bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of crosstalk between parallel microstrips using finite‐difference time‐domain method
Authors: Maeda Shuji , Kashiwa Tatsuya , Fukai Ichiro 
Published: July 2007

AbstractRecently, malfunctions by crosstalk between signal lines have become a problem in an electronic circuit which has been more densely organized and handles signals at higher frequencies. To prevent malfunctions due to these noises, it is important to find the relationship of the crosstalk with the materials and structures of the circuit board. Especially, as the density is increased, the use of multilayered configuration is increased so that the understanding of the crosstalk between interconnects arranged in a three‐dimensional fashion is increasingly more important.Usually, the analysis of crosstalk has been carried out by means of the equivalent circuit analysis. It is not easy to adjust the number of discretizations and the analysis between the three‐dimensional (3‐D) interconnects.In reference to the foregoing, this paper describes a crosstalk analysis between parallel microstrips by means of the finite‐difference time‐domain (FD‐TD) method which, among the 3‐D electromagnetic field analysis methods, requires small memory and computational time. Good agreement is confirmed between the thoretical and experimental results on the crosstalk waveforms and the crosstalk coefficient. Hence, the effectiveness of the FD‐TD method for the crosstalk analysis has been confirmed. It is believed that the FD‐TD method is extremely effective for analysis in the circuit design.
Study of the thermal stability of AI12 W/W/Si contact structure by AES analysis
Authors: Sasaki Katsutaka , Noya Atsushi , Takeyama Mayumi , Bando Masato 
Published: July 2007

AbstractThe thermal stability of the contact system of the AI12W intermetallic compound film with Si was investigated by AES analysis. The diffusion of Si into the film is observed in the AI12W/Si direct contact system at temperatures above 250°C, while the Si diffusion in the AI12W/W/Si system can be completely blocked up to 550°C, but the barrier properties of the W layer interposed are thickness‐dependent; W layer must be thick enough to separate the AI atoms in AI12W layer from the Si substrate. It is shown that the use of AI12W films combined with W in contact systems is a useful metallization technology for Si‐LSI.
A 40‐Msps 10‐bit video BiCMOS analog‐to‐digital converter
Authors: Sugimoto Yasuhiro , Tsugaru Kazunori 
Published: July 2007

AbstractA 40‐Msps 10‐bit video A/D converter LSI has been developed. A 0.8‐μm BiCMOS technology is applied. The two‐step parallel type conversion scheme is adopted, using the MOS analog switch and bipolar comparator. A redundant structure is employed using 5 bits for the coarse stage and 5.5 bits for the fine stage. Three points of voltages in the coarse ladder circuit are transferred to the fine ladder resistor circuit and are used as the upper‐end, middle‐point and lower‐end voltages.Wire connection configuration for the fine ladder resistors is redesigned so that the error is reduced and the speed is improved. A high‐speed circuit with a preamplifier is used in the fine comparator. Protection functions for the overflow and underflow are also provided. With this design, the S/N ratio of 60 dB is realized, for the clock frequency of 40 MHz and the full‐scale 50‐kHz input. The designed LSI operates with the 5‐V single supply. Power consumption is 700 mW, the number of elements is 7000, and the chip size is 4.1 × 4.8 mm2. The following performance is obtained by overall evaluation of the printed board containing the S&H IC and DAC. The D.G. and D.P. for 40‐MHz clock are 1 percent and 1 deg, respectively. The S/N ratio is 52 dB for 10 MHz full‐scale input and 48 dB for 20‐MHz full‐scale input. A future problem involves the on‐chip implementation of the S&H circuit.
Pulse response of high Tc superconductive transmission line
Authors: Furusawa Satoshi , Morisue Michitada , Asahina Jyoji 
Published: July 2007

