bluuebunny/crossref_metadata_2025_split huggingface dataset:
A surface‐mountable ceramic 3‐dB directional coupler
Authors: Takasugi Atsunori , Kitoh Ryozo , Awai Ikuo , Hano Mitsuo 
Published: July 2007

AbstractIn the lossless symmetric reciprocal four port represented by the directional coupler, it is possible to cal culate an invariant from the measured results of thesparameters. As a result, an integrated directional coupler was fabricated with high‐permittivity ceramic waveguide (DEW: dielectric E‐plane waveguide) and a coupling of 3 dB was obtained.
Finite‐element analysis of two‐dimensional chirowaveguides
Authors: Maruyama Shinji , Koshiba Masanori 
Published: July 2007

AbstractThe finite element formulation for three‐dimensional (3‐D) chirowaveguides cannot be applied to 2‐D ones because all components of the electromagnetic field in chiral media, even if a 2‐D system is considered, are coupled. In this paper, the finite element formulation is described for the analysis of 2‐D chirowaveguides. to show the validity of the present formulation, numerical results are shown for homogeneous chirowaveguides and are compared with exact solutions. Furthermore, to demonstrate the applicability of the present approach, chirowaveguides with graded chirality admittance profiles are investigated.
Gain characteristics of Pr3+‐doped fluoride fiber amplifier
Authors: Yamada Makoto , Shimizu Makoto , Ohishi Yasutake , Kanamori Terutoki , Sudo Shouichi , Temmyo Jiro 
Published: July 2007

AbstractUsing the high‐efficiency Pr3+‐daped fluoride fiber and the high‐output LD module and an optimization of amplifer setup, a high‐gain LD pumped Pr3+‐doped fluoride fiber amplifier is developed. the noise characteristics and the temperature dependence are studied in detail and the following results are obtained.the noise figure of the Pr3+‐doped fluoride fiber amplifier is 3.4 dB. However, the noise figure increases with the signal wavelength in the region of signal wavelength larger than 1.3 μm due to the effect of the base level absorption and signal light‐excited absorption.the temperature dependence of the amplifier characteristics is caused by the change of luminescence life of1G4by the change of nonradiating transition probability from1G4level to3F4level. As the fiber temperature is reduced, the signal gain increases monotonically while the noise figure decreases at a signal wavelength over 1.31 μm and the saturation output decreases.
Optical power monitor for two‐beam laser diodes using electric operational circuits
Authors: Shinoda Masahisa , Satoh Yasuyuki , Karaki Morihiro , Kime Kenjiro , Ishii Mitsuo 
Published: July 2007

AbstractThis paper presents a method for monitoring individual laser beams from an array‐type, two‐beam laser diode with two emission points in one laser chip using an electric operational circuit. the characteristics of the two‐beam monitoring system are evaluated by experiment. This system analytically monitors optical output powers on the principle that the two laser beams are received at different ratios by a photodiode having two detecting surfaces located near the laser facet. the main feature of the system is the possibility of signal separation using a simple circuit configuration and adjustmentfree arrangement of the photodiode.Evaluation of a trial two‐beam monitoring circuit has revealed that a gain deterioration of 3 dB is exhibited at 1 MHz. Crosstalk, which represents the degree of signal separation, depends on frequency and is ‐54 dB at 10 kHz and ‐23 dB at 1 MHz, exhibiting excellent separation characteristics. These results can be used without problems in optical disk drives incorporating two‐beam laser diodes. Thus, they demonstrate the effectiveness and practicality of the proposed system.
A new method for measuring absorption losses in an infrared optical fiber
Authors: Ishiwatari Hiromasa 
Published: July 2007

