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This paper proposes a beam splitter with one emitter and two collectors each on the left and right based on anisotropy of the group velocity. An anisotropic medium is represented by a two-dimensional square lattice tight-binding model. The transport property of the beam splitter is analyzed by means of the boundary-type solution method. At the center of the band where the anisotropy of the group velocity is strong, the incident beam is split into two and propagates along the diagonal directions of the square lattice with almost no diffraction. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(12): 67–75, 2002; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecjb.1114 [ABSTRACT FROM AUTHOR]

This paper assumes a simple model for the DRAW (direct-read/after-write) optical disk using a Te-alloy recording medium. The scattering of the light-beam by the pit or boss of arbitrary shape on the boundary of three-layered dielectrics is analyzed by the boundary-element method. The sum and the differential signal output characteristics of the two-split-type optical detector also is discussed. The results of simulation are shown Mr the effect of the adjacent pit in the square and V- shaped pregrooved models, the dependencies of the sum and the differential signals on the tracking error, and the dependencies of the sum and the differential signals on the pit depth, when the signal recording pit is provided in the two types of pregrooved models. [ABSTRACT FROM AUTHOR]

A novel intersection waveguide-type polarization splitter based on total reflection using the birefringence of the GaInAsP/Inp superlattice waveguide is proposed and analyzed in this paper. The semivectorial finite difference beam propagation method (FD-BPM) (which handles both TE and TM modes) is used in the analysis. The waveguide structure including the GaInAsP/InP superlattice is designed; and it is shown that, although with a superlattice core the refractive index for the TM mode is reduced by approximately 0.4 percent, there is no change for the TE mode. Based on this result, the optimal structural parameters such as superlattice layer number, rib height (h), intersecting angle (θ), and port separation length (Lsp) are investigated using a 1.55-μm wavelength. It is found that the TE and TM modes can be separated with an insertion loss of less than 0.4 dB for both modes and a crosstalk of less than -35 dB using an intersecting angle of 5° and a device length of approximately 0.9 mm. It is shown that compared to conventional devices, the device length in the proposed device structure can be reduced by using total reflection. The wavelength dependence of the device is also analyzed. [ABSTRACT FROM AUTHOR]