Abstract: An optical modulator may include a lower waveguide, an upper waveguide, and a dielectric layer disposed therebetween. When a voltage potential is created between the lower and upper waveguides, these layers form a silicon-insulator-silicon capacitor (also referred to as SISCAP) guide that provides efficient, high-speed optical modulation of an optical signal passing through the modulator. In one embodiment, at least one of the waveguides includes a respective ridge portion aligned at a charge modulation region which may aid in confining the optical mode laterally (e.g., in the width direction) in the optical modulator. In another embodiment, ridge portions may be formed on both the lower and the upper waveguides. These ridge portions may be aligned in a vertical direction (e.g., a thickness direction) so that ridges overlap which may further improve optical efficiency by centering an optical mode in the charge modulation region.

Abstract: A method and apparatus for rotating a portion or segment of a casing string in a relatively highly deflected well bore. A straight well bore portion is provided adjacent the completion interval, beyond the deflected portion. A casing string is made up with a segment connected by a swivel to the remainder of the string. This segment is located in the straight portion of the bore. A drill string is lowered into the casing into engagment with a rotatable swivel portion fixed to the casing segment. The drill string is rotated to rotate the casing segment independently of the remainder of the casing string. This facilitates removal of excess mud cake from the annulus adjacent the casing segment, and also placement of cement in the annulus.