bluuebunny/crossref_metadata_2025_split huggingface dataset:
Driving theory of power reed switch in inhomogeneous magnetic field
Authors: Iimori Ken‐Ichi 
Published: July 2007

AbstractThe energy source for driving the power reed switch is considered to be due to the magnetization energy provided to the power reed switch magnet piece by the magnetic field formed by a permanent magnet or an electromagnetic coil. Of the permanent magnets, i.e., the driving system by a ferrite magnet or a rare earth magnet in which the recoil permeability is close to unity, the magnetic field distribution of the power reed switch magnet piece can be derived analytically. Further, the magnetization energy can be derived easily by an approximate calculation.On the other hand, if the reference magnetization energy for driving the power reed switch is obtained a priori which is compared with the magnetization energy by an arbitrarily shaped permanent magnet, the driving force of the power reed switch is found to be obtained accurately. As a result, it becomes possible to design a magnetic proximity switch taking into consideration the magnetic stability in an environment with a permanent magnet. Thus, stabilization of the product quality and improvement of the reliability are expedited significantly. A speedy introduction of the products is enhanced.
Design, fabrication, and experiment of gaas traveling‐wave directional coupler optical modulators
Authors: Hayashi Hideki , Ishikawa Takuya , Ishikawa Takuya , Takahashi Yoshihiro 
Published: July 2007

AbstractTo increase the operating speed of a GaAs directional coupler (coupled‐waveguide) optical modulator, a new device with traveling‐wave electrodes is designed and fabricated. The device with a coupling length of 1 cm operated in the traveling‐wave mode with a layered configuration identical to the lumped element operation is found to be subject to the effect of the slow‐wave mode and to a large dielectric loss in the thick n+ layer so that the modulation bandwidth is only 300 MHz. It is found that the thickness of the n− layer must be reduced to decrease the effect of the slow‐wave mode and the dielectric loss. A new device structure is proposed in which this thinner n+ layer is realized on a semi‐insulating layer. The switching voltage was 10.4 V in a device for 1.06 μm light with a coupling length of 8 mm fabricated with a substrate grown by molecular beam epitaxy. The 3‐dB modulation bandwidth was measured to be 9.1 GHz. For the ratio of the modulation bandwidth to the switching voltage, the modulation efficiency is improved over those for the previous lumped element devices by more than 10 times.
Simple assembly technique for single‐mode optical fiber multi/demultiplexers
Authors: Kato Kuniharu , Nishi Isao , Hashimoto Kouhei 
Published: July 2007

AbstractA new technique is proposed for assembling singlemode fiber multi/demultiplexers by an easy adjustment process using alignment‐free fiber collimators. This technique utilizes a jig to position the collimators and adopts a collimator rotation process to reduce the increase in assembly loss.According to simulation and experiments, the assembly loss increase of a two‐channel multi/demultiplexer is confirmed to be 0.5 to 1.0 dB. Its value is half that of the multi/demultiplexer assembled without the easy adjustment process. A prototype multi/demultiplexer having 1.3‐and 1.5‐μm channels has been fabricated. The insertion loss of each channel was 1.8 dB and its deviation was within ±0.1 dB from 0 to 60d̀C.
Broadband active circulators
Authors: Toyoda Sachihiro , Satomura Yutaka 
Published: July 2007

AbstractThis paper describes three types of active circulators: the first structure consists of three dual gate FETs and its operating frequency range is 0.4 to 2.6 GHz. This circulator uses a phase‐divider circuit. The forward insertion loss is 0.4 dB while the isolation is 21 dB; the second structure consists of three each of RF transformers and AGC amplifiers. The operating frequency range of this active circulator is 0.3 to 1.4 GHz. The forward insertion loss is 0.3 dB and the isolation is 29 dB; and the third active circulator consists of three each of phase inverters and broadband amplifiers. The operating frequency range is 5 to 10 GHz. The isolation and the forward insertion loss are 27 and 0.3 dB, respectively. This circulator can be used for an input power of up to 19 dBm.
FM noise property of mutually optical injection‐locked semiconductor lasers considering propagation time between lasers
Authors: Iiyama Koichi , Hayashi Ken‐Ichi , Ida Yoshida 
Published: July 2007

AbstractLocking bandwidth and FM noise properties of mutually optical injection‐locked semiconductor lasers are described, taking into account an optical delay time between lasers. By introducing a figure of merit of optical injection specifying unilaterality of the optical injection, optical injection‐locking systems with an arbitrary inverse optical injection from a slave laser to a master laser can be described adequately.It is found from the analysis that for a short delay time, the locking bandwidth and the FM noise depend on both the round‐trip phase angle and the figure of merit of optical injection. In the case of a long delay time, the FM noise and the spectral linewidth are reduced significantly with increasing locking bandwidth.Finally, an undulation similar to that in the external cavity semiconductor laser appears in the FM noise spectrum. The experimental results obtained by using semiconductor lasers emitting at 0.83 μm agree well with the analytical results.
Structure of outside emitter silicon bipolar transistor (OSET) for high‐speed LSI
Authors: Uehara Keijiro , Higuchi Hisayuki 
Published: July 2007

AbstractTransistor structures suitable for high‐speed bipolar LSIs have been examined and OSET (outside emitter technology) transistors which enable an emitter region more than three times larger for the same base area are proposed. The feature of this transistor is the structure where the base contact region is placed in the center and a ring‐shaped emitter region is formed around it. As a result, the placement of the base and emitter regions is reversed compared to the conventional structure.With the OSET transistor with a ring‐shaped emitter region formed by a self‐aligned technology as a basis, a simple type with a simplified fabrication process, a ringed‐collector type with a ring‐shaped collector electrode outside the emitter to reduce the collector resistance and the area, and a central‐collector type which has a minimum active area have been examined.The central‐collector type transistor enables an emitter area of 2.6 μm2in the device area of 2 × 2 μm2, and the emitter occupies an extremely high portion of the device region. The OSET transistor that enables a dramatic reduction of parasitic capacitances (which occupy a large portion of the LSI delay time) with device scaling is considered suitable for ultrahigh‐speed LSIs.
Low noise MMIC amplifiers using HEMTs
Authors: Ayaki Nagisa , Nagahama Hiroki , Inoue Akira , Katoh Takayuki , Murase Isao , Kobiki Michihiro , Tanino Noriyuki , Yoshii Yutaka 
Published: July 2007

AbstractA 12‐GHz band, two‐stage monolithic HEMT (high‐electron mobility transistor) low‐noise amplifier and a broadband monolithic HEMT distributed amplifier have been developed. The HEMTs used in the amplifiers have a gate length of 0.5 μm and show a typical noise figure of 1.0 dB at 12 GHz. A noise figure of the two‐stage amplifier is less than 1.7 dB with a gain over 15.0 dB in the frequency range from 11.7 to 12.7 GHz. A noise figure of the distributed amplifier is less than 6.2 dB and gain of 7 ± 0.9 dB in the frequency range from 2 to 18 GHz.
Measurement of the residual birefringence distribution in glass laser disk by transverse zeeman laser
Authors: Umeda Norihiro , Kohwa Hiroyuki 
Published: July 2007

AbstractThis paper considers the measurement of the residual birefringence distribution in a glass laser disk by means of birefringent measurement equipment with a frequency‐stabilized transverse Zeeman laser as a light source.The birefringence by the residual distortion of a glass laser amplifying medium is an important factor in determining its optical performance. A method of accurate measurement of the birefringence phase difference and the principal axis direction has been conceived based on an optical heterodyne method using a frequency‐stabilized transverse Zeeman laser which is a two‐frequency orthogonally polarized light source. This measurement system consists of a rotating half‐wave plate, a rotating linear polarizer, a detector and electric phase meter and a personal computer.In this paper, the measurement principle and the error analysis are clarified with the use of Stokes parameters. The data processing method for the measured results and the experimentally observed minimum detection limit are described. With the present measurement system, birefringent measurement of an elliptic glass laser disk is carried out and its residual birefringence distribution is clarified.
Fabrication of SiO2 thin films by ECR plasma anodization
Authors: Matsumura Koki 
Published: July 2007

