bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the electro–optic polarizer having parallel electrodes on the same surface
Authors: Fujii Katunori , Iida Yoshinao 
Published: July 2007

AbstractElectro‐optic effect elements have attracted special interest recently and these generally have parallel electrodes on the same surface. Therefore, the electric field is not uniform and has complicated distribution. Moreover, knowledge of the electric field distribution is important to the element design, and the authors analyzed the case of the interdigital electrodes. However, the analysis of the electric field of the parallel electrodes was not investigated satisfactorily.This paper analyzes the electric field of the parallel electrodes for many varieties of electrode dimensions and the element thickness with the conformal representation. Moreover, the character of the electro‐optic polarizer having the parallel electrodes is discussed. The analysis result has clarified the relations between the electrode dimension: i.e., the element thickness and the half‐wave voltage. Further, the results are clarified as follows. For the first electro‐optic effect, the transmitting light is generally uniform between the electrodes (about 95% electrode distance). However, for the second electro‐optic effect, the uniform transmitting light can be obtained when the thickness of the element is about 0.2 × D −0.25 × D, where D is the distance between the outside electrodes.
Effect of the Si‐SiO2 interface state density and the charge in the SiO2 film on the electrical properties in Pt–diffused MOS structure
Authors: Kato Hideo , Shibata Yasuo , Kuwano Hiroshi 
Published: July 2007

AbstractThe effect of Pt‐diffusion on the electrical properties in the Pt‐diffused MOS structure has been investigated. In these structures, the Pt‐diffusion ambient has a direct effect on the electrical properties;, the samples which were Pt‐diffused in oxygen ambient show a large positive flatband voltage shift, and those which were Pt‐diffused in nitrogen ambient show little flatband voltage shift but have a memory effect. We measured the dependence of flatband voltage on the oxide thickness and evaluated the distribution of the Si‐SiO2 interface state density. We also measured the oxide charge density. From these experimental results, we show that the large shift of the flatband voltage is caused mainly by the charges generated within the oxide film and that the Si‐SiO2 interface state density distribution varies reversibly according to the memory effect.
Numerical analysis of silicon–clad planar optical waveguides
Authors: Kumagami Hiroshi , Koshiba Masanori , Suzuki Michio 
Published: July 2007

AbstractThe results of the numerical calculations related to the propagation characteristics of silicon‐clad planar optical waveguides are presented. The finite‐element method is used for the calculations. First, the propagation characteristics of TE modes in waveguides of silicon layer/dielectric core/homogeneous dielectric substrate are investigated. The results are compared with those of the exact solution to confirm the correctness of the present method. In this case, the phase and attenuation constants both oscillate periodically with the silicon thickness. Then, the TM modes are analyzed and it is indicated that the propagation constants are different from those of the TE modes and that propagation constants do not necessarily oscillate periodically with the silicon thickness. Whether or not the oscillations are present depends on the refractive‐index difference between the dielectric core and the silicon layer. Next, to reduce the propagation losses of the silicon‐clad planar optical waveguides with interesting characteristics, the new structures of silicon layer/inhomogeneous dielectric substrate or silicon layer/dielectric buffer layer/ inhomogeneous dielectric substrate, are proposed. It is shown that the propagation losses of these silicon‐clad planar optical waveguides expressed in decibels, are reduced by one order of magnitude compared with the previous planar waveguides.
Analysis of josephson triode
Authors: Yoshimori Shigeru , Kawamura Mitsuo 
Published: July 2007