AbstractThis paper studies the transmission characteristics of the microstrip line consisting of a YBCO high temperature superconducting material and investigates the effect of attenuation and distortion of the pulse propagating along such a transmission line. The effectiveness of high temperature superconducting material for interchip and intrachip interconnections is described. Presently, the high temperature superconducting thin film devices are often made on an MgO substrate that has rather high permittivity and a high dielectric loss. Calculation of the characteristics of the transmission line based on the two fluid model is used to demonstrate that the effect of the dielectric loss of the substrate becomes significant at the frequency range below 20 GHz; further, the attenuation constant increases by two orders of magnitude in comparison to the case without the loss caused by the substrate. However, the attenuation constant is smaller than that of the A1 interconnect at 77 K and the phase constant is almost constant independent of frequency so that this transmission line has excellent properties.The distorted wave is derived by simulation when a pulse is applied to this transmission line. It is demonstrated that the line of an MgO substrate at 77 K is superior as a transmission line. On the other hand, a YBCO microstrip line was fabricated on an MgO substrate. The attenuation and phase constants were measured and compared with the theoretical values.
An optoelectronic device using Au‐diffused Pb2CrO5 thin films
Authors: Toda Kohji , Yoshida Shinzo 
Published: July 2007

AbstractTo form a thin‐film line‐image sensor with high density and a high‐speed response, an optoelectronic device was fabricated using a gold‐diffused Pb2CrO5 thin film; its basic characteristics were evaluated as well. A Pb2CrO5 film was deposited using the electron beam evaporation method; this was followed by the deposition of an Au film. The Au was then thermally diffused. As a result, the photoresponse was increased by 150 times, without degrading the spectral response characteristic and the photocurrent/dark current ratio.After Au diffusion, the bias voltage dependence of the photocurrent changed from a parabolic to a linear relationship and the γ coefficient changed from 0.5 to 0.7. In addition, the photoresponse and the transient characteristic in the pulse voltage operation of the Pb2CrO5 thin‐film sensor array were improved. It was confirmed experimentally that the resulting device is suitable for high‐speed and high‐density read‐out.
LSI‐oriented scanning systems using tree structures
Authors: Kondo Toshio 
Published: July 2007

AbstractTwo types of scanning systems using N‐ary tree structures are proposed for high‐speed intelligent processing in an SIMD parallel processor. The scanning systems are constructed by connecting operating elements to each other with hierarchical bypasses or hierarchical and selective propagation paths. After evaluating their operating times, the amount of hardware, and LSI implementation, the following conclusions were reached: (1) the number of serially operating elements in the propagation path is only O(N logN M); (2) enlarging the N‐value decreases the amount of hardware; (3) the selective‐type scanning system is twice as fast as the bypass‐type system although both require almost the same amount of hardware; and (4) a 42‐ary tree structure leads to a simple and dense chip layout.
Soliton‐type femtosecond pulse lasers
Authors: Ishida Yuzo , Nakano Hidetoshi 
Published: July 2007

AbstractThe propagation of optical pulses in optical fibers through an optical soliton has been studied widely. The results of the studies have contributed not only to the development of ultrafast optical communication but also to the creation of a soliton laser designed for generating ultrashort optical pulses. The soliton concept is applied successfully to the generation mechanism of ultrashort optical pulses in a laser cavity. This paper will describe the generation of femtosecond optical pulses in soliton lasers and in solitons in the laser cavity.
Optical sheet memory system
Authors: Ohyama Shinji , Nagae Yoshiharu , Takasaka Masahiro 
Published: July 2007

AbstractThis paper proposes a system for information storage and delivery. It is based on the new concept where the information corresponding to 10 still pictures and approximately 3 min of sound are encoded digitally and printed on a postcard as a dot pattern to be read and restored. The system is called an optical postcard system. In this study, after the basic technologies for the realization of this system are investigated, the printed optical postcard and the reproducing system are constructed experimentally. As a result of there production experiment, the information recorded on the postcard is read and the original picture and sound signal are played back. This indicates that the information can be delivered by optical postcard. The proposed idea of an information storage/delivery system can be applied not only to postcard‐sized sheet, but also to sheets of various sizes. Also, there can be various applications which differ from
the use of the traditional information media, e.g., the the use of the traditional information media, e.g., the zine.
Generation of ultrafast laser pulses by electrooptic modulation
Authors: Kobayashi Tetsuro 
Published: July 2007

