摘要:

AbstractLiTaO3is considered resistant to optical damage and it has a small dispersion. Thus, LiTaO3is expected as a solution to such problems as dc drift and optical damage in an LiNbO3waveguide.This paper describes a design method for a singlemode, three‐dimensional optical waveguide by means of proton exchange and annealing on a Z‐cut LiTaO3 substrate. A phase modulator with a different annealing time was designed and r33S was measured by the phase modulation method. It is found that the measured value of 6 pm/V immediately after exchange is recovered to 22 pm/V (about 70 percent of the bulk value) by annealing for more than 30 min at 400°C.By the resonance method, r33Twas measured. the result is larger by 30 percent than the measured r33S. After annealing for 30 min, the value was almost equal to the bulk value. Further, by the SIMS (secondary ionmass spectroscopy) analysis, the change of the concentration profiles of Li and H+ before and after annealing is determined. It is found that Li returns to the surface from the interior of the substrate by annealing and H+ is diffused in the depth direction. This suggests that the crystallography of the proton‐exchanged layer approaches that before exchange so that the degradation ofrconstants is rec

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770501

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

年代:1994

数据来源: WILEY

摘要:

AbstractPressure‐extruded infrared optical fiber is a polycrystalline structure with grain sizes of 30 to 70 μm, and it exhibits a large amount of attenuation. the attenuation due to scattering is more than one‐half the total attenuation and is induced by the residual strain, surface roughness, and grain boundary defects. In the investigation of loss mechanisms, it is indispensable to measure separately the different losses such as absorption loss and scattering loss. Since the scattering loss can be measured by an integrating sphere sliding along the fiber axis, the absorption loss is obtained by the subtraction of the scattering loss from the total loss.This paper proposes a new method for directly measuring the absorption loss, and experiments using this method were carried out. the method is based on the thermal expansion associated with temperature rise due to the absorption. It is shown that the absorption loss can be evaluated by measuring the time response of the elongation of the fiber in which the laser power is absorbed. In addition a new measuring method for the heat transfer coefficient of the fiber also is proposed.Using these methods, the absorption and scattering losses of KRS‐5 optical fiber were measured. the results indicate that the scattering loss is about 1.5 times larger than the absorptio

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770502

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

年代:1994

数据来源: WILEY

摘要:

AbstractBismuth germanium oxide (Bi12GeO20) is an optical rotary power (ORP) crystal; and, when used in longitudinal voltage sensors, its performance is influenced by such rotary‐power performance. That is, as the ORP angle Φ is increased, the sensor sensitivity |m| is decreased. Here, the relation between ORP angle Φ and sensitivity |m| of the longitudinal voltage sensor is investigated and the corresponding equation is derived. Further, by changing the crystal thickness. the ORP angle Φ is varied between 20 and 80 degrees and the measured sensitivities of the voltage sensor are compared against the calculated results. it is found that agreement is quite good between the calculated results based on the derived equation and the measured data.with the existence of ORP, the method of suppressing its degrading effects upon the sensitivity is devised and the effectiveness of the method is verified experimentally. Finally, based on the results of the present investigations, the conditions for direct vectorial addition of the measured quantities via the optical sensor are determined and the voltage relative to the ground of the three‐phase circuits are processed optically as the addition of three vectors. As a result, it is verified experimentally that the zero‐sequence voltage can be measured with high

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770503

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

年代:1994

数据来源: WILEY

摘要:

AbstractWhen the wave propagation in an optical circuit is studied by means of the beam‐propagation method, a problem is the reflection of the radiated wave at the virtual boundary surrounding a finitely large region to be investigated. In this paper, it is assumed that the field near the virtual boundary is an outward propagation wave. A method is proposed for transmitting this radia tion without reflection by using the relationship satisfied by this wave as the boundary condition. the method is then applied to the beam‐propagation method based on the finite‐element method. the amount of increase of the computation effort necessary for including this transparent boundary condition is negligibly small in comparison with the amount of computation needed for the successive analysis of the wave propagation. Hence, the method is very effe

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770504

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

年代:1994

数据来源: WILEY

摘要:

AbstractAs a numerical solution of the electromagnetic waveguide transfer problem with a three‐dimensional discontinuity, the solution in which the finite‐element method is applied to the electromagnetic field at the discontinuity while the eigenmode expansion method is applied to the field in the waveguide is a powerful one. In such a solution, a method for connecting the electromagnetic fields in the waveguide to those in the discontinuity must be considered.This paper proposes a method in which the Galerkin method using the waveguide modal functions as the weighting functions is used for connecting the field on the boundary between the waveguide and the discontinuity. Since the connecting boundary can be taken very closely to the discontinuity in this method, the size of the matrix equation to be solved is small so that the amount of computation is small. There is no restriction between the number of expansion basis of the field by the finiteelement method and that of expansion modes in the eigenmode expansion method. Also, the matrix equation to be solved is symmetric. the matrix to represent the scattering at the discontinuity can directly be analyzed numerically.The method is applied in this paper to the simplest discontinuity problem in an axisymmetric coaxial line system to verify the validity of the met

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770505

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe thermal diffusion of boron in the SiGe/Si heterostructure during thermal treatment in inert gas was investigated. It was proved experimentally that in the SiGeB/Si structure where the boron concentration in the SiGe layer was higher than that in the Si underlayer, the redistribution of boron from the SiGe layer to the Si layer was less than that in the Si mono‐layer. Also, the thermal stability of boron improved and thep+n junction was shallower than that in the Si monolayer.To clarify this symptom and to use it in the device process, the equation for the boron diffusion in the hater ostructure structure was derived using the chemical potential. the theoretical equation indicated that boron diffused from the Si layer to the SiGe layer in such a manner that the crystalline strain due to the introduction of Ge was compensated. the experimental results were supported by this theoretical prediction. In addition, it was clarified that the theoretical equation was justified quantitatively by computer simulation.A new method of forming a shallow p+n junction using the SiGeB/Si heterostructure was proposed based on a theoretical equation, and the guiding principle for the optimization of the process was clarifie

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770506

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

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper discusses the behavior of metal and the bonding mechanism at the interface between Sn‐Sb solder and an evaporated Al‐Cr‐Ni‐Ag multilayer used for bonding a silicon chip to a substrate. As the treatment temperature increases, alloying among Ag, Ni, and Cr and diffusion of Al toward the metal surface are accelerated. the multilayer is composed of a mixture of the forementioned metals. When soldering is carried out, Ag and Ni disappear from the interface and the solder has direct contact with the Cr layer. Even in this case, the adhesion is still secure.After soldering, the Cr layer at the interface contains metals in the multilayer and solder compositions and the Sb‐based intermetallic compound is formed at the interface. the adhesion force between the Sn‐Sb solder and Cr layer is determined by the diffusion of metals to the Cr layer and the formation of the intermetall

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770507

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

年代:1994

数据来源: WILEY

摘要:

AbstractA new heat‐aided recording method, thermal rheography, which employs no ink film is proposed. With this method, a paste ink is directly heated and melted through a porous thermal‐print head, upon which it passes through holes engraved in the heating elements. Since the recording process uses no ink film, the operational cost is low and the need for a film‐feed mechanism is eliminated.To realize this method: 1) the relation between paste ink composition and recording characteristics; and 2) the construction of porous thermal‐printing‐head are investigated. the method can attain according density 1.0 with energy 30 mI/mm2, compatible with G3 thermalsensitive paper

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770508

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

年代:1994

数据来源: WILEY

摘要:

AbstractSiO2thin films were prepared by the sol‐gel method. the properties of the films such as film thickness, etching rate in hydrofluoric acid, Vicker's hardness, and the effect of the thermal treatment on the molecular structure were investigated. As a result, it was found that the etching resistance and hardness were improved as the treatment temperature increased. These changes in the properties were related to the density and water content in the film.The molecular structure analysis by the29Si solid‐state NMR and Raman spectroscopy revealed that the unstable distorted Si‐O‐Si bonds formed in the solution were broken and stable straight Si‐O‐Si bonds were formed during the high‐temperature treatment. As the number of the stable Si‐O‐Si bonds increases, the hardness and density of th

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770509

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

年代:1994

数据来源: WILEY

摘要:

AbstractRecently, there has been renewed interest in the thermoelectric power generation based on the thermoelectric element with a view to the recycling of wasted heat. the existing theory on this subject, however, has been derived from a macroscopic viewpoint such as thermal balance. Since no differential equation is solved, it was not possible to analyze even fundamental subjects such as derivation of the temperature profile inside the element.In this paper, by means of a newly derived nonlinear thermoeleetric differential equation, the temperature profiles and generated output power are analyzed accurately with actual material data. From the analysis, various conclusions are derived. Further, the analysis results by a differential equation which is a linear approximation of the original nonlinear equation are compared with those of the nonlinear equation. It is shown that good agreement is obtained. Also, the previous theory is compared with the analysis results of the linear differential equation. It is pointed out that the previous theory has a certain degree of validity.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770510

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

年代:1994

数据来源: WILEY