Abstract: Disclosed are an improved system and a related method for compensating the chromatic dispersion of a given length of a transmission fiber over a given spectral band by employing at least two chromatic dispersion compensating fibers that, with respect to the slope of the slope of the chromatic dispersion (SSi), have values of opposite signs.

Abstract: An apparatus suitable for ultrasonically cleaning objects is disclosed. The apparatus includes a housing and a cleaning chamber within the housing. The apparatus also includes drainer that can be moved between a cleaning position in a lower region of the apparatus and a draining position in an upper region of the apparatus. The drainer is configured to engage at least a portion of the upper region of the housing to thereby position the drainer in the draining position. The apparatus also includes a transducer for transmitting ultrasonic energy into the cleaning chamber.

Abstract: An improved p-type gallium nitride-based semiconductor device is disclosed. The device includes a structure with at least one p-type Group III nitride layer that includes some gallium, a first silicon dioxide layer on the p-type layer, a layer of a Group II metal source composition on the first SiO2layer, and a second SiO2 layer on the Group II metal source composition layer.

Abstract: A method is disclosed for attaching a bonding pad to the ohmic contact of a diode while reducing the complexity of the photolithography steps. The method includes the steps of forming a blanket passivation layer over the epitaxial layers and ohmic contacts of a diode, depositing a photoresist layer over the blanket passivation layer, opening a via through the photoresist above the ohmic contacts and on the blanket passivation layer, removing the portion of the blanket passivation layer defined by the via to expose the surface of the ohmic contact, depositing a metal layer on the remaining photoresist, and on the exposed portion of the ohmic contact defined by the via, and removing the remaining photoresist to thereby concurrently remove any metal on the photoresist and to thereby establish a metal bond pad on the ohmic contact in the via.

Abstract: A method of forming a bipolar device includes forming at least one p-type layer of single crystal silicon carbide and at least one n-type layer of single crystal silicon carbide on a substrate. Stacking faults that grow under forward operation of the device are segregated from at least one of the interfaces between the active region and the remainder of the device. The method of forming bipolar devices includes growing at least one of the epitaxial layers to a thickness greater than the minority carrier diffusion length in that layer. The method also increases the doping concentration of epitaxial layers surrounding the drift region to decrease minority carrier lifetimes therein.

Abstract: The invention relates to a multimode optical fibre having a refractive index profile, comprising a light-guiding core surrounded by one or more cladding layers. The present invention furthermore relates to an optical communication system comprising a transmitter, a receiver and a multimode optical fibre.

Abstract: The invention is a promotional structure, such as a greeting card, which is collapsible to fit into a flat envelope for mailing, and which unfolds into the shape of a recognizable type of building, such as a house. Some of the panels are flexibly joined to one another while others (or portions of others) carry reusable fasteners, such as ribbons corresponding to complementary holes on adjacent panels. When the structure is unfolded and the fasteners join the corresponding panels, the panels define the building's shape and its promotional theme. The design provides a structure well suited for distributing promotional material in a medium that is different than traditional greeting cards or brochures, and the structure may be fabricated either from a plurality of panels secured to each other or from the die-cutting and scoring of a single sheet of material.

Abstract: A method is disclosed for preparing carrier wafers for semiconductor device manufacture. The method includes the steps of sorting a plurality of standard carrier wafer blanks into batches by thickness to define a batch of starting carrier wafers that are within a predetermined tolerance of one another, reducing the thickness of the sorted carrier wafers to within 10 microns of a final target thickness, and polishing the sorted carrier wafers to the final target thickness. The polished carrier wafers are mounted to device precursor wafers having at least one semiconductor epitaxial layer on a substrate by joining one surface of a carrier wafer to the epitaxial layer on a substrate. The thickness of the device precursor wafer is then reduced by removing material from the device precursor substrate opposite the joined epitaxial layer.

Abstract: An instrument and process for accelerating the solid phase synthesis of peptides is disclosed. The method includes the steps of deprotecting a protected first amino acid linked to a solid phase resin by admixing the protected linked acid with a deprotecting solution in a microwave transparent vessel while irradiating the admixed acid and solution with microwaves, then activating a second amino acid by adding the second acid and an activating solution to the same vessel while irradiating the vessel with microwaves, then coupling the second amino acid to the first acid while irradiating the composition in the same vessel with microwaves, and cleaving the linked peptide from the solid phase resin by admixing the linked peptide with a cleaving composition in the same vessel while irradiating the composition with microwaves.

Abstract: A method is disclosed for obtaining a high-resolution lenticular pattern on the surface of a light emitting diode. The method comprises imprinting a patterned sacrificial layer of etchable material that is positioned on a semiconductor surface that is in turn adjacent a light emitting active region, and thereafter etching the imprinted sacrificial layer and the underlying semiconductor to transfer an imprinted pattern into the semiconductor layer adjacent the light emitting active region.