AbstractThe passive mode locking traditionally used frequently for generation of ultrafast optical pulses has a problem in generality and controllability although the method can generate short pulses. On the other hand, it is considered that the method based on electrooptic modulation cannot reduce the pulsewidth and the speed is slow even though the controllability is superior.This paper describes the research on the forced mode‐locking method for possible ultrashort and ultrafast properties and the external direct modulation pulse generation method, even though the highly controllable electrooptic modulation is used. First, the forced mode‐locking method is described in which the locking modulator (mode locker) with a pulse‐like transparency in itself and a deflector and a composite resonator are used.Next, a method is described in which short pulses on the order of subpicoseconds can be generated regardless of the laser bandwidth by means of the pulse‐generating modulator outside the laser cavity. (An example is a modified Fabry‐Perot modulator.) Further, an optical pulse synthesizer with a possibility of generating subpico‐second to several tens of femtosecond pulses is described in which the narrowband large signal electrooptic modulator and a deflector are used for generating optical sidebands with a wide optical bandwidth and they are combined for generation of arbitrary‐shaped optical pulse after the phase and amplitude are controlled. The concept is compared with the experiments. Some methods are still under development.
Fast recovery of excitonic absorption bleaching in tunneling Bi‐quantum well
Authors: Tackeuchi Atsushi , Inata Tsuguo , Muto Shunichi , Sugiyama Yoshihiro , Fujii Toshio 
Published: July 2007

AbstractExcitons in a quantum well of a semiconductor exhibit large optical nonlinearity. Therefore, a quantum well of a semiconductor is regarded as a key to realizing a device which can control light using light. However, the lifetime of excitons, which are generated optically, is several nanoseconds to several tens nanoseconds. Therefore, the nonlinear optical effect including absorption saturation continues for the lifetime of the excitons.To shorten the lifetime of the excitons without disturbing the optical nonlinearity, a new superlattice structure is proposed called the “tunneling bi‐quantum well.” This structure uses the tunneling effect and measures the absorption recovery time. As a result, it was found that in a tunneling bi‐quantum well in a GaAs/AlGaAs system with a barrier width of 1.7 nm, the absorption recovery time was as short as 1 ps.
Equivalent characteristic impedance formula of waveguide and its applications
Authors: Ishihara Fujio , Iiguchi Shinichi 
Published: July 2007

AbstractThe equation widely known as the characteristic impedance of the waveguide is defined from the voltage in the cross section, wall current along the axial direction and Poynting vector. For the rectangular waveguide, the impedance has a form proportional to (b/a)λ. However, it is not possible to derive a correct reflection coefficient with this form of characteristic impedance. It has been predicted empirically by the present authors and others that the characteristic impedance connected directly to the reflection coefficient has a form proportional to bλg. However, investigation of the theoretical foundation has not been carried out clearly.In this paper, based on the fundamental differential equation describing the characteristics of the nonuniform waveguide, a transmission line equivalent to the waveguide is derived. By means of this transmission line, the forementioned characteristic impedance is proven to be theoretically correct. Here, this quantity is called the equivalent characteristic impedance.Based on this result, it is proved that there are several different procedures for the analysis of the characteristics of the tapered waveguide and that they all arrive at the same results. The theoretical results are verified by three different experiments. In addition, the applications of this equivalent characteristic impedance are described for the design of the connecting tapered waveguide and the quarterwave transformer.
Polarization control of Q‐switch solid‐state lasers with intracavity SHG crystals
Authors: Taira Takunori , Sasaki Takao , Kobayashi Takao 
Published: July 2007

AbstractWavelength conversion of a laser beam by nonlinear optics has been widely developed for practical applications because optical output with different wavelengths can be obtained efficiently without disturbing the coherence of the fundamental wave. Especially, in the intracavity second harmonic generation (SHG) technique which utilizes a nonlinear optical crystal in the laser cavity, the efficiency and output are high because an intense fundamental wave is used; KTP (KTiOPO4) is an excellent crystal with a high nonlinear optical coefficient. However, when it is placed inside a cavity, the polarization characteristic of the fundamental wave is disturbed because of the birefringence of the crystal. As a result, during Q‐switching, the loss of the fundamental wave in the polarizer increases and the oscillation threshold increases. Therefore, polarization control of the fundamental wave has been carried out by using a γ/4 plate.In this paper, the optical properties of a KTP crystal are analyzed using John's matrix and it is found that polarization control of the fundamental wave could be achieved with maintaining phase matching. Next, by analyzing the operation of the Q‐switch laser by the intracavity SHG‐method, optimization was carried out. As a result, low‐loss polarization control was realized without using a wavelength plate inside the cavity. Then a highly efficient SHG characteristic was realized, wherein the effective efficiency was 84 percent at repetition frequency of 1 kHz and the maximum output was 3.2 W at repetition frequency of 5 kHz.
Laminated polarizer with granular metallic films for short wavelength region (∼0.85 μm)
Authors: Ma Deshan , Tsuchida Kanji , Kawakami Shojiro , Kataoka Haruki 
Published: July 2007

