摘要:

AbstractNew optoelectronic logic operation systems are proposed by controlling the deflection angle of the beam from semiconductor lasers and basic experimental results are presented. The input signal of these systems is spatially coded optical patterns. All symmetrical operations for the two input signals (eight types including AND, OR, XOR, etc.) are realized by using two photodetectors, two amplifiers, and one beam‐scanning laser diode. These systems are advantageous because various logic gates can be realized by using only a small number of elements. Further, they are suitable for integration because the configuration, the delay time, and the size of the unit gates are almost the sam

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741001

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractFor the wavelength conversion by the Čerenkov‐radiation scheme in a nonlinear optical waveguide, a novel device structure is proposed which improves the efficiency and the characteristics over the conventional ones. An optimization of such a device structure is attempted. In this waveguide structure, a transverse distribution is provided not only for the linear refractive index but also for the nonlinear susceptibility.This paper shows that the second harmonic generation in a proton‐exchanged LiNbO3waveguide is expected to be enhanced by more than an order of magnitude by changing the region near the surface of the conventional structure into a domain‐inverted layer. Further, if the thickness of the domain‐inverted layer is controlled precisely, the selection of the guiding‐layer thickness (or the refractive index profile) can be relaxed substantially. This feature would be extremely attractive in designing actual device

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741002

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe noise characteristics of the Er3+‐doped optical fiber amplifier pumped by laser diodes (LD) at 0.98 μm and 1.48 μm are theoretically and experimentally studied. The noise figures of the optical fiber amplifiers pumped by a 0.98–μm band LD and a 1.48–μm band LD estimated from the beat noise between the signal noise and the spontaneous emission were 3.2 and 4.1 dB. It was found that the beat noise between spontaneous emissions and the shot noise of the spontaneous emission were smaller in the 0.98 μm‐band LD than in the 1.48–μm band LD. From these results, it was found that the optical fiber amplifier pumped by the 0.98–μm band LD has lower noise characteristics than those of the amplifier pumped by the 1.48 μm band LD.Further, the signal gain dependence, fiber length dependence and signal wavelength dependence of each noise component were studied. When the signal gain is kept constant, each noise component is not dependent on the fiber length and can be reduced monotonically by increasing the signal gain. When the wavelength deviates from the signal wavelength giving the maximum signal gain, the beat noise between the spontaneous emissions and the shot noise of the spontaneou

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741003

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper describes the experimental results of a single‐phase unidirectional magnetostatic forward volume wave transducer (MSFVW); this transducer effectively utilizes the reflections of metal strips placed asymmetrically in it. To design a single‐phase unidirectional transducer having internal reflectors, it is necessary to know the reflection characteristics of the metal strips but no study has been performed as yet to find the magnitude and phase of the reflection coefficient. Here, the reflection characteristics of a metal strip array for MSFVW are studied experimentally. For the single strip electrode, the reflection coefficient is in the range of 0.3 – 0.4, which is about one order higher than the value for surface acoustic wave (SAW) devices. Then it is shown for the first time that by properly utilizing the metal strip reflections, a unidirectional transducer can be realized without attaching an external phase shifter. The directivity of 13 dB was obtained for a transducer using four reflecting strips (which is a large value of directivity by a comparatively small number of elements). The phase of strip electrodes as determined from the direction was −90 deg, which is 180 deg different from the SAW

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741004

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper describes the theoretical and experimental investigations of an integrated wavelength filter consisting of an AlGaAs/GaAs MQW waveguide. This filter is made of a vertical directional coupler which performs forward coupling by means of a grating. It is small, and its center wavelength and bandwidth can be freely designed.The configuration of the filter is described first and a design guideline is shown to obtain a narrowband filter response with a short coupling length. As a result of the trial fabrication, narrowband filters with 3‐dB bandwidths of 2.5 nm and 3.2 nm were realized with coupling lengths of only 510 μm and 430 μm, respectively. Next, it was shown experimentally that the filter center wavelength can be shifted from 824 nm to 839.5 nm by controlling the grating period from 9.8 μm to 10.6 μm. Further, a method for reducing the sidelobe level is proposed by modulation of the grating duty ratio. Numerical results for such a proposal are desc

