High-Efficiency Micromirrors and Branched Optical Waveguides on Si Chips

Abstract

A comprehensive analysis of gened relativistic spacetimes which admit a shearfree, irrotational and geodesic time-like coogruence is presented. The equations governing the models for a gened energy-momentum tensor are wrilten down. Coordinates in which the metric of such spacetimes takes on a simplified form are established. The general subwses of 'zero anisotropic stress', 'zero heat-flux vector' and 'two-component Ruids' are investigated. In particular, perfect-fluid Friedmann-Robertson-Walker models and spatially homogeneous models are discussed. Models with a variety of physically relevant energy-momentum tensors are considered. Anisowopic fluid models and viscous fluid models with heat conduction are examined. Also. models with B perfect Ruid plus a magnetic field or with pure radiation. and models with two non-collinw perfect fluids (satisfying a variety of physical conditions) are inwtigated. In particular. models with a (single) perfect Ruid which is tilting with respect to the shem-free, vorticity-free and acceleration-free time-like congruence are discussed.PACS numbers: 0420J. 9880H

Groove-Buried Optical Waveguides Based on Metal Organic Solution-Derived Amorphous Ba0.7Sr0.3TiO3 Thin Films

“…In addition, high density also requires the use of sharp, e.g., 90 , bends. 18) Recently, with high index contrast in Si/SiO 2 waveguide and dielectric waveguide systems, micro-sized optical photonic devices such as bends, splitters, resonators, and switches for monolithic OEICs have been realized. [19][20][21][22][23][24] In our experiments, a groove-buried optical waveguide as a high-index contrast (Á ¼ 21:7%) system was constructed with an amorphous BST0.7-based core layer (n BST0.7 ¼ 1:94) 25) and a SiO 2 cladding layer (n SiO 2 ¼ 1:46) on a SiO 2 /Si grooved substrate by EBL and spin-coating.…”

“…6 was designed on the basis of a double corner mirror structure reported by our group. 18) The waveguide bend transition angle depends on the refractive index of an amorphous BST0.7-based core layer and a SiO 2 cladding layer. According to the rules of full reflection, the critical waveguide bend transition angle c equals 41.6 .…”