Masashi USAMI Shigeyuki AKIBA Katsuyuki UTAKA
The threshold current Ith of a 1.5 µm range InGaAsP/InP λ/4-shifted DFB laser with low-reflectivity ends was theoretically expected to be 10 mA or less. Experimentally, Ith of 14-16 mA at 20 and the sub-mode suppression ratio of about 35 dB or more in the temperature range of 10-70 were obtained.
Masaaki MATSUURA Tadatoshi TANIFUJI Yoshikazu YAMAMOTO
A 1.3 µm edge-emitting LED is used to launch an average optical power of 13.7 dBm into single-mode fibers. This permits analog video signal transmission over a distance of 42 km with a loss margin of 5 dB. No degradations of DG, DP, and signal-to-noise ratio have been observed.
Masahiro MURAGUCHI Takatomo ENOKI Kimiyoshi YAMASAKI Kuniki OHWADA
A 20 GHz band monolithic low noise amplifier combining improved SAINT-FET technology and optimized circuit design has been developed. The amplifier has a measured noise figure of less than 3.5 dB with a minimum gain of 4.2 dB over the 18.5 GHz to 20 GHz range. The optimal noise figure is 2.9 dB with a gain of 5.5 dB at 19 GHz. Standard threshold-voltage deviation of the process monitor FRTs is only 70 mV over the entire area of the 2-inch wafer.
Switching devices capable of handling more than 800 V exhibit relatively large switching loss. A new current feedback Bi-MOS consisting of a Bipolar Junction Transistor, MOS-FET and current transformer is proposed in this note. The new device reduces switching loss in 100 kHz operation and is expected to result in a DC-DC converter efficiency greater than 90%.
Kimihiro SASAKI Masatoshi MORIKAWA Seijiro FURUKAWA
Emitter crowding effect and emitter Gummel number of amorphous SiC: H emitter HBT have been investigated. Collector current density has been remarkably enhanced by narrowing the emitter stripe width. The emitter Gummel number has been estimated as high as 21014s/cm4.
Masayuki IZUTSU Hidetoshi NAKANISHI Tadasi SUETA
The modulation performance of traveling-wave type LiNbO3 guided-wave light modulators with coplanar waveguide structure is studied. The analysis shows that the use of a y-cut plate offers a low voltage modulation with decreased electrode separation although the characteristic impedance becomes low.
Shigetarou IWATSU Satoshi ARIAKE Tadashi KIMURA Ken-ichi NODA
The scale factor temperature dependences of three important optical parts of phase modulation type optical fiber gyroscope, sensing coil, phase modulator and fiber coupler are described. Contribution of each part to the total temperature property is comparable. For each part, more than 5% of scale factor change per 1 is observed in the region from 20 to 45.
Nobumitsu HIROSE Yuuichi HARADA Shigeru YOSHIMORI Mitsuo KAWAMURA
We fabricated micro-contact Josephson junctions by self-alignment process, using double-layer-resist electron beam exposure and RIE. We chose Nb as superconductive materials. The junctions show the A.C. Josephson effect under the millimeter wave (70 GHz) radiation less than 100 µW and the 7th Shapiro step.
Osamu SHIMOMURA Yoshihiro TACHIBANA
This letter presents data of the electrical conductivity of KDP solution in the region of 1070 and 2040g KDP/100g water. It was found that there is a point where the slope of the temperature characteristic of the electrical conductivity change and it corresponds to the saturation point of the solution.
Ken-ichi HAYASHI Yoshio IDA Kazuo ARI Tooru MIZUMOTO
For the sake of small mechanical vibrational amplitude measurements using a laser diode and an optical fiber interferometer, two stabilized measuring systems based on different methods are described. The system stabilities compensating for environmental perturbations are experimentally confirmed. In both systems, the vibrational amplitude can be measured absolutely.
Masaaki KOBAYASHI Masahiro HONJO Shoji NAKAMURA Isamu YANO
The recording density 34 KFRPI was achieved by the use of transversal recording. A tape orientated transversal direction was employed and a ferrite head with 3.8 µm gap length and 15.5 µm track width was used. The frequency characteristics of transversal recording and its bitter patterns are described.
Tadashi TAKENAKA Yasushi SOMA Koichiro SAKATA
Lead zirconate PbZrO3-based materials were studied as a new piezoceramic group based on their dielectric and piezoelectric properties. In the PbZrx(ZN1/3Nb2/3)1xO3 system, the antiferroelectric phase changes to the ferroelectric phase at x=0.930.94. Piezoelectric properties are characterized by the large coupling factor of the thickness shear mode.
Kazuhiko SAKAKIBARA Seiichi MUROYAMA
This letter describes an analysis of a series resonant converter in which the effects of the output transformer's magnetizing inductance on the converter's output characteristics are considered. It is clarified that the output power decreases when the magnetizing inductance has a low value.
Yasutaka UCHIDA Masahito OBATA Hongyong ZHANG Masakiyo MATSUMURA
By using a strong oxidizing agent in liquid phase, more than 7 nm-thick silicon dioxide has been grown thermally in a single-crystal silicon substrate at 252 within 8 hrs under normal-pressure conditions. The oxidation characteristics have been presented. Its application to amorphous silicon MOS transistors has been also described. The field-effect mobility of the transistor was more than 0.22 cm2/Vs.
Koichiro SAWA Makoto HASEGAWA Kunio MIYACHI
This letter presents a newly developed automatic data-acquisition system for contact resistance in which a personal computer is used for control and data processing. And the experimental results on Ag-Pd alloy contacts are reported, especially concerning the relation between Pd contents and resistance.
Hitoshi YANAGIURA Hideo KOBAYASHI Junichi TAKAGI Nobuo TOMITA
This letter proposes a cylindrical accommodation block consisting of a number of plastic sheets placed radially. The basic structural design of the block has been made, and it is found that more than 1000-fiber splices, i.e. mass-splices of 200 fiber ribbons can be accommodated with the same size as the existing metallic cable joints.
Shigeyuki AKIBA Masashi USAMI Katsuyuki UTAKA
The corrugated waveguide parameters and the threshold current densities of the TE and TM modes in InGaAsP/InP λ/4-shifted DFB lasers with non-reflective ends were calculated and the TE/TM ratio over 30 dB was expected. The experimental TE/TM ratios of about 35 dB in a directly modulated condition were shown.
Hisao KAWASAKI Ichirou INAMI Atsushi TANAKA Hirokuni TOKUDA Mitsugu HIGASHIURA Shigekazu HORI Kiyoho KAMEI
0.25-µm gate low-noise high electron mobility transistors (HEMTs) have been developed, using epitaxial wafers grown by metal-organic-chemical vapour deposition (MOCVD) technique. Minimum noise figures of 0.75 dB and 1.2 dB with associated gains of 11.1 dB and 7.9 dB are obtained at 12 GHz and 18 GHz, respectively, at room temperature. These are the lowest noise figures yet reported for low-noise HEMTs fabricated on MOCVD epitaxial wafers.
Mitsuhiro YOKOTA Takashi TAKENAKA Otozo FUKUMITSU
Scattering of a three-dimensional Hermite-Gaussian beam mode by a dielectric circular cylinder at normal incidence is considered by using the complex-source-point method. The scattered fields are examined numerically for a lowest-order mode.