AbstractA laminated polarizer (LAMIPOL) is smaller in size and has a higher extinction ratio and lower insertion loss than the conventional polarizer. Therefore, it is suitable for optical integration. However, when a LAMIPOL with a conventional continuous metallic film is used in a short wavelength region, the property is not sufficiently good.On the other hand, we fabricated a Cu/SiO2 LAMIPOL and achieved an extinction ratio of 46 dB and insertion loss of 0.3 dB, which are better than theoretical values for the device with a continuous film. After detailed investigation of this particular device, it was found that the metal film had granular structure.To investigate the superior characteristic of a LAMIPOL with granular metallic films, a simple model for a granular Cu film was proposed, and the film parameters were estimated using the wavelength dependence of the optical transmittance and reflectance. Using these parameters, the wavelength dependencies of the attenuation constants of LAMIPOL for TE and TM waves were calculated. The agreement between the experimental and calculated results were excellent.
Nonlinear interaction between optical solitons and maximum transmission capacity
Authors: Shimizu Katsuhiro , Fujii Yoichi 
Published: July 2007

AbstractThe very short optical soliton pulse transmission for the very high‐speed communication system is limited by the dispersion of the fiber. The problems due to the neighboring solitons, especially in the wavelength‐multiplex soliton transmission, is analyzed theoretically. As a numerical example, the soliton pulse of 2 ps pulsewidth with the preemphasis factor 1.4 can transmit 150 Gbit/s pulses for 12 km and by the wavelength‐division multiplex system, the 20 channel pulses with the wavelength spacing 1 nm and of 5 ps pulsewidth can transmit the pulses by 400 Gbit/s.
Millimeter‐wave junction circuits using nonradiative dielectric waveguide
Authors: Kuroki Futoshi , Yoneyama Tsukasa 
Published: July 2007

AbstractThe nonradiative dielectric waveguide (NRD guide) is suitable for constructing millimeter‐wave circuits of complicated structure because of nonexistence of radiating wave at the bend and discontinuity based on the non‐radiative nature, the construction technique of the T‐junctions, the cascaded multiport junctions in NRD guide, and their performances at 50 GHz are described in this paper.First, a new T‐junction based on the mode transformation between the two types of nonradiative modes in the NRD guide is proposed and its operation is confirmed experimentally. Next, using this T‐junction, a three‐port and a five‐port junction have been fabricated and tested. Reasonable output levels of ‐3 dB and ‐6 dB in average for the three‐port and five‐port junctions were obtained, respectively, over a bandwidth of about 2 GHz with the center frequency at 50 GHz. From this fact, it is evident that the radiation loss which cannot be suppressed in conventional dielectric waveguide junctions can be completely eliminated in the NRD‐guide junctions.The output ports of these junctions can be increased by stacking several T‐junctions. These junctions can be applied for feed network of millimeter‐wave planar antenna in the future.
Direct Overwrite Characteristics of InSbTe Phase‐Change Optical Disks and the Mechanism
Authors: Maeda Yoshihito , Andoh Hisashi , Nagai Masaichi , Ikuta Isao , Katoh Yoshimi , Tuboi Nobuyoshi , Minemura Hiroyuki , Satoh Yoshio , Ishigaki Masaji 
Published: July 2007

AbstractThis paper examines the direct overwrite characteristics of a 5.25‐inch diameter disk fabricated with an InSbTe ternary‐alloy recording film. This recording film has a novel optical property, namely that the reflectivity is larger in the amorphous (recorded) state than in the crystalline (erased) state. To improve the erasability in direct overwrite, melt‐erasing process was attempted and carried out above the melting point. A high erasability of more than 40 dB and a high carrier‐to‐noise ratio (C/N) of more than 50 dB were realized at the rotating speed of 1800 rpm. A simple model explaining the contribution of the thermal conditions of the melt erasing to the high erasability is proposed.
Tunable waveguide CO2 laser making use of three‐mirror‐type internal modulation method
Authors: Matsushima Tomoshi , Maeda Naoki , Nakao Masatoshi , Kobayashi Tetsuro , Sueta Tadasi 
Published: July 2007