AbstractPressure‐extruded infrared optical fiber is a polycrystalline structure with grain sizes of 30 to 70 μm, and it exhibits a large amount of attenuation. the attenuation due to scattering is more than one‐half the total attenuation and is induced by the residual strain, surface roughness, and grain boundary defects. In the investigation of loss mechanisms, it is indispensable to measure separately the different losses such as absorption loss and scattering loss. Since the scattering loss can be measured by an integrating sphere sliding along the fiber axis, the absorption loss is obtained by the subtraction of the scattering loss from the total loss.This paper proposes a new method for directly measuring the absorption loss, and experiments using this method were carried out. the method is based on the thermal expansion associated with temperature rise due to the absorption. It is shown that the absorption loss can be evaluated by measuring the time response of the elongation of the fiber in which the laser power is absorbed. In addition a new measuring method for the heat transfer coefficient of the fiber also is proposed.Using these methods, the absorption and scattering losses of KRS‐5 optical fiber were measured. the results indicate that the scattering loss is about 1.5 times larger than the absorption loss.
Influence of optical rotary power on optical voltage sensor using BGO crystal
Authors: Ohtsuka Masao , Shimomura Teruo 
Published: July 2007

AbstractBismuth germanium oxide (Bi12GeO20) is an optical rotary power (ORP) crystal; and, when used in longitudinal voltage sensors, its performance is influenced by such rotary‐power performance. That is, as the ORP angle Φ is increased, the sensor sensitivity |m| is decreased. Here, the relation between ORP angle Φ and sensitivity |m| of the longitudinal voltage sensor is investigated and the corresponding equation is derived. Further, by changing the crystal thickness. the ORP angle Φ is varied between 20 and 80 degrees and the measured sensitivities of the voltage sensor are compared against the calculated results. it is found that agreement is quite good between the calculated results based on the derived equation and the measured data.with the existence of ORP, the method of suppressing its degrading effects upon the sensitivity is devised and the effectiveness of the method is verified experimentally. Finally, based on the results of the present investigations, the conditions for direct vectorial addition of the measured quantities via the optical sensor are determined and the voltage relative to the ground of the three‐phase circuits are processed optically as the addition of three vectors. As a result, it is verified experimentally that the zero‐sequence voltage can be measured with high accuracy.
Bonding mechanism between Sn‐Sb solder and evaporated multilayers
Authors: Kurihara Yasutoshi , Saito Ryuichi 
Published: July 2007

AbstractThis paper discusses the behavior of metal and the bonding mechanism at the interface between Sn‐Sb solder and an evaporated Al‐Cr‐Ni‐Ag multilayer used for bonding a silicon chip to a substrate. As the treatment temperature increases, alloying among Ag, Ni, and Cr and diffusion of Al toward the metal surface are accelerated. the multilayer is composed of a mixture of the forementioned metals. When soldering is carried out, Ag and Ni disappear from the interface and the solder has direct contact with the Cr layer. Even in this case, the adhesion is still secure.After soldering, the Cr layer at the interface contains metals in the multilayer and solder compositions and the Sb‐based intermetallic compound is formed at the interface. the adhesion force between the Sn‐Sb solder and Cr layer is determined by the diffusion of metals to the Cr layer and the formation of the intermetallic compound.
Novel recording method employing direct ink heating: Thermal rheography
Authors: Yamaguchi Hiroyuki , Matsuki Makoto , Saitoh Takashi 
Published: July 2007

AbstractA new heat‐aided recording method, thermal rheography, which employs no ink film is proposed. With this method, a paste ink is directly heated and melted through a porous thermal‐print head, upon which it passes through holes engraved in the heating elements. Since the recording process uses no ink film, the operational cost is low and the need for a film‐feed mechanism is eliminated.To realize this method: 1) the relation between paste ink composition and recording characteristics; and 2) the construction of porous thermal‐printing‐head are investigated. the method can attain according density 1.0 with energy 30 mI/mm2, compatible with G3 thermalsensitive paper recording.
Synthesis, properties, and molecular structure analysis of Sio2 thin films prepared by Sol‐Gel method
Authors: Maekawa Sachiko , Okude Kojiro , Ohishi Tomoji 
Published: July 2007