Abstract: A high rate, upflow filtration system is described in which a compressible, fibrous lump filtration media is compressed to adjust the porosity and collector size of the media in the bed and to provide a porosity gradient within the bed proceeding from more porous to less porous in a direction opposite to the flow of fluid so that filtration proceeds in a direction from a more porous to a less porous filter bed. Larger particles are removed by the more porous media and successively smaller particles are removed as the filter bed becomes less porous. The system is capable of reducing the turbidity of influent municipal wastewater from about 8 NTU to about 2 NTU at a wastewater flow rate of from about 820 to 1230 L/m2·min (20 to 30 gal/ft2·min), at a bed compression ration of from about 15 to 40 percent, and at a backwash rate of from about 1 to 6 percent based on the total wastewater passing through the filter.

Abstract: In one embodiment the present invention is a method of conducting multiple step multiple chamber chemical vapor deposition while avoiding reactant memory in the relevant reaction chambers. The method includes depositing a layer of semiconductor material on a substrate using vapor deposition in a first deposition chamber followed by evacuation of the growth chamber to reduce vapor deposition source gases remaining in the first deposition chamber after the deposition growth and prior to opening the chamber. The substrate is transferred to a second deposition chamber while isolating the first deposition chamber from the second deposition chamber to prevent reactants present in the first chamber from affecting deposition in the second chamber and while maintaining an ambient that minimizes or eliminates growth stop effects. After the transferring step, an additional layer of a different semiconductor material is deposited on the first deposited layer in the second chamber using vapor deposition.

Abstract: The invention is a rapid prototype apparatus having a removable build chamber and a plurality of alignments surfaces that can be used to properly align the build chamber with the process chamber with minimal adjustments by a user. In one embodiment, the apparatus comprises a process chamber attached to a support housing and a build chamber that is removably attached to the support housing. The build chamber may be inserted into the support housing and is moveable between a load position and a build position. The build chamber includes a moveable build platform and a plurality of alignment surfaces that are each adapted to releasably engage a corresponding surface on the support housing. As the build chamber moves into the build position, the alignment surfaces align the build platform the process chamber. As a result, the apparatus may be used to accurately align the build chamber with the process chamber.

Abstract: A method of producing a high quality bulk single crystal of silicon carbide in a seeded growth system is disclosed. The method includes positioning the seed crystal in a crucible while exerting minimal torsional forces on the seed crystal to thereby prevent torsional forces from warping or bowing the seed crystal in a manner that that would otherwise encourage sublimation from the rear of the seed crystal or undesired thermal differences across the seed crystal.

Abstract: An instrument and associated method are disclosed for preparing samples for column chromatography.

Abstract: A laser scanning system in a rapid-protyping system is controlled during vector scanning by providing a commanded-position signal to each of first and second rotary motive devices to rotate respective mirrors of the scanning system, each mirror undergoing acceleration at the beginning of the vector, wherein the commanded-position signals are calculated based on physical mathematical modeling of the acceleration of the mirrors taking into account effects of inertia of the scanning system, and wherein actual positions of the mirrors are measured with fast-response devices and digital feedback control of the mirror positions is employed at a periodic rate sufficiently small to maintain a following error of the laser spot less than about 200 ?s at all times. A laser power control method employs a fast-response power meter for measuring laser power.

Abstract: A semiconductor light emitting diode includes a semiconductor substrate, an epitaxial layer of n-type Group III nitride on the substrate, a p-type epitaxial layer of Group III nitride on the n-type epitaxial layer and forming a p-n junction with the n-type layer, and a resistive gallium nitride region on the n-type epitaxial layer and adjacent the p-type epitaxial layer for electrically isolating portions of the p-n junction. A metal contact layer is formed on the p-type epitaxial layer. In method embodiments disclosed, the resistive gallium nitride border is formed by forming an implant mask on the p-type epitaxial region and implanting ions into portions of the p-type epitaxial region to render portions of the p-type epitaxial region semi-insulating. A photoresist mask or a sufficiently thick metal layer may be used as the implant mask.

Abstract: A semiconductor device is disclosed that includes a layer of Group III nitride semiconductor material that includes at least one surface, a control contact on the surface for controlling the electrical response of the semiconductor material, a dielectric barrier layer covering at least a portion of the one surface adjacent the control contact, the dielectric barrier layer having a bandgap greater than the bandgap of the Group III nitride and a conduction band offset from the conduction band of the Group III nitride; and a dielectric protective layer covering the remainder of the Group III nitride surface.

Abstract: An apparatus and method for growing bulk single crystals of silicon carbide is provided. The apparatus includes a sublimation chamber with a silicon vapor species phase outlet that allows the selective passage of atomic silicon vapor species while minimizing the concurrent passage of other vapor phase species. The apparatus can provide control of vapor phase stoichiometry within the sublimation chamber, which in turn can allow the production of bulk silicon carbide single crystals with reduced intrinsic point defects concentration.