AbstractA novel frequency‐tunable CO2 laser system using an internal modulator is proposed. In the proposed scheme, a tunable filter is used as the output laser mirror. One of the sideband components produced by the modulator is taken out efficiently by the filter as a frequency‐shifted output.From the analysis of internal modulation, the relation between frequency‐shifted output power and modulation index is obtained using the single‐pass laser gain as a parameter. It is shown that a laser with higher gain is favorable for this system. The effect of the modulator location in the laser cavity also is discussed.An experimental system using a CdTe internal modulator and a Fabry‐Perot interferometer was constructed. By the modulation experiment at the VHF band, the output power of 1.5 W was obtained for the frequency shift of ±150 MHz. The output power for ±1.45 GHz shift (UHF band) was 70 mW.Finally, possible output power for SHF modulation is estimated using the published data for a traveling‐wave modulator. Calculation shows that several hundred milliwatts of frequency‐shifted power would be obtainable by the proposed method.
Considerations of ultrahigh‐speed, low‐power active pull‐down NTL logic circuits
Authors: Usami Mitsuo , Nakamura Tohru , Shiozawa Noboru , Tanabe Masamichi , Mandai Takahiro 
Published: July 2007

AbstractLow‐power logic circuits are necessary in order to realize high‐integration, ultrahigh‐speed logic LSIs. For this purpose, a new circuit is proposed which adds an active pull‐down circuit to an NTL circuit with emitter follower which is a logic circuit with small logic swing of 500 mV. Compared to the conventional ECL circuit, this circuit achieves 2.75 times higher speed under 1 mW/gate power and an average wire capacitance of 0.57 pF per gate.As a result of fabricating this active pull‐down NTL logic circuit by 0.5 μm SICOS self‐aligned transistor with U‐groove, a minimum delay time of 25.3 ps, and the load drive capability of 50 ps/pF have been realized.Furthermore, this circuit can achieve even lower power with high speed by adding a pMOS transistor to the collector of input transistor. The simulation has shown that the circuit is four times faster compared to the conventional NTL circuit with an emitter follower with the same power consumption of 0.3 mW/gate and the load capacitance of 1 pF if a pMOS drain current of around 1 mA can be realized with conditionsVds, = ‐0.5 V andVgs= ‐1.3 V.
Geometrical law of total reflection for wave‐normal rays on the discontinuous interfaces in inhomogeneous media
Authors: Hashimoto Masahiro 
Published: July 2007

AbstractWhen the wave‐normal ray associated with a spherical wave is incident upon an interface between two homogeneous media and undergoes a total reflection, the angle of reflection differs slightly from the angle of incidence. The position of the image source, which so far has been known to be located at the position geometrically symmetrical to the real source, also shifts.This paper shows that similar phenomena occur for the case when the media are inhomogeneous. Moreover, it also shows that the expressions obtained for the location of the image source and its phase are completely coincident with those obtained earlier in homogeneous media.
Control of GaInAs/InP layer thickness for surface‐emitting lasers by chemical beam epitaxy
Authors: Uchida Takashi , Uchida Toshikazu , Koyama Fumio , Iga Kenichi 
Published: July 2007

AbstractTo grow a highly reflective semiconductor multilayer mirror and to grow a reproducible composition of GaInAsP/InP for surface‐emitting lasers, a high growth rate (a few μm/h) with a good thickness controllability is required. The authors have investigated the controllability of GaInAs/InP growth of chemical beam epitaxy (CBE). The maximum growth rate of 2.6 μm (InP) and 6.0 μm/h (GaInAs) was obtained without sacrificing surface morphology. With the growth rate being kept reasonably high, a good controllability of layer thickness was obtained and confirmed by growing a 6‐Å quantum well. The thickness error for InP and GaInAs was 1.5 and 2.0 percent, respectively.