AbstractThe Josephson junction is an oscillator driven by constant current. Therefore, the integrated device of the weak‐link type Josephson junction for detecting electromagnetic waves using the junction as a local oscillator can be considered. The superconducting device proposed by Likharev based on this concept is the Josephson triode consisting of three Josephson junctions. This paper describes the analysis of the Josephson triode which is the superconducting device for the heterodyne detection. First, the static characteristics are analyzed by use of the equivalent circuit and the fundamental equations. The necessary conditions for the normal resistances are derived. It is shown by numerical analysis that the millimeter wave heterodyne detection characteristics of the triode are identical with the theory and experiment for a tunnel junction. Moreover, the results analyzed numerically can be explained by analytical considerations and the simplified equivalent circuit of the Josephson triode is derived. The relations between the intermediate frequency output power and the local oscillator power are represented analytically via the simplified equivalent circuit of the triode.
Characteristics of β‐SIC films grown from an SiHC13‐C3H8‐H2 system
Authors: Furumura Yuji , Doki Masahiko , Mieno Fumitake , Maeda Mamoru 
Published: July 2007

AbstractBeta‐phase silicon carbine (β‐SiC) layers have been grown on silicon substrates at a growth temperature of 1000°C and at a low pressure of 200 Pa from an SiHC13‐C3H8‐H2 system. Silicon substrates are 4‐inch silicon wafers, and (111) tilted substrates with 4° off‐axis and (100) substrates with no off‐axis are both used. It was found from X‐ray diffraction and reflection high‐energy electron diffraction (RHEED) analysis that β‐SiC single‐crystal films are obtained on (111) tilted substrates, but not on (100) substrates under the conditions used in this experiment. By forming an n‐p heterojunction between a P‐doped β‐SiC layer and a p‐type substrate and measuring its rectifying characteristics, the saturation current density at 2 V in the reverse‐biased region was found to be below 2 × 10−6 A/cm2.
Theoretical determination of equivalent circuit parameters for reflective SAW metallic gratings
Authors: Mitobe Seiichi , Koshiba Masanori , Suzuki Michio 
Published: July 2007

AbstractA theoretical method is described for determining equivalent circuit parameters for metallic gratings on arbitrary piezoelectric substrates. In this paper, to consider an energy storage effect, we adopt the equivalent circuit model proposed by Li et al. The finite‐element method is used to calculate the upper and lower cutoff frequencies of the stop band for metallic gratings of infinite periodic structure, and circuit parameters are determined from these values. Therefore, in this equivalent circuit, all the effects of piezoelectric perturbation, mechanical perturbation, and energy storage are taken into account. To show the validity and usefulness of this approach, for aluminum strips on some useful piezoelectric substrates (LiNbO3, quartz, LiTaO3, Li2B4O7), equivalent circuit parameters for each of the metallic gratings are determined and SAW reflection characteristics are computed. Result show that for the Li2B4O7 substrate, the reflection magnitude per strip is large and the influence of the change of strip thickness on the center frequency shift is small.
Inspection device for testing the mounted condition of chip components on printed wiring boards
Authors: Yabuzaki Syunichi , Yamataka Yasuo 
Published: July 2007

AbstractAn automatic inspection device has been developed for detecting chip components missing from or improperly positioned on printed wiring boards after the components have been attached temporarily with adhesive and then soldered. Errors are detected by illuminating the back of a mask with holes that correspond to the component locations against the board and observing light leakage. The locations of defect signals are displayed on a TV monitor and memorized as coordinates on a rectangular coordinate system that corresponds to the visual field of the TV camera to provide quantitative data on defect locations. Defect signals and external noise are recorded simultaneously for the first few frames. Succeeding frames are checked for a continuous signal to eliminate problems due to external noise. If a continuous signal is not detected, it is assumed that only noise exists. Device performance is as follows: 1) inspection time–2 s or less for boards with 500 chips or less; 2) inspection accuracy—±0.3 mm maximum. Although the simple structure of the device ensures low cost, the device is extremely effective in actual use.
Speed performance optimization in ECL gate array
Authors: Kato Shuichi , Tatsuki Makoto , Kuramitsu Yohichi , Horiba Yasutaka 
Published: July 2007

