bluuebunny/crossref_metadata_2025_split huggingface dataset:
Josephson threshold logic circuit and its application
Authors: Harada Yutaka , Hatano Yuji , Yamashita Kunio , Kawabe Ushio 
Published: July 2007

AbstractThis paper proposes a Josephson threshold logic circuit, which is best suited to high‐speed operations. Using the proposed circuit, the adder can be constructed by four Josephson elements. The scale of the circuit can be reduced both in the number of circuits and the number of logic stages, compared with the conventional Josephson logic circuits. The circuit is shown to be useful in the realization of the high‐speed and highly integrated adders and multipliers. Then it is demonstrated that the Josephson threshold logic circuit can be constructed by the magnetically coupled interferometer element, the current‐injection interferometer element and the direct‐coupled element. A typical circuit construction is shown with the adder as an example. To verify the correct operation of the Josephson threshold logic circuit, a 1‐bit adder by magnetically coupled interferometer elements was constructed by Nb‐Pb alloy process, and the operation of the circuit was verified.
Realizations of simulation inductors using mutators with differentiators
Authors: Tanno Yorimoto , Watanabe Masato , Member Shingo Isozaki, Associate 
Published: July 2007

AbstractMany methods of simulating inductors and capacitors have been proposed for the integration of electronic circuits. By using mutators, excellent simulation capacitors and inductors can be obtained with simple circuit configuration. This paper describes the realization of frequency‐independent simulation inductors using mutators. A mutator is an active two‐port linear network for transforming one type of nonlinear element into another type. There are three classes of mutators: L ‐ R mutator, C ‐ R mutator, and L ‐ C mutator. The relationships pertaining to an L ‐ R mutator are classified into four types. A new approach is proposed to realize a type‐2 L ‐ R mutator and a type‐4 L ‐ R mutator with R, C and operational amplifiers using a differentiator configuration. The principle of the simulation inductors by those circuits is presented. This simulation inductor is characterized by the independent adjustment of its inductance and Q, and variable L which changes linearly with the value of a resistor.
A simple measurement technique for the refractive‐index change caused by the thermooptic effect
Authors: Kishioka Kiyoshi 
Published: July 2007

AbstractWhen a thin metallic film electrode deposited on the surface of a glass substrate is heated, a change is produced in the refractive index due to the thermooptic effect in the substrate, which is proportional to the temperature distribution. Due to the gradient of the refractive index produced below the electrode, the laser beam passing through the substrate is deflected toward the electrode. This paper presents a simple technique for the measurement of the refractive‐index change below the electrode, which utilizes the deflection of laser beam. The method is applied to fused silica, Pyrex glass, Tempax glass and B‐270 glass and the measured results are shown. Together with the increment of the refractive index, a constant determining the temperature distribution of the substrate and the temperature of the electrode are also measured. To verify the validity of the method, the thermal coefficient representing the temperature dependence of the refractive index is calculated from the measured refractive‐index increment and the electrode temperature. The result for the fused silica is compared with the previously reported value. As a result, it is seen that the value obtained by the proposed method agrees well with the published value. A discussion is also made on the accuracy of the measured values.
Surface acoustic wave convolver using multiple waveguide
Authors: Nakagawa Yasuhiko , Makio Satoshi 
Published: July 2007

AbstractA new elastic convolver is proposed in which a nonlinear interaction of surface acoustic waves (SAW) on multiple waveguides is used. Theoretical and experimental investigations are carried out. When two SAWs with angular frequency of ω and wavenumber of β, and with ω and‐β propagate in opposite directions on N waveguides, the parametric mixing phenomenon generates a SAW with a sum frequency traveling in the direction normal to the waveguide. The generation efficiency increases: (i) when the width of one of the waveguides is one‐half the wavelength of the sum frequency SAW; (ii) with the number N of the waveguides with the maximum occurring at N = 8 ∼ 10; and (iii) with the larger velocity difference (ΔV/V). Generation of the sum frequency SAW is possible only with the guided mode of SAW. The present convolver can be matched easily with the external circuit, because the convolution output is extracted with an interdigital electrode (IDT).
Automating inspection of aluminum circuit pattern of LSI wafers
Authors: Hara Yasuhiko , Fushimi Satoru , Ooshima Yoshimasa , Kubota Hitoshi 
Published: July 2007