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741005

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper discusses the sample‐and‐hold IC to be placed in front of the 10‐bit serial‐parallel analog/digital converter (ADC). The realization of an IC in operation with a +5‐V single supply is discussed, considering the integration with ADC and the system‐on‐chip implementation in the future. The buffer circuit with a configuration based on NPN and PNP complementary elements is employed. The combination of PMOS and NPN elements is newly devised and applied, as a way to realize the high‐speed PNP element.Applying 1.2‐μm BiCMOS process to this circuit, IC is constructed and evaluated. As a result, the performances of maximum operating frequency 40 MHz, the signal‐to‐noise ratio of 63 dB for the 8‐MHz full‐scale signal input, the acquisition time of 20 ns for 1‐V step input, D.G. of less than 1 percent and D.P. of less than 0.5° are obtained. Thus, the sample‐and‐hold IC with the single voltage suppl

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741006

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractIn the analysis of switched circuits, the same number of different state equations must be solved as the number of states of the circuit depending on the on‐off of the switches. As a result of this property, the analysis of the switched circuits is made complex and requires a long time.The authors have developed a numerical analysis program called EISCAP for the switched circuits. In this program for CAD, the particular solution of the state equation is derived using the inverse of the coefficient matrix. It may happen, however, that capacitors are connected in series or inductors are connected in parallel by the switching operation. Then the coefficient matrix of the state equation becomes singular, and the particular solution cannot be derived using the inverse matrix.This paper proposes an analysis procedure for the case where the coefficient matrix of the state equation is singular. The proposed procedure has the following features: (1) the traditional EISCAP program can directly be used by a simple matrix manipulation; (2) the analysis can be executed when the data of the circuit containing series capacitors or parallel inductors are directly inputted, which has been impossible in other circuit analysis programs; and (3) the result of simulation agrees well with the result of measuremen

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741007

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractAs the basic study to realize a blue‐color light‐emitting diode using CuAlxGa1‐xS2crystals, heterojunction diodes were fabricated by the vacuum deposition of ann‐type ZnyCd1‐yS thin film on the {112} surface of ap‐type CuGaS2single crystal grown by the iodine transport method. It was found that the {0001} surface of ZnyCd1‐yS is oriented in parallel to the substrate when the substrate is not heated, that the film is transparent to green and blue color, and that the resistivity is extremely low wheny= 0.2 to 0.4. When single crystalline CuGaS2is annealed in saturated sulfur vapor, the resistivity decreases.Next, the current‐voltage characteristic of a diode was investigated. When sulfur‐annealed CuGaS2single crystal was used, the series resistance of the diode was low and the forward characteristic could be explained by using series and parallel resistances in the equivalent circuit. On the other hand, the reverse current showed almost an ohmic characteristic at low voltage but it increased nonlinearly with an increase of the reverse voltage. Wheny≠ 0, a yellowish‐orange or red light emission was observed when the diode was forward‐biased. Wheny= 0, no light emission was observed although the electrical property of

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741008

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractSilicon films deposited by low‐pressure chemical vapor deposition (CVD) technique was crystallized by ultraviolet (UV) pulse laser annealing and its crystallinity was evaluated by X‐ray diffraction and transmission electron microscopy.Although the average grain size of laser‐annealed Si films was smaller than that of Si films annealed at 600°C for 24 hr, in the former film, the density of defects was lower and the grain size was more uniform. In both laser annealed and thermally annealed films, most of the defects in the grains were twin defects whose twin faces were oriented indirection and went across the entire grain. In the depth direction, two layers were observed: one had large grains and the other had small grains below. For Si films 330 nm in thickness and for laser intensity of 200 mJ/cm2, crystallization seemed to be initialized not only from the surface but also from the Si‐SiO2interface.The texture of the films was either random (111) or textured (110), depending on the film deposition temperature and laser intensity. The laser absorption coefficient depended on the crystallinity of the film prior to laser illumination and the threshold energy for laser crystallization was larger for polysilicon films than for originally amorpho

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741009

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractTo fabricate a multilayer wiring using a low thermal expansion polyimide film, the adhesion of polyimide film on a thermally cured polyimide film must be secured. When the surface was plasma‐treated by O2‐CF4= 1:1 gas, the adhesion was 30 times stronger (peel strength: at least 500 g/cm) than in the untreated case (peel strength: 15 g/cm). The film on the plasma‐treated surface maintained strong adhesion for long periods of time in a high‐temperature and high‐humidity environment. The cause of improved adhesion was investigated by evaluating the plasma‐treated polyimide surface by XPS and it was found that functional group, which seems to be COF,

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741010

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY