Abstract: A fluid monitor determines the quality, intensity and/or level of a fluid by transmitting a beam of light through the fluid and evaluating any changes to the shape of the beam as a result of being transmitted through the fluid. The monitor includes a light source and a lens which generate an incident beam of light having a predefined cross sectional shape. The beam is transmitted through a volume of the fluid, which modifies the shape of the beam as a function of the fluid quality, intensity and/or level. The beam can be polarized before being transmitted through the fluid or after beam transmission. The polarized beam is directed to a detector which evaluates the horizontal and vertical components of the beam and provides a shape signal to a detection circuit. The detection circuit processes the shape signal received from the detector to determine the quality, intensity and/or level of the fluid based on any variations from the predefined shape of the incident beam.

Abstract: A monolithic optoelectronic integrated circuit having an optical emission portion (18) and a drive portion (11, or 22 and 21). The drive portion is capable of accepting TTL and standard CMOS logic voltage levels. In a first embodiment, the monolithic optoelectronic integrated circuit (10) has a light emitting diode (18) driven by a dual gate FET (11). In a second embodiment, the monolithic optoelectronic integrated circuit (20) has a light emitting diode (18) driven by two FETs (22 and 21). In each embodiment (10 or 20), a gate (13 or 23) of the respective drive circuit accepts the TTL or standard CMOS logic voltage. Further, in each embodiment current limiting is accomplished by coupling a gate with the source of the FET (11 or 22). Thus, the output of the light emitting diode (18, 18) is controlled by an input signal to the drive circuit.

Abstract: A buried-heterostructure laser modulator for modulating a laser beam includes two adjacent thin epitaxial first layers of oppositely doped semi-conductor material and a thin epitaxial buried layer of undoped semi-conductor material located between the two adjacent first layers. The buried layer forms a single mode optical channel having a width larger than a height thereof with the width equal to or greater than a width of a diffraction limited waveguide mode of the laser beam. Two thin epitaxial second layers of similarly and heavily doped semiconductor material are provided respectively adjacent the respective first layers of the same doping. One of these second layers is provided on a side of a semi-insulating substrate and two strip lines of opposite bias are provided on the side of the substrate and connect to a respective second layer of the same bias. The two adjacent first layers are preferably AlGaAs and the buried layer is preferably GaAs with a width less than about 1.

Abstract: A semiconductor device structure comprises a semiconductor substrate having a semiconductor layer of the same conductivity type formed on its first surface. A drain contact is formed on the second surface of the substrate and conductive regions having the opposite conductivity type of the substrate are formed in the semiconductor layer and are separated by a predetermined distance. Channel regions having the same conductivity type as the substrate are disposed above the conductive regions and source regions are disposed therein. A shielding region is then formed on the surface of the device structure in the area between the conductive regions. The structure allows for reduced or eliminated gate-drain capacitance, reduced output conductance and increased breakdown voltage capability.

Abstract: A high efficiency light emitting diode is achieved through the use of a patterned metal contact. The metal contact is insulated from the structure of the light emitting diode to prevent current flow and subsequent light generation underneath the electrical bond pad. This shifts the drive current out to the patterned portion of the bond pad or metal contact.

Abstract: A process for growing an epitaxial ribbon of mono-crystalline material involves formation of an endless belt of monocrystalline composition. The belt is driven about a closed path to bring portions sequentially to epitaxial growth and ribbon stripping zones. One or more epitaxial layers of monocrystalline material at least initially compositionally different from the belt are grown on the belt in the epitaxial growth zone(s). Stripping of such epitaxial layer(s) occurs in the stripping zone to form an epitaxial ribbon of indefinite length. Finally, the ribbon is wound upon a mandrel for storage or transport before further processing. The belt is formed by slicing a boule into flat strips of uniform thickness, their ends being then beveled to preselected crystallographic orientation. Ends of the strips are juxtaposed, defining a notch between them. Material is epitaxially grown on the beveled end surfaces to fill each notch.