A two-dimensional device simulator has been developed to analyze optical and electrical properties of laser diodes. The simulator can treat various kinds of laser diodes with arbitrary configurations and material systems. Analysis of transverse-mode stabilized InGaAlP laser diodes has made it clear that the optical mode behavior and the current distribution strongly depend on the ridge stripe configuration.

In this paper, a method for analyzing the transmission, reflection and scattering of the thin-film waveguide with partial periodic structure is proposed. This method results in the Fredholm integral equation of the second kind. The results of analyses based on the first order approximate solutions are given.

In integrated optics, it is very important to provide efficient optical coupling between fibers and waveguide devices. In this letter, we propose a fiber-waveguide coupler, whose guide width varies in propagation direction, and show its better coupling behavior than an uniform coupler.

Relationship between temperature and specific gravity of ethanol solution of urea were measured under various concentrations. Solubility and supersolubility curves of urea to ethanol were obtained. Ethanol was found to be suitable as solvent to the growth of single crystal of urea.

High quality KDP crystals can be grown even in growth rate of 3 mm/day by electrodialysis method with pH control. This method has auxiliary electrodes set in the growth chamber.

2.4 Gbt/s WDM and bidirectional transmission experiments has been demonstrated in the 1.55µm window. The penalties due to cross talk in the demultiplexer are investigated. The system experiments of WDM and bidirectional transmission result in the system penalties of less than 0.3 dB.

Numerical simulation of AlGaAs/GaAs HBT's with various n^--collector structures are performed to study the cutoff frequency characteristics. A thinner n^--layer with higher doping density is desirable to achieve higher cutoff frequency. Effects of the velocity overshoot are pronounced in a case with a thinner n^--layer.

An efficient module generator for a micro-power CMOS op amp has been developed. Given a set of performance specifications, the generator optimizes the circuit performance using a non-linear optimization method and produces the corresponding layout.

Josephson junction is induced in a superconducting film when quasiparticles are injected partially by light illumination. In this paper the distribution of excess quasiparticles and energy gaps generated optically in the film are studied theoretically as a function of light power. As a result, it is shown that the critical current of the induced Josephson junction can be controlled by light power.

Radiating light from breaking arc discharge observed by CCD image sensor, are described by temporal changes of total intensity, maximum intensity, its position and spread of light. The results of silver contact show that movement of arc can be analyzed by this manner.

A new method for detecting the projections on the spherical pearls was proposed using an optical system, a CCD-TV camera with an image processor.

The pearl color sorting system was miniaturized using a CCD-TV camera which provides the R, G and B color signals, compared with the previously reported system with the MOS-TV camera and the TV monitor.

Stationary solution analysis shows a transition from quasi-periodic to fundamental oscillations at critical external force strength, E_c when the external periodic force increases in self-sustained hard-mode oscillation equation. But detailed numerical analysis reveals another critical external force, (E_c). For E quasi-periodic, and for EE_c fundamental oscillations exist stably, however amplitude modulated oscillation is observed in the transition region EE_c.

Recently, several tearing methods have been studied for efficient analysis of the large scale network. In this paper, we apply the gate level node tearing method to bipolar circuit simulation by direct method and show the concrete estimation of its availability.

Two-dimensional pattern of an electric potential around a horizontally-placed root of adzuki bean was detected by a multi-electrode measuring system. The vectors of electric current calculated from the electric potential pattern show a long route from the basal part of the root to the apical part.

A Radial Line Slot Antenna (RLSA) is a high gain planar antenna for receiving DBS (satellite TV) in 12 GHz band. To suppress grating lobes from the array, a slow wave structure is installed in the upper waveguide of RLSA. This letter proposes a novel slow wave structure filled up with expanded polyethylene. The basic design and the performances of the antenna are summarized. The measured gain of 36.3 dBi and efficiency of 75% at 12 GHz confirms the potential of this slow wave structure.

A new kind of optical modulator, utilizing a laser diode optical amplifier, which can solve the insertion loss problem for optical modulators, is proposed and demonstrated. Fabricated devices have shown 10 dB fiber to fiber optical gain and 600 MHz modulation bandwidth at 1.55µm wavelength.