AbstractAn automatic inspection method of defects of aluminum‐circuit patterns (cuts, short‐circuits and other irregularities) formed on the top layer of multiple‐layer LSI wafers was studied. The defects in question are irregularities greater than half the pattern width, since the aluminum‐circuit patterns have relatively large irregularities along the boundaries of the patterns, and it is not necessary to detect them as defects.The wafers have multiple‐layer patterns consisting of aluminum and polysilicon, etc., and it is generally difficult to distinguish the aluminum‐circuit patterns alone from others. We found a method of detecting aluminum‐circuit pattern clearly by using bright‐field and dark‐field illumination (an illumination from a diagonal direction) simultaneously, and by making the intensity of the latter stronger. A method of detecting defects of a pattern was also examined in which a pair of patterns is compared and their mismatching is regarded as a defect. A pattern‐matching error‐detection method was developed. In this method, a position of patterns which makes the integration of the logic exclusive‐or sum minimum is measured in real time. A method of aligning a pair of patterns was also developed. The detection of defects having the size of 1 μm (3 pixels) was achieved by detecting a mismatching part of asymmetrical shapes in the two patterns which are aligned.
Wavelength stabilization of a semiconductor laser in high‐speed modulation using the Rb‐D2 absorption line
Authors: Sato Takashi , Sugai Hiroyuki , Shimba Minoru 
Published: July 2007

AbstractThe wavelength stabilization of a semiconductor laser under high‐speed modulation is reported. The applied stabilization method uses the difference between an atomic absorption line and oscillation wavelength as a feedback signal. In this paper, this method was applied under high‐speed modulation. The broadening of the oscillation wavelength width by generated sidebands under high‐speed modulation distorts the feedback signal and degrades the stability. However, the wavelength stability (Allan variance) 10−10 ∼ 10−8 was obtained by using the Rb D2 absorption line under the modulation frequence 50 to 200 MHz and the modulation current smaller than 1.6 mAp‐p.
Phase matched SHG of surface polariton along a silver layer on a slab‐type optical waveguide
Authors: Sasaki Keisuke , Kawagishi Hideyuki , Ishijima Yoshihiro 
Published: July 2007

AbstractThe existence is found for coupled guidedand surface polariton‐modes, in a slab‐type waveguide with a silver thin layer on top of it. The phase‐matched condition for the second harmonic generation (SHG), due to the fundamental and surface polariton modes, is determined. In waveguides of this structure, the realization of long propagation‐length (i.e., long interaction‐length) is possible in a waveguide with energy storage (Corning glass 7059), to compensate for the losses due to excitation of plasma polaritons. The generation of the phase matched second harmonics due to the surface polaritons is experimentally observed. The waveguide is tapered perpendicular to the direction of propagation. The theoretical phase matched condition between the fundamental and second harmonic waves is determined for a specific silver thickness on top of the slab waveguide. This phase‐matched condition is confirmed experimentally. The output of a Q switched Nd: YAG laser is used as the fundamental wave.
I‐V characteristics of photodetector using the GaAs MESFET
Authors: Umeda Tokuo , Cho Yoshio 
Published: July 2007

AbstractThe experimental results of the optical response characteristics of GaAs MESFET photodetectors were analyzed numerically, using the optical response mechanism of the FET. The device used was designed for the X‐band applications and the numerical analysis was carried out mainly on the IV characteristics. As a result, the experimental results were explained successfully by taking into account the influence of the optically controlled channel current.
Finite‐element analysis of dielectric slab waveguide with finite periodic corrugation
Authors: Hirayama Koichi , Koshiba Masanori , Suzuki Michio 
Published: July 2007