AbstractIn ECL circuits with multiple current paths, the delay time depends on the current distributions between the switching stage and the emitter‐follower stage. An optimum current distribution ratio exists for the load capacitance. However, in the application to the gate array, it is not possible to provide an optimum current distribution ratio for each gate. In this paper, the speed performance of the gate array is studied statistically for multiple gate groups. Also, the delay time of the ECL circuit is given as an analytical expression. As a result, the current distribution ratio optimizing the speed performance of the gate array in the ECL circuit structure is analyzed. It is found that the optimum current distribution ratio is regulated by the average load capacitance applied to the gate and the capacitance added to the collector node of the basic gate circuit. Although the ratio decreases in proportion to the increase of the average load capacitance, it does not depend on the current level of the basic gate circuit.A gate array consisting of 900 internal gate cells with different current distribution ratios has been fabricated. The measured delay time characteristics of various basic gate circuits and the load capacitance distributions in the LSI have been combined and the distribution of the delay time has been derived. Although there is some discrepancy between the calculated and measured data for the average delay time, the measured optimum current distribution agrees very well with the calculated value. Hence, a design of mask patterns optimizing the current distribution for the speed performance has become possible.
Switching noise in josephson AC power circuits
Authors: Ohhata Masanobu , Yoshikiyo Haruo 
Published: July 2007

AbstractTo find a way to reduce the switching noise in Josephson gates, the circuit connecting the regulator and the gate is analyzed so that a quantitive design guideline for the noise is obtained. First, to simplify the mechanism of noise generation, the regulator and the gate are simplified. It is shown that the regulator can be approximated by grounding of the power bus and the gate by a ramp function generator. By these simplifications, the switching noise generated in the circuit connecting the regulator and the gate is analyzed and a simple approximate formula for noise voltage amplitudes is presented. Finally, a circuit is fabricated for trial and the noise is analyzed with a Josephson sampling circuit to confirm the effectiveness of the approximate formula.
Noise in an IMPATT diode oscillator with second harmonic signals
Authors: Fukushima Makoto 
Published: July 2007

AbstractMultifrequency operation of IMPATT diode oscillators is important for the improvement of the oscillation efficiency of fundamental signals and for the extraction of higher‐order harmonics.This paper proposes a method to analyze the noise characteristics of IMPATT diodes in multifrequency operations with higher‐order harmonics, and shows the calculation results.In the analysis, a Read diode model is assumed first and the diode noise is analyzed for fundamental and second harmonic operations. Then numerical calculations are carried out to show the characteristics of the noise generated in the diode as AM and FM oscillator noise. In this numerical calculation, AM and FM noises are represented, respectively, as an N/C ratio and as a frequency fluctuation, and their variations with the amplitude and phase relation of the electric field for fundamental and second harmonic signals. Furthermore, the dependences of output power and external Q value of the oscillator on the phase of fundamental and second harmonic signals are also shown, and the optimum phase relation is described.
Study of impulsive noise characteristics in telecommunication line
Authors: Kuribayashi Masashi , Ishida Yukinori , Fujiwara Mitsugu , Ideguchi Tsuyoshi 
Published: July 2007

AbstractThis paper discusses the duration time rate as an evaluation measure of the impulsive (nonstationary) telecommunication line noise. The expression for the duration time rate is derived by applying the excursion probability theory of the nonstationary random process. The validity of the expression was verified by experiment. First, the non‐stationary property of the impulsive noise is demonstrated. The duration time rate for the impulsive noise is derived using the expected number of excursions, which is the solution of the excursion probability problem, as well as the expected excursion duration time. Then it is shown that the impulsive noise passed through the equalizer can be approximated by the quasi‐stationary noise, considering the frequency response of the equalizer. From a practical viewpoint, the impulsive noise before equalization is assumed as the quasi‐normal stationary noise, and the expressions are derived for the mean duration time rate and the mean error rate after equalization, using the solution of the excursion probability problem. Finally, the contact noise is considered as an example of the impulsive noise. The power spectrum and the auto‐correlation function are derived for the noise at the output of the equalizer. It is shown experimentally that the equalized impulsive noise can be considered as the quasi‐stationary noise. Numerical investigations are made for the mean duration time rate and the mean error rate derived in this paper. As a result, it is indicated that the expressions for the mean duration time rate and the mean error rate derived in this paper are useful for the evaluation of the impulsive noise.
Water propagation blocking properties of submarine optical fiber cables
Authors: Yoshizawa Nobuyuki , Ohnishi Masatoshi , Ishihara Koushi , Negishi Yukiyasu 
Published: July 2007