A term rewriting system is said to be rpoterminating if it's termination is proved with the recursive path ordering method. The direct sum R₁M₂ of term rewriting systems R₁ and R₂ is rpo-terminating iff both R₁ and R₂ are so.

The jitter accumulation and its suppression are investigated in the hierarchical Master-Slave synchronization network which applies a king of simple digital signal processing type PLLs, the multiply detecting and averaging PLLs, as the synchronizers. The multiply detecting and averaging means averaging the multiple phase errors detected to produce an output phase correction. The measurement of phase jitter used is its variance and two parameters, named as the normalized relative increment and suppression rate, are introduced to describe the jitter accumulation and its suppression along the hierarchical. It is noted that, the suppression of the systematic jitter accumulation is enhanced proportionally to the averaging times, and much more effect can be obtained on the suppression of the random jitter than the systematic. But for the quantization jitter caused by the quantized output phase correction of synchronizers, the suppression rate is less than -1.76 dB (10 log₁₀ (2/3) dB) for any large averaging times, and thereby it should be made small enough to be negligible.

The thin coated fiber design against lateral force is discussed and a 0.5 mm diameter Polyetherimido coated optical fiber which has equivalent optical loss increase properties against lateral force to conventional 0.9 mm diameter Nylon coated optical fibers is proposed. The method of calculating critical lateral force which causes loss increase is shown. Using the result, it is possible to design coated optical fibers having no loss increase at a given lateral force.

This paper describes a newly developed triangular mesh device simulator, TRIMEDES. TRIMEDES is merged into a supervised simulation system which covers the range from pattern layout to topography/process simulation and also to device simulation. TRIMEDES features an automatic triangular mesh generation capability, and a liking method between a topography/process simulator and a device simulator. The procedure employed in the triangular mesh generation involves the following techniques; (1) primary mesh generation, (2) feedback rate method in order to achieve smooth element size variation, and (3) relaxation technique after mesh generation to suppress obtuse triangles. This procedure proves to be effective and robust in the mesh generation for nonplanar device structures. In order to link the device simulator TRIMEDES to the topograhpy/process simulator, the device shape is represented as closed-loop string topography data and a triangular mesh is generated based on the string data. The pre-processor of the mesh generator has been developed, which rearranges the string data to cope with the mesh generation. The geometrical shape of a device can be reflected in the device simulation, since the string shape data of the topography/process simulation are smoothly transferred to the device simulator.

The characteristics of W-type single-mode fiber with low-dispersion below 2 ps/km/nm over the 1.5-1.6µm wavelength range are theoretically discussed. It is clarified that the tolerance of the core radius and refractive index difference satisfying this dispersion conditions are 0.05µm and 0.01%. Bend-optimized W-type fibers are designed so as to minimize the bending sensitivity. It is also clarified that the allowable bending radius is reduced to less than 4 cm for the W-type fibers with a mode field diameter of 7µm.

We introduce alternating multihead finite automata with constant leaf-sizes (AMHFACLs), and investigate several properties of these automata. The main results of this paper are as follows: (1) two-way sensing AMHFACLs can be simulated by two-way nondeterministic simple multihead finite automata, (2) for one-way AMHFACLs, k+1 heads are better than k, and (3) for one-way alternating simple multihead finite automata with constant leaf-sizes, sensing versions are more powerful than non-sensing versions.

This paper proposes a unique type of signature testing for VLSIs, called referenceless signature testing. This testing automatically produces a reference value, i.e., correct signature, during its test intervals and compares it with compacted output of the circuit under test, i.e., signature. This makes testing much easier because it does not need the reference value, usually pre-calculated by simulation. This paper also proposes an extended form of this testing which offers economical and highly accurate one by using by-directional LFSRs for RAMs and sequential circuits. The proposed approach is successfully applied to these circuits, because the reference value can be automatically produced with their store operations and bi-directional input sequences for test data. An application of this testing to self-dual combinational circuits is also demonstrated in this paper.