Influence of high GeO2 concentration on the optical-loss in high numerical-aperture optical fibers has been investigated. It is shown that a large amount of OH ions are permanently trapped near Ge sites like near Si sites in binary GeO2-SiO2 glasses. The full Ge-OH absorption spectrum, including overtones, is very similar to the Si-OH spectrum but shifts to longer wavelength with increasing GeO2 concentration. Rayleigh scattering increases proportionally to GeO2 concentration and raises the transmission loss of the fibers, especially in shorter wavelength region. The minimum loss is, nevertheless, expected to be less than 1 dB/km even in the fibers containing GeO2 up to several tens of mol% because of a slight reduction of infrared absorption. The transmission loss of 0.8 dB/km at 1.55 µm was achieved by a 27 mol% GeO2-doped core fiber made by the VAD method.

This letter presents the connectivity number of 1-voxels in a 3-D digitized binary picture, and gives the necessary and sufficient condition that a 1-voxel in a 3-D picture is deletable. A shrinking algorithm for a 3-D object is suggested by using these results.

Making good use of low impedance and short wavelength characteristics of high dielectric substrate whose dielectric constant (εr) is 39 to 139, and advanced microwave integrated circuit (MIC) technology has been proposed to realize low-cost highly-reliable and small size UHF power amplifiers. Numerical calculation of single and parallel-coupled microstrip parameters on the high-dielectric constant substrate has been presented at first. Then the thick film technique application possibilities are discussed for high-dielectric substrate MICs, which is more suited for low price and mass production than conventional thin film technique. Based on theoretical and experimental estimation results, an amplifier with εr39 substrate has been developed to replace TWTs in television transposers, which provides a rated output peak power of 32 W with low distortion characteristics over the 650770 MHz frequency range. A compact 500 MHz-band 12 W class-C amplifier has also been developed successfully with use of εr139 substrate.

This paper presents a new method to calculate the asymptotic variances as a measure of accuracy in the estimation of rate constants of a compartmental system. Several numerical tests have been performed to analyze the effects of sampling conditions on the asymptotic variances. It is shown that there exists the optimal sampling interval which minimizes the asymptotic variances.

A method for designing two-dimensional FIR fan filters has been developed. With the proposed method, any size (i.e., even or odd) fan filter can be designed by extending a 1-D FIR prototype filter. This extension is performed by rotating and linearly interpolating the frequency response of the 1-D FIR prototype, and cascading an attenuator. The 2-D FIR fan filter obtained has specified number of fans and specified pass orientation. This has not been accomplished by conventional methods. The principle of the extension, examples of designing and the application in filtering are presented.

Traveling-wave light intensity modulator was constructed using the 5 µm wide strip optical waveguide of z-cut LiNbO3 and the asymmetric stripline as the modulator electrode. The half-wave voltage of 23 V and the extinction ratio of 97% were achieved. Modulation was performed up to 18 GHz.

This letter presents definitions of connectivity among volume cells of a three-dimensional (3-D) digitized binary picture, and an explicit formula to calculate the Euler number of a 3-D object in a given 3-D picture.

This paper shows an improved rate equation by which the phase relation of the carriers and inhomogeneous property are taken into account for injection lasers. The direct modulation characteristics were analyzed as an application of this improved rate equation. A more general discussion was obtained for the resonance-like phenomenon and its suppression effect. For the undoped AlGaAs DH laser with index guiding structure, it is found that the resonance-like phenomenon is mainly suppressed by effect of spatial diffusion of injected carriers, reduction of the thresh-old level and lateral singlemode-operation. We also found that other mechanisms, such as mixing effect of the spontaneous emission, variation of longitudinal mode number and the intra-band relaxation, hardly affect to suppress the resonance-like phenomenon.

System for the measurement of the respiratory response of human is introduced. This system has the facilities to supply the air which is mixed with CO2 or N2O. The subject inhales the gas of which contents variation can be controlled by the program. The system also measures the respiratory response of the subject which is caused by the changes of atmospheric circumstances, i.e., CO2 inhalation and records data. To check the concentration of agent gas according to the program, micro computer is used. Flow volume of expired gas, heart rate, concentration of supplied gas and that of expired gas are collected. One of the experiments in case of CO2 inhalation is shown. In this experiment the subject inhales the air which is mixed with CO2. Its pertition is 5% of the total volume.

The features of n-channel polysilicon-gate MOS integrated circuits with ion-implanted polysilicon resistor load are described. A ring-oscillator circuit and a divider circuit are used for the performance evaluations. Switching delay time of 1.0 ns and power-delay product as small as 0.1 pJ are obtained at 2V supply voltage for the ring-oscillator. In a divider circuit, input frequency up to 80 MHz can be divided at 2V. The electrical characteristics can be varied by changing sheet resistance of the load resistors, while the power-delay product are nearly constant. Based on the experimental results, electrical characteristics of resistor load MOS circuits using the scaled-down MOS FET's are discussed.

A method to obtain optimal channel graphs (least blocking probability) is described, for a class of 4-stage link systems without parallel" limitation. Slip notation, introduced to classify and identify channel graphs effectively, makes their comparison tractable. General blocking probability calculation procedure is obtained for this purpose. Generalized optimums are concretely determined for a range of small link sizes, and assured by the comparison with every non-slip type. Former parallel" optimums are proved to be inferior, but practically sufficient according to numerical results. Necessary conditions for generalized optimums are shown based on a theorem.