AbstractA transit transmission system for a long‐distance digital transmission line using a submarine optical fiber cable is expected to be used at water depth of 8000 m and transit distance of 40 km. This paper introduces a fundamental design for a submarine optical‐fiber cable for deep‐sea use, which can block water propagation within the cable if it is cut accidentally on the sea bed. Evaluations of the water‐blocking properties and signal transmission characteristics of the cable are presented also. The water propagation in the cable can be approximated by the stationary laminar flow of viscous fluid in a capillary tube. The distance of the water propagated is proportional to 0.5 power of the water pressure and 0.3 to 0.5 power of time. The transmission loss of the prototype submarine optical cable (with the water propagation blocking properties) is less than 0.04 dB/km. The propagation of water within the cable is estimated to be less than 800 m per month at water depth of 8000 m. This shows that the cable has practical application.
Improvement in crystalline quality of silicon on fused silica by zone melting recrystallization
Authors: Fukami Akira , Kobayashi Yutaka 
Published: July 2007

AbstractIn the silicon‐on‐insulator (SOI) zonemelting crystallization method using a high‐frequency induction heating, an improvement has been examined for the crystalline quality of recrystallized silicon on a silica substrate. It is easy to obtain the (100) crystalline‐orientation by connecting island‐shaped areas with wide and short bridges (both made of polycrystal Si on a silica substrate). The (100) crystalline‐orientation can more easily be formed with a hexagon island area which has small angles to the bridge rather than a simple square. The reason can be explained by a thermal resistance during their recrystallization. When the bridge is wide and short so that its thermal resistance is small, there is an adequate thermal flow through it. This helps the recrystallization, otherwise it is supercooled. There was no subboundary in the side where the recrystallization occurred earlier, while subboundaries as crystalline defects were generally observed. This is considered to be due to the fact that the solid‐liquid boundary during the recrystallization has no significant micro irregularity. By utilizing this property, and by choosing appropriately the dimensions of the island and bridge, recrystallized Si with no subboundaries can be obtained.
Lift‐off technology for preparation of josephson junction integrated circuits using deep‐UV photoresist
Authors: Hirano Mikio , Yano Shinichiro , Yamada Hiroji , Kawabe Ushio 
Published: July 2007

AbstractA new lift‐off process for a microscopic pattern formation in a Josephson junction integrated circuit has been developed using high resolution deep‐UV photoresist (MRS). The single‐layer photomask with an overhang structure suitable for a lift‐off process was fabricated using a deep UV contact exposure and development process. Using a low temperature (70°C) lift‐off process with MRS, it was possible to form a Pb‐alloy pattern with the line width and line spacing of 0.8 μm and obtain the 1.5 μm □ contact window through the SiO film.With the new lift‐off process using MRS, experimental Pb‐alloy type Josephson junction integrated circuit chips, which were formed by 1.0 μm design rule, were fabricated. As a result, it was confirmed that this process was suitable for forming patterns with dimensions less than 1 μm. However, the remains of MRS in the lower electrode surface in the window caused the scattering of the junction currents. The remains could then be removed with a cleaning treatment of the lower electrode using ozone (O3) generated by a UV with ultrashort wavelengths.
Study of matching load on nonuniform coaxial transmission line and its application to wideband impedance transformer
Authors: Sano Seigo , Mochizuki Manabu , Muto Shinzo , Ito Chiaki , Ito Hiroshi 
Published: July 2007

AbstractTwo nonuniform coaxial transmission lines have been fabricated in which the primary parameters of the line vary parabol‐ically and cosinusoidally. The characteristic impedances and the matched loads have been measured and the application to a broadband impedance transformer has been studied. The results show that the characteristic impedance distribution of the nonuniform coaxial transmission line does not coincide with the nominal characteristic impedance Z0(x) but agrees with the solution Zp+ (x) of the differential equation for the impedance derived from the telegrapher's equation. It is also demonstrated experimentally that the standing wave in the transmission line vanishes completely if Zp+(l) is connected at the terminal (x = l) and, hence, this value provides an effective matched load. It is found that under this matched condition both of the nonuniform coaxial transmission line eleoents operate as an impedance transformer over an extremely wide frequency range exceeding 0.5 GHz.
Electrical properties and characterization of Al‐Nb amorphous films
Authors: Sasaki Katsutaka , Noya Atsushi , Umezawa Toshiji 
Published: July 2007

AbstractTo take advantage of the high resistivity and small TCR in amorphous alloys, an Al‐Nb amorphous alloy thin film was prepared by dc sputtering. The thermal aging stability of the film was investigated by the heat treatment in the atmosphere. The film surface was characterized by AEC and XPS analyses. As a result of characterization, it was found that the segregated Al atoms to surface were oxidized preferentially and that a protective oxide film was formed on the surface. The oxidized film did not grow by the heat treatment at 300°C but the structure of the alloy film prepared showed relaxation. The increase in ρ and TCR due to the structural relaxation was discussed in accordance with the electric condition mechanism of liquid alloy. Moreover, nitrogen doping into the film was attempted in order to control the structural relaxation.
Quasi‐matched‐velocity traveling‐wave‐type electrodes for light modulators and their analysis
Authors: Sanagi Minoru , Nakajima Masamitsu 
Published: July 2007

AbstractTo increase the bandwidth of the traveling‐wave‐type light modulator, it is necessary to decrease the difference between the velocity of the modulation wave and that of light. The velocity mismatch was improved by incorporating a buffer material with low dielectric constant between the electrodes and substrate so that the modulation efficiency does not deteriorate and the capacitance between the electrodes is minimized. Considering not only the bandwidth but also the ratio between the driving power and the bandwidth (P/Δf), three types of structures have been proposed.For the theoretical analysis, the modulation wave traveling through the electrodes was assumed to be a TEM wave and the model of the two‐dimensional static electric field was adopted. However, since the structure was complicated, a numerical calculation was needed in which the boundary element method was used. The structure with least P/Δf ratio was chosen by using the result of the calculation. As a result of further calculation on the chosen structure with the various thickness of the buffer layer, it was found that the bandwidth is improved drastically and the ratio of P/Δf becomes small by increasing the width of the buffer layer.
Circular to rectangular waveguide mode conversion through a parabolic cylinder waveguide–TEON incident
Authors: Wada Osami , Nakajima Masamitsu 
Published: July 2007

AbstractThe output mode of the gyrotron used as a high‐power millimeter wave source for nuclear fusion plasma heating is the TEOn of a circular waveguide. It is desirable that this mode be converted to a linearly polarized mode such as the TEmO in a rectangular waveguide. This paper discusses mode conversion from a circular TEOn mode to rectangular waveguide modes in an oversized waveguide system in which a parabolic cylinder waveguide with its axis as a focal axis is inserted between the circular and rectangular waveguides. First, an approximate analysis is introduced based on the geometrical optics approximation by taking advantage of an oversized waveguide system. Subsequently, the mode matching method is used by expanding the fields into eigen‐modes. The results for the optimum length of the parabolic cylinder waveguide obtained by the mode matching period agreed with those from the geometrical optics approximation. Hence, to a certain extent, an estimate based on the geometrical optics is effective in the oversized waveguide system. Since no accurate eigenvalues have been reported for the parabolic cylinder waveguide, the computed results are presented.