摘要:

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 G

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750701

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

年代:1992

数据来源: WILEY

摘要:

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 p

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750702

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

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper analyzes the problem of scattering of a plane electromagnetic wave by a resistive strip grating placed on a multilayered anisotropic substrate. As the method for analysis, the procedures by Teitler and Berreman which can handle the electromagnetic fields in anisotropic medium are extended to which the space harmonic expansion is applied. The currents on the resistive strips are determined by applying Galerkin's method to the resistive boundary condition on the plane with a strip grating. Numerical examples are presented for the reflection coefficients and diffraction efficiencies. First, the results are given in comparison with the data from other publications in the case where the grating is in air or on a grounded dielectric substrate. Afterward, the examples with anisotropic media are presented.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750703

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

年代:1992

数据来源: WILEY

摘要:

AbstractAs an application to the upconverter which converts infrared light to visible light by means of a three‐wave sum frequency conversion, an infrared upconverter‐spectrometer is proposed which uses rotating scanning of a periodic nonlinear medium (consisting of layers of media with the sign of nonlinear optical coefficient alternately inverted). In this structure, the wavelength selection capability of the phase matching in the parametric interaction is used. The resolving power and the maximum output (conversion efficiency), which are important basic characteristics in the infrared upconverter‐spectrometer, are studied theoretically. The resolving power versus the incident angle of the pumping light is studied in detail with the medium dispersion and the two‐dimensional size taken into account.As examples, the infrared upconverter‐spectrometers for 10‐ and 3‐μm bands using GaAs and LiNbO3as the periodic nonlinear media have been considered and their resolving power has been derived numerically. Excellent visible detectors can be used in these infrared spectrometers. In addition, they can use isotropic media with ordinary dispersion and large nonlinear optical coefficients. By means of rotating scanning of the crystal, they can have high sensitivity and high response time. Depending on the direction of incidence of the pumping light, a resolving power higher than that of conventional structures c

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750704

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

年代:1992

数据来源: WILEY

摘要:

AbstractAn automatic synthesizing method of holographic stereograms (HSs) has been studied for computer‐graphic images, and experimental results of image reconstruction have been presented. In the synthesis of the HSs, raytraced image data of 180 frames were generated, changing a viewpoint. Then these data were recorded on a holographic film of about 70 mm x 300 mm using a liquid crystal television panel as a spatial light modulator. The fabrication time of one HS was about 50 min. In image reconstruction with a 5‐mW He‐Ne laser, it has been possible to display three‐dimensional images which have a good parallax

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750705

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe current‐voltage characteristics of p+pn+structure polycrystalline silicon diodes and the energy distribution of traps in the grain boundaries are measured before and after plasma hydrogenation. Plasma hydrogenation increases the forward current and reduces the reverse current. The energy distribution of nonhydrogenated film has a peak around the midgap; this peak disappears after hydrogenation. The change in diode current produced by plasma hydrogenation can be explained by this difference in the energy distribution of the trap

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750706

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe oxide growth and the characterization of a thin protective layer peculiar to an aluminum surface have been examined by varying the composition of Al‐Nb alloy films and by nitrogen doping. At room temperature, an aluminum oxide layer was formed on an Al‐Nb alloy surface by preferential oxidation. In the Al‐Nb alloy with an Al‐rich composition, Nb underneath the oxide layer was not oxidized, while in the alloy with an Nb‐rich composition, oxidized Nb was present on the oxidized surface layer even at room temperature and the oxidized layer grew as the temperature increased.The lower oxides of Nb which were already present at room temperature enhance the oxidation of Al, causing a decrease of the activation energy for oxidation. As a result, the oxidized layer grows as the temperature increases. To confirm the presence of activation process of Al oxidations by impurity doping, an Al‐rich alloy was doped with nitrogen. The result shows that a similar activation process accelerates the oxide growth by nitrogen doping. It was then concluded that the possible activation process of the Al cations is involved in the mechanism of losing the protectivity in t

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750707

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

年代:1992

数据来源: WILEY

摘要:

AbstractIn addition to the previously reported angstrom‐order porous structure, the micron‐order porous structure was found in anodized silicon. The micron‐order structure can easily be observed by a scanning microscope if the anodized silicon is etched by using weak acid. The structure can be divided into the columnar structure perpendicular to the layer, the roof structure covering the layer surface, and the needle structure parallel to the columnar structure. Shallow depressions are present at the interface between the layer and substrate. The needle structure is strongly dependent on the temperature of the anodizing chemical

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750708

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

年代:1992

数据来源: WILEY

摘要:

AbstractA control scheme to achieve wafer‐to‐wafer temperature uniformity in the reaction tube used for oxidation, diffusion, or annealing during semiconductor processes is proposed. In the analytical model, self‐radiation loss, radiation between neighboring wafers, radiation from the tube wall, and thermal diffusion on a wafer surface are taken into account. The temperature monitoring points were the inlet, middle, and outlet of the reaction tube.The analysis indicates that if the tube wall temperatures at the inlet and outlet are 6 percent higher than that at the center of the tube, the wafer‐to‐wafer temperature becomes uniform. In the experiment, taking the silica tube temperature as the tube wall temperature, the increase in the temperatures at the inlet and outlet must be 5.6 percent to achieve wafer‐to‐wafer temperature uniformity, while it should be 6.9 percent if the temperature of the secondary tube is considered to be the tube wall temperature.Experiment results verify the effectiveness of the model. At the same time, the tube wall temperature is assumed to be influenced not only by the temperature of the silica tube but also by that of the secondary tube. The model predicts that the wafer temperature increased by 1°C if the tube wall temperature is increased as described in the foregoing. However, in the experiment, the wafer temperature increases by

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750709

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

年代:1992

数据来源: WILEY

摘要:

AbstractSilicon oxynitride films (SiNXOY) were deposited at deposition temperatures between 100 and 300°C using mercury‐sensitized photochemical vapor deposition. The light source was a low‐pressure mercury lamp and the source gas was a mixture of NH3gas and 5 percent SiH4gas (95 percent N2gas). The quality and interface property of these films were better than those of plasma‐CVD films. However, in the former films, the film quality was unstable and degraded rapidly with time when the deposition temperature was low.Electron spectroscopy for chemical analysis (ESCA) indicated that the invasion of oxygen from air to the film caused a change in the film composition, resulting in the degradation of film property with time. The photochemical vapor deposition and plasma‐vapor deposition SiNXOYfilms were used as an antireflective coating for a single‐crystal‐Si solar cell; and it was found that using the former films, the short‐circuit current density and effective conversion efficiency were higher than by using the latter films. The difference in the foregoing results was believed to be due to the improvement of the interface property by photochemical de

ISSN:8756-663X    

DOI:10.1002/ecjb.4420750710

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

年代:1992

数据来源: WILEY