AbstractTo calculate the reflection/transmission characteristics of a dielectric slab waveguide with finite periodic corrugation, a numerical approach based on the finite‐element method is proposed. Although the finite‐element method has already been applied to discontinuity problems in dielectric waveguides, it was virtually impossible from the viewpoints of computation time and computer capacity to apply the finite‐element method directly to a waveguide with many discontinuities such as a finite periodic waveguide. In the present article, a “substructure” has been introduced to the finite‐element formulation to treat a large number of discontinuities. Consequently, the interaction of surface waves and radiated waves among all discontinuities is automatically taken into account. Also, an unbounded waveguide is replaced by a corresponding bounded one; this creates a problem where an artificial boundary should be set. It was found that in a finite periodic waveguide, a good approximate solution can be obtained by choosing the position of the artificial boundary with an adequate distance from the waveguide, since the dependence of the solution on the position of the artificial boundary is not significant. The validity and usefulness of this method was confirmed by comparing the numerical results with the values obtained from other theoretical methods and the experimental values.
A study on error rate monitoring in mobile satellite communication systems
Authors: Sakai Tsutomu , Nakajima Shigeo , Mishima Hiraku 
Published: July 2007

AbstractMobile satellite communication systems employ the wide area accessibility of a satellite. Digital signal transmission systems which enable communication by highly efficient voice encoding techniques and error correcting techniques, even on low C/N channels, are being studied and developed in many countries. This paper studies error rate monitoring for application to antenna tracking control and transmitting power control in mobile satellite communication systems. A soft decision error correction method, which is expected to be available in a wide range of C/N, is proposed and its performance is clarified theoretically and experimentally. Considering the application to ship antenna tracking control, the monitoring accuracy on fading channels is evaluated experimentally. A simulation experiment is carried out for an electronic tracking control with switching arrays, and the reception level degradation due to tracking error is clarified. Simulation results of transmitting power control against rain attenuation are also given.
A low‐drift DC amplifier utilizing thermal feedback
Authors: Lino Shoichi , Sanada Toru , Hashiguchi Sumihisa 
Published: July 2007

AbstractIn electronic measurement, industrial measurement, medical instrumentation and industrial control, there are several practical problems in dc amplifier characteristics such as initial offset voltage, temperature drift, time drift, noise and input bias current. In some applications, a dc amplifier with a good long‐term stability is required. This paper presents a method for realizing a dc amplifier suitable to these applications. After characteristics of the components used are matched as much as possible, a thermal feedback is introduced that suppresses the effect of the ambient temperature fluctuation. First, a model of the system is introduced and the thermal coupling stage of the first stage affecting the drift is analyzed so that the parameters necessary for suppression of the temperature drift are obtained. Next, this model is used for derivation of the degree of suppression of the drift by the present method. A method of selecting the parameters and a design procedure are discussed. It is found that the temperature drift can be suppressed by 40 dB at an extremely low‐frequency range in the test amplifier and the temperature coefficient is 0.36 μV/°C. At specific frequencies, the improvement is 16 dB at 0.27 mHz and 10 dB at 0.6 mHz.
Finite–element method analysis of microwave and optical waveguides—trends in countermeasures to spurious solutions
Authors: Koshiba Masanori , Hayata Kazuya , Suzuki Michio 
Published: July 2007

AbstractThis paper presents a review of finite‐element methods for the analysis of microwave and optical waveguides, particularly focusing on the recent results for suppressing or eliminating techniques of the spurious solutions that have become a subject of discussion to date. The finite‐element method analysis of electromagnetic waveguides can be divided into four classes: (1) scalar wave analysis by the one‐dimensional finite‐element method; (2) vectorial wave analysis by the one‐dimensional finite‐element method; (3) scalar wave analysis by the two‐dimensional finite‐element method; and (4) vectorial wave analysis by the two‐dimensional finite‐element method. Spurious solutions appear in (4), and, depending on the variational expression used, they also appear in (2). Placing emphasis on (2) and (4), particularly on (4), various finite‐element formulations are presented such as axial fields of E and H, full vector H field, full vector E field, transverse fields of E and H, and transverse fields of E or H formulations, and various approaches capable of suppressing or eliminating the spurious solutions are reviewed in detail.
Design method for triple–clad silica core optical fibers with zero total dispersion at wavelengths of 1.3 and 1.55 μm
Authors: Furukawa Shinichi , Nakazawa Kazushige , Hinata Takashi , Hosono Toshio 
Published: July 2007

