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A study on asymmetric integrated optical Y-branches proposes the use of single-mode asymmetric Y-branches using microprisms to enhance their performance as compared to conventional single-mode asymmetric Y-branches. The configuration of the suggested asymmetric Y-branch, 3-dB power divider is presented. Applications of asymmetric Y-branches in integrated optical circuits will be of great interest in the near future. Experimental results are presented.

A useful design rule for the low-index prism structure was obtained by the concept of phase matching. The designed low-index prism bends were observed to have low-loss and large-angle properties similar to high-index prism bends. Field distortion caused by the prism is discussed as well as the influences of prism length, width and index on the propagation loss. A comparison of the field distribution and design rule of the high-and low-index prism bends was performed.

An improved multigrid technique for the quasi-TEM analysis of a microstrip line embedded in an inhomogeneous anisotropic dielectric medium is presented. A general finite-difference form for the inhomogeneous anisotropic medium is derived by the finite-volume discretization of Gauss' theorem. By the analogy between the quasi-TEM and the steady current problems, this general form can be interpreted by Kirchhoff's current law. Then, the electric potential distribution in this complicated dielectric structure can be regarded as that on a resistive network, which makes the formulation easier. The resulting matrix equation for the potential distribution on the finest grid is solved by the improved multigrid iteration, where the coarse-grid operator is derived directly from the finest grid operator by the help of an equivalent resistive network. Three numerical examples show that the convergence rate is hardly dependent of the number of unknowns and the complexity of the dielectric media. Moreover, the numerical results are in good agreement with those by the other method when special cases are considered. Index Terms - Microstrip, multigrid, quasi-TEM.

The use of micro-prisms to improve the design of three-dimensional bends of step-index waveguides is considered. The approach, which applies to both embedded and buried waveguides, includes a micro-prism design rule to address phase mismatch which leads to bending loss. According to a simulation carried out by the finite-difference beam propagation method, the improved bends achieve dramatic gains in their transmission capabilities.

A newly developed large-angle low-loss direction-coupler type power divider has a designed ratio between output waveguides and employs a micro-prism at the bend corner to restrict radiation loss, compensating for phase mismatch due to bending. The semivectorial beam propagation method simulates a 93% normalized transmitted power of the power divider with a bend angle of 10 degrees. Less than 0.953 dB loss is calculated for a symmetric large-angle 3-dB directional coupler with eight microprisms.

A new low-loss abrupt bend structure for optical waveguide utilizes a microprism to compensate for the phase front phase difference after and before the bend corner. The compensation helps align the phase front of the eigenmode properly. Simulations indicate a 95% normalized transmitter power at 10 degrees of bend angle. A phase compensation rule and its corrections help derive the optical parameters of the prism.

This paper studies the transient behaviors of solitary waves in a relativistic plasma with nonisothermal electrons. In particular, the modified Korteweg-de Vries (K-dV) equation is solved numerically with a Gaussian function as the initial condition. In addition, it is found that the time evolution of solitons from the initial profile is quite similar to that of a K-dV equation with the exception that the soliton speeds are faster. It is also found that the relativistic ions and the nonisothermal electrons tend to have a similar effect on the soliton behavior of the wave, with the effect of nonisothermal electrons being more noticeable.

Analyzes the fabrication of the single and multiple aluminum-gallium arsenide quantum-well structures using liquid-phase epitaxy. Details on the experiments; Results of the study; Conclusions.

Presents a study which examined a hysteresis phenomena of metal-tantalum-oxide-silicon-oxide-silicon capacitors due to leakage current through tantalum oxide. Observation on the C-V behavior of the capacitor; Effects of the direct current and alternating current (ac) resistances of tantalum oxide; Importance of the measurement conditions and the effect of the ac resistance of tantalum oxide on the determination of flat-band capacitance.