulation has enabled the quantitative evaluation of the dependences of TFT characteristics on grain size and grain boundary trap density, and the current‐voltage characteristics obtained as a result are in good agreement with the measured characteristics over a wide range from the on‐state region to the subthreshold region. Furthermore, in combination with the carrier generation model, high‐field phenomena such as the kink effect and avalanche breakdown can be analyzed in detail.By analyzing the mechanism of short channel effects that are inherent in poly‐Si TFT using this simulator, this effect has been attributed to the accumulation of carriers generated by avalanche in the poly‐Si thin film.
Analysis of microstrip crossovers using the nonorthogonal finite‐difference time‐domain method
Authors: Kitamura Toshiaki , Nakamura Satoru , Hira Masafumi , Kurazono Sadao 
Published: July 2007

AbstractMultilayered monolithic microwave integrated circuits (MMIC) have been proposed with a view to reducing the size and increasing the degree of integration of the MMIC. It has been demonstrated that new circuit configurations can be realized and the design capability can be improved. By the use of a multilayered MMIC, the circuit can be laminated so that the circuit size can be made smaller. However, since the circuit is laminated, qualitative evaluation of the crosstalks between the upper and lower transmission lines becomes important. Most of the previous analyses on the microstrip line crossover focused on the case where the two lines cross orthogonally.In this research, the finite‐difference time‐domain (FD‐TD) method applicable to an arbitrary coordinate system is used for the analysis of the crosstalk when two transmission lines cross at an arbitrary angle.First, the FD‐TD method that can be applied to an arbitrary coordinate system is summarized. Next, it is confirmed that the results of the present analysis for a single microstrip line do not depend on the mesh shape and that the present analysis results agree with those by other methods for a microstrip bend with an arbitrary angle. Finally, a three‐dimensional crossover of micro‐strip lines with an arbitrary angle is analyzed. the normalized frequency characteristics, cross‐angle dependence, and the interdistance dependence of thesparameters are presented.