Abstract: Apparatus for processing a compressed input bitstream representing an information signal. The apparatus processes the compressed input bitstream in a way that changes the information signal represented by the compressed input bitstream, and comprises a layered decoder that decodes the compressed input bitstream to provide a decoded bitstream, a decoded bitstream processor that processes the decoded bitstream to provide a modified bitstream, a layered encoder that re-encodes the modified bitstream to provide a compressed output bitstream, and a selective interconnection path. The layered decoder includes serially-connected decoding modules. The decoded bitstream processor processes the decoded bitstream in a way that modifies the information signal. The layered encoder includes serially-connected encoding modules, each of which corresponds to one of the decoding modules in the layered decoder.

Abstract: An imaging system includes a compound elliptical concentrator having an illumination source at an entry aperture and having an exit aperture directed to project light onto the surface of an object. The compound elliptical concentrator includes first and second reflective surfaces that are arcs of different ellipses. The ellipse that defines the arc of the first reflective surface has one focus that is proximate to an entry end of the second reflective surface. The ellipse that defines the arc of the second reflective surface has a focus that is proximate to the entry end of the first reflective surface. The other foci of the ellipses are at or beyond the exit aperture of the compound elliptical concentrator and are preferably symmetrically aligned with respect to the surface to be imaged. The reflective surfaces are on the opposite sides of a plane of symmetry and are configured such that multiple reflections of extreme rays from the illumination source are deterred.

Abstract: A small position detection and positioning device detects relative displacement between two members with high precision. A moving medium-type memory device using such positioning device is also provided. The position detection device includes a linear array of first electrodes at equal pitches on one of the two members that have relative displacement in at least one dimension, and a linear array of at least one second electrode on the other member. The first electrodes are positioned opposite the second electrodes and separated from them by a minute gap. The first electrodes are divided into a first electrode set composed of alternate ones of the first electrodes, and a second electrode set composed of alternate ones of the first electrodes not in the first electrode set. A signal source which applies a first alternating signal to the first electrode set and a second alternating signal that differs in phase by 180.degree.

Abstract: A substantially n-type substrate structure having a p-type surface for use in semiconductor devices as a substitute for a p-type semiconductor substrate. The substrate structure comprises a substrate region and a buffer region. The substrate region is a region of n-type compound semiconductor, and includes a degeneratively n-doped portion adjacent its first surface. The buffer region is a region of compound semiconductor doped with a p-type dopant. The buffer region is located on the first surface of the substrate region and includes a surface remote from the substrate region that provides the p-type surface of the substrate structure. The buffer region also includes a degeneratively p-doped portion adjacent the degeneratively n-doped portion of the substrate region. The substrate structure includes a tunnel junction between the degeneratively n-doped portion of the substrate region and the degeneratively p-doped portion of the buffer region.

Abstract: A memory device that comprises a planar memory medium and a probe device mounted opposite the planar memory medium. The probe device includes a substrate having a substrate surface and probe cells arrayed on the substrate surface. Each of the probe cells comprises a probe, an auxiliary electrode and a probe driving circuit. The probe is formed in the substrate, includes part of the substrate surface, and additionally includes a conductive needle projecting towards the memory medium. The conductive needle includes a needle tip adjacent the memory medium. The auxiliary electrode is mounted on the probe, and is located between the probe and the memory medium. The auxiliary electrode is disposed substantially parallel to, and spaced from, the substrate surface. The driving circuit is formed in the substrate and projects from the substrate surface towards the memory medium. The probe driving circuit has outputs electrically connected to the auxiliary electrode and the memory medium.

Abstract: A thin micromechanical device is fabricated in a way that is mechanically compatible with wafer handling for conventional-thickness wafers. A removable bonding layer bonds a fabrication wafer to a substantially conventional-thickness handle wafer to form a bonded wafer pair. The micromechanical device is formed in the fabrication wafer by subjecting the bonded wafer pair to processing including wafer handling for conventional-thickness wafers. The micromechanical device is formed to include part of the fabrication wafer. Finally, the bonding layer underlying the micromechanical device is removed to release the micromechanical device from the handle wafer.