AbstractAnodization of single‐crystalline silicon was carried out under microwave plasma created by electron cyclotron resonance (ECR), and the anodization characteristic and oxide film property were evaluated. The growth rate of the oxide film depended strongly on the oxygen pressure and the growth rate reached the maximum under relatively high oxygen pressure.Since the plasma parameters and substrate temperature were dependent on the oxygen pressure, the oxidation was thought to be dependent on the supply of oxygen atoms from plasma and the generation of silicon atoms and dangling bonds at the Si‐oxide interface.The X‐ray photoelectron spectra revealed the formation of stoichiometric SiO2. This result provided insight into the oxide growth process. In addition, the electric conduction in an MOS device formed using this oxide was investigated. As a result, it was found that the dc high field conduction prior to the self‐healing breakdown was based on the tunneling of electrons injected by Schottky emission through the oxide. Also, the negative resistance observed after the self‐healing breakdown was caused by the formation of space charges caused by the impurity ions.
Delay‐time evaluation of submicron BiCMOS, CMOS, and bipolar ecl gates
Authors: Higuchi Hisayuki , Tachibana Suguru , Suzuki Makoto 
Published: July 2007

AbstractThe following results have been obtained by evaluating the circuit delay times of submicron BiCMOS, CMOS, and ECL gates by the same criterion: (1) analytical relationships to represent the delay time of each circuit by device parameters have been developed; (2) these relationships have been verified by the circuit simulator using BiCMOS device parameters with minimum dimension of 0.5 μm; (3) using submicron devices for each circuit, the delay time ratio of CMOS, BiCMOS and ECL is 4:2:1; (4) reduction of the device parasitic capacitance is more effective in improving BiCMOS gate delay than that of CMOS gate; and (5) reduction of the parasitic capacitance can make the BiCMOS gate operate as fast as the ECL gate.
Polarization characteristics of alumina films anodized with large current density
Authors: Okano Mamoru , Saito Mitsunori , Miyagi Mitsunobu 
Published: July 2007

AbstractTo use an anodic alumina film as an optical functional device, the optical characteristics of the film was evaluated experimentally. Alumina film anodized in sulfuric acid with high current density has a polarization characteristic. The extinction ratio increases with the increase of the current density. When alumina film is used as an optical polarizer, the insertion loss can be reduced by filling the pores with dielectric material.
Analysis of electromagnetic field induced over ground by lightning having an angle of inclination
Authors: Ichikawa Satoshi , Saitoh Yukio 
Published: July 2007

AbstractWhen the time response of the electromagnetic field induced on the ground by lightning is calculated, investigation of both the lightning channel and ground permittivity is required. The lightning channel has been treated as normal to the ground. In this paper, however, a study is presented for the case in which the channel is inclined at an angle from the normal direction. Derivation of the theoretical expressions of the electromagnetic field is carried out by Laplace transform in the complex frequency domain.The derived theoretical equation consists of complicated terms containing an infinite integral called Sommerfeld integral. It is not possible to transform into the time domain by an analytical process. Hence, the inverse numerical Laplace transform is used for transformation into the time domain.
Design theory of a diode video detector for the submillimeter wave region using an open‐type biconical resonator
Authors: Daiku Yoshiaki , Ono Shoichi 
Published: July 2007

