Abstract: In a ridge waveguide serial interferometer mode conversion is induced by a first mode conversion section, a phase difference between modes is introduced by propagation over a length of waveguide and optical interference is produced following further mode conversion induced in a second mode conversion section. The first mode conversion section has a first radius of curvature, which is equal to a second radius of curvature of the second mode conversion section. The ridge waveguide interferometer advantageously provides an equal phase dependency as a function of temperature.

Abstract: In a ridge waveguide serial interferometer mode conversion is induced by a first mode conversion section, a phase difference between modes is introduced by propagation over a length of waveguide and optical interference is produced following further mode conversion induced in a second mode conversion section. The first mode conversion section has a first radius of curvature, which is equal to a second radius of curvature of the second mode conversion section. The ridge waveguide interferometer advantageously provides an equal phase dependency as a function of temperature.

Abstract: An optical device, such as an electro-absorption modulator, has a waveguide formed onto a base. Electrodes adjacent the waveguide are used to selectively apply an electric field to the device in order to control the passage of light through the device. To prevent overheating of the device in a region near the point of optical entry, the electrode, which acts as a thermal conduit to dissipate heat from the waveguide is extended over the region. To prevent undesirable electrical contact between the electrode and the region, the normally electrically conducting contact layer between the electrode and the waveguide is removed in that region and replaced by an isolation dielectric.

Abstract: Disclosed is a print quality test structure for devices manufactured by lithography. The test structure allows for visual inspection of the print quality of the device. The test structure decouples the effects of overexposure, underexposure and focus so that corrections can be made for future device manufacturing. By visually inspecting each device during lithography, devices of poor quality can be reworked, and costly testing on all devices can be avoided through device screening.

Abstract: A portable computer is sized to fit into a businessman's attache case and may be seated on a surface for use in either a normal position or a tilted forward position. The portable computer includes a housing having a base, a front top cover, a rear top cover and a foot door. The front top cover is pivotally attached to the front of the rear top cover and the rear top cover is fixedly attached to the base. Computer electronics (i.e. printed circuit boards), and two floppy disk drives are mounted inside the housing on the base at the rear and a full size keyboard is mounted inside the housing on the base at the front. A battery pack is disposed in the rear top cover of the housing. A full size liquid crystal display monitor is mounted on the front top cover. The foot door is movably mounted on the back of the base. When the front top cover is pivoted open the display screen is viewable and the keyboard is accessible.