Abstract: A mesa-structure avalanche photodiode in which a buffer region in the surface of the mesa structure effectively eliminates the sharply-angled, heavily doped part of the cap layer that existed adjacent the lightly-doped n-type multiplication layer and p-type guard ring before the buffer region was formed. This reduces electric field strength at the ends of the planar epitaxial P-N junction and prevents edge breakdown in this junction. The lateral extent of the guard ring is defined by a window formed in a masking layer prior to regrowth of the guard ring. This guard ring structure eliminates the need to perform additional processing steps to define the lateral extent of the guard ring and passivate the periphery of the guard ring.

Abstract: A VCSEL that laser comprises a first mirror layer, an active layer including a quantum well region and a diffusion enhancing region, and a second mirror layer. The first and second mirror layers are layers of doped semiconductor material having a first and a second conductivity mode, respectively. The active layer is a layer of semiconductor material adjacent the first mirror layer. The second mirror layer is adjacent the active layer, remote from the first mirror layer. The diffusion enhancing region is a region of the active layer in which the semiconductor material of the active layer is doped with an acceptor impurity to such a high concentration that holes induced in the quantum well region by the diffusion enhancing region predominate over electrons in the quantum well region by about one order of magnitude.

Abstract: Picture signals representing a stored image stored in an image storage medium are generated. A stimulation beam having a monotonic non-uniform intensity distribution and a sensor array including a rectangular array of pixels each generating an image signal are provided. Each pixel generates in response to light. An image of an object area of the stored image is formed on the sensor array to define in the object area a fixel corresponding to each pixel of the sensor array. The object area is a small fraction of the area of the stored image. The stored image is stimulated by forming a stimulation spot substantially centered in the object area of the stored image using the stimulation beam. The stored image is scanned with the object area and the stimulation spot. This defines fixels in the stored image and generates a picture signal for each fixel. The picture signal for each fixel represents the accumulation of light emitted by the fixel in response to the stimulation spot.

Abstract: A position detection device that comprises a first substrate, a second substrate, an alternating current (AC) bridge comprised of four variable capacitors, and a detection circuit. The first and second substrates have a flat first electrode surface and a flat second electrode surface, respectively. The second substrate is mounted opposite the first substrate with the first electrode surface opposite the second electrode surface and separated from the second electrode surface by a minute gap. The second substrate and the first substrate are movable relative to one another in the plane of the electrode surfaces. Each of the variable capacitors is composed of a first capacitor electrode located on the first electrode surface and a second capacitor electrode located opposite the first capacitor electrode on the second electrode surface.

Abstract: A VCSEL 101 comprising an optical cavity having an optical loss and a loss-determining element 117 coupled to the optical cavity. The loss-determining element 117 progressively increases the optical loss of the optical cavity with increasing lateral distance from the optical axis 105. The optical cavity includes a first mirror region 111, a second mirror region 107, a plane light-generating region 125 sandwiched between the first mirror region 111 and the second mirror region 107, perpendicular to the optical axis 105, and an element 113 that defines the lateral extent of the optical cavity in the plane of the light-generating region 125. The first mirror region 111 and the second mirror region 107 are both conductive and have opposite conductivity modes.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a light sensor, a laser, a convex beam-splitting surface, and a package that includes a header. The light sensor generates an electrical signal representing an intensity of light energy falling on it, and is mounted on the header. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The laser is mounted in the package adjacent the light sensor with the light-emitting face substantially parallel to the light-receiving face of the light sensor. The convex beam-splitting surface reflects a fraction of the radiated light beam towards the light sensor as a reflected light beam, and transmits the remainder of the radiated light beam as the output light beam. The convex beam-splitting surface is supported in the radiated light beam by the package.

Abstract: A gas-phase etchant is provided. The gas-phase etchant includes at least one halogen in gaseous form and/or at least one halogen halide in gaseous form. A Group III-nitride crystal is heated to a temperature in the range of 500.degree.-900.degree. C. and is etched in a flow of the gas-phase etchant. The gas-phase etchant may additionally include hydrogen. The gas-phase etchant may alternatively be diluted with inert gas, and the Group III-nitride crystal may be etched in a flow of the gas-phase etchant diluted with the inert gas.