AbstractThis paper describes the design method for triple‐clad silica core optical fibers with zero total dispersion at wavelengths of 1.3 and 1.55 μm; (ac, Sc) is the point where the total dispersion (= S) at wavelengths of 1.3 μm becomes equal to that at 1.55 μm when the core radius (= a) is varied. We denote the relative index difference between the core and the mth clad at 1.55 μm by Δm+1 (> 0, m × 1, 2, 3), the thickness of the mth clad by tm (m × 1, 2, 3), the cut‐off wave length for the second mode by λc and the equivalent bending radius (= radius where the bending loss is 0.01 dB/km as R. The following conclusions have been obtained: (1) even if the conditions for the zero dispersion are satisfied in an ideal triple clad (TC type), the zero dispersion condition cannot be satisfied when fluctuations and round shoulders happen to exist in the clad layers (nonideal TC type); (2) to fabricate fibers of TC type and nonideal TC type with |Sc| < 0.1 ps/km/nm, λc ≤ 1.15 μm and R < 5 cm. The following conditions should be satisfied: Δ2 = 2Δ4, Δ3 ≤ Δ4, Δ4 ≥ 0.7% and t1/ac ≤ 1.04 for t2/t1 × 0.5; (3) if the item (2) is satisfied, the sensitivities of Sc to ac, Δ2, and Δ3 for wavelength of 1.3 μm are constant when t1/ac ≤ 2.0. However, at wavelength of 1.55 μm, they decrease as t1/ac decreases; and (4) R for wavelength of 1.55 μm is about 10 times larger than R for wavelength of 1.3 μm.In this paper, the total dispersion is computed by the differentiation formula for determinant. Therefore the significant digits of the total dispersion in our results are more than four.
DC–coupled broadband and gain controllable monolithic amplifier circuits
Authors: Ishihara Noboru , Akazawa Yukio , Konaka Shinsuke , Kawarada Kuniyasu 
Published: July 2007

AbstractThis paper will describe a method for broadening the bandwidth of gain controllable monolithic amplifier circuits for the purpose of the application to the repeater circuits in the Gb/s optical transmission systems. The gain controllable differential amplifier circuit exhibits narrower bandwidth because of larger parasitic capacitance components in comparison with basic differential amplifier circuits due to the complicated circuit configuration to control the gain. Also, when the peaking method for broadening the bandwidth is applied, the peaking amounts exceed the optimum value and becomes unstable in the low‐gain operation even if the peaking amounts are optimized for the high‐gain operations. In this paper, a new gain controllable amplifier circuit using the bias current dependency of differential resistance of diodes is proposed. Furthermore, the circuit is fabricated by using the Si Bipolar Super Self‐Aligned process Technology (SST). A broadband characteristic of 1.6 GHz bandwidth and 29‐dB gain controllable width has been obtained. These are sufficient for the application to the Gb/s optical repeater circuits.
Nonlinear susceptibility of cesium and sodium atoms for frequency upconversion from 10‐μm atmospheric window to the visible
Authors: Mishima Teruhito , Hisadome Kenji , Members Ichiro Sakuraba, 
Published: July 2007

AbstractThis paper presents a calculation of the third‐order nonlinear susceptibility for the frequency upconversion of 10‐μm atmospheric window to the visible band. The following cases are compared.Two‐photon resonance 1 at 6 d 2D3/2, and 2 at 6 d 2D5/2 of cesium to generate difference frequency. 3 Two‐photon resonance at 7 s 2S1/2 of cesium to generate sum frequency. 4 Two‐photon resonance at 3 d 2D5/2 of sodium to generate sum frequency. Density matrix is used in the calculation, and the spinorbit coupling and the Doppler effect are considered. The major results are the following. In 1, a large nonlinear susceptibility and large number density is obtained at relatively low temperature. The nonlinear susceptibility has the maximum at the wavelength of 12.1 μm. In 2, a large nonlinear susceptibility and large number density are obtained at relatively low temperature. The nonlinear susceptibility increases with the increase of infrared wavelength. In 3, a system free from polarization property can be constructed, but the temperature must be raised by more than 100°C, compared with the forementioned two cases. In 4 the largest nonlinear susceptibility is obtained for the wavelength of 9.1 μm. However, the temperature must be raised by several hundreds degree compared with the cases of 1 and 2.
Analysis of remotely sensed image data by means of category decomposition
Authors: Member Minoru Inamura, 
Published: July 2007

