摘要:

AbstractThis paper describes the design method for triple‐clad silica core optical fibers with zero total dispersion at wavelengths of 1.3 and 1.55 μm; (ac, Sc) is the point where the total dispersion (=S) at wavelengths of 1.3 μm becomes equal to that at 1.55 μm when the core radius (=a) is varied. We denote the relative index difference between the core and themth clad at 1.55 μm by Δm+1(>0,m× 1, 2, 3), the thickness of themth clad bytm(m× 1, 2, 3), the cut‐off wave length for the second mode by λcand the equivalent bending radius (= radius where the bending loss is 0.01 dB/km asR. The following conclusions have been obtained: (1) even if the conditions for the zero dispersion are satisfied in an ideal triple clad (TC type), the zero dispersion condition cannot be satisfied when fluctuations and round shoulders happen to exist in the clad layers (nonideal TC type); (2) to fabricate fibers of TC type and nonideal TC type with |Sc|<0.1 ps/km/nm, λc≤ 1.15 μm andR<5 cm. The following conditions should be satisfied: Δ2= 2Δ4, Δ3≤ Δ4, Δ4≥ 0.7% andt1/ac≤ 1.04 fort2/t1× 0.5; (3) if the item (2) is satisfied, the sensitivities ofSctoac, Δ2, and Δ3for wavelength of 1.3 μm are constant whent1/ac≤ 2.0. However, at wavelength of 1.55 μm, they decrease ast1/acdecreases; and (4)Rfor wavelength of 1.55 μm is about 10 times larger thanRfor wavelength of 1.3 μm.In this paper, the total dispersion is computed by the differentiation formula for determinant. Therefore the significant digits of the total dispersio

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701101

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

年代:1987

数据来源: WILEY

摘要:

AbstractPattern peak‐shifts due to the interference of adjacent magnetization transitions in digital recording are one of the main causes of limiting its recording density. This paper aims to supply design data on pattern peak‐shifts, giving experimental data of peak‐shift in various transition patterns, and comparing them with the calculated results obtained from the superposition of isolated read signals. A magnetic tape system was used in which a nonlinear interference effect occurs easily during the write process.The relationship between the peak‐shift in a magnetic transition pattern Δxand the minimum magnetic transition intervalbis given in a normalized graph coordinated by Δx/bandb/(W50/2), whereW50is the half‐width of an isolated read signal. For example, the design value ofb/(W50/2) for required value of Δx/b≤ 25% is about 1.3, 1.0 and 1.2 or greater for the NRZ‐I, FM and MFM code systems, respectively. The nonlinear interference in a recording process occurs so that each magnetization transition is pushed toward the direction of medium motion. In a region where this effect occurs strongly, the calculated results do not agree with

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701102

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

年代:1987

数据来源: WILEY

摘要:

AbstractSince the power generated by a solar cell depends strongly on the weather condition, particularly the intensity of the solar light, these cells are usually employed in combination with secondary batteries. However, the latter has problems in maintainability and safety. Therefore it is desirable to use ac power in place of a secondary battery if the solar cells are used in general households. For such a purpose, it is necessary to insert between the solar cell and the ac power source an inexpensive interface circuit that is simple and reliable. In this paper, an interface circuit made of a voltage‐controlled variable‐frequency oscillator, an inverter and a coupling inductor is reported. With this circuit, it became possible to extract an almost maximum power from the solar cell at the varying solar intensity. The output is converted to ac and connected automatically with the commercial ac source. The operating principle and the experimental results will be repor

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701103

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

年代:1987

数据来源: WILEY

摘要:

AbstractThis paper formulates a new finite‐element representation for the vector analysis of dielectric waveguides, using the transverse magnetic‐field component. This approach starts from the earlier finite‐element formalism using all magnetic‐field components. Considering the condition V ΔH× 0 by the same technique as in the master‐slave method, and eliminating the longitudinal magnetic‐field component, the equation only for the transverse magnetic‐field component is derived and solved. By this scheme, the spurious solutions (nonphysical solutions), which have been produced inevitably in the earlier vector finite‐element analysis, is now eliminated completely from both fast‐ and slow‐wave regions. To verify the validity and the effectiveness of the present scheme, the analysis is made for a dielectric‐loaded rectangular waveguide. The results of analysis are compared with those of exact analysis and by other methods, indicating the effectiveness of the present finite‐element formulation. The present method does not involve any arbitrary constant, such as the penalty coefficient in the penalty method. The size of the matrix equation to be solved is two‐thirds that of the penalty method, which improves the efficiency of numeric

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701104

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

年代:1987

数据来源: WILEY

摘要:

AbstractAn analysis method based on the finite element method is proposed for solving the problem of diffraction of a plane wave by a dielectric grating. For both the TE and TM wave incidences, a systematic formulation is presented. Although numerous analysis methods have been reported on dielectric gratings, it is necessary in general to divide a grating into several layered planar dielectric gratings when a dielectric grating with an arbitrary profile is analyzed. On the other hand, the finite element method used in this paper enables direct treatment of a dielectric grating with an arbitrary profile without multilayered division. In practice, gratings made of grooves with rectangular, sinusoidal and trapezoidal profiles created on the surface of a semi‐infinite dielectric medium are analyzed. The results of analysis on the diffraction characteristics are presented. Next, as an example for groove gratings with complex geometry, the analysis results of the diffraction efficiency are presented for a holographic grating fabricated at IBM. The analysis results agree well with those by other methods and with experimental values so that the validity and usefulness of the present method are confirme