AbstractSiO2 thin films were prepared by the sol‐gel method. the properties of the films such as film thickness, etching rate in hydrofluoric acid, Vicker's hardness, and the effect of the thermal treatment on the molecular structure were investigated. As a result, it was found that the etching resistance and hardness were improved as the treatment temperature increased. These changes in the properties were related to the density and water content in the film.The molecular structure analysis by the 29Si solid‐state NMR and Raman spectroscopy revealed that the unstable distorted Si‐O‐Si bonds formed in the solution were broken and stable straight Si‐O‐Si bonds were formed during the high‐temperature treatment. As the number of the stable Si‐O‐Si bonds increases, the hardness and density of the films increases.
Circuit theoretical approach for the quantum wells and periodic potentials
Authors: Sanada Hirofumi , Nagai Nobuo , Ohtani Naoki , Miki Nobuhiro 
Published: July 2007

Abstractcircuit‐theoretical treatment has been investigated as a systematic and easy method to obtain a guideline for the analysis and design of energy levels by quantum wells and minibands by periodic potentials. the existing circuit‐theoretical approach considers only the case in which the wave function is continuous in the heterointerface under an effective mass approximation.In this paper, by means of the interface matrix which represents general boundary conditions at the heterointerface, a method for circuit‐theoretical analysis is presented for the energy level and the miniband of quantum wells and periodic potentials made of various materials. It is shown that the eigenenergy level and the complex eigenenergy level in the quantum well structure can be formulated in terms of the real and complex frequencies. As numerical examples, the quantum wells made of GaAs/AlxGa1‐xAs and InAs/GaSb are considered and the relationship of the eigenenergy level and the complex eigenenergy level to the well structure is shown. By means of the repetition parameters in the circuit theory, numerical examples are given for the minibands by GaAs/AlxGa1 ‐xAs and InAs/GaSb due to the periodic potential.
A method of analyzing negative resistive and equivalent capacitance of CMOS crystal oscillators
Authors: Toki Masahiro , Fuchisawa Takashi 
Published: July 2007

AbstractA method is investigated for an analysis of the level characteristics of the two‐port active impedance in a CMOS quartz crystal oscillator circuit used widely as a clock source of electronic devices. As a result, it was found that the negative resistance and the equivalent capacitance for arbitrary circuit parameters can be analyzed in relation to the characteristics of the CMOS‐IC itself over a small signal to a large steady‐state signal.The analysis is useful for discussions of initiation of the oscillation in addition to the investigations as to up to what frequency the oscillation takes place definitely with a sufficient small signal negative resistance and to what the resonator current is under the steady‐state oscillation.
Integrated wideband amplifier for three‐channel video signals
Authors: Sano Yuji , Ohsawa Michitaka 
Published: July 2007

AbstractA three‐channel integrated wideband video IC with the possibility of application in high resolution display of 1M pixel was developed.This paper reports first the construction of a wideband voltage amplifier circuit in which a wide output signal dynamic range is obtained. With respect to the construction of this circuit, by compensating for the nonlinearity of the bipolar transistor and the logarithmic compression of the signal voltage, an attempt is made to expand the dynamic range. Moreover, by using an opposite‐phase current to cancel the negative resistance component appearing in the input impedance when compensating for the nonlinearity, it was attempted to flatten the frequency characteristic.With the present circuit construction, by overcoming the process limitation of low‐voltage tolerance, it was possible to ensure wideband characteristics in excess of 140 MHz. In addition, the wideband suppression method of signal crosstalk appearing between channels as side effects of tracking characteristic improvement due to three‐channel integration is reported.By suppressing the influence of common impedance and the differential transmission of each signal, it was possible to suppress lower than ‐43.6 dB the crosstalk between channels below 100 MHz. By the development of this IC, the miniaturization and lowering of cost of high‐resolution display and the improvement of adjustment accuracy and stability characteristics could be achieved.
Backplane power source capability
Authors: Sugiura Nobuaki 
Published: July 2007

AbstractA backplane is attached to a subrack into which equipment is mounted. Each subrack has a different function and can handle different types of equipment. the backplane is used as a power source for printed circuit boards installed in the subrack. the backplane power source capability is determined by the number of power and ground inner layers, the copper sheet thickness of the inner layer, and the copper sheet area.An equivalent circuit model of the backplane power source is set up to study the heat balance conditions during backplane power source operation. the heat balance is related to the generation, conduction, and radiation of heat. Using this model, the power source capability related to the different backplane structures is simulated and the results are compared. the results showed that the 2‐mm grid press‐in pin alignment is better than the 2.54‐mm stagger grid alignment. the backplane power source capabilities and structural parameters also are determined.
Twin‐counter digital‐loop preset frequency synthesizer (TC‐DLPS)
Authors: Tarusawa Yoshiaki , Yamao Yasushi , Nojima Toshio 
Published: July 2007

AbstractA twin‐counter digital‐loop preset frequency synthesizer (TC‐DLPS) is proposed which is a newly developed form of the phase‐locked loop (PLL) frequency synthesizer having high‐speed frequency switching and small size with low power consumption. the phase detector of the TC‐DLPS consists of two counters, i.e., a high‐speed counter and a low‐speed counter, which yields a highly sensitive phase detection with low power consumption and the time constant of the loop can be decreased. Moreover, the voltage‐controlled oscillator (VCO) can be preset precisely at the time of frequency switching. In this way, the frequency‐switching time can be reduced to one‐tenth compared to the conventional PLL synthesizer.The operation of the TC‐DLPS is explained and the possibility of reducing the PLL time constant is shown by the transient analysis of the linear transfer function. Moreover, the frequency‐switching characteristics of the prototype circuit are shown in the 800‐MHz band.
Noise characteristics of long‐wavelength monolithically integrated pin‐FETS
Authors: Akahori Yuji , Ikeda Mutsuo , Kouzen Atsuo , Itaya Yoshio 
Published: July 2007

AbstractThe noise characteristics of a monolithically integrated pin‐FET were analyzed using the circuit simulator SPICE. This device consists of InGaAs p‐i‐n photodiodes (PDs) and In GaAs‐channel junction field‐effect transistors (JFETs). the equation for the metal‐semiconductor field‐effect transistor (MESFET) model of the SPICE simulator is modified to fit the noise characteristics of the fabricated InGaAs channel JFETs. Then the noise parameters are extracted by fitting the simulation results to the measured noise characteristics of the pin‐FET. the sensitivity degradation caused by the noise from the two noise sources in the monolithic pin‐FETs is analyzed by circuit simulations using these noise parameters. the noise sources considered in this analysis are the load FET at the common‐source amplifier stage and the level‐shift diodes introduced to provide the operation with a single power supply.Finally, the measured sensitivity differences among the channels of the fabricated four‐channel pin‐FET array are analyzed and it is shown that they agree with the simulation results when the flicker noise is proportional to 1/f0.8 where f is the frequency. This simulation technology is useful for analyzing the noise factors that dominate the noise characteristics and can be used to predict the sensitivity when designing monolithic photo‐receivers.
Mode‐field‐converting fiber for coupling to photonic devices
Authors: Yanagawa Hisaharu , Ono Takahiro , Oyobe Akira 
Published: July 2007

AbstractA mode‐field‐converting (MFC) fiber is proposed to reduce mode‐field mismatch loss which is produced when an optical fiber and a photonic device chip are butt‐coupled to each other. an MFC fiber is fabricated by fusion‐splicing a specially designed device‐compatible fiber with an ordinary transmission‐line fiber and by heating the spliced point to form an index‐and‐dimensional taper. Also proposed is an elliptic‐mode‐field (EMF) fiber which is composed of an elliptic core and two claddings to yield a highly elliptic mode field.An EMF fiber with an ellipticity of 2 and MFC fibers with the EMF fiber were fabricated experimentally and the lowest conversion loss of 0.09 dB was obtained. the MFC fiber was designed for coupling to a semiconductor optical switch and achieved shape conversion. Arrays of eight MFC fibers also were fabricated, and the lowest loss was 0.11 dB with a size conversion ratio of 2. the MFC fiber array was designed for coupling to a high‐Δ silica waveguide. Those loss values around 0.1 dB were sufficiently lower than the corresponding initial mode‐field mismatch losses of 0.7 and 1.7 dB; and, thus, the loss reduction effect of an MFC fiber was confirmed experimentally.
State‐of‐the art of a‐Si TFT/LCD
Authors: Tsukada Toshihisa 
Published: July 2007