AbstractPerformance of Schottky diodes has been improved significantly so that they can be used at frequencies in the submillimeter‐wave band and beyond. At the same time, various submillimeter‐wave detector circuits have been proposed and studied. These circuits contain antennas on the assumption of free space propagation since there exist no established transmission lines at submillimeter‐wave frequencies. The authors have carried out studies on the design theory of biconical circuits as a form for submillimeter‐wave detector circuits. In this paper, this was improved as an open resonator and its equivalent circuit was derived. Based on the latter, a design procedure was established. The responsibility used for the quantum‐type detectors was extended so that the figure of merit for an open‐type detector was defined and evaluated. With an expanded model of the detector based on the proposed method, detection of 8 to 100 GHz was successful so that the equivalent circuit and the design method were confirmed experimentally.
Application of variably graded mesh to the spatial network method
Authors: Kukutsu Naoya , Yoshida Norinobu , Fukai Ichiro 
Published: July 2007

AbstractAs a method to carry out a three‐dimensional time domain response including the transient response, the authors have applied the spatial network method to a number of electromagnetic wave problems. Since the entire analysis region was subdivided equally in this method, the spatial difference mesh size was required to be determined such that the minimum dimension in the analysis region can be expressed sufficiently. Hence, the storage capacity required for the variables for the entire region was enormous.Techniques to alleviate this problem can be either the method in which the discretization of a certain region is made finer geometrically without changing the mesh shape or the one in which the mesh spacing is varied equivalently so that the discretization of a particular region is made finer as rectangular meshes. The latter approach is taken in this paper. We assume a wave with a velocity proportional to the length of the transmission line. As a result, the formulation is carried out under an assumption that each transmission line has a different characteristic impedance. Further, in the formulation process, the treatment of the Bergeron representation at the boundary of different mesh sizes is carried out by two methods. In one method, hypothetical nodes are installed, whereas in another method buffer zones are introduced.
Difference of flux control between two‐dimensional orthogonal core and three‐dimensional orthogonal core
Authors: Oka Hideo 
Published: July 2007

AbstractThis paper points out that when the primary and the secondary sides of the ferte orthogonal core, which is one of the three‐dimensional orthogonal cores, are modified, it can be regarded as a two‐dimensional orthogonal core. It is shown also that because of its shape, this type of core has the same flux control as the original ferrite orthogonal core. However, there is a difference in the flux control mechanism in the primary and the secondary sides due to the difference of orthogonal dimensions. Based on the results of investigations, the flux control and ac (alternate current) magnetization characteristics are measured for the ferrite orthogonal core and the two‐dimensional orthogonal core. By comparing their characteristics, the flux control and other performances are demonstrated.
Path integral representation of generalized nonlinear schroudinger equations—application to optical soliton problems
Authors: Hayata Kazuya , Koshiba Masanori 
Published: July 2007

AbstractThe nonlinear Schrödinger equation (NLSE) is one of the partial differential equations appearing in a number of research areas including mathematics, physics, engineering, and biology. Its applicable area is quite wide. In this paper, as a solution method for an NLSE accompanied with modification or perturbation (generalized NLSE), the path integral method (PIM) is used. The basic concept, formulation, and actual numerical calculation algorithm are described.The PIM introduced by Feynman is a nonrelativistic quantum mechanical formulation based on the Lagrangian form. Since the final formula obtained in this paper takes a standard Fourier transform type, it is possible to use the fast Fourier transform (FFT) so that a quantum jump in numerical efficiency has been attained. It should be noted that only one Fourier transform operation is needed per unit propagating section. As a generalized NLSE, a set of coupled nonlinear Schrödinger equations with a perturbation is considered. As a specific example of application, numerical results for optical solitons are presented.
An address access time measurement method for high‐speed mos static rams
Authors: Nishimura Yasumasa , Niiro Mitsutaka , Tanaka Koji , Hamada Mitsuhiro 
Published: July 2007