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701105

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe problem of Cerenkov instability by the relativistic electron beam propagating along a constant static magnetic field applied in the axial direction of the slow‐wave structure with a circular cross section is analyzed based on the relativistic equation of motion for cold electrons and Maxwell's equations. As practical slow‐wave structures, a circular corrugated waveguide, a coaxial corrugated waveguide, and a dielectric loaded waveguide have been assumed. The maximum growth rates of the space charge and cyclotron Cerenkov instabilities are calculated numerically for each structure. It is found that for both instabilities, the growth rate is the maximum in the case of a corrugated coaxial waveguide in which the electron beam is propagating near the waveguide wall. In all three slow‐wave structures, the growth rate of the cyclotron Cerenkov instability can be made substantially smaller than that of the space‐charge Cerenkov inst

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701106

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

年代:1987

数据来源: WILEY

摘要:

AbstractThis paper describes the shear horizontal (SH) wave devices for frequency modulation and demodulation in the HF band. By means of a numerical analysis, it is found that the zeroth‐order symmetric SH mode in a horizontally poled piezoelectric ceramic plate is useful for this purpose. It has a low dispersion, low velocity and high coupling coefficient. SH wave devices as small as IC chips are useful in the HF band. The frequency characteristics of the frequency modulator and demodulator are from dc to 200 kHz and their linear conversion bandwidth is 60 kHz. These devices are useful for signal processing devices and sensors in the HF ban

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701107

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

年代:1987

数据来源: WILEY

摘要:

AbstractA double tubed coaxial line type microwave plasma CVD system has been developed for a‐Si:H film deposition using hydrogen and argon gases with pure SiH4gas as the material gas. The film quality was evaluated as a function of the plasma condition.Since the spreads of hydrogen and argon plasmas were in the range of 2‐3 cm and 8‐9 cm, respectively, the substrate was placed 10 cm from the end of the discharge tube to avoid bombardment of the substrate by high‐energy particles. The film fabricated under hydrogen plasma showed superior characteristics. The film deposited at the substrate temperature between 150 and 200°C were of high quality; predominantly SiH bond rather than SiH2bond, a large value for the photo‐dark conductivity ratio (σp/σd− 105) and a small density of dangling bonds.A high‐quality film can be fabricated under hydrogen plasma because a large amount of hydrogen radicals covers the film surface, thereby causing a thermal structural relaxation of silane radicals. This relaxation results when the silane radicals increase their surface mobility after the soft landing on

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701108

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

年代:1987

数据来源: WILEY

摘要:

AbstractThis paper describes the structural and electrical properties of V3Si films formed by solid‐phase‐reaction for Josephson superconductive thin‐film devices. To evaluate the film structure, the high‐speed ion backscattering technique, X‐ray diffraction technique, and SEM technique were employed. The resistivity of the film was measured by the four‐terminal method at temperatures between 4.2 and 300°K. In addition, the sueprconductive transition temperature was obtained. From these results, the following observations were made: (1) the V3Si phase is formed by using a V film on a thermally oxidized Si substrate, but there is a minimum SiO2thickness depending on the temperature for the thermal treatment; (2) a V3Si film can be formed on either amorphous silica glass or single‐crystalline quartz. However, when the V3Si film forms on the silica glass, it tends to crack and has a large ΔTc. When the film is formed on a single‐crystalline quartz, there is a strong growth preferentially, and ΔTcis smaller; (3)Tcis dependent on the thickness of the V film and the thickness of the V film should be more than 1500 Å to obtai

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701109

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

年代:1987

数据来源: WILEY

摘要:

AbstractCircuit simulation programs with much higher accuracy than those presently available are required to achieve analog circuits with higher accuracy. For the simulation method which is a factor in determining the accuracy of circuit simulation, a charge‐oriented simulation method has been proposed and utilized effectively. On the other hand, in terms of a device model which is another factor, there has been no current and capacitance model consistent with the forementioned simulation method and available for submicron devices. This paper proposes a submicron CMOS device model which is used in the charge oriented circuit simulation to achieve higher‐accuracy circuit analysis. The features of this model are: (1) continuity of drain conductance at the pinch‐off voltage ensures accurate expression of the drain conductance which is especially important in designing analog circuits; (2) minority carriers in the pinch‐off region are considered to express accurately the current and capacitance characteristics in the saturation region. By comparing the drain current vs. drain voltage characteristics for 0.6 μm and 1.0 μm devices and the capacitance characteristics for a 0.8 μm device reported elsewhere it is shown that the calculated values are in good agreement with the measured values. Thus, our model is confirmed to be applicable to the high‐accuracy design of submicron C

ISSN:8756-663X    

DOI:10.1002/ecjb.4420701110

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

年代:1987

数据来源: WILEY