Abstract: A jack socket comprises a body in which are formed an axial bore adapted to receive a phone jack, an annular groove in at least two locations spaced along the axial bore, concentric with, perpendicular to, and facing radially into the axial bore, and an access port extending radially through the body into each annular groove. A toroidal coil spring is housed in each annular groove, and includes a radially-inward facing circumference projecting into the axial bore to contact the circumference of the jack plug. An electrical connection extends through the access port to the coil spring mounted in each annular groove. A jack socket installable in a mounting hole and requiring no more access to the back of the mounting hole during installation than that provided by the mounting hole comprises a body shaped and dimensioned to be closely received by the mounting hole. An axial bore and plural radial bores are formed in the body.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package, a laser, a light sensor, and a beam splitter. The beam splitter is mounted in the package, together with the laser and the light sensor. The laser has one and only one light-emitting face from which it radiates a light beam as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling on it. The beam splitter divides the radiated light beam into a fraction and a remainder, the remainder being the output light beam. The beam splitter operates by diffraction, scattering, or transmission to direct the fraction of the radiated light beam towards the light sensor.

Abstract: A vertical cavity surface emitting laser (VCSEL) that generates light having a desired wavelength, greater than one micron. The laser comprises a substrate, a lower mirror region, an active region and an upper mirror region. The substrate consists essentially of GaAs. The lower mirror region is adjacent the substrate and is lattice matched to the substrate. The active region is sandwiched between the upper and lower mirror regions, and includes a central quantum well region and a gallium arsenide layer sandwiched between the quantum well region and each of the lower mirror region and the upper mirror region. The central quantum well region includes a quantum well layer consisting essentially of GaN.sub.x As.sub.(1-x). The GaN.sub.x As.sub.(1-x) of the quantum well layer has a lattice constant and a band gap dependent on x. The value of x sets the bandgap of the GaN.sub.x As.sub.(1-x) of the quantum well layer to a value corresponding to light generation at the desired wavelength, greater than one micron.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package in which are mounted a laser, a light sensor and a coupler. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling it. The coupler couples a fraction of the radiated light beam to the light sensor, and provides the remainder of the radiated light beam as the output light beam. Since the light coupled to the light sensor by the coupler is a fraction of the radiated light beam, the electrical signal generated by the light sensor also represents the intensities of the radiated light beam and of the output light beam.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package in which are mounted a laser, a light sensor and a coupler. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling it. The coupler couples a fraction of the radiated light beam to the light sensor, and provides the remainder of the radiated light beam as the output light beam. Since the light coupled to the light sensor by the coupler is a fraction of the radiated light beam, the electrical signal generated by the light sensor also represents the intensities of the radiated light beam and of the output light beam.

Abstract: A light modulator having the small volume and low power consumption of LCD displays together with the higher resolution and faster response time of CRT displays. The light modulator includes a substrate pair, an opaque light shielding layer, a shutter assembly composed of a shutter plate and a shutter suspension, and electrodes. The substrate pair includes a first substrate and a second substrate positioned parallel to each other and spaced from one another to define a cavity. The opaque light shielding layer is located on one of the substrates, and defines a translucent window. The shutter assembly is located in the cavity. The shutter plate is movably mounted adjacent the window by the shutter suspension. The shutter suspension includes elastic support members disposed between the shutter plate and the substrate pair.

Abstract: The optical component comprises a first I/O port, a second I/O port and a polarization-changing optical element located between the first I/O port and the second I/O port. The second I/O port is optically aligned with the first I/O port. The first I/O port includes a first opposed walk-off crystal pair and a second opposed walk-off crystal pair. The second opposed walk-off crystal pair is a mirror image of the first opposed walk-off crystal pair. Each opposed walk-off crystal pair comprises two walk-off crystals. Each walk-off crystal has a walk-off direction. Each walk-off crystal includes an attachment face substantially parallel to the walk-off direction, a first face orthogonal to the attachment faces, and a second face opposite the first face. The walk-off crystals are attached to one another with their attachment faces in contact, and their walk-off directions opposed.