AbstractWith the advance of a high‐speed MOS static RAM (SRAM), it is considered a problem to measure the access time of SRAM more accurately. In the measurement of the address access time, it is assumed that a large number of address signals are all simultaneously forced on SRAM. In the actual measurement of SRAM, however, it is difficult to determine the forcing time of the address signals at the input of SRAM. Consequently, the foregoing condition is difficult.This paper considers the measurement of the address access time of the high‐speed SRAM and proposes a method whereby the forcing time of the address signal can easily be measured and corrected on the memory tester. In the method, the GND bounce generated in SRAM itself in response to the given address signal is measured in the reference SRAM. Then the variation of the address signal forcing time is evaluated quantitatively and corrected. The proposed method is applied to a commercial memory tester to measure the address access time in 64‐kbit CMOS SRAM with the maximum access time of 15 ns. As a result, the variation of the address signal forcing time is kept within ±100 ps, and the measurement error of the SRAM address access time with different testers is within 1 ns, which is satisfactory.
Electromagnetic field analysis of a system including space charge by combined equivalent circuit of scalar and vector wave equations
Authors: Kimura Hideaki , Yoshida Norinobu , Fukai Ichiro 
Published: July 2007

AbstractWith the recent advancement in semiconductor technology, high‐frequency applications of the elements have been developed rapidly. In the high‐frequency region, coupling of electromagnetic field and the elements cannot be defined by current and electrode voltage. It must be treated as a whole system.To solve this problem, unified analysis of electromagnetic field and semiconductor devices is required. In the past, the solution of the steady Poisson equation has been the principal goal in the analysis of semiconductor elements. However, for the devices operating at frequencies higher than microwave frequencies, it is strictly necessary to solve the Helmholtz equation considering time and loss terms.This paper explains that the unified analysis of electromagnetic field and semiconductor devices is possible by a combined equivalent circuit of scalar and vector wave equations along with Lorentz gauge or continuity equation, for a system including space charge and current. Moreover, the validity of this method is checked by applying it to a simple example.
Phase modulation with microchannel spatial light modulator (MSLM)
Authors: Hara Tsutomu 
Published: July 2007

AbstractAn attempt has been made to use a spatial light modulator to realize a system which controls the optical phase in a two‐dimensional (2‐D) fashion. Many of the spatial light modulators make use of the intensity modulation of the light. Very few can be used purely as a phase modulator. The microchannel spatial light modulator (MSLM) is an electron tube made of a photocathode, microchannel plate (MCP) and an electrooptic crystal (55‐deg cut LiNbO3). A theoretical study is conducted on the mechanism in which the optical phase is modulated by the writing optical energy incident on the photo‐cathode. To measure the phase variation by the device, Michaelson interferometer was used in the reading optics. The variation of the interference light intensity by the writing optical energy is obtained experimentally and from the obtained value the phase variation was derived. It is found that the phase can be inverted by the writing of the optical energy of 18 nJ/cm2 when the reading light (γ = 632.8 nm) polarized in the direction normal to the x‐axis of the crystal is used.
Effect of Au underlayers on perpendicular magnetic anisotropy of CoOx films
Authors: Hiratsuka Nobuyuki , Taguchi Kazuhiro , Ichikawa Tomonori , Fujita Minoru , Sugimoto Mitsuo 
Published: July 2007

AbstractPartially oxidized cobalt films were deposited by the reactive evaporation method on an underlayer Au film and on a polymer film with a rough surface. The purpose of this study is to investigate the influence of these underlayers on the structure and perpendicular magnetic anisotropy of the partially oxidized cobalt films. The gold film was sputter‐deposited by using an Au target. The acceleration voltage and sputtering period for Au deposition were varied to form an Au film with different surface textures, i.e., island‐like, mesh‐like, and flat surfaces.CoOx films were deposited on these underlayers. The measurement of the magnetic properties and the SEM observation of the film cross section were carried out. When a CoOx film was deposited on an Au film with an island‐like surface texture, the CoOx film had a columnar structure perpendicular to the underlayer surface and the diameters of the columns were small. Because of this columnar structure, the perpendicular magnetic anisotropy was improved. When a CoOx film was deposited on a polymer film whose surface was roughened by sputter‐etching, the CoOx film had a columnar structure with a small columnar diameter.From the foregoing results, it was found that the columnar structure and perpendicular magnetic anisotropy of a CoOx film can be controlled by changing the surface condition of the underlayer.