A model for analysis of life test data on typical electronic components is presented. Since viewpoint and manner for analysis of life test data is not established for humidity accelerated life tests, some life-time characteristics under humid environments are mainly considered in order to illustrate utility and applicability of the proposed model. Obtained results indicate that the model makes up possible to interpret some different models proposed by some researchers on the humidity accelerated life tests from a consistent manner connecting the life-time characteristic of components with fundamental nature of failure mechanism of each component. The model will allow to us to understand each of data obtained from some types of life tests on various electronic components as an essential part connected with whole information on life characteristic of the components under various use and environmental conditions.

This paper describes measurements of fiber loss and splice loss by backward Rayleigh scattering in fibers. Fiber loss measuring accuracy less than0.04 dB is obtained, and the repeatability is very good in comparison with conventional cut-back method. For splice loss measurement, the measuring accuracy is the same as the above. It is found that the splice loss measured by the backscatter method is different from the true value for fibers with different Rayleigh-scattering losses. To obtain the true value, several correction method for the measured value are proposed. Application of the backscatter method to fault location reveals that even an 8.6 km distant fiber end-face without Fresnel reflection can be discriminated.

Recent progress in the theory of nonlinear waves" has clarified that various nonlinear dispersive soliton transmission equations can be transformed into certain types of bilinear equations. In this paper, a general form of bilinear soliton transmission equations which have a form of simultaneous equations for two dependent variables is presented. Then, a method is presented for constructing their generalized soliton solutions, which are solutions expressing solitons in a background o ripples. As a result, it turns out that if these bilinear soliton transmission equations have N-soliton solutions, they also have the generalized soliton solutions. Moreover, taking the modified Korteweg-de Vries equation as typical example of the soliton transmission equations which are treated in this paper, it is also shown that its initial value problem can be solved using its generalized soliton solution. Since the results for the modified Korteweg-de Vries equation can be easily extended to all soliton transmission equations which can be transformed into a certain type of coupled bilinear equations and whose N-soliton solutions can be written by determinants, it also turns out that transmission characteristics of a wide class of nonlinear dispersive transmission equations reducible to coupled bilinear equations can be clarified by making use of their generalized soliton solutions. A simple application of these results to a design problem of soliton transmission lines is also noted.

Sintering process of porous performs made by a vapor-phase axial deposition (VAD) method has been investigated. SEM observation indicates that the final stage of sintering is the collapsing process of closed pores in the transparent glass body. A bubble-free transparent perform is easily obtained by sintering in the helium gas atmosphere, but hard in the argon gas atmosphere under the usual zone-sintering condition. An interpretation of the experimental results is presented based on the elementary model for final stage of the sintering process; the closed pore collapsing depends on the balance between gas permeation rate into the surrounding glass and pore expansion rate during temperature increase.

A synthesis of high frequency active RC filters using an operational amplifier with single pole characteristics is presented. As a measure of the quality of filters, the pole sensitivity with respect to the gain bandwidth product GB of the amplifier is used and it is shown that the absolute value of the pole sensitivity has a minimum limit. The synthesis is based on the predistortions of Q and center frequency errors caused by the finite GB of the amplifier. The proposed circuit has quite stable temperature characteristics and examples show illustrative differences of the temperature responses between the proposed circuit and conventional ones.

A fast algorithm for computing the maximum number of prime implicants of n-variable symmetric Boolean function is described. A dynamic programming technique is used in the algorithm. The total logarithmic computing time cost and the total uniform computing time cost by a random access machine are O (n4) and O (n3), respectively. The algorithm can be implemented faster by a parallel computer. The corresponding computing time costs by a parallel computer with O (n) processors are O (n3) and O (n2), respectively.

The source coding problems are studied on the Slepian-Wolf-type system with a remote source (Fig. 1) and the Wyner-Ziv-type system with a remote source (Fig. 4). For the former, inner and outer bounds are obtained on the admissible rate region to attain a prescribed distortion tolerance. For the latter, the rate-distortion function is derived. As examples, a Gaussian remote source and a binary remote source are analyzed.

One parameter family of solutions of the second Painlevé equation, which describes long time asymptotic behavior of waves in certain soliton transmission lines, are constructed through its bilinear form. It is then shown that the derived solutions have the Painlevé characteristic, i.e., they have no movable critical points.

Gyrotropic thin-film waveguides with isotropic top layers are discussed using hybrid modes. The fundamental propagation properties of optical waves and TE-TM mode conversion efficiencies are estimated. When refractive indices of isotropic top layers are equal to those of substrates, 50% TE-TM mode conversion efficiency required for non-reciprocal circuits of optical isolators can be realized with gyrotropic films. From a fabricational point of view, these structures are very useful for constructing thin-film optical isolators because no severe control on film thickness is necessary and film growth of amorphous materials on YIG crystal films is possible for top layers. The design data for non-reciprocal circuits consisting of ZnO/YIG/GGG layered structure are presented from the hybrid mode analysis. The thickness of YIG and ZnO are 3.43 µm and 1.03 µm respectively and the length of the device is 2.28 mm. The non-reciprocal circuits of this structure can be experimentally fabricated by RF sputtering method.