AbstractThe pattern recognition of a spectral characteristic which is the same method as the latter recognition, is one of the most widely used in remotely sensed multispectral image processing. There are many pixels in remotely sensed image data in which multiple categories are mixed within an instantaneous field of view. This paper points out that a conventional category classification in which the generalized distance of a feature space is used as the evaluation standard of the similarity is not necessarily suitable for the contents of pixels in remotely sensed image data. Also, it is more logical to use a method based on the calculation of the areaoccupation rate (the mixture ratio) of each category. From the viewpoint of the composition and decomposition of the categories, the generalized inverse matrices, least‐square, and quadratic programming were reexamined, and they are compared with conventional methods by using numerical examples. The results confirm the usefulness of the categorydecomposition method and problems of the conventional category‐classification methods including the maximum‐likelihood method (i.e., misclassification of pixels containing multiple categories). As a conclusion, if a more accurate calculation of the mixture ratio becomes available by a further development of the method, a higher order of information than that by a conventional categoryclassification processing applied to the image data on the earth surface will be obtained; it will even be possible to exceed the limit of the space‐resolution of a remote sensor.
Growth and evaluation of large KDP Single Crystals for High–power harmonic generation by temperature decrease method
Authors: Shimomura Osamu 
Published: July 2007

AbstractIn the growth of KDP single crystals by the temperature decrease method, the dimensions of equipment for the growth of the crystal whose dimensions are desired for type I and type II phase matching of SHG are discussed, where the (001) plate and (101) plate are used as seed crystals, respectively. It is shown that the equipment has the smallest dimensions in the growth of the crystals for type II with the seeds of the (101) plate. Then the large crystals are grown with the seeds of the (101) plate and their optical characteristics are described.
A Phenomenological consideration on E x B discharges
Authors: Tanizuka Noboru 
Published: July 2007

AbstractBecause of the varieties and the potentialities in technological and scientific applications of E x B type discharges, a systematic theory to interpret phenomena occurring there must be developed. This paper proposes to develop a theory of a small fluctuating electric field by which the electric field of the crossed field system is superposed. The resonance between the fluctuation and the motion of ions confined in the field system induces a convergence to a component of the ionic motion. As a result, under a certain condition, the chaotic ions in the field system form spokes. These phenomena (spoke formation process and spoke rotation) observed in E x B devices are interpreted by comparing the theoretical results.
Characteristics of Leaky Surface Acoustic Waves on LiNbO3 and the New Cut
Authors: Shimizu Yasutaka , Murakami Kyoji 
Published: July 2007

AbstractRecently, surface acoustic wave devices have been used in many fields, for example as filters and so forth. However, since the device characteristics are determined by the substrate, the superior substrate for surface acoustic wave applications has been investigated. In this study, the leaky surface acoustic wave propagating in LiNbO3 has been evaluated theoretically and experimentally. First, the contour maps of the characteristics have been obtained for an arbitrary cut, and the propagation characteristics of the leaky surface acoustic wave in the LiNbO3 have been investigated. As a result, the standard for the substrate selection has been established. It was proven theoretically and experimentally that the proper selection of the cut could provide both the high electrical‐mechanical coupling coefficient (15%) and such excellent thermal characteristics as zero temperature coefficient which could not be obtained by conventional devices using Rayleigh wave propagation. As a result, a large electrical‐mechanical coupling (13.1%) which agreed with the theoretical value, has been obtained and the thermal characteristic (50 ppm/°C), much superior to that of conventional devices, has been obtained.