AbstractThe state‐of‐the‐art in active‐matrix liquid‐crystal displays based on amorphous silicon thin‐film transistors is described. This type of display appears to be the most promising flat‐panel display, and its mass production has just started to deliver 10‐inch class displays with 300‐K pixels. These display panels will have larger diagonal sizes and higher resolution than previous ones. the production of panels with more than one million pixels has also started.The factors controlling the design of these large and high‐resolution panels are the gate‐busline delay and the charging and discharging of the signal voltage on the pixel electrode. Analytical results show the panels larger than 30 inches and with a resolution exceeding 1, 000 lines can be designed. Another factor that affects the size and resolution of the panels is the parasitic capacitance of thin‐film transistor (TFT), which degrades the display quality.The fabrication process is then discussed along with such technical breakthroughs as stacked‐layer gate insulators and aluminum‐gate TFTs.
Poly‐Si TFT and driver integration technology
Authors: Ohshima Hiroyuki , Matsueda Yojiro 
Published: July 2007

AbstractPolycrystalline silicon thin‐film transistors (poly‐Si TFTs) are currently used in active‐matrix liquid‐crystal displays (LCDs). Driver integration technology of poly TFTs results in compact, high‐resolution TFT‐LCDs. Various kinds of TFT driver circuits are discussed, and their performances are evaluated in the present paper. the use of a quartz substrate for conventional, high‐tempera‐ture processed poly‐Si TFTs limits their application to small LCDs. Low‐temperature processed poly‐Si TFTs on glass substrates will result in larger‐size LCDs at lower cost.
Design of high‐quality TFD‐LCDS
Authors: Mizobata Eishi , Hirai Yoshihiko , Shimizu Kousaku , Uchida Hiroyuki , Kaneko Setsuo 
Published: July 2007

AbstractThe design of high‐quality thin‐film diode liquidcrystal displays (TFD‐LCDs), which are candidates for low‐cost displays, was studied and 9.3‐inch panels were designed and fabricated. the image quality was then investigated. the TFD structure and area, SiNxdeposition conditions, the thickness of the SiNxfilm, and the driving conditions are the main TFD‐LCD design parameters. the SiNxdeposition conditions and the film thickness had already been optimized and fixed prior to our study. In this study, the TFD area and the bias ratio were first investigated by means of a simulator. This showed that the TFD area and the bias ratio must have optimum values in order to satisfy the response time, contrast ratio, and reliability requirements of high‐quality displays; 9.3‐inch color TFD‐LCDs have been designed and fabricated. the TFD structure is of the bridge type. the TFD area is 64 μm2and the bias ratio is 1:9. the panels use a scan line inverse driving method. the image quality is the same as predicted in the simulation and good enough for high‐quality displays.
Three‐axis balanced driving‐type optical head for high‐density optical disc player
Authors: Matsui Tsutornu , Kitahara Shin‐Ichi , Yamagata Hideto , Hanaki Shin‐Ichi 
Published: July 2007

AbstractIn the optical disc player, there is a necessity to correct the jitter caused by the disc eccentricity and rotation irregularity as well as focusing. For this correction, there are both the electrical correction method using a two‐axis optical head with memory and the mechanical correction method of a three‐axis optical head. If the goal is the simplification of the electrical circuit and the lowering of cost, the latter method is advantageous. However, in the tilting of the conventional field lens, the motion of the lens occurs in the direction of track and jitter and, for those in which the numerical aperture is 0.55 and larger, since good convergence characteristics are not obtained with respect to tilting of the lens, the three‐axis method is hardly realized.Therefore, the lens holder is held by parallel plate springs of rubber material. Thus, by contriving the electrical circuit driving the lens holder for the center of gravity of the lens holder to coincide with the center of the drive, the rotation of the axis could be controlled and an actuator realizing only translational motion effectively in the direction of the three axes (balanced drive method) was proposed and realized. an optical head based on this method was constructed and, with a high‐density (Hi‐Vision laser diode type) disc, a MUSE signal signal‐to‐noise (SN) ratio above 36 dB could be realized and an excellent image was confirmed.